Neuroendocrine and cardiovascular responses to high-dose corticosteroid therapy in canine endotoxin shock

The neuroendocrine and cardiovascular responses to endotoxin administration and the effects of subsequent high-dose corticosteroid therapy have been investigated in dogs. Shock was induced in anaesthetised animals by a large bolus of E. coli endotoxin (5 mg/kg) followed by a continuous infusion (2 mg/kg per hour). One hour after induction of shock, the circulating volume was expanded using a colloidal gelatin solution. Fifteen minutes later, one group of five animals received a bolus of methylprednisolone sodium succinate 30 mg/kg, while a control group of five animals was given an equivalent volume of isotonic saline. The administration of endotoxin produced reductions in mean arterial pressure, cardiac index and left ventricular dp/dtmax, together with increases in systemic and pulmonary vascular resistances. These haemodynamic changes were associated with increases in arterial plasma levels of adrenaline, noradrenaline, cortisol, immunoreactive beta-endorphin and immunoreactive metenkephalin. Cardiovascular improvement followed volume replacement and was associated with reductions in circulating catecholamines. No significant haemodynamic or neuroendocrine changes were demonstrated in the 2 h following steroid therapy.     

The effect of insulin dose on the measurement of insulin sensitivity by the minimal model technique. Evidence for saturable insulin transport in humans.

Administration of exogenous insulin during an intravenous glucose tolerance test allows the use of the minimal model technique to determine the insulin sensitivity index in subjects with reduced endogenous insulin responses. To study the effect of different insulin administration protocols, we performed three intravenous glucose tolerance tests in each of seven obese subjects (age, 20-41 yr; body mass index, 30-43 kg/m2). Three different insulin administration protocols were used: a low-dose (0.025 U/kg) infusion given over 10 min, a low-dose (0.025 U/kg) bolus injection, and a high-dose (0.050 U/kg) bolus injection, resulting in peak insulin concentrations of 1,167 +/- 156, 3,014 +/- 483, and 6,596 +/- 547 pM, respectively. The mean insulin sensitivity index was 4.80 +/- 0.95 x 10(-5), 3.56 +/- 0.53 x 10(-5), and 2.42 +/- 0.40 x 10(-5) min-1/pM respectively (chi +/- SEM; P = 0.01). The association of higher peak insulin concentrations with lower measured insulin sensitivity values suggested the presence of a saturable process. Because results were not consistent with the known saturation characteristics of insulin action on tissue, a second saturable site involving the transport of insulin from plasma to interstitium was introduced, leading to a calculated Km of 807 +/- 165 pM for this site, a value near the 1/Kd of the insulin receptor. Thus, the kinetics of insulin action in humans in these studies is consistent with two saturable sites, and supports the hypothesis for transport of insulin to the interstitial space. Saturation may have an impact on minimal model results when high doses of exogenous insulin are given as a bolus, but can be minimized by infusing insulin at a low dose.     

Experimental central nervous system aspergillosis therapy: efficacy, drug levels and localization, immunohistopathology, and toxicity

We have shown previously that high-dose lipid amphotericin preparations are not more efficacious than lower doses in aspergillosis. We studied toxicity, drug concentrations and localization, and quantitative infection concurrently, using a 4-day model of central nervous system (CNS) aspergillosis to assess early events. Mice given Aspergillus fumigatus conidia intracerebrally, under a cyclophosphamide immunosuppressive regimen, were treated for 3 days (AmBisome at 3 or 10 mg/kg of body weight, Abelcet at 10 mg/kg, amphotericin B deoxycholate at 1 mg/kg, caspofungin at 5 mg/kg, or voriconazole at 40 mg/kg). Sampling 24 h after the last treatment showed that AmBisome at 3 but not at 10 mg/kg, as well as Abelcet, caspofungin, and voriconazole, reduced brain CFU. All regimens reduced renal infection. Minor renal tubular changes occurred with AmBisome or Abelcet therapy, whereas heart, lung, and brain showed no drug toxicity. Amphotericin B tissue and serum concentrations did not correlate with efficacy. Endothelial cell activation (ICAM-1 and P-selectin in cerebral capillaries) occurred during infection. Amphotericin B derived from AmBisome and Abelcet localized in activated endothelium and from Abelcet in intravascular monocytes. In 10-day studies dosing uninfected mice, minor renal tubular changes occurred after AmBisome or Abelcet at 1, 5, or 10 mg/kg with or without cyclophosphamide treatment; nephrosis occurred only with Abelcet in cyclophosphamide-treated mice. Hepatotoxicity occurred with AmBisome and Abelcet but was reduced in cyclophosphamide-treated mice. Marked CFU reduction by AmBisome at 3 mg/kg occurred in association with relatively more intense inflammation. Abelcet renal localization appears to be a precursor to late nephrotoxicity. Hepatotoxicity may contribute to high-dose Abelcet and AmBisome failures. Our novel observation of endothelial amphotericin localization during infection may contribute to amphotericin mechanism of efficacy.     

5-Fluorouracil (5-FU)/leucovorin in comparison to other current chemotherapy protocols in metastasizing colorectal carcinoma]

17 patients with metastasizing colorectal cancer were treated in a phase II-study with systemic intravenous chemotherapy (Petrelli N, Proc ASCO 286, 1987) consisting of leucovorin 500 mg/m2 in a 2 hr infusion and 5-fluorouracil (5-FU) 600 mg/m2 bolus one hour after the commencement of the leucovorin infusion. Limiting toxicities were gastrointestinal, in form of nausea/vomiting of WHO grade 3 (n = 1) and of diarrhoea of maximal grade 4 (n = 5), as well as haematological with a maximal nadir of leucocytes of WHO grade 4 (n = 1) and of thrombocytes of WHO grade 1 (n = 1). Of the 14 evaluable patients an objective response was achieved in 21% of cases (CR: n = 1, PR: n = 2). 64% of the patients showed no change and 14% showed progression of their disease, 7 out of the 17 patients have died; the median survival was 24 months. With respect to objective remission, our result of 21% response rate is lower than the median of 32% of 24 different studies comprising 695 patients; nevertheless, the present response rate is within the range observed in the published studies of between 0% and 67%. In order to estimate the antitumoral efficacy of the new regimen 5-FU/leucovorin more objectively, a retrospective comparison of the therapy regimens used most frequently in disseminated colorectal cancer (5-FU monotherapy, 5-FU/methotrexate (MTX), 5-FU/MTX/low dose leucovorin, 5-FU/cisplatin, 5-FU/leucovorin) has been performed. The continuous administration of 5-FU monotherapy, with an objective response rate of 26%, was superior to standard 5-FU monotherapy as a bolus injection or short-term infusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

A double-blind, multicentre comparison of intravenous dolasetron mesilate and metoclopramide in the prevention of nausea and vomiting in cancer patients receiving high-dose cisplatin chemotherapy

The potent serotonin receptor (5-HT₃) antagonists are new highly selective agents for the prevention and control of chemotherapy-induced nausea and vomiting that have been shown to be comparable to or more effective than traditional metoclopramide regimens. This study was designed to compare the antiemetic efficacy of dolasetron and metoclopramide in chemotherapy-naive and non-naive cancer patients receiving high-dose cisplatin-containing chemotherapy. This multicentre, double-blind, randomized trial compared the efficacy and safety of single i.v. doses of dolasetron mesilate salt (1.2 or 1.8 mg/kg) and metoclopramide (7 mg/kg) in 226 patients for the prevention of acute emesis and nausea associated with the administration of high-dose (80 mg/m²) cisplatin. Efficacy and safety were evaluated for 24 h. Complete responses were achieved by 57%, 48%, and 35% of patients given dolasetron mesilate 1.8 mg/kg (P=0.0009 vs metoclopramide), dolasetron mesilate 1.2 mg/kg (P=0.0058 vs metoclopramide), and metoclopramide, respectively. Overall, dolasetron was significantly more effective than metoclopramide for time to first emetic episode, nausea, patient satisfaction, and investigator global assessment of efficacy. Males, chemotherapy-naive patients, and alcoholics had higher response rates. Dolasetron was well tolerated, with mild-to-moderate headache most commonly reported. Twelve percent of patients receiving metoclopramide reported extrapyramidal symptoms compared with 0% of patients receiving dolasetron. In conclusion, dolasetron mesilate was effective for the prevention of CINV with high-dose cisplatin. Single i.v. doses of dolasetron mesilate were more effective than 7 mg/kg metoclopramide in preventing nausea and vomiting induced by highly emetogenic cisplatin-containing chemotherapy. In addition, 1.8 mg/kg dolasetron mesilate consistently produced the highest response rates and appears to be the most effective dose for further clinical development.     

Effects of posttreatment with propofol on mortality and cytokine responses to endotoxin-induced shock in rats

OBJECTIVE: To clarify the effects of posttreatment with propofol administration on mortality rate and cytokine responses to endotoxin-induced shock in rats. DESIGN: Randomized prospective laboratory study. SETTING: University laboratory. SUBJECTS: Thirty-three male rats. INTERVENTIONS: Animals were randomly assigned to one of three groups (n = 11 per group): a) endotoxemic group, receiving intravenous Escherichia coli endotoxin (20 mg/kg over 2 mins); b) early posttreatment group, treated identically to the endotoxemic group with the additional administration of propofol (10 mg/kg bolus, followed by infusion at 10 mg x kg(-1) x hr(-1)) 1 hr after the injection of endotoxin; and c) late posttreatment group, treated identically to the endotoxemic group with the additional administration of propofol (10 mg/kg bolus, followed by infusion at 10 mg x kg(-1) x hr(-1)) 2 hrs after the injection of endotoxin. MEASUREMENTS AND MAIN RESULTS: Hemodynamics and arterial blood gases were recorded, and mortality rate and plasma cytokine concentrations were calculated for the 5-hr observation. The mortality rate 5 hrs after endotoxin injection was 73% for the endotoxic, 9% for the early posttreatment, and 36% for the late posttreatment groups. The mortality rate for the early posttreatment group was significantly lower than that for the other groups. The increases in plasma cytokine (tumor necrosis factor-alpha and interleukin-6 and -10) concentrations were less for the early posttreatment group than the other two groups. CONCLUSIONS: The early posttreatment of propofol after endotoxin injection drastically reduced the mortality rate of rats and attenuated their cytokine responses. Moreover, propofol attenuated the production of tumor necrosis factor-alpha. These findings suggest that propofol administration may be beneficial during sepsis.     

Influence of three modes of administration on the penetration of latamoxef into interstitial fluid and fibrin clots and its in-vivo activity against Haemophilus influenzae

The extravascular penetration and bactericidal activity of latamoxef against beta-lactamase positive Haemophilus influenzae were studied in a rabbit model. All groups of animals received over 24 h an identical dose of 100 mg/kg of latamoxef given by three different intravenous modes of administration including a single large injection of 100 mg/kg, four 25 mg/kg intermittent injections every 6 h, and a continuous infusion of 100 mg/kg over 24 h. A single large injection resulted in significantly higher peak levels and higher initial area under the curve of concentrations of drug in serum, interstitial fluid, and fibrin clots than other modes of administration. Continuous infusion resulted in an accumulation of drug in clots which rose from 1.0 microgram/g at 4 h to 4.9 micrograms/g at 24 h (P value less than 0.01). The rate of killing of H. influenzae imbedded in fibrin clots was greatly influenced by the different modes of therapy. Even though all regimens resulted in peak concentrations which were more than 80 times the MIC (0.03 mg/l) in the fibrin clots, rapid killing (from 10(7) to less than 10(2) micro-organisms per g of clots in less than 6 h) was only observed with a single bolus. Continuous infusion and intermittent injections of latamoxef resulted in limited in-vivo bactericidal activity. Large doses of latamoxef given at long intervals may be more effective than intermittent dosing or continuous infusion.     

Bimonthly Regimen of High-Dose Leucovorin, Infusional 5-Fluorouracil, Epirubicin and Cisplatin (Modified ECF) as Adjuvant Chemotherapy in Resected Gastric Adenocarcinoma

Background: The administration of the de Gramont regimen in combination with cisplatin and epirubicin (modified ECF) has previously been reported as a treatment for advanced gastric cancer, but here we report this regimen combination in an adjuvant setting for the first time. Methods: Forty-eight patients with curatively resected gastric cancer were treated. Each 2-week cycle consisted of epirubicin (50 mg/m(2)), cisplatin (50 mg/m(2)), 5-fluorouracil (5-FU) IV bolus (400 mg/m(2)) and 5-FU IV (2,400 mg/m(2)) over 46 h plus leucovorin IV (400 mg/m(2)) over 2 h. Postoperative chemoradiotherapy was also administered to the patients when indicated. We retrospectively reviewed the patients who were treated with modified ECF. Results: The median disease-free survival (DFS) was 40.7 months and the 1-, 3- and 5-year DFS rates were 78.5, 55.7 and 44.6%, respectively. The most common grade 3-4 toxicities were hematological and gastrointestinal. Conclusion: A modified ECF regimen may be an effective and convenient treatment with tolerable toxicities for the adjuvant treatment of gastric cancer. It may provide an alternative regimen to the standard ECF when a continuous ambulatory infusion pump is not feasible or not preferred by the patient.     

Enhancement of cytocidal and antitumor effect of cisplatin by caffeine in human osteosarcoma

A nontoxic dose of caffeine enhanced the cytotoxicity of cisplatin in human osteosarcoma cells (OST strain). Synergistic cytotoxicity was seen in vitro in OST cells when 2 mmol caffeine was added to a nontoxic dose of cisplatin (2 micrograms/ml). Caffeine reduced S-phase, G2/M-phase, and S-and-G2/M-phase accumulation by cisplatin on the DNA histogram, and nuclear fragmentation of tumor cells was frequently observed. Flow cytometric analysis appeared to be useful in assessing the efficacy of the combination of cisplatin and caffeine. The antitumor effect of the combination of cisplatin and caffeine was examined in OST transplanted to BALB/C athymic mice. Regression of the tumor was observed when cisplatin was given at a dose of 10 mg/kg. When 4 mg of caffeine was given once a day for three days after the administration of cisplatin, marked regression of the tumor was observed in groups treated with 5 or 10 mg/kg of cisplatin, without significant weight loss. These results indicate that caffeine enhances the antitumor effect of cisplatin on transplanted osteosarcoma in BALB/C athymic mice.     

Enhanced Toxicity for Mice of Combinations of Bacterial Endotoxin with Antitumor Drugs

The toxicity of Salmonella typhosa 0901W endotoxin to mice was potentiated by (per kilogram) 1 mg of colchicine, 20 mg of emetine, 100 mg of 6-mercaptopurine, 100 mg of 6-methylmercaptopurine riboside, 75 mg of methotrexate, 2 mg of sparsomycin, or 2.5 mg of vinblastine. No potentiation of endotoxin lethality was evident with simultaneously administered (per kilogram): 200 mg of cytosine arabinoside, 450 mg of dibromomannitol, 100 mg of 5-fluorouracil, 125 mg of 5-fluorouracil deoxyriboside, 8 mg of mitomycin C, 1 mg of nitrogen mustard, or 10 mg of tris(1-aziridinyl)-phosphine sulfide. With the exception of colchicine, all drugs prolonged the duration of sleep after the administration of 80 mg of hexobarbital per kg. Simultaneous injection of endotoxin with 100 mg of 6-mercaptopurine per kg, 75 mg of methotrexate per kg, or 1 mg of vincristine per kg resulted in significantly greater lethality than administration either prior to or after the drug. However when endotoxin was administered prior to 100 mg of 5-fluorouracil per kg, lethality was significantly increased. The route of administration of endotoxin and 5-fluorouracil, 6-mercaptopurine, methotrexate, or vincristine did not influence overall lethality. Pretreatment of mice with multiple doses of Escherichia coli endotoxin resulted in a significant reduction in the lethality of 6-mercaptopurine- or vincristine-endotoxin combinations, but had no influence on 5-fluorouracil- or methotrexate-endotoxin combinations. Endotoxin-pretreated mice were more susceptible to vincristine alone and more resistant to high doses of 5-fluorouracil. The lethality of 6-mercaptopurine was increased by simultaneous administration of gram-negative isolates from feces of human patients with neoplastic disease.     

Comparison of a 48-hour infusion of 5-fluorouracil without folinic acid with 24-hour folinic acid/5-fluorouracil in patients with metastatic colorectal cancer refractory to bolus folinic acid/5-fluorouracil. A prospective cohort study

BACKGROUND: Out of various high-dose 5-fluorouracil (5-FU) regimens given with or without folinic acid (FA), the optimal 5-FU schedule has still to be defined as treatment for metastatic colorectal cancer (CRC). Consequently, we compared toxicity, response and survival following two FA/5-FU regimens in 55 CRC patients refractory to bolus FA/5-FU. METHODS: Twenty-eight patients (group A) received 5-FU (60 mg/kg body weight) for 48 h, and 27 (group B) received 2-hour infusions of FA (500 mg/m(2)) and 24-hour infusions of 5-FU (2600 mg/m(2)) until disease progression. RESULTS: Both groups were adequately matched with respect to patient characteristics. While overall toxicities were rare, hand-foot syndrome was more common in A. Tumor control was achieved in 57 and 44%, for A and B, respectively. Survival times were 16 months in A and 9 months in B. CONCLUSIONS: Since both 5-FU infusion protocols showed equivalent palliative effects, FA may be questioned in second-line 5-FU regimens.     

Effects of a novel anticoagulant compound (TV7130) in an ovine model of septic shock

We compared the effects of a new compound (TV7130) with those of activated protein C (APC) in a large animal model of septic shock. Thirty-two fasted, anesthetized, invasively monitored, mechanically ventilated female sheep received 1.5 g/kg body weight of feces into the abdomen to induce sepsis. Immediately after feces injection, all animals received a bolus followed by a continuous infusion of saline (n = 8, bolus 1.5 mL for 15 min, infusion 1.5 mL/[kg·h]), low-dose TV7130 (n = 8; 0.4 mg/kg bolus, 0.4 mg/[kg·h] infusion), high-dose TV7130 (n = 8; 0.8 mg/kg bolus, 0.8 mg/[kg·h] infusion), or APC (n = 8; saline bolus, APC infusion of 0.024 mg/[kg·h]). Experiments were pursued until each sheep's spontaneous death. There were no significant differences among groups in heart rate or cardiac index, but mean arterial pressure, systemic vascular resistance index, and left ventricular stroke work index decreased less in the high-dose TV7130 and APC groups than in the other groups. Gas exchange was preserved better in the high-dose TV7130 and APC groups. Interleukin 6 and lactate concentrations were lower in the high-dose TV7130 and APC groups than in the other groups. Functional capillary density and proportion of perfused vessels, evaluated in the sublingual region using sidestream dark-field videomicroscopy, were significantly higher in the TV7130 and APC groups than in the vehicle group at 16 h. Survival time was significantly longer in the high-dose TV7130 and APC groups than in the other groups (log-rank test, P = 0.0002). TV7130 has similar effects to APC and may be a promising agent for the management of severe sepsis.     

Enhanced anti-tumour effect of cisplatin with low-voltage electrochemotherapy in hamster oral fibrosarcoma

The aim of this study was to determine the effects of low-voltage electrochemotherapy with intraperitoneal cisplatin on hamster oral fibrosarcoma. Oral fibrosarcoma was transplanted submucosally into the cheek pouch mucosa of 100 hamsters. After transplantation, the hamsters were randomly divided into four equal groups. These groups received no treatment (D-E-); 2 mg/kg body weight cisplatin treatment without electroporation (D+E-); electroporation without cisplatin treatment (D-E+); or 2 mg/kg body weight cisplatin treatment followed by electroporation (D+E+). Electrical pulse treatment together with cisplatin injection markedly reduced the size of the tumour, whereas cisplatin injection or electrical pulse treatment alone did not. These results clearly indicate that the anti-tumour effect of cisplatin on hamster oral fibrosarcoma was considerably potentiated or enhanced by the administration of local electrical pulses at low voltages.     

Montelukast ameliorates kidney function and urinary bladder sensitivity in experimentally induced renal dysfunction in rats

Effect of montelukast on the renal dysfunction induced by cisplatin was investigated. A single dose of cisplatin (7 mg/kg, i.p.) induced nephrotoxicity, which was manifested by increasing the sensitivity of isolated urinary bladder rings to acetylcholine (ACh) together with a significant elevation of serum creatinine, blood urea nitrogen, and lactate dehydrogenase. On the other hand, serum albumin was significantly decreased. Moreover, renal dysfunction was further confirmed by a significant increase in lipid peroxides that were measured as malondialdehyde (MDA) in kidney tissue homogenate. Kidney reduced glutathione (GSH) content and superoxide dismutase (SOD) activity were measured, which were decreased and increased, respectively. Administration of montelukast (10 mg/kg/day, p.o.) 5 days before and 5 days after cisplatin injection significantly ameliorated the renotoxic effects of cisplatin, as judged by a significant reduction in the responses of isolated bladder rings to ACh. The deleterious changes induced by cisplatin treatment in kidney function parameters and oxidative stress markers were significantly mitigated by montelukast treatment. Conclusion: Montelukast may be a beneficial remedy for cisplatin‐induced renal dysfunction.     

Association between increased atrial natriuretic peptide and reduced cisplatin nephrotoxicity in rats.

Plasma atrial natriuretic peptide (ANP) concentrations were monitored in two experimental models of protection from cisplatin nephrotoxicity. Sprague-Dawley rats made diabetic with streptozotocin (65 mg/kg) were protected from cisplatin-induced nephrotoxicity when compared to control rats as indicated by reduced plasma creatinine (0.49 +/- 0.02 vs. 0.9 +/- 0.06 mg/dl; P less than .001) and blood urea nitrogen concentrations (18.51 +/- 1.4 vs. 43.08 +/- 2.1 mg/dl; P less than .001). Plasma ANP was also increased with experimental diabetes (76.5 +/- 8.98 fmol/ml) vs. normoglycemic controls (43.8 +/- 8.9 fmol/ml; P less than .02). When diabetic rats were treated with insulin, the renal protection observed with the diabetic state was reversed (creatinine, 0.70 +/- .05 mg/dl); plasma ANP concentrations were also reduced (52.2 +/- 15.2 fmol/ml). Renal platinum concentrations were significantly lower in the diabetic group and the reversal of diabetic-induced renal protection with insulin was associated with increased renal platinum concentrations. In rats given a single i.p. dose of cisplatin (5 mg/kg), a reduction in cisplatin-induced nephrotoxicity was observed when 5% NaCl was the vehicle of choice compared to that seen in rats given the same dose of drug in 0.9% saline (creatinine, 0.43 +/- 0.07 with 5% NaCl vs. 0.63 +/- 0.03 with 0.09% NaCl). NaCl (5%) administration also resulted in increased plasma ANP concentrations when compared to rats receiving equivalent volumes of 0.9% NaCl (88.4 +/- 6.2 vs. 50.5 +/- 5.6 fmol/ml, respectively). These data suggest that increased endogenous ANP may be a mechanism of renal protection common to both experimental diabetes and hypertonic saline administration. Chronically increased ANP may prevent renal accumulation of platinum in the kidney.     

Clinical experiences with high-dose methotrexate

40 patients with various forms of malignant disease, who had already been subjected to conventional regimens of treatment, were treated between 1976 and 1981 at the Department of Chemotherapy, Vienna University, with high-dose methotrexate (MTX) as sole therapeutic agent. 18 patients received MTX in moderately high doses of 250 mg/m2 to 750 mg/m2 at 10-day intervals. 19 patients were treated with high doses of 5 to 15 g MTX at 10-day intervals. In 2 cases of severe malignant non-Hodgkin's lymphoma one patient received 2 X 1 g MTX with an interval of 19 days between doses and the other received a single dose of 5 g MTX by infusion. One patient with alveolar soft part cell sarcoma was given ultra-high therapy, with a cumulative dose of 205 g. None of the patients in the group given moderately high-dose MTX therapy, whereas three in the high-dose group had an objective remission. Objective remission was obtained neither in the two lymphoma patients nor in the ultra-high-dose treated case. Complications such as leucopenia and/or thrombopenia were found in 9%, reversible transaminase activity increases in 45%, as well as a decrease in creatinine clearance in 10% of the cases. Irreversible severe kidney insufficiency was found in none of the cases. One patient with lymphoma died as a result of severe toxic epidermiolysis with involvement of the gastrointestinal mucosa, whilst the other suffered from pulmonary complications in the form of the respiratory distress syndrome. On the basis of our experience the use of high-dose MTX therapy as an alternative method following trials of all conventional regimens is not recommended.     

Diphenhydramine as a Protective Agent in a Rat Model of Acute, Lethal Organophosphate Poisoning

OBJECTIVE: To evaluate the effects of diphenhydramine chloride (DPH) on mortality in a rat model of acute, severe organophosphate poisoning (OP). METHODS: Wistar rats (n = 40) were randomized to pretreatment with either normal saline (controls), 5 mg/kg atropine, 3 mg/kg DPH, 15 mg/kg DPH, or 30 mg/kg DPH given as a single intramuscular injection 5 minutes prior to a subcutaneous injection of 25 mg/kg dichlorvos (n = 8 per group). The primary endpoint was 10-minute survival. Survival at 24 hours was a secondary endpoint. Comparison of survival rates between groups was carried out by ANOVA and the Student-Newman-Keuls test. RESULTS: Dichlorvos exposure resulted in profound fasciculations within 2 minutes of injection in all cohorts. In controls, fasciculations were followed by respiratory arrest within 10 minutes (0% survival). The rats receiving atropine pre-treatment exhibited similar fasciculations (nicotinic effects) without subsequent respiratory arrest, resulting in a significant improvement in survival (88%, p < 0.001). The DPH-treated rats exhibited a significant dose-dependent reduction in mortality, with the 3 mg/kg, 15 mg/kg, and 30 mg/kg groups demonstrating 0%, 25%, and 100% survival, respectively. There was no additional mortality between 10 minutes and 24 hours in any group. There was no significant difference in survival between the high-dose DPH and the atropine groups. CONCLUSIONS: Diphenhydramine chloride significantly reduced mortality in rats with acute, severe dichlorvos exposure.     

Apoptosis in normal tissues induced by anti-cancer drugs

To investigate the damage mediated by anti-cancer drugs in normal cells, we examined the effect of such drugs on apoptosis of normal cells of the small intestinal epithelium and the bone marrow by in situ DNA end-labelling and transmission electron microscopy. Mice received a single dose of 5-fluorouracil (5-FU) or cisplatin, or repeated daily doses of 5-FU for 7 days. In mice treated with a single dose of 5-FU 50 mg/kg or cisplatin 5 mg/kg, the number of apoptotic cells appearing in the small intestine 12 h after injection was relatively small, but increased steadily reaching a peak after 36 h and then decreasing to close to that in the control group by 48 h. In bone marrow cells, results were similar in mice treated with single doses of 5-FU 50 mg/kg but apoptosis increased much less in those treated with cisplatin 5 mg/kg. The proportion of apoptotic cells reached peak values earlier at higher concentrations of 5-FU or cisplatin both in small intestine and in bone marrow. In the mice treated repeatedly with 5-FU 50 mg/kg, the proportion of apoptotic small intestinal epithelial cells reached a succession of peaks at 48-h intervals. Mice treated repeatedly with 5-FU 50 mg/kg also showed a rapid increase in diarrhoea symptoms and a steady decrease in the height of villi. Our results suggest it may be possible to prevent the side-effects of anti-cancer drugs by inhibiting apoptosis in the gastrointestinal tract.     

In vitro renal toxicity and in vivo therapeutic efficacy in experimental murine cryptococcosis of amphotericin B (Fungizone) associated with Intralipid.

We compared the experimental toxicities and activities of deoxycholate amphotericin B (d-AmB) dissolved in glucose (Dd-AmB) or mixed with 20% Intralipid (ILd-AmB). In vitro, ILd-AmB against renal tubular cells in primary culture. In vivo, the toxicities and activities of Dd-AmB and ILd-AmB were studied in DBA2 mice with cryptococcosis. The maximum tolerated dose of intravenously administered d-AmB, i.e., the dose that induced less than 15% mortality because of toxicity, was 1.7 to 2.5 times higher when it was administered as ILd-AmB than when it was administered as Dd-AmB. Both treatments given intravenously at the same dose were equivalent for improving the survival of mice and reducing CFU counts in infected tissue, but at maximum tolerated doses, ILd-AmB (2 mg/kg of body weight) was more effective than Dd-AmB (0.8 to 1.2 mg/kg). AmB concentrations in spleen, liver, lung, and kidney were measured by high-pressure liquid chromatography 4 and 24 h after a single injection of 1.2 mg of Dd-AmB per kg, 1.2 mg of ILd-AmB per kg, or 2 mg of ILd-AmB per kg. In a given organ, AmB levels were similar after administration of 1.2 mg of Dd-AmB or ILd-AmB per kg but were significantly higher after administration of 2 mg of ILd-AmB per kg. The lower level of toxicity of ILd-AmB might be explained by circular dichroism experiments, showing that ILd-AmB contained 10-fold less soluble oligomeric AmB, which is believed to be the toxic form of the drug, than Dd-AmB. We conclude that ILd-AmB is as efficient as Dd-AmB and is better tolerated than Dd-AmB in mice with experimental cryptococcosis. By allowing higher doses of AmB to be infused, Intralipid enhances AmB concentrations in infected sites, and thus the therapeutic activity of the drug.     

The protective effect of melatonin on cisplatin nephrotoxicity

Regarding the mechanisms of cisplatin (CP) nephrotoxicity, several hypotheses have been put forward, among which oxidative stress (including depletion of glutathione and production of lipid peroxide) is noticeable. This investigation elucidates the role of the antioxidant system in CP-induced nephrotoxicity and the nephroprotection by melatonin. Balb/c mice were injected i.p. with: 1) vehicle control; 2) a single dose of 6.5 mg/kg cisplatin, CP group; 3) melatonin in a dose of 10 mg/kg for 5 days after CP injection, CP-M group; 4) melatonin (10 mg/kg) for 5 days before and after CP injection, M-CP-M group; 5) melatonin in a dose of 10 mg/kg for 5 days, M group. Mice were sacrificed 5 days after CP injection to determine blood urea nitrogen (BUN) and serum creatinine. Renal lipid peroxidation (LP) and glutathione (GSH) levels were evaluated in kidney homogenates. Cisplatin administration resulted in increased LP, BUN and serum creatinine levels and decreased GSH levels, whereas melatonin reversed these effects. Morphological kidney damage was apparent in the CP group. Mentioned degeneration was moderate in the CP-M group, whereas morphological findings of the M-CP-M group implied a well preserved kidney tissue. When M was administered alone, it didn't cause any significant change in biochemical parameters. Both C and M groups exhibited similar biochemical and morphological findings in light and transmission electron microscope observation. In conclusion, the present study suggests that melatonin may be of therapeutic benefit when used with CP.