Co-treatment with melanotan-II,a potent melanocortin,does not protect against cisplatin ototoxicity

Cisplatin, an important chemotherapeutic agent, has severe dose-limiting side effects including peripheral neurotoxicity and ototoxicity. Peripheral neurotoxicity can be delayed or prevented by simultaneous treatment with a class of neuropeptides known as melanocortins. Examples are ORG 2766, alpha-melanocyte stimulating hormone (alpha-MSH) and melanotan-II (MT-II). In albino guinea pigs, our group has found that ORG 2766 and alpha-MSH can also reduce cisplatin-induced ototoxicity. In this study we investigated the possibly protective effects of MT-II upon cisplatin ototoxicity. Guinea pigs, equipped with a permanent round-window electrode for electrocochleography, were treated with cisplatin (1.5 mg/kg/day intraperitoneal) and simultaneously with MT-II (30 or 3 microg/kg/day subcutaneous) or saline until a 40 dB suppression of the compound action potential (CAP) threshold (3 microV criterion) at 8 kHz occurred. This -40 dB criterion was reached after 5-18 days. Thereafter, the treatment was stopped, but electrocochleography was continued for another 4 weeks. The number of days in which the -40 dB criterion was reached in the MT-II co-treated group did not differ from the period in the saline group. Ten days after the end of the treatment a spontaneous recovery of the CAP was observed in all groups and at all frequencies, although it was more pronounced at lower frequencies. Also with respect to recovery, no differences were found between the saline and the MT-II co-treated group. Thus, in contrast with the otoprotective properties of other melanocortins, MT-II has no protective properties against cisplatin-induced ototoxicity, at least not with the doses applied here.     

Partial recovery of cisplatin-induced hearing loss in the albino guinea pig in relation to cisplatin dose

The objective of the present study was to further characterize cochlear recovery after cisplatin damage. We equipped albino guinea pigs with permanent round window electrodes. Cisplatin was injected i.p. on a daily basis at either 1.5 or 2.0 mg/kg/day. Treatment was stopped when the criterion of > or =40 dB loss in the compound action potential iso-response level at 8 kHz had occurred. Either shortly (1-3 days) or long (4 weeks or more) after this stop, the endocochlear potential (EP) was measured and all animals were sacrificed for histology. At a cisplatin dose of 2.0 mg/kg/day, the time needed to reach the criterion hearing loss varied from 5 to 11 days. With 1.5 mg/kg/day this period lasted longer, the cumulative dose being the first-order predictor. The cochlear potentials gradually recovered in the first 2 weeks after treatment. At the lower frequencies, recovery was often complete. At the higher frequencies complete recovery was never seen. EP was depressed when measured just after treatment but had normal values long after. Basal outer hair cell (OHC) loss was found for both the short and the long post-treatment period. Thus, loss and recovery of cochlear potentials can for a large part be explained by loss and recovery of the EP. Recovery is limited by permanent OHC loss.     

Systemic co-treatment with alpha-melanocyte stimulating hormone delays hearing loss caused by local cisplatin administration in guinea pigs

It has previously been demonstrated that ototoxicity induced by systemic administration of cisplatin is reduced by concomitant administration of melanocortins, like alpha-melanocyte stimulating hormone (alpha-MSH). However, these experiments were hampered by large interanimal variability. Therefore, we re-investigated the effects of systemically administered alpha-MSH during local (intracochlear) administration of cisplatin. Guinea pigs, implanted with a round-window electrode, allowing daily monitoring of the compound action potentials (CAPs), and a mini-osmotic pump, pumping either 0.5 microl/h physiological saline or cisplatin solution (15 microg/ml), were co-treated daily with a subcutaneous bolus injection of either alpha-MSH (75 microg/kg) or physiological saline for 1 week or until the electrocochleogram showed a persistent decrease in CAP amplitude (40 dB threshold shift at 8 kHz). Next, the animals were sacrificed and the cochleas were processed for histology. After 2-3 days, cisplatin alone caused a threshold shift at all frequencies (2-16 kHz). Co-administration with alpha-MSH consistently delayed the criterion threshold shift by 1 day. When the 40 dB criterion had been reached, similar outer hair cell losses in both the cisplatin/alpha-MSH- and cisplatin/saline-treated groups were observed. This experiment confirms that direct administration of cisplatin into the cochlea results in considerably less interanimal variability than systemic administration and that co-treatment with alpha-MSH delays cisplatin ototoxicity. Since cisplatin was delivered directly to the cochlea, the ameliorating effect of alpha-MSH probably involves a cochlear target.     

'CatWalk' automated quantitative gait analysis as a novel method to assess mechanical allodynia in the rat; a comparison with von Frey testing

A characteristic symptom of neuropathic pain is mechanical allodynia. In animal models of neuropathic pain, mechanical allodynia is often assessed using von Frey filaments. Although the forces applied with these filaments are highly reproducible, there are various disadvantages of using this method. Testing paradigms and definitions of withdrawal threshold are not standardised. Moreover, measurements may be influenced by various conditions, such as ambient temperature, humidity, weight bearing of the limb and stress. We have therefore investigated another technique to assess mechanical allodynia, the 'CatWalk' automated quantitative gait analysis. With this computer-assisted method of locomotor analysis, it is possible to objectively and rapidly quantify several gait parameters, including duration of different phases of the step cycle and pressure applied during locomotion. We tested rats with a chronic constriction injury of the sciatic nerve, a model of neuropathic pain, both with von Frey filaments and the CatWalk method. We demonstrate that these rats minimise contact with the affected paw during locomotion, as demonstrated by a reduction in stance phase and pressure applied during stance. Moreover, these parameters show a high degree of correlation with mechanical withdrawal thresholds as determined by von Frey filaments. We therefore suggest that the CatWalk method might serve as an additional tool in the investigation of mechanical allodynia.     

Effects of enriched housing on functional recovery after spinal cord contusive injury in the adult rat

To date, most research performed in the area of spinal cord injury focuses on treatments designed to either prevent spreading lesion (secondary injury) or to enhance outgrowth of long descending and ascending fiber tracts around or through the lesion. In the last decade, however, several authors have shown that it is possible to enhance locomotor function after spinal cord injury in both animals and patients using specific training paradigms. As a first step towards combining such training paradigms with pharmacotherapy, we evaluated recovery of function in adult rats sustaining a spinal cord contusion injury (MASCIS device, 12.5 mm at T8), either housed in an enriched environment or in standard cages (n = 15 in both groups). The animals in the enriched environment were stimulated to increase their locomotor activity by placing water and food on opposite sides of the cage. As extra stimuli, a running wheel and several other objects were added to the cage. We show that exposure to the enriched environment improves gross and fine locomotor recovery as measured by the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale, the BBB subscale, the Gridwalk, and the Thoracolumbar height test. However, no group differences were found on our electrophysiological parameters nor on the amount of spared white matter. These data justify further studies on enriched housing and more controlled exercise training, with their use as potential additive to pharmacological intervention.     

ARCON: accelerated radiotherapy with carbogen and nicotinamide in non small cell lung cancer: a phase I/II study by the EORTC.

BACKGROUND: Non small cell lung cancers (NSCLC) are rapidly proliferating tumours, which are characterized by the presence of extensive hypoxic components, especially in patients with advanced loco-regional disease. Previous studies suggest a deleterious impact of acute (perfusion-limited) hypoxia on the outcome of radiotherapy for these tumours. AIM: This pilot study was aimed at determining the feasibility and tumour response rates that can be achieved with an ARCON regime in patients with locally advanced, staged IIIA or B, NSCLC tumours. METHODS: The phase I/II study included three steps: accelerated fractionation (AF) combined with carbogen (ten analysable patients), AF together with the daily administration of nicotinamide (n = 11 ) and AF with both carbon and nicotinamide (n = 14). Radiotherapy was based on a large daily dose per fraction (2.75 Gy up to 55 Gy in 4 weeks). Nicotinamide was administered at a dose of 6 g per patient per treatment day and carbogen was inhaled for 5 min before and during radiotherapy. RESULTS: The incidence of grade 3 + acute toxicity during the irradiation did not exceed 10%, neither in the lung parenchyma nor in the mediastinum. No significant difference was found in loco-regional, radio-induced toxicity among the three study steps. Although a similar fraction of patients showed grade 2 or 3 emesis in all the steps, of the 25 patients entered in the two Nicotinamide containing steps 10 (40%) developed grade 2 or greater reactions which significantly detracted from their quality of life. There was no significant difference in tumour clearance rate among the three steps. The percentage of objective responses at 2 months was 60, 54 and 57% in steps 1, 2 and 3, respectively. CONCLUSION: The feasibility of this ARCON protocol, using 2.75 Gy doses per fraction over 4 weeks, is good as regards radiotherapy-related side effects but it appears necessary in future to reduce the dose of Nicotinamide to reduce the incidence of nausea and vomiting. There was no significant difference in time to progression among the three study steps.     

Mechanische freiheitsentziehende Maßnahmen im Krankenhaus

Physical restraints have been subject of extensive public debate during recent years. Reliable epidemiological data demonstrate that these devices are used as routine measures in nursing homes. However, less is known about the frequency of physical restraint use in hospitals. This overview aims to identify and critically appraise prevalence and incidence studies on physical restraints in hospitals. A systematic literature search covering CINAHL, Embase, and Medline revealed 72 references. Eight studies met the inclusion criteria. Only 4 studies present a precise definition of physical restraint measures, and these definitions vary. Bedrails are included in only 2 studies. Data collection methods cover interviews with nurses, analysis of patients’ records, and direct observations. Only 4 studies mention the rationale for the chosen sample size. Two out of 8 studies mention valid steps to avoid bias. Overall, the methodological quality of the studies was limited. Only one small study presents data from German hospitals. Future epidemiological studies should adapt internationally consented quality criteria.     

Excretory urography with iohexol: evaluation in children

A multicenter clinical study was conducted using iohexol, a second-generation nonionic contrast medium, for excretory urography performed in 130 children. Doses of iohexol (300 mg iodine/ml) ranged between 150 and 660 mgI/kg (0.5 and 2.2 ml/kg). Iohexol was tolerated well, and no significant adverse reactions occurred. Sixty-five iohexol urograms were evaluated to determine the minimum dose for adequate visualization of the kidneys and collecting systems. A dose greater than 300 mgI/kg (1.0 ml/kg) always resulted in a urogram of diagnostic quality, while visualization was insufficient for diagnosis in 10% of studies done with doses of 150-300 mgI/kg (0.5-1.0 ml/kg). Another 65 iohexol urograms were compared in a blinded manner with a similar number of studies performed using iothalamate meglumine at comparable iodine concentration and dose. Visualization of calyces and pelvoinfundibular structures achieved with iohexol was rated better with statistical significance, but there was no difference in visualization of the renal parenchyma or ureters. Use of iohexol in excretory urography may be advantageous in children who are at greatest risk for an adverse reaction to contrast media or in those most likely to benefit from use of a low osmolality contrast agent.