A vanguard randomised feasibility trial comparing three regimens of peri-operative oxygen therapy on recovery after major surgery.

International recommendations encourage liberal administration of oxygen to patients having surgery under general anaesthesia, ostensibly to reduce surgical site infection. However, the optimal oxygen regimen to minimise postoperative complications and enhance recovery from surgery remains uncertain. The hospital operating theatre randomised oxygen (HOT-ROX) trial is a multicentre, patient- and assessor-blinded, parallel-group, randomised clinical trial designed to assess the effect of a restricted, standard care, or liberal peri-operative oxygen therapy regimen on days alive and at home after surgery in adults undergoing prolonged non-cardiac surgery under general anaesthesia. Here, we report the findings of the internal vanguard feasibility phase of the trial undertaken in four large metropolitan hospitals in Australia and New Zealand that included the first 210 patients of a planned overall 2640 trial sample, with eight pre-specified endpoints evaluating protocol implementation and safety. We screened a total of 956 participants between 1 September 2019 and 26 January 2021, with data from 210 participants included in the analysis. Median (IQR [range]) time-weighted average intra-operative Fi O2 was 0.30 (0.26-0.35 [0.20-0.59]) and 0.47 (0.44-0.51 [0.37-0.68]) for restricted and standard care, respectively (mean difference (95%CI) 0.17 (0.14-0.20), p < 0.001). Median time-weighted average intra-operative Fi O2 was 0.83 (0.80-0.85 [0.70-0.91]) for liberal oxygen therapy (mean difference (95%CI) compared with standard care 0.36 (0.33-0.39), p < 0.001). All feasibility endpoints were met. There were no significant patient adverse events. These data support the feasibility of proceeding with the HOT-ROX trial without major protocol modifications.

Ease and comfort of pre-oxygenation with high-flow nasal oxygen cannulae vs. facemask: a randomised controlled trial.

The Difficult Airway Society recommends that all patients should be pre-oxygenated before the induction of general anaesthesia, but this may not always be easy or comfortable and anaesthesia may often be induced without full pre-oxygenation. We tested the hypothesis that high-flow nasal oxygen cannulae would be easier and more comfortable than facemasks for pre-oxygenation. We randomly allocated 199 patients undergoing elective surgery aged ≥ 10 years to pre-oxygenation using either high-flow nasal oxygen or facemask. Ease and comfort were assessed by anaesthetists and patients on 10-cm visual analogue scale and six-point smiley face scale, respectively. Secondary endpoints included end-tidal oxygen fraction after securing a definitive airway and time to secure an airway. A mean difference (95%CI) between groups in ratings of -0.76 (-1.25 to -0.27) cm for ease of use (p = 0.003) and -0.45 (-0.75 to -0.13) points for comfort (p = 0.006), both favoured high-flow nasal oxygen. A mean difference (95%CI) between groups in end-tidal oxygen fraction of 3.89% (2.41-5.37%) after securing a definitive airway also favoured high-flow nasal oxygen (p < 0.001). There was no significant difference between groups in the number of patients with hypoxaemia (Sp O2 < 90%) or severe hypoxaemia (Sp O2 < 85%) lasting ≥ 1 min or ≥ 2 min; in the proportion of patients with an end-tidal oxygen fraction < 87% in the first 5 min after tracheal intubation (52.2% vs. 58.9% in facemask and high-flow nasal oxygen groups, respectively; p = 0.31); or in time taken to secure an airway (11.6 vs. 12.2 min in facemask and high-flow nasal oxygen groups, respectively; p = 0.65). In conclusion, we found pre-oxygenation with high-flow nasal oxygen to be easier for anaesthetists and more comfortable for patients than pre-oxygenation with a facemask, with no clinically relevant differences in end-tidal oxygen fraction after securing a definitive airway or time to secure an airway. The differences in ease and comfort were modest.

A retrospective audit of postoperative days alive and out of hospital, including before and after implementation of the WHO surgical safety checklist.

We implemented the World Health Organization surgical safety checklist at Auckland City Hospital from November 2007. We hypothesised that the checklist would reduce postoperative mortality and increase days alive and out of hospital, both measured to 90 postoperative days. We compared outcomes for cohorts who had surgery during 18-month periods before vs. after checklist implementation. We also analysed outcomes during 9 years that included these periods (July 2004-December 2013). We analysed 9475 patients in the 18-month period before the checklist and 10,589 afterwards. We analysed 57,577 patients who had surgery from 2004 to 2013. Mean number of days alive and out of hospital (95%CI) in the cohort after checklist implementation was 1.0 (0.4-1.6) days longer than in the cohort preceding implementation, p < 0.001. Ninety-day mortality was 395/9475 (4%) and 362/10,589 (3%) in the cohorts before and after checklist implementation, multivariable odds ratio (95%CI) 0.93 (0.80-1.09), p = 0.4. The cohort changes in these outcomes were indistinguishable from longer-term trends in mortality and days alive and out of hospital observed during 9 years, as determined by Bayesian changepoint analysis. Postoperative mortality to 90 days was 228/5686 (4.0%) for Maori and 2047/51,921 (3.9%) for non-Maori, multivariable odds ratio (95%CI) 0.85 (0.73-0.99), p = 0.04. Maori spent on average (95%CI) 1.1 (0.5-1.7) fewer days alive and out of hospital than non-Maori, p < 0.001. In conclusion, our patients experienced improving postoperative outcomes from 2004 to 2013, including the periods before and after implementation of the surgical checklist. Maori patients had worse outcomes than non-Maori.

Haemodynamic profiles of etomidate vs propofol for induction of anaesthesia: a randomised controlled trial in patients undergoing cardiac surgery.

BACKGROUND: Etomidate is frequently selected over propofol for induction of anaesthesia because of a putatively favourable haemodynamic profile, but data confirming this perception are limited. METHODS: Patients undergoing cardiac surgery were randomised to induction of anaesthesia with propofol or etomidate. Phase I (n=75) was conducted as open-label, whereas Phase II (n=75) was double blind. Mean arterial blood pressure (MAP) and boluses of vasopressor administered after induction were recorded. The primary endpoint was the area under the curve below baseline MAP (MAP-time integral) during the 10 min after induction. Secondary endpoints were the use of vasopressors over the same period, and the effect of blinding on the aforementioned endpoints. Groups were compared using regression models with phase and anaesthetist as factors. RESULTS: The mean difference between etomidate and propofol in the MAP-time integral below baseline was 2244 mm Hg s (95% confidence interval, 581-3906; P=0.009), representing a 34% greater reduction with propofol. Overall, vasopressors were used in 10/75 patients in the etomidate group vs 21/75 in the propofol group (P=0.38), and in 20/74 patients during the blinded phase vs 11/76 during the open-label phase (P=0.31). The interaction between randomisation and phase (open-labelled or blinded) was not significant for either primary (P=0.73) or secondary endpoints (P=0.90). CONCLUSIONS: Propofol caused a 34% greater reduction in MAP-time integral from baseline after induction of anaesthesia than etomidate, despite more frequent use of vasopressors with propofol, confirming the superior haemodynamic profile of etomidate in this context. The proportion of patients receiving vasopressors increased slightly, albeit not significantly, in both groups in the blinded phase. CLINICAL TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, ACTRN12614000717651.

Observations on the estrogenic activity and concentration of 17beta-estradiol in the discharges of 12 wastewater treatment plants in southern australia.

There is very little information on the overall level of estrogenic activity, or concentrations of specific hormonal compounds in wastewater treatment plant (WWTP) discharges in Australia, compared with Europe, Japan, and North America. To partly address this, in 2004, water samples were collected as "grab" or "spot" samples from 12 WWTP facilities across southern Victoria at the point at which effluent enters the environment, either as recycled water or direct discharge to the receiving water. The WWTPs were of a variety of treatment types and served a diverse range of rural and regional municipalities. For instance, of the 12 WWTPs, 3 served municipalities with populations greater than 100,000, 4 with populations between 20,000 and 100,000, and 5 with populations less than 5,000. The principal treatment process in six was an activated sludge system, and three were trickle-filter-based systems. The remaining plants fall into a "miscellaneous" category, each plant having a mixture of treatment processes within the overall systems. The estrogenic activity and 17beta-estradiol concentrations of the samples were assessed using a yeast-based, in vitro reporter gene assay and enzyme-linked immunosorbant assays, respectively. Most of the effluents showed estrogenic activity in the assays (hER, no response: 7.9 ng/L EEQ; mER, no response: 44.5 ng/L EEQ). There was no correlation between estrogenic response and the results of a concurrent toxicity assay, suggesting that a lack of bioassay response was related to lack of estrogenic compounds, rather than the direct toxic effect of the sample. Estradiol concentrations were for the most part in the range 2-5 ng/L, with one sample at 18 ng/L. Despite the assurance our results might provide (of minimal impact in most cases if there is significant dilution), there is still a need for further extensive on-ground reassurance research to provide data for higher-level risk assessment by industry and government agencies. In particular, more research is warranted to verify the estrogenic activity and to expand the range of specific hormone/metabolites reported in these studies. Moreover, studies are required to determine if the estrogenic activity reported in this and other recent Australian studies is sufficient to induce a physiological effect in exposed aquatic organisms, especially Australian native fish.

Hepatic xenobiotic metabolism of cylindrospermopsin in vivo in the mouse.

Cylindrospermopsin (CYN) is a hepatotoxin isolated from the blue-green alga Cylindrospermopsis raciborskii. The role of both glutathione (GSH) and the cytochrome P450 enzyme system (P450) in the mechanism of toxicity of CYN has been previously investigated in in vitro systems. We have investigated the role of GSH and P450 in vivo in mice. Mice pre-treated with buthionine sulphoximine and diethyl maleate to deplete hepatic GSH prior to dosing with 0.2mg/kg CYN showed a seven-day survival rate of 5/13 while the control group rate was 9/14. Dosing mice with 0.2mg/kg CYN produced a small decrease in hepatic GSH with a characteristic rebound effect at 24h. The magnitude of this effect is however small and combined with the non-significant difference in survival rates after GSH depletion suggest depletion of GSH by CYN could not be a primary mechanism for CYN toxicity. Conversely, pre-treatment with piperonyl butoxide, a P450 inhibitor, protected mice against CYN toxicity giving a survival rate of 10/10 compared with 4/10 in the control group (p < 0.05 Chi squared) and was protective at doses up to 0.8 mg/kg, suggesting activation of CYN by P450 is of primary importance in the mechanism of action.

A Phase II trial of cisplatin plus WR-2721 (amifostine) for metastatic breast carcinoma: an Eastern Cooperative Oncology Group Study (E8188).

BACKGROUND: Cisplatin has minimal antitumor activity when used as second- or third-line treatment of metastatic breast carcinoma. Older reports suggest an objective response rate of 8% when 60-120 mg/m2 of cisplatin is administered every 3-4 weeks. Although a dose-response effect has been observed with cisplatin, the dose-limiting toxicities associated with cisplatin (e.g., nephrotoxicity, ototoxicity, and neurotoxicity) have limited its use as a treatment for breast carcinoma. WR-2721 or amifostine initially was developed to protect military personnel in the event of nuclear war. Amifostine subsequently was shown to protect normal tissues from the toxic effects of alkylating agents and cisplatin without decreasing the antitumor effect of the chemotherapy. Early trials of cisplatin and amifostine also suggested that the incidence and severity of cisplatin-induced nephrotoxicity, ototoxicity, and neuropathy were reduced. METHODS: A Phase II study of the combination of cisplatin plus amifostine was conducted in patients with progressive metastatic breast carcinoma who had received one, but not more than one, chemotherapy regimen for metastatic disease. Patients received amifostine, 910 mg/m2 intravenously over 15 minutes. After completion of the amifostine infusion, cisplatin 120 mg/m2 was administered over 30 minutes. Intravenous hydration and mannitol was administered before and after cisplatin. Treatment was administered every 3 weeks until disease progression. RESULTS: Forty-four patients were enrolled in the study of which 7 (16%) were ineligible. A median of 2 cycles of therapy was administered to the 37 eligible patients. Six partial responses were observed for an overall response rate of 16%. Most patients (57%) stopped treatment because of disease progression. Neurologic toxicity was reported in 52% of patients. Seven different life-threatening toxicities were observed in patients while receiving treatment. CONCLUSIONS: The combination of cisplatin and amifostine in this study resulted in an overall response rate of 16%. Neither a tumor-protective effect nor reduced toxicity to normal tissues was observed with the addition of amifostine to cisplatin in this trial.

A sensitive and specific assay for glutathione with potential application to glutathione disulphide, using high-performance liquid chromatography-tandem mass spectrometry.

We have utilised the combination of sensitivity and specificity afforded by coupling high-performance liquid chromatography (HPLC) to a tandem mass spectrometer (MS-MS) to produce an assay which is suitable for assaying glutathione (GSH) concentrations in liver tissue. The sensitivity suggests it may also be suitable for extrahepatic tissues. The method has been validated for GSH using mouse liver samples and also allows the assay of GSSG. The stability of GSH under conditions relevant to the assay has been determined. A 20-microl amount of a diluted methanol extract of tissue is injected with detection limits of 0.2 pmol for GSH and 2 pmol for GSSG. The HPLC uses an Altima C18 (150 x 4.6 mm, 5 microm) column at 35 degrees C. Chromatography utilises a linear gradient from 0 to 10% methanol in 0.1% formic acid over 5 min, with a final isocratic stage holding at 10% methanol for 5 min. Total flow rate is 0.8 ml/min. The transition from the M+H ion (308.1 m/z for GSH, and 613.3 m/z for GSSG) to the 162.0 m/z (GSH) and 355.3 m/z (GSSG) fragments are monitored.

Relationships between non-occupational cadmium exposure and expression of nine cytochrome P450 forms in human liver and kidney cortex samples.

This study was undertaken to assess associations between age, gender, cigarette smoke and non-workplace cadmium exposure, and liver pathology and inter-individual variation in cytochrome P450 (CYP) expression in human tissues. Autopsy specimens of twenty-eight Queensland residents whose ages ranged from 3 to 89 years were analyzed for the presence of nine CYP protein isoforms by immunoblotting. All subjects were Caucasians and their liver cadmium contents ranged from 0.11 to 3.95 microg/g wet weight, while their kidney cadmium contents were in the range of 2 to 63 microg/g wet weight. CYP1A2, CYP2A6, CYP2D6, CYP3A4, and CYP3A5 were detected in liver but not in kidney, and CYP1A1 and CYP1B1 were not found in liver or kidney. Lowered liver CYP2C8/19 protein contents were found to be associated with liver pathology. Importantly, we show elevated levels of CYP2C9 protein to be associated with cadmium accumulation in liver. No mechanism that explains this association is apparent, but there are two possibilities that require further study. One is that variation in CYP2C9 protein levels may be, in part, attributed to an individual's non-workplace exposure to cadmium, or an individual's CYP2C9 genotype may be a risk factor for cadmium accumulation. A positive correlation was found between liver CYP3A4 protein and subject age. Levels of liver CYP1A2 protein, but not other CYP forms, were increased in people more exposed to cigarette smoke, but there was no association between CYP1A2 protein and cadmium. CYP2A6 protein was found in all liver samples and CYP2A6 gene typing indicated the absence of CYP2A6 null allele (CYP2A6(D)) in this sample group, confirming very low prevalence of homozygous CYP2A6(D) in Caucasians. CYP2A6 gene types W/W, W/C, and C/C were not associated with variations in liver microsomal CYP2A6 protein. CYP2D6 protein was absent in all twenty-five kidney samples tested but was detectable in liver samples of all but two subjects, indicating the prevalence of the CYP2D6 null allele (CYP2D6(D)) in this sample group to be about 7%, typical of Caucasian populations.

Reversibility of the chronic effects of di(2-ethylhexyl)phthalate.

Fischer-344 rats treated with 12,500 ppm (728 and 879 mg/kg/d for male and females, respectively) and B6C3F1 mice treated with 6,000 ppm (1,227 and 1,408 mg/kg/d, respectively) di(2-ethylhexyl)phthalate (DEHP) in the diet for 78 weeks were allowed to recover for an additional 26 weeks on control diet. Blood was analyzed at weeks 78 and 104 from 10 animals per sex per group; animals were sacrificed at weeks 79 and 105 for histopathologic examination. The results are compared with data from animals continuously exposed to these dietary levels for 104 weeks (10, 11). Body weights and food consumption were measured monthly. BUN, albumin, and globulin that were significantly different for rats exposed to DEHP throughout 104 weeks, were comparable to controls for the recovery group. Reversibility of chronic effects on erythrocyte count, hemoglobin, and hematocrit values was apparent only for female rats. Chronic exposure demonstrated effects on liver, kidney, and testes weights. All organ weight effects except for testes for the Recovery group of rats, and all organ weight effects for mice, were reversible. Pigmentation of Kupffer cells and renal tubules present in chronically treated rats were not observed for the Recovery group. Lesions in the testes and pituitary gland were not reversible in rats. This may be a reflection of the senescence of the hypothalamic-gonad axis in rats. Cessation of exposure for mice resulted in amelioration of effects in the kidneys, liver, and testes. The extent of reversibility suggests that many chronic effects may be associated with a metabolic phenomenon such as peroxisome proliferation, which also reverted to control levels after 26 weeks of recovery.

Changes in zinc and copper homeostasis in human livers and kidneys associated with exposure to environmental cadmium.

This study was undertaken to assess changes in zinc and copper homeostasis in human tissues that could be attributed to human exposure to environmental cadmium, using samples of lung, liver and kidney cortex of 61 Queensland residents, aged 2 to 89 years, who had died of accidental causes. None of the subjects were exposed to cadmium in the workplace. Levels of zinc in liver and kidney cortex samples showed inverse associations with donor age whereas zinc in lung only showed inverse association with gender. Lung zinc levels in females were 14% lower than in males. Zinc in liver and kidney cortex samples were found to exist in at least two pools; one was associated with cadmium that bound to metallothionein (MT) and the other was associated with non-MT bound copper. In liver, the amounts of zinc in the MT pool were smaller compared to those in non-MT pool given that only 7% of zinc variations were explained by cadmium whereas 22% of the liver zinc variations were accounted for by non-MT bound copper. In sharp contrast, larger amounts of zinc in kidney cortex samples were in the MT pool, compared to those in the non-MT pool given that cadmium was found to explain 69% of total zinc variation whereas copper explained only 17% of kidney zinc variations. The levels of copper in liver were found to be increased by 45-50% in subjects with high cadmium exposure level, compared to subjects of similar ages with medium exposure level. The levels of zinc and copper in kidney cortex samples in the subjects with high cadmium exposure were both found to be significantly elevated compared to those found in the medium-exposure group whereas copper contents were about 19-23% greater than in medium- as well as low-exposure groups. Taken together these results indicate increased sequestration of zinc and copper in liver and kidney cortex samples. The increases in metal sequestrations were observed in liver samples having cadmium contents of greater than 1 microg/g wet weight and in kidney cortex having cadmium contents of greater than 26 microg/g wet weight. Zinc and copper contents in lung of this sample group, however, were not associated with cadmium due probably to lower exposure levels compared to those of liver and kidney.

Chronic toxicity of di(2-ethylhexyl)phthalate in mice.

B6C3F1 mice were treated with 0, 100, 500, 1500, or 6000 ppm di(2-ethylhexyl)phthalate (DEHP) in the diet for up to 104 weeks. Blood and urine were analyzed at Weeks 26, 52, 78, and 104 from 10 animals per sex per group. Body weights and food consumption were measured weekly for the first 16 weeks, then monthly thereafter. Survival was reduced for mice receiving 6000 ppm DEHP. Overall weight gains were significantly lower for the 6000-ppm male group, but there was no difference among female groups. Food consumption was not affected by exposure. No biologically significant changes in clinical chemistry, hematology, or urinalysis were observed. After 104 weeks of exposure, kidney weights for the 500- and 1500-ppm male, and 6000-ppm male/female groups were significantly lower than for the controls. Significantly higher liver weight was seen for the 500-, 1500-, and 6000-ppm male groups and the 6000-ppm female group of mice. Testis weights for the 500-, 1500-, and 6000-ppm males were significantly lower than for the controls. Uterine weights for the 6000-ppm group were significantly lower than for the controls. All organs were examined for histopathology. The incidence of hepatocellular lesions has been reported separately (R. M. David et al., 1999. Toxicol. Sci. 50, 195-205). Tumors were observed at > or = 500-ppm dosages, where peroxisome proliferation was significantly increased. A NOEL for both tumors and peroxisome proliferation was 100 ppm. In the study presented here, bilateral hypospermia in the testes of male mice, hepatocyte pigmentation and cytoplasmic eosinophilia in the liver, and chronic progressive nephropathy of male and female mice were observed at 6000 ppm. Hypospermia and chronic progressive nephropathy were also observed at 1500 ppm, where peroxisome proliferation was 2.7-6.8-fold higher than controls. Many lesions observed in rats were not seen in mice. A dose level of 500 ppm (98.5-116.8 mg/kg/day) was identified as a no-observed-adverse-effect level (NOAEL) for noncarcinogenic effects.

Progestin effects on long-term growth, death, and Bcl-xL in breast cancer cells.

The effect of progestins on proliferation of breast cancer has been a controversial area. We have consistently reported progestin stimulation of proliferation in the progesterone receptor-rich human breast cancer cell line T47D. Other authors, under other conditions, have agreed that progestins stimulate, but for just one turn of the cell cycle. To our knowledge, this is the first in vitro report to show progestin stimulation of human breast cancer cell growth for multiple, probably unlimited, cell cycles, while control cells are dying. This is accompanied by progestin up-regulation of the antiapoptotic protein bcl-xL, no effect on the proapoptotic protein bax, and, surprisingly, diminution of the antiapoptotic protein bcl-2. Thus, progestins both serve as survival factors and stimulate proliferation, implying a possible similar role in breast cancer patients. The data support the notion that many patients may benefit more from combined antiprogestin-antiestrogen therapy than from antiestrogen alone, and suggest bcl-x(L) as a possible target for breast cancer therapy.

Evidence for a synergistic interaction between cadmium and endotoxin toxicity and for nitric oxide and cadmium displacement of metals in the kidney.

This study was undertaken to examine changes in Zn and Cu homeostasis in the liver and kidney of rats caused by cadmium (Cd) or lipopolysaccharide (LPS) administration. Twenty-five male, 7- to 8-week-old Wistar rats were divided into five groups: saline only treatment, saline treatment and food deprivation, exposure to a single dose of Cd, exposure to LPS alone, and exposure to Cd + LPS. Changes in plasma nitrate concentrations and hepatic and renal Zn and Cu contents were measured together with urinary excretion rates for the metals and nitrate on 3 consecutive days: 24 h before treatment and 24 and 48 h after treatments. Cd exposure alone for 48 h caused a nearly 2-fold increase in plasma nitrate levels with no changes in urinary nitrate excretion whereas LPS treatment caused plasma nitrate levels to increase by 10-fold and urinary nitrate excretion to increase by 4-fold. Administration of LPS 24 h after Cd exposure caused a 10-fold increase in plasma nitrate concentrations and a 100-fold increase in urinary nitrate excretion compared to the rates prior to LPS administration. These results indicate a synergistic interaction between Cd and LPS toxicity. Cd exposure also caused a marked increase in hepatic Zn levels, but LPS did not cause any changes in hepatic Zn or Cu content. In sharp contrast, both Zn and Cu contents were decreased in the kidneys by 16 and 36% in animals exposed to Cd or LPS. A correlation analysis of measured variables reveals that renal Cu contents were inversely associated with plasma nitrate concentrations while urinary Cu excretion on day 3 showed a strong positive correlation with both urinary nitrate and Cd excretions on the same day. A linear regression analysis shows 20% of the variation in urinary Cu excretion was associated with urinary Cd excretion on the same day. It is concluded that reductions in renal Cu contents caused by Cd or LPS administration may be a result of Cd and NO displacement of Cu previously bound to metallothionein.

Chronic toxicity of di(2-ethylhexyl)phthalate in rats.

Fischer 344 rats were treated with 0, 100, 500, 2500, or 12,500 ppm di(2-ethylhexyl)phthalate (DEHP) in the diet for up to 104 weeks. Blood and urine were analyzed at weeks 26, 52, 78, and 104 from 10 animals per sex per group. Survival was slightly but not statistically reduced for rats receiving 12,500 ppm DEHP. Body weights and food consumption were significantly reduced for rats receiving the highest dose level of DEHP and occasionally for the male 2500-ppm group. BUN and albumin were significantly higher and globulin lower at nearly every sampling interval for the 12,500-ppm group compared with the controls. There was an increase in the mean activities of AST and ALT at 104 weeks, but no statistically significant differences were seen. Erythrocyte count, hemoglobin, and hematocrit values for the 12,500-ppm group were significantly lower than controls at nearly every sampling interval. No other differences in hematology were seen. No toxicologically significant changes were observed in urinalysis. At termination, relative lung weights for the 2500- and 12,500-ppm male groups of rats were significantly higher than for the controls. Absolute and relative liver and kidney weights for the 2500- and 12,500-ppm male rats, and liver weights for 12,500-ppm female rats were higher compared with the controls. Absolute and relative testes weights for the 12, 500-ppm male rats were lower compared with the controls. All organs were examined for histopathology. The incidence of hepatocellular lesions has been reported separately and correlated with the induction of peroxisomal enzyme activity (David et al., 1999). A dose level of 500 ppm was the NOEL for peroxisome proliferation. Bilateral aspermatogenesis in the testes, castration cells in the pituitary gland, spongiosis hepatis, and pancreatic acinar cell adenoma were observed for 12,500-ppm male rats. Aspermatogenesis and spongiosis hepatis were observed for 2500-ppm male rats, and aspermatogenesis was seen at 500 ppm. DEHP exposure exacerbated age-, species- or strain-related lesions such as mineralization of the renal papilla and chronic progressive nephropathy in male rats. Kupffer cell pigmentation and renal tubule pigmentation were seen in male and female 12,500-ppm rats. The increased incidence of spongiosis hepatis correlated with increased palmitoyl CoA oxidase activity, but the incidence of pancreatic acinar cell adenoma was increased only at the highest dose level of 12,500 ppm. These lesions, although typical of those seen with other peroxisome proliferators, may respond differently depending on the potency of the peroxisome proliferator. A dose level of 500 ppm (28.9-36.1 mg/kg/day) was considered to be the NOAEL.

Safe levels of cadmium intake to prevent renal toxicity in human subjects.

The present review attempts to provide an update of the scientific knowledge on the renal toxicity which occurs in human subjects as a result of chronic ingestion of low-level dietary Cd. It highlights important features of Cd toxicology and sources of uncertainty in the assessment of health risk due to dietary Cd. It also discusses potential mechanisms for increased susceptibility to Cd toxicity in individuals with diabetes. Exposure assessment on the basis of Cd levels in foodstuffs reveals that vegetables and cereals are the main sources of dietary Cd, although Cd is also found in meat, albeit to a lesser extent. Cd accumulates particularly in the kidney and liver, and hence offal contains relatively high amounts. Fish contains only small quantities of Cd, while crustaceans and molluscs may accumulate larger amounts from the aquatic environment. Data on Cd accumulation in human kidney and liver obtained from autopsy studies are presented, along with results of epidemiological studies showing the relationship between renal tubular dysfunction and kidney Cd burden. These findings suggest that a kidney Cd level of 50 microg/g wet weight is a maximum tolerable level in order to avoid abnormal kidney function. This renal Cd burden corresponds to a urinary Cd excretion of 2 microg/d. Accordingly, safe daily levels of Cd intake should be kept below 30 microg per person. Individual variations in Cd absorption and sensitivity to toxicity predicts that a dietary Cd intake of 30 microg/d may result in a slight renal dysfunction in about 1% of the adult population. The previous guideline for a maximum recommended Cd intake of 1 microg/kg body weight per d is thus shown to be too high to ensure that renal dysfunction does not occur as a result of dietary Cd intake.

Chronic peroxisome proliferation and hepatomegaly associated with the hepatocellular tumorigenesis of di(2-ethylhexyl)phthalate and the effects of recovery.

This study compared the levels of cell proliferation and peroxisome proliferation in rodent liver with tumor incidence, to provide more information on the relationship between these events following chronic exposure. Fischer 344 rats were treated with 0, 100, 500, 2500, or 12,500 ppm DEHP, and B6C3F1 mice were treated with 0, 100, 500, 1500, or 6000 ppm DEHP in the diet for up to 104 weeks. Additional groups of rats and mice received the highest concentration for 78 weeks and then the control diet for an additional 26 weeks (recovery groups). Animals were terminated at weeks 79 and 105 for histopathologic examination. Elevated palmitoyl CoA oxidation activity and higher liver-to-body weight ratios were observed for the 2500- and 12,500-ppm groups of rats, and for the 500-, 1500-, and 6000-ppm groups of mice at Week 105. No increase in palmitoyl CoA oxidation activity was evident in the recovery group, and relative liver weights were near control levels following recovery. No hepatic cell proliferation was detected at Weeks 79 or 105 in either species although preliminary data indicated that cell proliferation did occur within the first 13 weeks of exposure. A significantly higher incidence of hepatocellular tumors was only observed for the 2500- and 12,500-ppm group and its recovery group of rats, and for the 500-, 1500-, and 6000-ppm groups and the recovery group of mice. The tumor incidences were reduced for the recovery groups compared with the groups fed DEHP continuously for 104 weeks. The data indicate that high levels of peroxisome proliferation and hepatomegaly are associated with DEHP hepatocarcinogenesis in rodent liver, and that the tumorigenic process may be arrested by cessation of DEHP treatment, suggesting that extended treatment with DEHP acts to promote tumor growth.

Unique toxic peptides isolated from sawfly larvae in three continents.

D-Amino acid containing peptides have been found to be responsible for sawfly larvae poisoning in many parts of the world. These compounds, unique in the animal kingdom, were isolated from three different species of sawfly indigenous to Australia, Denmark and South America. The octapeptide, lophyrotomin, is the major toxin in the Australian and Danish species and is present in small amounts in the South American sawfly. Pergidin, the main toxin in the South American sawfly, is a heptapeptide containing a phosphoseryl residue. This, as far as we are aware, is the first example of such a peptide to be isolated from an animal source. Small amounts of pergidin have been found in the other two species. All available evidence suggests that both peptides are biosynthesised 'de novo' possibly as a protective device, however it cannot be excluded that microorganisms may be responsible. These compounds are stable to enzymatic breakdown because of their configuration and their strong chemical bonding and lipophilic character provide a potential for residues to remain in the host animal and cause significant changes.

The use of controlled-release oxycodone for the treatment of chronic cancer pain: a randomized, double-blind study.

To compare the effectiveness and safety of controlled-release (CR) oxycodone tablets with immediate-release (IR) oxycodone in patients with chronic cancer pain, a multicenter, randomized, double-blind, parallel-group study was performed in 111 patients with cancer pain. Patients were treated with 6 to 12 tablets or capsules of fixed-combination opioid/nonopioid analgesics per day at study entry. Patients received 30 mg of CR oxycodone tablets every 12 hr or 15 mg of IR oxycodone four times daily for 5 days. No titration or supplemental analgesic medications were permitted. The mean (+/- SE) baseline pain intensity (0 = none, 1 = slight, 2 = moderate, 3 = severe) was 1.5 +/- 0.1 for the CR oxycodone-treated group and 1.3 +/- 0.1 for the group given IR oxycodone (P > 0.05). The 5-day mean pain intensity was 1.4 +/- 0.1 and 1.1 +/- 0.1 for the CR and IR groups, respectively (P > 0.05). Discontinuation rates were equivalent (33%). There was no significant difference between treatment groups in the incidence of adverse events. This study demonstrates that cancer pain patients given 6 to 12 tablets or capsules of fixed-dose combination analgesics can be equally well treated with CR oxycodone administered every 12 hr or IR oxycodone four times daily at the same total daily dose. CR oxycodone offers the benefits of twice daily dosing.

H-ras activation is an early event in the ptaquiloside-induced carcinogenesis: comparison of acute and chronic toxicity in rats.

Bracken fern (Pteridium spp.) produces cancer of the urinary bladder and oesophagus in grazing animals and is a suspected human carcinogen. The carcinogenic principle ptaquiloside (PT), when activated to a dienone (APT), forms DNA adducts which eventually leads to tumor. Two groups of female Sprague-Dawley rats were given a chronic dose of 3 mg APT weekly for 10 weeks either by intravenous (i.v.) tail vein or by intragastric (i.g.) route. A third group was given a weekly dose of 6 mg of APT for 3 weeks by the i.g. route corresponding to acute dosing. Both chronic i.v. and i.g. dosed animals showed ischemic tubular necrosis in the kidney but only i.v. dosed animals developed adenocarcinomas of the mammary glands. Acutely dosed i.g. animals produced apoptotic bodies in the liver, necrosis of blood cell precursors in the bone marrow and ischemic tubular necrosis in the kidney but they did not develop tumors. No mutations were found in the H-ras and p53 genes in the mammary glands of either the i.g. rats or the tumor-bearing i.v. rats. However, the mammary glands of a fourth group of rats, which received APT by i.v. and killed before tumor development, carried Pu to Pu and Pu to Py double mutations in codons 58 and 59 of H-ras. This study indicates that the route of administration plays a role in the nature of the disease expression from ptaquiloside exposure. In addition to confirming the role of APT in the PT-induced carcinogenesis our finding suggests that activation of H-ras is an early event in the PT-carcinogenesis model.