Standardizing assessment of adverse effects in rheumatology clinical trials. Status of OMERACT Toxicity Working Group March 2000: Towards a common understanding of comparative toxicity/safety profiles for antirheumatic therapies

This paper describes the background and current status of an OMERACT facilitated effort to improve the consistency of adverse event reporting in rheumatology clinical trials, The overall goal is the development of an adverse event assessment tool that would provide a basis for use of common terminology and improve the consistency of reporting severity of side effects within rheumatology clinical trials and during postmarketing surveillance. The resulting Rheumatology Common Toxicity Criteria Index encompassed the following organ systems: allergic/immunologic, cardiac, ENT, gastrointestinal, musculoskeletal, neuropsychiatric, ophthalmologic, pulmonary and skin/integument. Before this tool is widely accepted, its validity, consistency, and feasibility need to be assessed in clinical trials.

Patient based method of assessing adverse events in clinical trials in rheumatology: the revised Stanford Toxicity Index

We describe the progress towards developing a patient rated toxicity index that meets all of the patient-important attributes defined by the OMERACT Drug Safety Working Party, These attributes are frequency, severity. importance to patient, importance to the clinician, impact on economics, impact on activities, and integration of adverse effects with benefits. The Stanford Toxicity Index (STI) has been revised to collect all attributes with the exception of impact on activities. However, since the STI is a part of the Health Assessment Questionnaire (HAQ). impact on activities is collected by the HAQ. In particular, a new question asks patients to rate overall satisfaction, taking into consideration both benefits and adverse effects. The nest step in the development of this tool is to ensure that the STI meets the OMERACT filter of truth, discrimination, and feasibility. Although truth and feasibility have been confirmed by comparisons within the ARAMIS database, discrimination needs to be assessed in clinical trials.

Toxicity and uptake mechanism of cylindrospermopsin and lophyrotomin in primary rat hepatocytes

The toxicities and uptake mechanisms of two hepatotoxins, namely cylindrospermopsin and lophyrotomin, were investigated on primary rat hepatocytes by using microcystin-LIZ (a well-known hepatotoxin produced by cyanobacteria) as a comparison. Isolated rat hepatocytes were incubated with different concentrations of hepatotoxins for 0, 24, 48 and 72 h. The cell viability was assayed by the tetrazolium-based (MTT) assay. Microcystin-LR, cylindrospermopsin and lophyrotomin all exhibited toxic effects on the primary rat hepatocytes with 72-h LC50 of 8, 40 and 560 ng/ml, respectively. The involvement of the bile acid transport system in the hepatotoxin-induced toxicities was tested in the presence of two bile acids, cholate and taurocholate. Results showed that the bile acid transport system was responsible for the uptake, and facilitated the subsequent toxicities of lophyrotomin on hepatocytes. This occurred to a much lesser extent with cylindrospermopsin. With its smaller molecular weight, passive diffusion might be one of the possible mechanisms for cylindrospermopsin uptake into hepatocytes. This was supported by incubating a permanent cell line, KB (devoid of bile acid transport system), with cylindrospermopsin which showed cytotoxic effects. No inhibition of protein phosphatase 2A by cylindrospermopsin or lophyrotomin was found. This indicated that other toxic mechanisms besides protein phosphatase inhibition were producing the toxicities of cylindrospermopsin and lophyrotomin, and that they were unlikely to be potential tumor promoters. (C) 2001 Elsevier Science Ltd. All rights reserved.

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 - MTbound 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 mug/g wet weight and in kidney cortex having cadmium contents of greater than 26 mug/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.

Adaptation to chronic eccentric exercise in humans: the influence of contraction velocity

We compared changes in muscle fibre composition and muscle strength indices following a 10 week isokinetic resistance training programme consisting of fast (3.14 rad(.)s(-1)) or slow (0.52 rad(.)s(-1)) velocity eccentric muscle contractions. A group of 20 non-resistance trained subjects were assigned to a FAST (n = 7), SLOW (n = 6) or non-training CONTROL (n = 7) group. A unilateral training protocol targeted the elbow flexor muscle group and consisted of 24 maximal eccentric isokinetic contractions (four sets of six repetitions) performed three times a week for 10 weeks. Muscle biopsy samples were obtained from the belly of the biceps brachii. Isometric torque and concentric and eccentric torque at 0.52 and 3.14 rad(.)s(-1) were examined at 0, 5 and 10 weeks. After 10 weeks, the FAST group demonstrated significant [mean (SEM)] increases in eccentric [29.6 (6.4)%] and concentric torque [27.4 (7.3) %] at 3.14 rad(.)s(-1), isometric torque [21.3 (4.3)%] and eccentric torque [25.2 (7.2) %] at 0.52 rad(.)s(-1). The percentage of type I fibres in the FAST group decreased from [53.8 (6.6)% to 39.1 (4.4)%] while type lib fibre percentage increased from [5.8 (1.9)% to 12.9 (3.3)%; P < 0.05]. In contrast. the SLOW group did not experience significant changes in muscle fibre type or muscle torque. We conclude that neuromuscular adaptations to eccentric training stimuli may be influenced by differences in the ability to cope with chronic exposure to relatively fast and slow eccentric contraction velocities. Possible mechanisms include greater cumulative damage to contractile tissues or stress induced by slow eccentric muscle contractions.

Ataxia-telangiectasia: chronic activation of damage-responsive functions is reduced by alpha-lipoic acid

Cells from patients with the genetic disorder ataxia-telangiectasia (A-T) are hypersensitive to ionizing radiation and radiomimetic agents, both of which generate reactive oxygen species capable of causing oxidative damage to DNA and other macromolecules. We describe in A-T cells constitutive activation of pathways that normally respond to genotoxic stress, Basal levels of p53 and p21(WAF1/CIP1), phosphorylation on serine 15 of p53, and the Tyr15-phosphorylated form of cdc2 are chronically elevated in these cells. Treatment of A-T cells with the antioxidant alpha -lipoic acid significantly reduced the levels of these proteins, pointing to the involvement of reactive oxygen species in their chronic activation. These findings suggest that the absence of functional ATM results in a mild but continuous state of oxidative stress, which could account for several features of the pleiotropic phenotype of A-T.

Reversal of cardiovascular remodelling with candesart

Cardiovascular remodelling, defined as ventricular and vascular hypertrophy together with fibrosis, characterises hypertension following inhibition of the production of the endogenous vasodilator, nitric oxide (NO). This study has determined whether the cardiovascular remodelling following chronic NO synthase inhibition can e reversed by administration of the selective angiotensin II AT(1)-receptor antagonist, candesartan. Male Wistar rats were treated with L-nitroarginine methyl ester (L-NAME, 400 mg/l in drinking water) for eight weeks and with candesartan cilexetil (2 mg/kg/day by oral gavage) for the last four weeks. L-NAME-treated rats became hypertensive with systolic blood pressure increasing from 110 +/- 4 mmHg (control) to 170 +/- 10 mmHg. Rats developed left ventricular hypertrophy (control 1.70 +/- 0.06; L-NAME 2.10 +/- 0.04 mg/kg body wt) with markedly increased deposition of perivascular and interstitial collagen. Candesartan returned blood pressure, left ventricular weights and collagen deposition to control values. Echo cardiographic assessment showed concentric hypertrophy with an increased fractional shortening; this was reversed by candesartan treatment. Heart failure was not evident. In the isolated Langendorff heart, diastolic stiffness increased in L-NAME-treated rats while the rate of increase in pressure (+dP/dt) increased after eight weeks only; candesartan reduced collagen deposition and normalised +dP/dt. In isolated left ventricular papillary muscles, the potency (negative log EC50) of noradrenaline as a positive inotropic compound was unchanged, (control 6.56 +/- 0.14); maximal increase in force before ectopic beats was reduced from 5.0 +/- 0.4 mN to 2.0 +/- 0.2 mN. Noradrenaline potency as a vasoconstrictor in thoracic aortic rings was unchanged, but maximal contraction was markedly reduced from 25.2 +/- 2.0 mN to 3.0 +/- 0.3 mN; this was partially reversed by candesartan treatment. Thus, chronic inhibition of NO production with L-NAME induces hypertension, hypertrophy and fibrosis with increased toxicity and significant decreases in vascular responses to noradrenaline. These changes were at least partially reversible by treatment with candesartan, implying a significant role of AT(1)-receptors in L-NAME-induced cardiovascular changes.

Early toxicity from preoperative radiotherapy with continuous infusion 5-fluorouracil for resectable adenocarcinoma of the rectum: A phase II trial for the Trans-Tasman Radiation Oncology Group

Purpose: To assess the toxicity and the efficacy of preoperative radiotherapy with continuous infusion 5-fluorouracil (5-FU) for locally advanced adenocarcinoma of the rectum. Methods and Materials: Eligible patients had newly diagnosed localized adenocarcinoma of the rectum within 12 cm of the anal verge, Stage T3-4, and were suitable for curative resection. Eighty-two patients were treated with radiotherapy-50.4 Gy in 28 fractions in 5.6 weeks, given concurrently with continuous infusion 5-FU, using either 96-h/week infusion at 300 mg/m(2)/day or 7-days/week infusion at 225 mg/m(2)/day. Results: The median age was 59 years (range, 27-87), and 67% of patients were male. Pretreatment stages of the rectal cancer were T3, 89% and resectable T4, 11%, with endorectal ultrasound confirmation in 67% of patients. Grade 3 acute toxicity occurred in 5 of 82 patients (6%; 95% confidence interval [CI], 2-14%). Types of surgical resection were anterior resection, 61%; abdominoperineal resection, 35%; and other procedures, 4%. There was no operative mortality. Anastomotic leakage after low anterior resection occurred in 3 of 50 patients (6%; 95% CI, 1-17%). The pathologic complete response rate was 16% (95% CI, 9-26%). Pathologic Stages T2 or less occurred in 51%. Conclusion: Preoperative radiotherapy with continuous infusion 5-FU for locally advanced rectal cancer is a safe regimen, with a significant downstaging effect. It does not seem to lead to a significant increase in serious surgical complications. (C) 2001 Elsevier Science Inc.

Effect of chronic clonidine treatment on transmitter release from sympathetic varicosities of the guinea-pig vas deferens

1 Previous studies have demonstrated that chronic pre-synaptic inhibition of transmitter release by morphine evokes a counter-adaptive response in the sympathetic nerve terminals that manifests itself as an increase in transmitter release during acute withdrawal. In the present study we examined the possibility that other pre-synaptically acting drugs such as clonidine also evoke a counter-adaptive response in the sympathetic nerve terminals. 2 In chronically saline treated (CST) preparations, clonidine (0.5 muM) completely abolished evoked transmitter release from sympathetic varicosities bathed in an extracellular calcium concentration ([Ca2+](o)) of 2 mM. The inhibitory effect of clonidine was reduced by increasing [Ca2+](o) from 2 to 4 mM and the stimulation frequency from 0.1 to 1 Hz. 3 The nerve terminal impulse (NTI) was not affected by concentrations of clonidine that completely abolished evoked transmitter release. 4 Sympathetic varicosities developed a tolerance to clonidine (0.5 muM) following 7-9 days of chronic exposure to clonidine. 5 Acute withdrawal of preparations following chronic clonidine treatment (CCT) resulted in a significant (P

Effect of chronic morphine treatment on alpha(2)-adrenoceptor mediated autoinhibition of transmitter release from sympathetic varicosities of the mouse vas deferens

1 The effect of chronic morphine treatment (CMT) on sympathetic innervation of the mouse vas deferens and on alpha (2)-adrenoceptor mediated autoinhibition has been examined using intracellular recording of excitatory junction potentials (EJPs) and histochemistry. 2 In chronically saline treated (CST) preparations. morphine (1 muM) and the alpha (2)-adrenoceptor agonist (clonidine, 1 muM) decreased the mean amplitude of EJPs evoked with 0.03 Hz stimulation by 81+/-8% (n=16) and 92+/-6% (n=7) respectively. In CMT preparations, morphine (1 muM) and clonidine (1 muM) decreased mean EJP amplitude by 68+/-8% (n = 7) and 79+/-8% (n = 7) respectively. 3 When stimulating the sympathetic axons at 0.03 Hz. the mean EJP amplitude recorded from smooth muscles acutely withdrawn from CMT was four times greater than for CST smooth muscles (40.7+/-3.8 mV, n = 7 compared with 9.9+/-0.3 mV, n = 7). 4 Part of the increase in mean EJP amplitude following CMT was produced by a 31% increase in the density of sympathetic axons and varicosities innervating the smooth muscle. 5 Results from the present study indicate that the effectiveness of alpha (2)-adrenocrptor mediated autoinhibition is only slightly reduced in CMT preparations. Most of the cross tolerance which develops between morphine, clonidine and alpha (2)-adrenoceptor mediated autoinhibition occurs as a consequence of increased efficacy of neuromuscular transmission which is produced by an increase in the probability of transmitter release and an increase in the density of sympathetic innervation.