Post-transcriptional down-regulation of expression of transcription factor NF1 by Ha-ras oncogene.

NF1 is a family of polypeptides that binds to discrete DNA motifs and plays varying roles in the regulation of gene expression. These polypeptides are also thought to mediate the expression of differentiation-specific markers such as adipocyte and mammary cell type-specific genes. The expression of a number of cellular differentiation-specific markers is down-regulated during neoplastic transformation. We therefore investigated whether oncogenic transformation interferes with the action of NF1. Stable transfection of activated Ha-ras into a number of murine cells correlated with a down-regulation of the expression of the NF1 genes NF1/CTF and NF1/X. The down-regulation was not at the transcriptional level but at the level of stability of the NF1 mRNAs. The level of the DNA binding activity of the NF1 proteins was also reduced in Ha-v-ras-transformed cells, and the expression of a gene that depends on this family of transcription factors was specifically repressed. These results demonstrate that an activated Ha-ras-induced pathway destabilizes the half-life of mRNAs encoding specific members in the NF1 family of transcription factors, which leads to a decrease in NF1-dependent gene expression.

Molecular and therapeutic characterization of anti-ectodysplasin A receptor (EDAR) agonist monoclonal antibodies.

The TNF family ligand ectodysplasin A (EDA) and its receptor EDAR are required for proper development of skin appendages such as hair, teeth, and eccrine sweat glands. Loss of function mutations in the Eda gene cause X-linked hypohidrotic ectodermal dysplasia (XLHED), a condition that can be ameliorated in mice and dogs by timely administration of recombinant EDA. In this study, several agonist anti-EDAR monoclonal antibodies were generated that cross-react with the extracellular domains of human, dog, rat, mouse, and chicken EDAR. Their half-life in adult mice was about 11 days. They induced tail hair and sweat gland formation when administered to newborn EDA-deficient Tabby mice, with an EC(50) of 0.1 to 0.7 mg/kg. Divalency was necessary and sufficient for this therapeutic activity. Only some antibodies were also agonists in an in vitro surrogate activity assay based on the activation of the apoptotic Fas pathway. Activity in this assay correlated with small dissociation constants. When administered in utero in mice or at birth in dogs, agonist antibodies reverted several ectodermal dysplasia features, including tooth morphology. These antibodies are therefore predicted to efficiently trigger EDAR signaling in many vertebrate species and will be particularly suited for long term treatments.

Pharmacodynamic, pharmacokinetic and pharmacogenetic aspects of drugs used in the treatment of Alzheimer's disease.

With the aging population and its rapidly increasing prevalence, dementia has become an important public health concern in developed and developing countries. To date, the pharmacological treatment is symptomatic and based on the observed neurotransmitter disturbances. The four most commonly used drugs are donepezil, galantamine, rivastigmine and memantine. Donepezil, galantamine and rivastigmine are acetylcholinesterase inhibitors with different pharmacodynamic and pharmacokinetic profiles. Donepezil inhibits selectively the acetylcholinesterase and has a long elimination half-life (t½) of 70 h. Galantamine is also a selective acetylcholinesterase inhibitor, but also modulates presynaptic nicotinic receptors. It has a t½ of 6-8 h. Donepezil and galantamine are mainly metabolised by cytochrome P450 (CYP) 2D6 and CYP3A4 in the liver. Rivastigmine is a so-called 'pseudo-irreversible' inhibitor of acetylcholinesterase and butyrylcholinesterase. The t½ of the drug is very short (1-2 h), but the duration of action is longer as the enzymes are blocked for around 8.5 and 3.5 h, respectively. Rivastigmine is metabolised by esterases in liver and intestine. Memantine is a non-competitive low-affinity antagonist of the NMDA receptor with a t½ of 70 h. Its major route of elimination is unchanged via the kidneys. Addressing the issue of inter-patient variability in treatment response might be of special importance for the vulnerable population taking anti-dementia drugs. Pharmacogenetic considerations might help to avoid multiple medication changes due to non-response and/or adverse events. Some pharmacogenetic studies conducted on donepezil and galantamine reported an influence of the CYP2D6 genotype on the pharmacokinetics of the drugs and/or on the response to treatment. Moreover, polymorphisms in genes of the cholinergic markers acetylcholinesterase, butyrylcholinesterase, choline acetyltransferase and paraoxonase were found to be associated with better clinical response to acetylcholinesterase inhibitors. However, confirmation studies in larger populations are necessary to establish evidence of which subgroups of patients will most likely benefit from anti-dementia drugs. The aim of this review is to summarize the pharmacodynamics and pharmacokinetics of the four commonly used anti-dementia drugs and to give an overview on the current knowledge of pharmacogenetics in this field.

Particulate soil organic carbon and stratification ratio increases in response to crop residue decomposition under no-till

In soils under no-tillage (NT), the continuous crop residue input to the surface layer leads to carbon (C) accumulation. This study evaluated a soil under NT in Ponta Grossa (State of Paraná, Brazil) for: 1) the decomposition of black oat (Avena strigosa Schreb.) residues, 2) relation of the biomass decomposition effect with the soil organic carbon (SOC) content, the particulate organic carbon (POC) content, and the soil carbon stratification ratio (SR) of an Inceptisol. The assessments were based on seven samplings (t0 to t6) in a period of 160 days of three transects with six sampling points each. The oat dry biomass was 5.02 Mg ha-1 at t0, however, after 160 days, only 17.8 % of the initial dry biomass was left on the soil surface. The SOC in the 0-5 cm layer varied from 27.56 (t0) to 30.07 g dm-3 (t6). The SR increased from 1.33 to 1.43 in 160 days. There was also an increase in the POC pool in this period, from 8.1 to 10.7 Mg ha-1. The increase in SOC in the 0-5 cm layer in the 160 days was mainly due to the increase of POC derived from oat residue decomposition. The linear relationship between SOC and POC showed that 21 % of SOC was due to the more labile fraction. The results indicated that the continuous input of residues could be intensified to increase the C pool and sequestration in soils under NT.

Molecular weight of hydroxyethyl starch : is there an effect on blood coagulation and pharmacokinetics ?

Résumé Fondement : le développement de solutions d'hydroxy-éthyl-amidons (HEAS) avec peu d'impact sur la coagulation sanguine, mais un effet supérieur sur la volémie, par comparaison aux HEAS couramment utilisés, est d'un grand intérêt clinique. Nous posons l'hypothèse que des solutions de haut poids moléculaire et de bas degré de substitution possèdent ces caractéristiques. Méthode : trente porcs ont été perfusés avec trois HEAS différents (20 ml/kg) de même degré de substitution (0.42) mais de poids moléculaire différent (130, 500 et 900 kDa). Une série de prélèvements sanguins ont été effectués sur 24 heures, sur lesquels des analyses de coagulation sanguine étaient effectuées par thromboélastographie et dosages plasmatiques. De plus, la concentration plasmatique ainsi que le poids moléculaire in vivo ont été déterminés, ainsi que des paramètres de pharmacocinétiques, ceci en se basant sur un modèle bi-compartimental. Résultats : les analyses de thromboélastographie et les tests de coagulation plasmatique n'ont pas démontré d'altération plus marquée de la coagulation sanguine après l'utilisation des solutions des HAES 500 et HAES 900, par comparaison avec celle de HAES 130. Par contre, les HAES 500 et HAES 900 ont présenté une plus grande aire sous la courbe (area under the curve), dans la relation concentration en fonction du temps [1542 (142) g min litre-1, p<0.001, 1701 (321) g min litre-1, p<0.001] par rapport au HAES 130 [1156 (223) g min litre-1]. La demi-vie alpha (t ½α) était plus longue pour les HAES 500 [53.8 (8.6) min, p<0.01] et HAES 900 [57.1 (12.3) min, p<0.01 ]que pour le HAES 130 [39.9 (10.7) min]. La demi-vie beta (t½β) était par contre similaire pour les trois types de HAES [de 332 (100) à 381 (63) min]. Conclusions : pour les HAES de bas degré de substitution, le poids moléculaire n'est pas un facteur clé en ce qui concerne l'altération de la coagulation. La persistance intravasculaire initialement plus longue des HAES de haut poids moléculaire et bas degré de substitution pourrait résulter dans un plus long effet volémique de ces substances. Abstract Background: The development of hydroxyethyl starches (HES) with low impact on blood coagulation but higher volume effect compared with the currently used HES solutions is of clinical interest. We hypothesized that high molecular weight, low-substituted HES might possess these properties. Methods: Thirty pigs were infused with three different HES solutions (20 ml kg-1) with the same degree of molar substitution (0.42) but different molecular weights (130, 500 and 900 kDa). Serial blood samples were taken over 24 h and blood coagulation was assessed by Thromboelastograph® analysis and analysis of plasma coagulation. In addition, plasma concentration and in vivo molecular weight were determined and pharmacokinetic data were computed based on a two-compartment model. Results: Thromboelastograph analysis and plasma coagulation tests did not reveal a more pronounced alteration of blood coagulation with HES 500 and HES 900 compared with HES 130. In contrast, HES 500 and HES 900 had a greater area under the plasma concentration-time curve [1542 (142) g min litre-1, P<0.001, 1701 (321) g min litre-1, P<0.001] than HES 130 [I 156 (223) g min litre-1] and alpha half life (t ½α) was longer for HES 500 [53.8 (8.6) min, P<0.01 ] and HES 900 [57. I (I 2.3) min, P<0.01 ] than for HES 130 [39.9 (I 0.7) min]. Beta half life (t½β), however, was similar for all three types of HES [from 332 (100) to 381 (63) min]. Conclusions. In low-substituted HES, molecular weight is not a key factor in compromising blood coagulation. The longer initial intravascular persistence of high molecular weight lowsubstituted HES might result in a longer lasting volume effect.

Pharmacokinetic variability of extended interval tobramycin in burn patients.

BACKGROUND: Aminoglycosides are mandatory in the treatment of severe infections in burns. However, their pharmacokinetics are difficult to predict in critically ill patients. Our objective was to describe the pharmacokinetic parameters of high doses of tobramycin administered at extended intervals in severely burned patients. METHODS: We prospectively enrolled 23 burned patients receiving tobramycin in combination therapy for Pseudomonas species infections in a burn ICU over 2 years in a therapeutic drug monitoring program. Trough and post peak tobramycin levels were measured to adjust drug dosage. Pharmacokinetic parameters were derived from two points first order kinetics. RESULTS: Tobramycin peak concentration was 7.4 (3.1-19.6)microg/ml and Cmax/MIC ratio 14.8 (2.8-39.2). Half-life was 6.9 (range 1.8-24.6)h with a distribution volume of 0.4 (0.2-1.0)l/kg. Clearance was 35 (14-121)ml/min and was weakly but significantly correlated with creatinine clearance. CONCLUSION: Tobramycin had a normal clearance, but an increased volume of distribution and a prolonged half-life in burned patients. However, the pharmacokinetic parameters of tobramycin are highly variable in burned patients. These data support extended interval administration and strongly suggest that aminoglycosides should only be used within a structured pharmacokinetic monitoring program.

The 5th anniversary of "Patient Safety in Surgery" - from the Journal's origin to its future vision.

A prospective study was undertaken to determine prognostic markers for patients with obstructive jaundice. Along with routine liver function tests, antipyrine clearance was determined in 20 patients. Four patients died after basal investigations. Five patients underwent definitive surgery. The remaining 11 patients were subjected to percutaneous transhepatic biliary decompression. Four patients died during the drainage period, while surgery was carried out for seven patients within 1-3 weeks of drainage. Of 20 patients, only six patients survived. Basal liver function tests were comparable in survivors and nonsurvivors. Discriminant analysis of the basal data revealed that plasma bilirubin, proteins and antipyrine half-life taken together had a strong association with mortality. A mathematical equation was derived using these variables and a score was computed for each patient. It was observed that a score value greater than or equal to 0.84 indicated survival. Omission of antipyrine half-life from the data, however, resulted in prediction of false security in 55% of patients. This study highlights the importance of addition of antipyrine elimination test to the routine liver function tests for precise identification of high risk patients.

Different behaviour of mouse-human chimeric antibody F(ab')2 fragments of IgG1, IgG2 and IgG4 sub-class in vivo.

Mouse-human chimeric monoclonal antibodies (MAbs) of 3 different human IgG sub-classes directed against carcinoembryonic antigen (CEA) have been produced in SP-0 cells transfected with genomic chimeric DNA. F(ab')2 fragments were obtained by pepsin digestion of the purified chimeric MAbs of human IgG1, IgG2 and IgG4 sub-class and of parental mouse MAb IgG1. The 4 F(ab')2 fragments exhibit similar molecular weight by SDS-PAGE. They were labelled with 125I or 131I and high binding (80 to 87%) to purified unsolubilized CEA was observed. In vivo, double labelling experiments indicate that the longest biological half-life and the highest tumour-localization capacity is obtained with F(ab')2 from chimeric MAb of human IgG2 sub-class, whereas F(ab')2 from chimeric MAb IgG4 give very low values for these 2 parameters. F(ab')2 from chimeric MAb IgG1 and from parental mouse MAb yield intermediate results in vivo. Our findings should help to select the appropriate human IgG sub-class to produce chimeric or reshaped MAb F(ab')2 to be used for tumour detection by immunoscintigraphy and for radioimmunotherapy.

Impaired uptake of glutathione by hepatic mitochondria from chronic ethanol-fed rats. Tracer kinetic studies in vitro and in vivo and susceptibility to oxidant stress.

Isolated hepatocytes incubated with [35S]-methionine were examined for the time-dependent accumulation of [35S]-glutathione (GSH) in cytosol and mitochondria, the latter confirmed by density gradient purification. In GSH-depleted and -repleted hepatocytes, the increase of specific activity of mitochondrial GSH lagged behind cytosol, reaching nearly the same specific activity by 1-2 h. However, in hepatocytes from ethanol-fed rats, the rate of increase of total GSH specific radioactivity in mitochondria was markedly suppressed. In in vivo steady-state experiments, the mass transport of GSH from cytosol to mitochondria and vice versa was 18 nmol/min per g liver, indicating that the half-life of mitochondrial GSH was approximately 18 min in controls. The fractional transport rate of GSH from cytosol to mitochondria, but not mitochondria to cytosol, was significantly reduced in the livers of ethanol-fed rats. Thus, ethanol-fed rats exhibit a decreased mitochondrial GSH pool size due to an impaired entry of cytosol GSH into mitochondria. Hepatocytes from ethanol-fed rats exhibited a greater susceptibility to the oxidant stress-induced cell death from tert-butylhydroperoxide. Incubation with glutathione monoethyl ester normalized the mitochondrial GSH and protected against the increased susceptibility to t-butylhydroperoxide, which was directly related to the lowered mitochondrial GSH pool size in ethanol-fed cells.

Bioavailability of repeated oral administration of MDL 100,240, a dual inhibitor of angiotensin-converting enzyme and neutral endopeptidase in healthy volunteers.

BACKGROUND: MDL 100,240 (pyrido[2,1-a] [2]benzazepine-4-carboxylic acid,7-[[2-(acetylthio)-1-oxo-3-phenylpropyl]amino]-1,2,3,4,6,7,8, 12b-octahydro-6-oxo, [4S-[4alpha,7alpha(R(*)),12bbeta]]-) is a molecule possessing an inhibiting ability on both angiotensin converting enzyme (ACE) and neutral endopeptidase, the enzyme responsible for atrial natriuretic peptide (ANP) degradation. Such a dual mechanism of action presents a potential clinical interest for the treatment of hypertension and congestive heart failure. OBJECTIVES: To evaluate the bioavailability of MDL 100,240 and its accumulation over repeated oral administration, using ACE inhibition as a surrogate for plasma drug level and determining its profile after oral and i.v. administration. METHODS: First, in an open, one-period, single-dose study, the ACE inhibition profile was characterised following a 12.5 mg MDL 100,240 i.v. infusion. Second, in a three-group, parallel, randomised, double-blind study, each group of four subjects received q.d., over 8 days, 2.5, 10 or 20 mg of MDL 100,240 orally. The ACE inhibition profile was determined on day 1 and day 8. Trough plasma ACE was measured on days 2, 3 and 4. The recovery of ACE activity was monitored up to 72 h after the last dose of MDL 100,240. RESULTS: ACE inhibition profile was similar on day 1 and day 8, and trough inhibition remained unchanged after the 8 days of treatment with 10 mg or 20 mg. Following repeated 2.5-mg ingestion, trough inhibition increased from 33% to 44% after the eighth dose. The oral bioavailability of MDL 100,240 was estimated at 85%, not statistically different from 100%. The accumulation ratio at steady state was estimated at 112%. Expressing the accumulation ratio in terms of half-life, a t(1/2) of 0.31 days or 7. 5 h was estimated. CONCLUSION: MDL 100,240 (oral solution) has a good bioavailability, as estimated by ACE inhibition, and no drug accumulation seems to occur over 8 days with the 10-mg and 20-mg doses, but a slight rise in the trough level is observed with the 2. 5-mg dose.

Rat insulin turnover in vivo

Zucker lean and obese rats were injected under pentobarbital anesthesia with 125I-labeled insulin; at timed intervals from 30 to 120 sec, blood samples were extracted and used for the estimation of insulin levels by RIA. A group of rats from each series was maintained under a constant infusion of noradrenaline. For each insulin determination, a duplicate blood sample containing the same amount of insulin as that used in the RIA, but without the radioactive label, was used as a blank for insulin measurement. The radioactivity in these tubes was then used for the measurement of insulin label per ml blood. From plasma label decay curves and insulin concentrations, the insulin pool size, half-life, and rate of degradation were calculated. Obese rats had higher insulin levels (2.43 nM) and showed less effect of noradrenaline than their lean counterparts, in which insulin distribution volume shrank with noradrenaline treatment. The half-life of plasma insulin was similar in all groups (range, 226-314 sec). Pool size and overall degradation rates were higher in obese (198 femtokatals) than in lean rats (28 femtokatals). It is postulated that obese rats synthesize and cleave much more insulin than lean controls despite their higher circulating levels of insulin.

Plasma leptin turnover rates in lean and obese Zucker rats

Conscious female adult lean and obese Zucker rats were injected through the jugular vein with radioactive iodine-labeled murine leptin; in the ensuing 8 min, four blood samples were sequentially extracted from the carotid artery. The samples were used in a modified RIA for leptin, in which paired tubes received the same amount of either labeled or unlabeled leptin, thus allowing us to estimate both leptin levels and specific radioactivity. The data were used to determine the decay curve parameters from which the half-life of leptin (5.46 ± 0.23 min for lean rats and 6.99 ± 0.75 min for obese rats) as well as the size of its circulating pool (32 pmol/kg for lean rats and 267 pmol/kg for obese rats) and the overall degradation rate (96 fkat/kg for lean rats and 645 fkat/kg for obese rats) were estimated. These values are consistent with the hormonal role of leptin and the need for speedy changes in its levels in response to metabolic challenge.

In rats, oral oleoyl-DHEA is rapidly hydrolysed and converted to DHEA-sulphate

Background: Dehydroepiandrosterone (DHEA) released by adrenal glands may be converted to androgens and estrogens mainly in the gonadal, adipose, mammary, hepatic and nervous tissue. DHEA is also a key neurosteroid and has antiglucocorticoid activity. DHEA has been used for the treatment of a number of diseases, including obesity; its pharmacological effects depend on large oral doses, which effect rapidly wanes in part because of its short half-life in plasma. Since steroid hormone esters circulate for longer periods, we have studied here whether the administration of DHEA oleoyl ester may extend its pharmacologic availability by keeping high circulating levels. Results: Tritium-labelled oleoyl-DHEA was given to Wistar male and female rats by gastric tube. The kinetics of appearance of the label in plasma was unrelated to sex; the pattern being largely coincident with the levels of DHEA-sulfate only in females, and after 2 h undistinguishable from the results obtained using labelled DHEA gavages; in the short term, practically no lipophilic DHEA label was found in plasma. After 24 h only a small fraction of the label remained in the rat organs, with a different sex-related distribution pattern coincident for oleoyl- and free- DHEA gavages. The rapid conversion of oleoyl-DHEA into circulating DHEA-sulfate was investigated using stomach, liver and intestine homogenates; which hydrolysed oleoyl-DHEA optimally near pH 8. Duodenum and ileum contained the highest esterase activities. Pure hog pancreas cholesterol-esterase broke down oleoyl-DHEA at rates similar to those of oleoyl-cholesterol. The intestinal and liver esterases were differently activated by taurocholate and showed different pH-activity patterns than cholesterol esterase, suggesting that oleoyl-DHEA can be hydrolysed by a number of esterases in the lumen (e.g. cholesterol-esterase), in the intestinal wall and the liver. Conclusion: The esterase activities found may condition the pharmacological availability (and depot effect) of orally administered steroid hormone fatty acid esters such as oleoyl-DHEA. The oral administration of oleoyl-DHEA in order to extend DHEA plasma availability has not been proved effective, since the ester is rapidly hydrolysed, probably in the intestine itself, and mainly converted to DHEA-sulfate at least in females.

Canakinumab (ACZ885) vs triamcinolone acetonide for treatment of acute flares and prevention of recurrent flares in gouty arthritis patients refractory to or contraindicated to nsaids and/or colchicine.

Purpose: Current treatments for arthritis flares in gout (gouty arthritis) are not effective in all patients and may be contraindicated in many due to underlying comorbidities. Urate crystals activate the NALP 3 inflammasome which stimulate production of IL-1β, driving inflammatory processes. Targeted IL-1β blockade may be an alternative treatment for gouty arthritis. Canakinumab (ACZ885) is a fully human monoclonal anti- IL-1β antibody with a long half-life (28 days). Method: This was an 8-weeks, dose-ranging, multicenter, blinded, double-dummy, active-controlled trial of patients ≥18 to ≤80 y with an acute gouty arthritis flare, refractory to or contraindicated to NSAIDs and/or colchicine. Patients were randomized to 1 subcutanous (sc) dose of canakinumab (10, 25, 50, 90, or 150 mg) or 1 intra muscular (im) dose of triamcinolone acetonide (TA) [40 mg]. The primary variable was assessed 72 h post-dose, measured on a 0-100 mm VAS pain scale. Secondary variables included pain intensity 24 and 48 h post dose, time to 50% reduction in pain intensity, and time to recurrence of gout flares up to 8 weeks post dose. Results: 200 patients were enrolled (canakinumab n=143, TA n=57) and 191 completed the study. A statistically significant dose response was observed at 72 h. The 150 mg dose reached superior pain relief compared to TA starting from 24h: estimated mean difference in pain intensity on 0-100 mm VAS was -11.5 at 24 h, -18.2 at 48 h, and -19.2 at 72 h (all p<0.05). Canakinumab 150 mg provided a rapid onset of pain relief: median time to 50% reduction in pain was reached at 1 day with canakinumab 150 mg vs 2 days for the TA group (p=0.0006). The probability of recurrent gout flares was 3.7% with canakinumab 150 mg vs. 45.4% with TA 8 weeks post treatment, a relative risk reduction of 94% (p=0.006). Serious AEs occurred in 2 patients receiving canakinumab (appendicitis and carotid artery stenosis) and 1 receiving TA (cerebrovascular disorder). Investigator's reported these events as not study drug related. There were no discontinuations due to AEs. Conclusion: Canakinumab 150 mg provided faster onset and superior pain relief compared to TA for acute flares in gouty arthritis patients refractory to or contraindicated to standard treatments. The 150 mg dose of canakinumab prevented recurrence of gout flares with a relative risk reduction compared to TA of 94% at 8 weeks post-dose, and was well tolerated.

Fecal pellets collection as a method for assessing egesta of the marine cave-dwelling mysid Hemimysis speluncula

Egesta of a cave-dwelling mysid (Hemimysis speluncola Ledoyer, 1963) was studied in a submarine cave of Medes Islands, NW Mediterranean by in situ fecal pellet collecting. Fecal pellet production and gut fullness of mysids during incubation experiments are used to estimate mysid egestion rates. Intrinsic factors related with the natural history of this species such as population structure, density of mysids, daily rhythms and pellet decomposition rates are tested for their influence on the egestion rate. The effects of methodological artifacts, such as the stress induced by both incubation and preservation procedures, are also studied. An average mysid egests about 2.5 pellets per day into the cave. The time of day is the main factor affecting egestion. The highest deposition rate is between 2 to 4 hours after sunrise when about 38 % of the total daily pellet production becomes egested. Fecal pellet morphology changes with mysid demographic classes: immature mysids produce slender and thick pellets, whereas mature mysids produce only thick pellets. Immature classes show higher percentages of full guts than mature ones. Mysid density in the incubators does not affect the results on gut fullness, but it causes a decrease in the number of pellets collected after incubation. Coprorhexia seems to be the only plausible process to explain this paradox. The incubation procedure does not increase deposition rate significantly. Time of incubation is critical because the half-life of fecal pellets is about 2.5 hours. Fixation with liquid nitrogen decreases gut fullness and also deposition rates. Higher values are obtained with 70 % ethanol and 5 % formalin solutions which show very similar results for both gut fullness and pellet deposition rates. Nevertheless, ethanol is not suitable as fixative because it enhances the opacity of the body. Several suggestions are given in order to optimize the reliability of further in situ experiments for evaluation of egesta of Hemimysis speluncola in submarine caves.