Showing papers on "Toxicity published in 2003"
TL;DR: Results from the lung histopathology component of the study indicated that pulmonary exposures to quartz particles produced dose-dependent inflammatory responses, concomitant with foamy alveolar macrophage accumulation and lung tissue thickening at the sites of normal particle deposition.
1,476 citations
TL;DR: These BFR groups were selected because of a large volume production (PBDEs, TBBPA and derivates), and availability of some toxicity data in spite of much lower production volumes (HBCD and PBBs), and the increase in levels of PBDEs in human (breast milk) and wildlife samples during later time made it especially interesting to include this BFR group.
1,031 citations
TL;DR: The recent finding that NADPH oxidase knockout mice were equally sensitive to acetaminophen and had equal nitration of tyrosine suggests that the superoxide is not from the activation of Kupffer cells.
Abstract: The analgesic acetaminophen causes a potentially fatal, hepatic centrilobular necrosis when taken in overdose. The initial phases of toxicity were described in Dr. Gillette's laboratory in the 1970s. These findings indicated that acetaminophen was metabolically activated by cytochrome P450 enzymes to a reactive metabolite that depleted glutathione (GSH) and covalently bound to protein. It was shown that repletion of GSH prevented the toxicity. This finding led to the development of the currently used antidote N-acetylcysteine. The reactive metabolite was subsequently identified to be N-acetyl-p-benzoquinone imine (NAPQI). Although covalent binding has been shown to be an excellent correlate of toxicity, a number of other events have been shown to occur and are likely important in the initiation and repair of toxicity. Recent data have shown that nitrated tyrosine residues as well as acetaminophen adducts occur in the necrotic cells following toxic doses of acetaminophen. Nitrotyrosine was postulated to be mediated by peroxynitrite, a reactive nitrogen species formed by the very rapid reaction of superoxide and nitric oxide (NO). Peroxynitrite is normally detoxified by GSH, which is depleted in acetaminophen toxicity. NO synthesis (serum nitrate plus nitrite) was dramatically increased following acetaminophen. In inducible nitric oxide synthase (iNOS) knockout mice, acetaminophen did not increase NO synthesis or tyrosine nitration; however, histological evidence indicated no difference in toxicity. Acetaminophen did not cause hepatic lipid peroxidation in wild-type mice but did cause lipid peroxidation in iNOS knockout mice. These data suggest that NO may play a role in controlling lipid peroxidation and that reactive nitrogen/oxygen species may be important in toxicity. The source of the superoxide has not been identified, but our recent finding that NADPH oxidase knockout mice were equally sensitive to acetaminophen and had equal nitration of tyrosine suggests that the superoxide is not from the activation of Kupffer cells. It was postulated that NAPQI-mediated mitochondrial injury may be the source of the superoxide. In addition, the significance of cytokines and chemokines in the development of toxicity and repair processes has been demonstrated by several recent studies. IL-1beta is increased early in acetaminophen toxicity and may be important in iNOS induction. Other cytokines, such as IL-10, macrophage inhibitory protein-2 (MIP-2), and monocyte chemoattractant protein-1 (MCP-1), appear to be involved in hepatocyte repair and the regulation of proinflammatory cytokines.
984 citations
TL;DR: Except photosynthetic microalgae, POEA accounted for more than 86% of Roundup toxicity and the toxicity contribution of POEA was shown to be species-dependent, mainly due to its high acidity.
562 citations
TL;DR: It remains to be determined to what extent toxicity to normal tissues will limit application of apoptosis-based therapies for cancer treatment, and hope that improved clinical outcomes may not be far from realization is offered.
493 citations
TL;DR: MC-LR was found to be the most potent toxin followed by MC-YR and MC-RR, and liver histology showed time dependent severe pathological lesions like congestion, haemorrhage, portal mononuclear cell infiltration and obliteration of chromatin material.
395 citations
TL;DR: Increased efforts to identify both patient-specific risk factors and disease-related factors will help to define patient subsets at risk as well as increase the predictability of unexpected hepatotoxicity in drug development.
381 citations
TL;DR: It is suggested that lowering of serum total cholesterol may not be the earliest clinically-measurable response to treatment in the rat and it is confirmed that serum and liver PFOS concentrations on repeated dosing are proportional to dose and cumulative dose.
367 citations
TL;DR: The results of the present study suggest the usefulness of RBC AChE measurement as a good biomarker in the estimation of malathion-induced oxidative stress affecting blood and liver.
Abstract: Organophosphorus compounds may induce oxidative stress leading to generation of free radicals and alterations in antioxidant and scavengers of oxygen free radicals (OFRs). The effect of subchronic exposure to malathion in the production of oxidative stress was evaluated in male Wistar rats. Administration of malathion (100, 316, 1000, 1500 ppm) for 4 weeks increased catalase (CAT), superoxide dismutase (SOD) activities as well as malondialdehyde (MDA) concentration in red blood cells (RBC) and liver. However, acetylcholinesterase (AChE) and cholinesterase (ChE) activities were decreased in these samples. The increase in RBC and liver lipid peroxidation correlated well with the inhibition in RBC AChE and liver ChE activities. Elevation of MDA concentrations and increased activities of CAT and SOD showed significant correlations in both RBC and liver samples when different doses of malathion were used. The results of the present study suggest the usefulness of RBC AChE measurement as a good biomarker in the estimation of malathion-induced oxidative stress affecting blood and liver.
338 citations
TL;DR: Increased exposure to toxic metabolites of cyclophosphamide leads to increased liver toxicity and nonrelapse mortality and lower overall survival after hematopoietic cell transplantation.
329 citations
TL;DR: Although no patients developed acute kidney toxicity, delayed kidney toxicity remains a major concern, limiting the cumulative dose to ~25 Gy would seem to be to identify more effective renal protective agents, in order to be able to increase the cumulative injectable activity and hence tumour dose.
Abstract: The aim of this study was to determine the maximum tolerated dose of 90Y-DOTATOC per cycle administered in association with amino acid solution as kidney protection in patients with somatostatin receptor-positive tumours. Forty patients in eight groups received two cycles of 90Y-DOTATOC, with activity increased by 0.37 GBq per group, starting at 2.96 and terminating at 5.55 GBq. All patients received lysine ± arginine infusion immediately before and after therapy. Forty-eight percent developed acute grade I–II gastrointestinal toxicity (nausea and vomiting) after amino acid infusion whereas no acute adverse reactions occurred after 90Y-DOTATOC injection up to 5.55 GBq/cycle. Grade III haematological toxicity occurred in three of seven (43%) patients receiving 5.18 GBq, which was defined as the maximum tolerable activity per cycle. Objective therapeutic responses occurred. Five GBq per cycle is the recommended dosage of 90Y-DOTATOC when amino acids are given to protect the kidneys. Although no patients developed acute kidney toxicity, delayed kidney toxicity remains a major concern, limiting the cumulative dose to ~25 Gy. The way forward with this treatment would seem to be to identify more effective renal protective agents, in order to be able to increase the cumulative injectable activity and hence tumour dose.
TL;DR: The induction of such detoxifying enzymes by curcumin suggest the potential value of this compound as protective agent against chemical carcinogenesis and other forms of electrophilic toxicity.
Abstract: Dietary antioxidants protect laboratory animals against the induction of tumours by a variety of chemical carcinogens. Among possible mechanism of protection against chemical carcinogenesis could be mediated via-antioxidant-dependent induction of detoxifying enzymes. Curcumin, a yellow pigment from Curcuma longa, is a major component of turmeric and is commonly used as a spice and food colouring material and exhibits antiinflammatory antitumour, and antioxidant properties. In this study we therefore investigated the effect of dietary supplementation of curcumin on the activities of antioxidant and phase II-metabolizing enzymes involved in detoxification, and production of reactive oxygen species were quantified in ddY male mice. Dietary supplementation of curcumin (2%, w/v) to male ddY mice for 30 days significantly increased the activities of glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and catalase to 189%, 179%, 189%, and 181% in liver and 143%, 134%, 167% and 115% in kidney respectively as compared with corresponding normal diet fed control (P<0.05-0.001). Parallel to these changes, curcumin feeding to mice also resulted in a considerable enhancement in the activity of phase II-metabolizing enzymes viz. glutathione S-transferase and quinone reductase to 1.7 and 1.8 times in liver and 1.1 and 1.3 times in kidney respectively as compared with corresponding normal diet fed control (P<0.05-0.01). In general, the increase in activities of antioxidant and phase II-metabolizing enzymes was more pronounced in liver as compared to kidney. The induction of such detoxifying enzymes by curcumin suggest the potential value of this compound as protective agent against chemical carcinogenesis and other forms of electrophilic toxicity. The significance of these results can be implicated in relation to cancer chemopreventive effects of curcumin against the induction of tumours in various target organs.
TL;DR: The data suggest that sub-lethal exposure of cypermethrin alters the biochemical, haematological parameters and enzymes of organs tissue and enzymes in brain, liver and kidney of the fish and exert stress on the fish.
Abstract: The effect of exposure to sub-lethal concentrations of cypermethrin, a synthetic pyrethroid pesticide, on biochemical parameters of muscle, blood and enzyme activities in brain, liver and kidney of the Indian major carp, Labeo rohita was studied. The sub-lethal exposure studies were done for up to 45 days at 1/10 and 1/50 of 96 h LC(50) of cypermethrin. The 96 h LC(50) was found to be 0.139 ppm. RNA levels decreased while DNA levels were elevated. Acid phosphatase was unchanged while alkaline phosphatase was depleted. Brain acetylcholinesterase activity was decreased significantly (P<0.05) over a period of 45 days at both cypermethrin concentrations. Lactate dehydrogenase activity in brain and liver was elevated, but inhibited in kidney. Succinate dehydrogenase and ATPase activities were depleted in brain, kidney and liver. There was a decrease in serum protein level over control at both concentrations of the pyrethroid. Blood glucose level and total leucocytes were elevated compared with controls at either concentration from day 15 to day 45. Haemoglobin percentage and total erythrocytes decreased in both sub-lethal concentrations. Extracts of the herb Datura stramonium were effective in countering the toxicity of this pesticide. Our data suggest that sub-lethal exposure of cypermethrin alters the biochemical, haematological parameters and enzymes of organs tissue and exert stress on the fish. Plant extracts may be useful in counteracting some of these effects.
TL;DR: The principle that a Salmonella bacterium can be utilized as a delivery vehicle of the cytosine deaminase gene to malignant tissue and that the delivered gene is functional is supported, at doses at or below 3 × 107 CFU/m2.
Abstract: We performed a pilot trial in refractory cancer patients to investigate the feasibility of intratumoral injection of TAPET-CD, an attenuated Salmonella bacterium expressing the E. coli cytosine deaminase gene. A total of three patients received three dose levels of TAPET-CD (3 x 10(6)-3 x 10(7) CFU/m(2)) via intratumoral injection once every 28 days as long as progression of disease or intolerable toxicity was not observed. From days 4 to 14 of each 28 day cycle, patients also received 5-fluorocytosine (5-FC) at a dose of 100 mg/kg/day p.o. divided three times daily. Six cycles of treatment were administered. No significant adverse events clearly attributable to TAPET-CD were demonstrated. Two patients had intratumor evidence of bacterial colonization with TAPET-CD, which persisted for at least 15 days after initial injection. Conversion of 5-FC to 5-fluorouracil (5-FU) as a result of cytosine deaminase expression was demonstrated in these two patients. The tumor to plasma ratio of 5-FU for these two colonized patients was 3.0, demonstrating significantly increased levels of 5-FU at the site of TAPET-CD colonization and insignificant systemic spread of the bacteria. In contrast, the tumor to plasma ratio of 5-FU of the patient who did not show colonization of TAPET-CD was less than 1.0. These results support the principle that a Salmonella bacterium can be utilized as a delivery vehicle of the cytosine deaminase gene to malignant tissue and that the delivered gene is functional (i.e. able to convert 5-FC to 5-FU) at doses at or below 3 x 10(7) CFU/m(2).
TL;DR: Results demonstrate that zfAHR2 mediates several endpoints of TCDD developmental toxicity in zebrafish, and most strikingly, zfahr2 morphants exposed to T CDD never developed edema.
TL;DR: It is shown that Oct1 and Oct2 together are essential for renal secretion of (small) organic cations, and a deficiency in these proteins may result in increased drug sensitivity and toxicity.
Abstract: The polyspecific organic cation transporters 1 and 2 (Oct1 and -2) transport a broad range of substrates, including drugs, toxins, and endogenous compounds. Their strategic localization in the basolateral membrane of epithelial cells in the liver, intestine (Oct1), and kidney (Oct1 and Oct2) suggests that they play an essential role in removing noxious compounds from the body. We previously showed that in Oct1(-/-) mice, the hepatic uptake and intestinal excretion of organic cations are greatly reduced. Since Oct1 and Oct2 have extensively overlapping substrate specificities, they might be functionally redundant. To investigate the pharmacologic and physiologic roles of these proteins, we generated Oct2 single-knockout and Oct1/2 double-knockout mice. Oct2(-/-) and Oct1/2(-/-) mice are viable and fertile and display no obvious phenotypic abnormalities. Absence of Oct2 in itself had little effect on the pharmacokinetics of tetraethylammonium (TEA), but in Oct1/2(-/-) mice, renal secretion of this compound was completely abolished, leaving only glomerular filtration as a TEA clearance mechanism. As a consequence, levels of TEA were substantially increased in the plasma of Oct1/2(-/-) mice. This study shows that Oct1 and Oct2 together are essential for renal secretion of (small) organic cations. A deficiency in these proteins may thus result in increased drug sensitivity and toxicity.
TL;DR: The present study suggests that melatonin may be of therapeutic benefit when used with MTX and elucidates the role of free radicals in MTX‐induced toxicity and the protection by melatonin.
Abstract: Regarding the mechanisms of methotrexate (MTX) hepatotoxicity and nephrotoxicity, several hypotheses have been put forward, among which oxidative stress (including depletion of glutathione) is likely. This investigation elucidates the role of free radicals in MTX-induced toxicity and the protection by melatonin. Wistar albino rats were injected with MTX intraperitoneally. Following a single dose of MTX (20 mg/kg), either saline (MTX group) or melatonin (10 mg/kg, MTX + Mel group) was administered for 5 days. In other rats, physiologic saline (control group) or melatonin (10 mg/kg, Mel group) was injected for 5 days, following a single injection of saline. On the sixth day, rats were killed to obtain blood, liver, and kidney tissue samples. Malondialdehyde (MDA), an end product of lipid peroxidation, and glutathione (GSH), a key antioxidant, levels were evaluated in blood and tissue homogenates. Reactive oxygen metabolite-induced inflammatory changes in kidney and liver tissues were evaluated by measuring myeloperoxidase (MPO) activity, an index of neutrophil infiltration. MTX administration resulted in increased MDA levels and MPO activity and decreased GSH levels in the blood, liver, and kidney whereas melatonin reversed these effects. When melatonin was administered alone, no significant changes in biochemical parameters were noted. In conclusion, the present study suggests that melatonin may be of therapeutic benefit when used with MTX.
TL;DR: Endostatin given daily as a 1-hour intravenous infusion was well tolerated without dose-limiting toxicity at doses up to 300 mg/m2, and serum concentrations were achieved that are associated with antitumor activity in preclinical models.
Abstract: Purpose: Endostatin is the first endogenous angiogenesis inhibitor to enter clinical trials. Laboratory investigations with endostatin have indicated broad antitumor activity coupled with remarkably low toxicity. A phase I trial of recombinant human endostatin was designed to evaluate toxicity and explore biologic effectiveness in patients with refractory solid tumors. Patients and Methods: Endostatin was administered as a 1-hour intravenous infusion given daily for a 28-day cycle. A starting dose of 30 mg/m2 was explored with subsequent dose escalations of 60, 100, 150, 225, and 300 mg/m2. Assessment of serum pharmacokinetics was performed on all 21 patients. Western blot assay and mass spectroscopy were employed to evaluate endostatin metabolism. Circulating levels of endogenous proangiogenic growth factors were examined. Tumor and tumor blood supply were imaged by dynamic computed tomography (CT), magnetic resonance imaging, ultrasound, and positron emission tomography. Results: Endostatin given on thi...
TL;DR: A relationship between metabolic events in APAP toxicity and the upregulation of NO, and IL-1b is suggested and covalent binding per se does not appear to be a toxic event in the development of toxicity.
TL;DR: The total abolition of protein synthesis may exaggerate the metabolite effects but cannot be considered a primary cause of cell death in hepatocytes over an acute time frame, and in cell types deficient in CYP450 enzymes, protein synthesis inhibition may play a more crucial role in the development of cytotoxicity.
Abstract: The toxicology of the cyanobacterial alkaloid cylindrospermopsin (CYN), a potent inhibitor of protein synthesis, appears complex and is not well understood. In exposed mice the liver is the main target for the toxic effects of CYN. In this study primary mouse hepatocyte cultures were used to investigate the mechanisms involved in CYN toxicity. The results show that 1–5 μM CYN caused significant concentration-dependent cytotoxicity (52%–82% cell death) at 18 h. Protein synthesis inhibition was a sensitive, early indicator of cellular responses to CYN. Following removal of the toxin, the inhibition of protein synthesis could not be reversed, showing behavior similar to that of the irreversible inhibitor emetine. In contrast to the LDH leakage, protein synthesis was maximally inhibited by 0.5 μM CYN. No protein synthesis occurred over 4–18 h at or above this concentration. Inhibition of cytochrome P450 (CYP450) activity with 50 μM proadifen or 50 μM ketoconazole diminished the toxicity of CYN but not the effects on protein synthesis. These findings imply a dissociation of the two events and implicate the involvement of CYP450-derived metabolites in the toxicity process, but not in the impairment of protein synthesis. Thus, the total abolition of protein synthesis may exaggerate the metabolite effects but cannot be considered a primary cause of cell death in hepatocytes over an acute time frame. In cell types deficient in CYP450 enzymes, protein synthesis inhibition may play a more crucial role in the development of cytotoxicity. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 243–251, 2003.
TL;DR: A better understanding of the pathogenesis of MTX neurotoxicity would offer the possibility of developing new therapeutic strategies for its treatment or prevention.
Abstract: Acute, subacute and chronic neurotoxicity have been observed after the administration of high-dose and/or intrathecal methotrexate (MTX). Acute toxicity is usually transient without permanent damage. Subacute and chronic toxicity are associated with changes in the brain and/or the spinal cord which may be progressive and even lead to coma and death in severe cases. It is believed that MTX can induce direct toxic effects to the CNS by damaging the neuronal tissue. Moreover, MTX interferes with the metabolic pathways of folates, excitatory amino acids, homocysteine, S-adenosylmethionine/S-adenosylhomocysteine, adenosine and biopterins, inducing biochemical alterations which have been associated with neurotoxic symptoms. It has been suggested that acute toxicity is partly mediated by adenosine, whereas homocysteine, S-adenosylmethionine/S-adenosylhomocysteine, excitatory amino acids and biopterins may play an important role in the development of subacute and chronic toxicity. A better understanding of the pathogenesis of MTX neurotoxicity would offer the possibility of developing new therapeutic strategies for its treatment or prevention.
TL;DR: It is concluded that weekly high-dose cisplatin administered in hypertonic saline is a feasible treatment regimen for advanced solid tumours treated in the period 1990–2001.
Abstract: In the present study we describe the toxicity of weekly high-dose (70–85 mg m−2) cisplatin in 400 patients (203 men, 197 women; median age 54 years) with advanced solid tumours treated in the period 1990–2001 who took part in phase I/II trials, investigating the feasibility and efficacy of weekly cisplatin alone, or in combination with paclitaxel or etoposide. Cisplatin was administered in 250 ml NaCl 3% over 3 h, for six intended administrations. The mean number of administrations was 5.3 (range, 1–6 administrations). Reasons not to complete six cycles were disease progression (7.5%), haematological toxicity (9%), nephrotoxicity (7%), ototoxicity (2.5%), neurotoxicity (1%), gastrointestinal toxicity (1%), cardiovascular complications (0.5%) or a combination of reasons including noncompliance and patient's request (5.5%). Logistic regression analysis was used to evaluate baseline parameters for prognostic value regarding toxicity. Leukopenia correlated with etoposide cotreatment, and thrombocytopenia with cisplatin dose and prior (platinum-based) chemotherapy. Risk factors for nephrotoxicity were older age, female gender, smoking, hypoalbuminaemia and paclitaxel coadministration. Neurotoxicity >grade 1 (11% of patients) was associated with prior chemotherapy and paclitaxel coadministration. Symptomatic hearing loss occurred in 15% with anaemia as the predisposing factor. We conclude that weekly high-dose cisplatin administered in hypertonic saline is a feasible treatment regimen.
TL;DR: Results of the study indicate that malathion pretreament may not essentially alter the anticholinesterase action of anilofos, but may enhance anil ofos-mediated oxidative damage to rat brain.
TL;DR: From a review of the literature, buprenorphine appears to be safe and effective in both mother and infant with an NAS that may differ from methadone both qualitatively and quantitatively.
TL;DR: Enhanced sensitivity of D. magna was shown to be the primary factor for temperature-dependent toxicity, and a temperature correction may be necessary when translating toxicity data from the laboratory to the field.
Abstract: Standard toxicity tests are performed at one constant, optimal temperature (usually 20 °C), while in the field variable and suboptimal temperatures may occur. Lack of knowledge on the interactions between chemicals and temperature hampers the extrapolation of laboratory toxicity data to ecosystems. Therefore, the aim of this study was to analyze the effects of temperature on cadmium toxicity to the waterflea Daphnia magna and to address possible processes responsible for temperature-dependent toxicity. This was investigated by performing standard toxicity tests with D. magna under a wide temperature range. Thermal effects on accumulation kinetics were determined by estimating uptake and elimination rates from accumulation experiments. To study temperature dependency of the intrinsic sensitivity of the daphnids to cadmium, the DEBtox model was used to estimate internal threshold concentrations (ITCs) and killing rates from the toxicity and accumulation data. The results revealed that increasing temperature lowered the ITC and increased the killing rate and the uptake rate of the metal. Enhanced sensitivity of D. magna was shown to be the primary factor for temperature-dependent toxicity. Since temperature has such a major impact on toxicity, a temperature correction may be necessary when translating toxicity data from the laboratory to the field.
Journal Article•
TL;DR: Few randomized controlled trials of antitumor drugs in older patients with cancer have been conducted, but a number of agents with favorable efficacy and toxicity profiles in elderly patients have been identified.
Abstract: Complications of cytotoxic chemotherapy are more common in older patients (65 years of age and older) with cancer than in younger patients, and the occurrence of myelosuppression, mucositis, cardiodepression, peripheral neuropathy, and central neurotoxicity can complicate treatment. Age-related physiologic changes that can increase the toxicity of chemotherapy are decreased stem-cell reserves, decreased ability to repair cell damage, progressive loss of body protein, and accumulation of body fat. A decline in organ function can alter the pharmacokinetics of many of the commonly used chemotherapeutic agents in some elderly patients, making toxicity less predictable. Comorbidities increase the risk of toxicity through their effects on the body. Furthermore, the drugs used to treat comorbidities may interact with chemotherapeutic drugs, potentially increasing toxicity in elderly patients. Prospective trials in older patients with lymphoma or solid tumors have found that age is a risk factor for chemotherapy-induced neutropenia and its complications. Anemia may be present because of the disease or its treatment, and, if left uncorrected, it can alter drug activity and increase toxicity. Being able to predict which elderly patients are at greater risk of toxicity on the basis of pretreatment factors would be valuable, and there is a need for prospective trials to determine regimen- and patient-specific prognostic factors. Effective management of the toxicity associated with chemotherapy with appropriate supportive care is crucial, especially in the elderly population, to give them the best chance of cure and survival, or to provide palliation. For example, management of neutropenic complications with colony-stimulating factors makes treatment with standard-dose chemotherapy possible, which can lead to better outcomes. A better understanding of drug activity and toxicity in older patients is necessary for developing guidelines for safe and effective treatment. Few randomized controlled trials of antitumor drugs in older patients with cancer have been conducted, but a number of agents with favorable efficacy and toxicity profiles in elderly patients have been identified.
TL;DR: The results demonstrated the pathophysiological relevance of caspase-independent, ROS-mediated pathways in response to lethal TNF-induced shock in mice and suggested that survival of TNF toxicity seemed to require a casp enzyme-dependent protective feedback on excessive reactive oxygen species (ROS) formation and phospholipase A2 activation.
Abstract: Dysregulated apoptotic cell death contributes to many pathological conditions, including sepsis, prompting the suggestion that caspase inhibition to block apoptosis could have useful therapeutic applications. Because the cytokine tumor necrosis factor (TNF, also known as TNF-α) is both pro-apoptotic and pro-inflammatory and is involved in septic shock, we tested whether caspase inhibition would alleviate TNF-induced toxicity in vivo. General caspase inhibition by the protease inhibitor zVAD-fmk exacerbated TNF toxicity by enhancing oxidative stress and mitochondrial damage, resulting in hyperacute hemodynamic collapse, kidney failure and death. Thus, survival of TNF toxicity depends on caspase-dependent processes. Our results demonstrated the pathophysiological relevance of caspase-independent, ROS-mediated pathways in response to lethal TNF-induced shock in mice. In addition, survival of TNF toxicity seemed to require a caspase-dependent protective feedback on excessive reactive oxygen species (ROS) formation and phospholipase A2 activation.
TL;DR: A clinical trial with a sufficient accrual to definitely rule out a tumor protective effect of amifostine needs to be conducted, and Substances reducing radiation-induced toxicity by modulating the biological response to radiation injury may represent an alternative concept in radioprotection.
TL;DR: The most significant factor correlated acute GI toxicity in gynecology patients undergoing IM-WPRT is Vol(SB,100), which is fit to a normal tissue complication probability (NTCP) function.
Journal Article•
TL;DR: In children, 4HPR administration up to 4000 mg/m(2)/day over 28 days, followed by a 7-day interruption, results in manageable toxicity and in drug plasma concentrations comparable with those that induce apoptosis in neuroblastoma cell lines.
Abstract: Purpose: Fenretinide (4HPR), a synthetic retinoid, induces apoptosis in neuroblastoma cells. A Phase I study in children with neuroblastoma was designed to determine maximum tolerated dose, toxicity, and pharmacokinetics. Experimental Design: Fifty-four patients received oral 4HPR, once daily, for 28 days, followed by a 7-day interruption, for up to 6 courses. The starting dose was 100 mg/m2/day. At least 3 patients were entered at each escalating 4HPR dose level. Pharmacokinetic sampling was performed on days 1 and 28 of the first course. Results: Fifty-four patients, of whom 53 were evaluable, received doses between 100 and 4000 mg/m2/day for a total of 168 courses. Additional dose escalation was precluded by capsule number intake. A total of 34 of 53 evaluable patients showed manageable, reversible toxicities, which were not dose related. One dose-limiting toxicity (nyctalopia grade 3) occurred after the 1000 mg/m2/day dose. Twelve patients showed grade 2 toxicity: skin xerosis (6 cases); nyctalopia (3 cases); hepatic toxicity (1 case); diarrhea (1 case); and headache (1 case). Stable disease was observed in 41 patients for a median period of 23 months (range 2–35+). After first administration, average 4HPR peak plasma levels ranged from 0.6 to 6 μm (after 100 and 4000 mg/m2/day, respectively) and increased 2-fold (to 1.3 and 12.9 μm, respectively) after the 28-day treatment. 4HPR half-life increased from 17 h after the first administration to 25 h after the 28th administration. Incidence of grade 2–3 toxicity was 0 of 12 (0%), 7 of 22 (31%), and 4 of 8 (50%) with peak 4HPR concentrations 10 μm, respectively. After repeated treatment, retinol levels decreased from 20 to 10% of pretreatment levels after all of the doses. Conclusions: In children, 4HPR administration up to 4000 mg/m2/day over 28 days, followed by a 7-day interruption, results in manageable toxicity and in drug plasma concentrations comparable with those that induce apoptosis in neuroblastoma cell lines.