Cyclosporine A dosing-time-dependent effects on plasma creatinine and body weight in male Wistar rats treated for 3 weeks.

Cyclosporine A (CsA) nephrotoxicity was assessed in 120 male Wistar rats (350 +/- 50 g) entrained to a 12-h cycle (light-dark 12:12); plasma creatinine level and body weight were examined in controls and in rats that had been treated daily with oral CsA or vehicle alone (olive oil-ethanol 90:10) for 21 days; daily dosing (40 mg/kg) was at one of six equally spaced given times during the 24-h cycle. The variations observed in both indexes were shown to be circadian dosing stage dependent. Nephrotoxicity was present as early as the third day of treatment with CsA; plasma creatinine level was enhanced by about 50% in rats dosed around the time of the change from darkness to light: at 22 HALO, 146.7 +/- 4.5 mumol/L, against 92.0 +/- 2.8 mumol/L for controls (p less than 0.05); and at 2 HALO, 148.3 +/- 10.0 mumol/L, against 95.0 +/- 4.3 mumol/L for controls (p less than 0.05). Thereafter, a remission episode was observed between days D5-D9. The more drastic effects were seen on days D16 and D21, in animals dosed in the beginning of the dark span (14 HALO): 185 +/- 10 mumol/L for CsA and 98.0 +/- 5.3 mumol/L for controls (p less than 0.01) and, to a lesser extent, in rats treated at the early resting phase (2 HALO): 152.4 +/- 31 mumol/L for CsA and 95.0 +/- 4 mumol/L for controls (p less than 0.05). The normal increase in body weight during the 21-day period (about 14 +/- 8% in controls) was impeded in CsA-administered rats, especially those dosed at the beginning of the activity span (14 HALO) that even suffered weight reduction. Differences in percentages of survivors were noticed, depending on dosing stage. About 40% of the animals in every time CsA-treatment group died, except for those dosed at the end of the resting period (10 HALO), when all animals died. In surviving rats, the cessation of CsA dosing resulted in a reversible effect on the study variables.     

Circadian time-dependent hepatic and renal toxicities to valproic acid in mice

This study aims to investigate whether hepatic and renal valproic acid (VPA) toxicities varied according to the dosing time in the 24-h scale in mice. VPA was administered by i.p. route to different groups of animals at four different circadian stages (1, 7, 13, and 19 h after light onset (HALO)). Biochemical study and histopathological examinations on liver and kidney sections were performed. The results showed that the hepatic and renal toxicity induced by VPA was time related. Animals treated at 19 HALO showed vacuolar degenerative changes, congestions, and inflammatory areas on liver parenchyma. Lesions within proximal tubules were observed in the kidney in groups treated at 19 HALO. The largest increases in alanine aminotransferase, alkaline phosphatase and plasma creatinine activities were also observed at 19 HALO. The obtained data indicate that the optimal hepatic and renal tolerance is observed when VPA was injected in the middle of the light-rest span of mice.     

Effect of pentoxifylline on cyclosporine-induced nephrotoxicity in rats

Effect of unique hemorrheologic agent pentoxifylline (PTX) was investigated on cyclosporine (CsA) induced nephrotoxicity in rats. Compared to saline control, CsA produced significant increase in blood urea and serum creatinine. Pentoxifylline treatment prevented the CsA-induced rise in blood urea and serum creatinine. Creatinine clearance (Ccr) and lithium clearance (Licr) was decreased with CsA. PTX treatment prevented the CsA-induced decrease in Ccr and Licr. Malondialdehyde (MDA) was increased with CsA compared to saline treated animals. PTX prevented the CsA-induced MDA rise. Kidney form CsA treated rat showed marked vacuolar degeneration of tubular epithelium with excess of microcalcification. Severity of the lesions was markedly reduced in rats treated with PTX plus CsA. The results indicate that PTX reduces CsA-induced renal toxicity in rats.     

Provinol prevents CsA-induced nephrotoxicity by reducing reactive oxygen species, iNOS, and NF-kB expression.

Cyclosporine A (CsA) use is associated with several side effects, the most important of which is nephrotoxicity that includes, as we previously showed, tubular injury and interstitial fibrosis. Recently, many researchers have been interested in minimizing these effects by pharmacological interventions. To do this, we tested whether the administration of a red wine polyphenol, Provinol (PV), prevents the development of CsA-induced nephrotoxicity. Rats were treated for 21 days and divided into four groups: control; group treated with PV (40 mg/kg/day by oral administration in tap water); group treated with CsA (15 mg/kg/day by subcutaneous injection); group treated with CsA plus PV. CsA produced a significant increase of systolic blood pressure; it did not affect urinary output, but caused a significant decrease in creatinine clearance. These side effects were associated with an increase in conjugated dienes, which are lipid peroxidation products, inducible NO-synthase (iNOS), and nuclear factor (NF)-kB, which are involved in antioxidant damage. However, PV prevented these negative effects through a protective mechanism that involved reduction of both oxidative stress and increased iNOS and NF-kB expression induced by CsA. These results provide a pharmacological basis for the beneficial effects of plant-derived polyphenols against CsA-induced renal damage associated with CsA.     

Effect of nifedipine in cyclosporine-induced nephrotoxicity in rats: roles of the thromboxane and endothelin systems

Cyclosporine (CsA) (45 mg/kg/day for 7 days) administration in female Wistar rats induced significant decrease in creatinine clearance (Ccr) and body weight loss (BWL). Urine volume (V) was not altered and proteinuria (PU) not provoked. These changes were associated with increased urinary endothelin 1 (ET-1) and thromboxane B(2)(TXB(2)) concentrations, and decreased urinary ratios of prostaglandin (6ketoPGF(1 alpha)and PGE(2)) to TXB(2)excretions.Nifedipine (NFD) (0.1 mg/kg/day for 7 days), a calcium channel blocker, administrated in addition to CsA, to another group of animals, significantly augmented Ccr and urine V but did not prevent BWL in comparison to CsA-only treated rats. The urinary ET-1 and TXB(2)concentrations displayed significant and non-significant decrease respectively, while the urinary excretion ratios of 6ketoPGF(1 alpha)/TXB(2)and PGE(2)/TXB(2)were significantly enhanced.These observations indicate that the partial protection of NFD in CsA-induced nephrotoxicity could be attributed to augmented urinary prostanoid ratios of renal vasodilators (6ketoPGF(1 alpha)and PGE(2)) to vasoconstrictor (TXB(2)) excretions, and also to reduced release of rather renal origin ET-1, the most potent mamalian vasoconstrictor peptide known to date. In a previous study, we found that NFD only slightly prevented structural renal damage, induced by CsA. So, the NFD protection refers only to functional toxicity and not to structural damage, mediated at least in part by the preservation of relatively high renal TXB(2)levels. However, other nephrotoxic factors and additional mechanisms could also be implicated in this CsA-induced syndrome.     

Reversal of established rat crescentic glomerulonephritis by blockade of macrophage migration inhibitory factor (MIF): potential role of MIF in regulating glucocorticoid production

Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine that also counter-regulates glucocorticoid action. We investigated whether immunoneutralization of MIF could reverse established experimental crescentic glomerulonephritis and if this treatment could modulate endogenous glucocorticoid levels. Accelerated anti-GBM glomerulonephritis was induced in six littermate pairs of rats. Once crescentic disease was established on day 7, one animal in each pair was given a daily injection of neutralizing anti-MIF antibody (Ab) or irrelevant isotype control Ab for 14 days and then killed on day 21. In addition, a group of 6 animals was killed on day 7 of disease without any treatment. Animals receiving the control Ab exhibited a rapidly progressive glomerulonephritis with severe renal injury (proteinuria), loss of renal function (creatinine clearance), anemia, and marked histologic damage (including glomerular crescent formation), compared with animals killed on day 7 without treatment. In contrast, anti-MIF Ab treatment partially reversed the disease by restoring normal renal function and reducing histological damage compared with untreated animals killed on day 7 (p < 0.05). Interestingly, anti-MIF Ab treatment also prevented severe anemia (p < 0.05). Reversal of disease was associated with a significant reduction in leukocyte infiltration and activation and renal interleukin-1 (IL-1) production. Importantly, anti-MIF Ab treatment caused a significant increase in endogenous serum corticosterone levels, which correlated with the reversal of disease parameters. In conclusion, this study has demonstrated that blocking MIF activity can partially reverse established crescentic glomerulonephritis and suggests that MIF operates by both enhancing the cellular immune response and suppressing the endogenous anti-inflammatory glucocorticoid response.     

Protection of glomerular filtration rate by the thromboxane receptor antagonist L655,240 during low dose cyclosporine administration

Cyclosporin A (CsA) alters the production of prostaglandins (PG) by the kidney. CsA causes an increase in renal vascular resistance, a decrease in renal blood flow, a decrease in glomerular filtration rate (GFR), and increases the renal production of the vasoconstrictor thromboxane. Recently, low dose CsA has been utilized in the treatment of refractory autoimmune diseases. To determine if low dose CsA administration could produce renal hemodynamic alterations and to determine if the thromboxane receptor antagonist L655,240 could prevent these alterations, we administered groups of rats either CsA, 5 mg/kg, subcutaneously and the L655,240 vehicle NaHCO₃ (CsA-NaHCO₃), or CsA and L655,240 (CsA-L655,240), or CsA vehicle and L655,240. The rats were administered the drugs for 7 days and then subjected to inulin and PAH clearances or kidneys were harvested for prostaglandin production studies. CsA significantly depressed GFR and renal plasma flow when compared to the L655,240 treated groups. There was no difference in inulin or PAH clearance between the CsA-L655,240 and CsA vehicle L655,240 groups. Glomerular prostaglandin production including thromboxane was depressed by CsA administration. No histologic alterations were noted in the glomeruli or the medullary portions of the kidney. We conclude that administration of low dose CsA, 5 mg/kg, for 7 days results in a decrease in renal blood flow and GFR without histologic alterations. Administration of the thromboxane receptor antagonist L655,240 prevents the renal hemodynamic alterations induced by CsA in this rat model.     

Protection of glomerular filtration rate by the thromboxane receptor antagonist L655,240 during low dose cyclosporine administration.

Cyclosporin A (CsA) alters the production of prostaglandins (PG) by the kidney. CsA causes an increase in renal vascular resistance, a decrease in renal blood flow, a decrease in glomerular filtration rate (GFR), and increases the renal production of the vasoconstrictor thromboxane. Recently, low dose CsA has been utilized in the treatment of refractory autoimmune diseases. To determine if low dose CsA administration could produce renal hemodynamic alterations and to determine if the thromboxane receptor antagonist L655,240 could prevent these alterations, we administered groups of rats either CsA, 5 mg/kg, subcutaneously and the L655,240 vehicle NaHCO3 (CsA-NaHCO3), or CsA and L655,240 (CsA-L655,240), or CsA vehicle and L655,240. The rats were administered the drugs for 7 days and then subjected to inulin and PAH clearances or kidneys were harvested for prostaglandin production studies. CsA significantly depressed GFR and renal plasma flow when compared to the L655,240 treated groups. There was no difference in inulin or PAH clearance between the CsA-L655,240 and CsA vehicle L655,240 groups. Glomerular prostaglandin production including thromboxane was depressed by CsA administration. No histologic alterations were noted in the glomeruli or the medullary portions of the kidney. We conclude that administration of low dose CsA, 5 mg/kg, for 7 days results in a decrease in renal blood flow and GFR without histologic alterations. Administration of the thromboxane receptor antagonist L655,240 prevents the renal hemodynamic alterations induced by CsA in this rat model.     

Maternal prolactin inhibition during lactation is associated to renal dysfunction in their adult rat offspring

The renal function of rats whose mothers had hypoprolactinemia at the end of lactation was evaluated during development. Lactating Wistar rats were treated with bromocriptine (BRO, 1?mg twice a day, s.c.) or saline on days 19, 20, and 21 of lactation, and their male offspring were followed from weaning until 180 days old. 1 rat from each of the 12 litters/group was evaluated at 2 time points (90 and 180 days). Body and kidney weights, sodium, potassium, and creatinine were measured. Values were considered significant when p<0.05. Adult BRO-treated offspring presented higher body weight (+10%), lower relative renal weight at 90 and 180 days (-9.2% and -15.7%, respectively), glomerulosclerosis, and peritubular fibrosis. At 90 and 180 days, creatinine clearance was lower (-32% and -30%, respectively), whereas serum potassium was higher (+19% and +29%, respectively), but there were no changes in serum sodium. At 180 days, higher proteinuria (+36%) and serum creatinine levels (+20%) were detected. Our data suggest that prolactin inhibition during late lactation programs renal function damage in adult offspring that develops gradually, first affecting the creatinine clearance and potassium serum levels with further development of hyperproteinuria and higher serum creatinine, without affecting sodium. Thus, precocious weaning programs some components of the metabolic syndrome, which can be a risk factor for further development of kidney disease.     

Effect of platelet activating factor antagonist treatment on gentamicin nephrotoxicity

To assess whether PAF could be involved in the gentamicin-induced nephrotoxicity, we have studied the effect of PAF antagonist BN-52021 on renal function in rats after gentamicin (GENTA) treatment. Experiments were completed in 21 Wistar rats divided into three groups: group GENTA was injected with gentamicin 100 mg kg(-1) body wt/day s.c. for 6 days. Group GENTA + BN received gentamicin and BN-52021 i.p. 5 mg kg(-1) body wt/day. A third group served as control. Rats were placed in meta-bolic cages and plasma creatinine and creatinine clearance were measured daily. GENTA group showed a progressive increase in plasma creatinine, a drop in creatinine clearance and an increase in urinary excretion of N-acetyl-beta-D-glucosaminidase and alkaline phosphatase. GENTA + BN group showed a lesser change in plasma creatinine and a creatinine clearance, but no difference with GENTA group in urinary excretion of NAG and AP were observed. Histological examination revealed a massive cortical tubular necrosis in rats treated with gentamicin, whereas in BN-52021 injected animals tubular damage was markedly attenuated. The present results suggest a role for PAF in the gentamicininduced nephro-toxicity.     

MicroRNA-34a suppresses invasion and metastatic in esophageal squamous cell carcinoma by regulating CD44

Cisplatin is a widely used antineoplastic agent in the treatment of head and neck cancer. However, it is highly nephrotoxic. Oxidative stress is the main mechanism responsible for cisplatin-induced nephrotoxicity. The aim of this study was to characterize cisplatin-induced nephrotoxicity, oxidative stress in peripheral blood mononuclear cells, and the relationship between them. Twenty-four patients were included in the study. Patients had their blood collected prior to cisplatin administration, and 5 and 20 days after initiating therapy, to assess renal function and to determine oxidative stress with MitoSOX?Red, H₂DCF-DA, and Amplex^® Red tests. Renal function was assessed by measuring serum creatinine, creatinine clearance, and blood urea nitrogen (BUN). Serum creatinine and creatinine clearance were used to grade nephrotoxicity using Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Compared to baseline values, the mean BUN and serum creatinine increased 135 and 100%, respectively, 5 days after cisplatin infusion. Mean creatinine clearance showed a 43% decrease compared to baseline value. Non-statistically significant changes in superoxide anion (O ₂ ^?? ), hydrogen peroxide (H₂O₂), and general reactive oxygen species production occurred. A higher production of H₂O₂ was correlated with variation in serum creatinine, and was associated with higher grades for serum creatinine increases and creatinine clearance reductions. Linear regression analyses showed an association between H₂O₂ production and serum creatinine, creatinine clearance, and BUN levels. These results were observed for 5 days following cisplatin administration. In conclusion, H₂O₂ production was significantly related to changes in all renal parameters that were evaluated, following the cisplatin infusion.     

Urinary aminopeptidase activities as early and predictive biomarkers of renal dysfunction in cisplatin-treated rats

This study analyzes the fluorimetric determination of alanyl- (Ala), glutamyl- (Glu), leucyl-cystinyl- (Cys) and aspartyl-aminopeptidase (AspAp) urinary enzymatic activities as early and predictive biomarkers of renal dysfunction in cisplatin-treated rats. Male Wistar rats (n = 8 each group) received a single subcutaneous injection of either saline or cisplatin 3.5 or 7 mg/kg, and urine samples were taken at 0, 1, 2, 3 and 14 days after treatment. In urine samples we determined Ala, Glu, Cys and AspAp activities, proteinuria, N-acetyl-β-D-glucosaminidase (NAG), albumin, and neutrophil gelatinase-associated lipocalin (NGAL). Plasma creatinine, creatinine clearance and renal morphological variables were measured at the end of the experiment. CysAp, NAG and albumin were increased 48 hours after treatment in the cisplatin 3.5 mg/kg treated group. At 24 hours, all urinary aminopeptidase activities and albuminuria were significantly increased in the cisplatin 7 mg/kg treated group. Aminopeptidase urinary activities correlated (p<0.011; r²>0.259) with plasma creatinine, creatinine clearance and/or kidney weight/body weight ratio at the end of the experiment and they could be considered as predictive biomarkers of renal injury severity. ROC-AUC analysis was made to study their sensitivity and specificity to distinguish between treated and untreated rats at day 1. All aminopeptidase activities showed an AUC>0.633. We conclude that Ala, Cys, Glu and AspAp enzymatic activities are early and predictive urinary biomarkers of the renal dysfunction induced by cisplatin. These determinations can be very useful in the prognostic and diagnostic of renal dysfunction in preclinical research and clinical practice.     

Role of macrophages in myocardial apoptosis following cardiac transplant. Influence of immunosuppressive treatment.

Cytotoxic T cells may induce myocardial apoptosis by histiocyte activation during rejection following allogenic heart transplant. The aim of the present investigation was to evaluate the macrophage response and its relationship to the programmed death of cardiomyocytes in rejection and during cyclosporin-A (CsA) treatment. An abdominal, heterotopic heart transplant rat model was used establishing two groups: singenic (ST) and allogenic (AL) transplant. 5 mg/kg/day (s.c.) CsA (Sandimun) was administered to half of the animals in each group. Morphological and structural analysis was performed 7, 14, 21, 30, 50 and 100 days post-transplant. Macrophages were detected using the monoclonal antibody (ED1). The TUNEL method was used to visualise apoptotic cells. Two weeks after ST in animals without immuno-suppressive treatment, the transplanted myocardium had been extensively infiltrated by inflammatory cells, many of which were ED1-positive. At 21 days follow-up, the number of labelled cells had fallen. In animals treated with CsA the amount of ED1-positive cells was lower than that seen in the anterior group. Only a few isolated cells of the infiltrate were TUNEL-positive. In the AT group, rejection took place between 9-15 days in the untreated animals. The myocardium was highly infiltrated by mononuclear cells. Some were ED1-positive. Small groups of apoptotic cells were visible in the infiltrate and in some vessel lumens. Rejection was resolved in animals treated with CsA. The macrophage response diminished during follow-up in a similar way to that occurring in the ST. Few cells showed TUNEL positivity. It may be concluded that: a) CsA treatment diminishes the amount of infiltrated macrophages; b) animals receiving ST or AT, show a low level of apoptosis; c) in the present model, the apoptosis of cardiomyocytes does not appear to be induced by macrophages; and d) in this model it is not possible to relate apoptosis and rejection.     

Circadian rhythm of irinotecan tolerability in mice

The toxicity of irinotecan (CPT-11), a topoisomerase-I inhibitor largely used in cancer patients, was investigated as a function of the circadian time of its administration in mice, with mortality, body weight loss, leukopenia, neutropenia, intestinal lesions, and bone marrow cell cycle phase distribution as end points. Four experiments were performed on a total of 773 male mice standardized with 12h light/12h darkness. Irinotecan was administered daily for 4 or 10 consecutive days (D1-4 and D1-10, respectively, in different experiments) at one of six circadian stages expressed in hours after light onset (HALO). The survival curves differed significantly as a function of the dosage and circadian time of drug administration by the D1-10 schedule, with 70% survival at 7 or 11 HALO and 51% at 19 or 23 HALO (p=0.039 from log rank test). CPT-11 administration at 19 or 23 HALO resulted in (1) greatest mean body weight loss at nadir; (2) most severe colic and bone marrow lesions and/or slowest recovery; and (3) deepest neutropenia nadir and/or slowest hematologic recovery. These circadian treatment time-related differences were statistically validated. The bone marrow cell cycle data revealed a four to eight-fold larger G2-M phase arrest following irinotecan administration at 19 or 23 HALO in comparison to the other times of drug administration, apparently representative of the repair of more extensive DNA damage (p < 0.001 from ANOVA) when the medication was given at these circadian times. Overall, CPT-11 was better tolerated by mice treated during the light (animals' rest) span. The results support the administration of CPT-11 to cancer patients in the second half of the night, during sleep, in order to improve drug tolerability.     

Circadian Rhythm of Irinotecan Tolerability in Mice

The toxicity of irinotecan (CPT-11), a topoisomerase-I inhibitor largely used in cancer patients, was investigated as a function of the circadian time of its administration in mice, with mortality, body weight loss, leukopenia, neutropenia, intestinal lesions, and bone marrow cell cycle phase distribution as end points. Four experiments were performed on a total of 773 male mice standardized with 12 h light/12 h darkness. Irinotecan was administered daily for 4 or 10 consecutive days (D1-4 and D1-10, respectively, in different experiments) at one of six circadian stages expressed in hours after light onset (HALO). The survival curves differed significantly as a function of the dosage and circadian time of drug administration by the D1-10 schedule, with 70% survival at 7 or 11 HALO and 51% at 19 or 23 HALO ( p = 0.039 from log rank test). CPT-11 administration at 19 or 23 HALO resulted in (1) greatest mean body weight loss at nadir; (2) most severe colic and bone marrow lesions and/or slowest recovery; and (3) deepest neutropenia nadir and/or slowest hematologic recovery. These circadian treatment time-related differences were statistically validated. The bone marrow cell cycle data revealed a four to eight-fold larger G2-M phase arrest following irinotecan administration at 19 or 23 HALO in comparison to the other times of drug administration, apparently representative of the repair of more extensive DNA damage ( p < 0.001 from ANOVA) when the medication was given at these circadian times. Overall, CPT-11 was better tolerated by mice treated during the light (animals’ rest) span. The results support the administration of CPT-11 to cancer patients in the second half of the night, during sleep, in order to improve drug tolerability.     

CISPLATIN-INDUCED VOMITING DEPENDS ON CIRCADIAN TIMING

We examined whether the clock time of cisplatin plus antiemetic and diuretic administration affects the amount of cisplatin-associated emesis and severity of renal toxicity. We treated 22 patients with urogenital cancer with two courses of chemotherapy containing 70 mg/m² of cisplatin. Cisplatin together with furosemide was administered in the morning (05:00) or evening (17:00) during two courses 1 month apart in a crossover fashion. Ondansetron was given either before or after cisplatin to control nausea and vomiting. The number of vomiting episodes, serum creatinine, serum urea nitrogen (BUN), creatinine clearance, and urinary β-N-acetyl glucosamidase (NAG) concentration were evaluated before and after each treatment course. Regardless of the timing of ondansetron, morning compared to evening cisplatin was always associated with greater vomiting in the first treatment course. However, prophylactic administration of ondansetron markedly diminished the impact of the clock time of cisplatin administration. Serum creatinine transiently decreased rather than increased 14 days after cisplatin and furosemide administration, while NAG excretion increased 3 days after cisplatin and furosemide administration. In the first course, serum creatinine levels were similar regardless of the clock time of cisplatin and furosemide administration. However, in the second course, serum creatinine rose in patients given evening cisplatin and furosemide, while it remained unchanged in those given morning cisplatin and furosemide. Moreover, the first course morning cisplatin and furosemide treatment was associated with less change in NAG excretion (less kidney toxicity) than the first course of evening cisplatin and furosemide treatment. The second course evening cisplatin and furosemide treatment was associated with an increase in NAG excretion compared to the first course of treatment, while morning cisplatin and furosemide treatment in the second course showed less change in NAG excretion compared to the first course. The clock time of cisplatin administration had an impact on the frequency of emesis. Prophylactic ondansetron, however, diminished the time-of-day dependency of cisplatin-induced vomiting. Administration of cisplatin and furosemide in the morning rather than evening appears to cause less renal damage, and this damage may be further reduced with aggressive hydration and routine administration of furosemide. (Chronobiology International, 18(5), 851-863, 2001)     

CISPLATIN-INDUCED VOMITING DEPENDS ON CIRCADIAN TIMING

We examined whether the clock time of cisplatin plus antiemetic and diuretic administration affects the amount of cisplatin-associated emesis and severity of renal toxicity. We treated 22 patients with urogenital cancer with two courses of chemotherapy containing 70 mg/m² of cisplatin. Cisplatin together with furosemide was administered in the morning (05:00) or evening (17:00) during two courses 1 month apart in a crossover fashion. Ondansetron was given either before or after cisplatin to control nausea and vomiting. The number of vomiting episodes, serum creatinine, serum urea nitrogen (BUN), creatinine clearance, and urinary β-N-acetyl glucosamidase (NAG) concentration were evaluated before and after each treatment course. Regardless of the timing of ondansetron, morning compared to evening cisplatin was always associated with greater vomiting in the first treatment course. However, prophylactic administration of ondansetron markedly diminished the impact of the clock time of cisplatin administration. Serum creatinine transiently decreased rather than increased 14 days after cisplatin and furosemide administration, while NAG excretion increased 3 days after cisplatin and furosemide administration. In the first course, serum creatinine levels were similar regardless of the clock time of cisplatin and furosemide administration. However, in the second course, serum creatinine rose in patients given evening cisplatin and furosemide, while it remained unchanged in those given morning cisplatin and furosemide. Moreover, the first course morning cisplatin and furosemide treatment was associated with less change in NAG excretion (less kidney toxicity) than the first course of evening cisplatin and furosemide treatment. The second course evening cisplatin and furosemide treatment was associated with an increase in NAG excretion compared to the first course of treatment, while morning cisplatin and furosemide treatment in the second course showed less change in NAG excretion compared to the first course. The clock time of cisplatin administration had an impact on the frequency of emesis. Prophylactic ondansetron, however, diminished the time-of-day dependency of cisplatin-induced vomiting. Administration of cisplatin and furosemide in the morning rather than evening appears to cause less renal damage, and this damage may be further reduced with aggressive hydration and routine administration of furosemide. (Chronobiology International, 18(5), 851–863, 2001)     

Temporal Variation in Serum Nitrite Levels in Rats and Mice

Although considerable evidence implicates involvement of nitric oxide (NO) in circadian regulation, little is known about possible 24h variations in basal NO metabolism. In this study, daily variations in serum nitrite levels were studied in locally bred mice and rats during the months of September and October. The serum was separated from blood samples obtained at six different times of the day and night (lh, 5h, 9h, 13h, 17h, and 21h after lights off [HALO] from male albino mice and rats). As an index of in vivo NO generation, serum nitrite levels (determined by the diazotization method) in rats exhibited significant temporal fluctuation (unpaired Student t test), with the concentration highest at 5 HALO and 21 HALO and lowest at 9 HALO. No such temporal variation was detected in mice in these studies conducted on locally bred animals in the autumn. (Chwnobiology International, 16(4), 527-532, 1999)     

XIIIth INTERNATIONALCOURSE ON CHRONOPHARMACOLOGYRuprecht-Karls-Universität HeidelbergSummer School 2012: 30 July – 4 August

Although considerable evidence implicates involvement of nitric oxide (NO) in circadian regulation, little is known about possible 24h variations in basal NO metabolism. In this study, daily variations in serum nitrite levels were studied in locally bred mice and rats during the months of September and October. The serum was separated from blood samples obtained at six different times of the day and night (lh, 5h, 9h, 13h, 17h, and 21h after lights off [HALO] from male albino mice and rats). As an index of in vivo NO generation, serum nitrite levels (determined by the diazotization method) in rats exhibited significant temporal fluctuation (unpaired Student t test), with the concentration highest at 5 HALO and 21 HALO and lowest at 9 HALO. No such temporal variation was detected in mice in these studies conducted on locally bred animals in the autumn. (Chwnobiology International, 16(4), 527–532, 1999)     

Glomerular filtration rate and blood pressure monitoring in awake baboons

Minimally invasive techniques were used to collect urine with an external catheter together with automated intermittent monitoring of arterial blood pressure in awake male baboons. Using endogenous creatinine, 24-hour creatinine clearances were measured for 2 to 3 consecutive days in four intact and in four uninephrectomized baboons. Despite large differences in urinary volume and sodium excretion, reproducibility of 24-hour creatinine clearances was within 15% in 15 of 19 studies obtained from 6 of 8 animals. Arterial blood pressure was monitored intermittently at 30 to 60 minute intervals over 24 hours with a Dinamap monitor and recorder. Mean blood pressure averaged 71 +/- 4.4 to 89 +/- 5.5 mm Hg in different animals. Blood pressure tended to be lower at night than during the day. In separate studies using 15 to 60 minute urine collection periods, inulin clearance was compared in awake and in anesthetized animals with endogenous or exogenous creatinine clearance measured simultaneously. The clearance of creatinine systematically exceeded the clearance of inulin, even in intact animals with a normal serum creatinine. The creatinine-to-inulin clearance ratio averaged 1.16 +/- 0.03 at a serum concentration of 0.7 to 0.8 mg/dl; 1.27 +/- 0.03 at a serum creatinine of 1.0 to 1.1 mg/dl and 1.56 +/- 0.04 at a serum creatinine greater than 10 mg/dl. All values exceed unity significantly (p less than 0.001). Thus, renal function, including inulin clearance, can be measured in awake baboons. Duplicate or triplicate 24-hour urine collections are needed to assess the reliability of creatinine excretion. However, creatinine clearance overestimates glomerular filtration rate, as it does in humans.