Pain management in internal medicine and effects of a standardised educational intervention: the FADOI-DOMINO study

PURPOSE

Few real-world data are available on the frequency and management of pain in Internal Medicine (IM). Aims of our study were to assess the prevalence of pain in IM, and to evaluate the effects on pain management of a standardised educational programme.

MATERIALS AND METHODS

The study was performed in 26 IM Units in Italy, with two cross-sectional surveys (PRE phase and POST phase) interspersed with an educational programme. In PRE phase each Centre reviewed the hospital charts of the last 100 consecutive patients hospitalised for any cause. An educational programme was conducted in each Centre by means of the 'outreach visit', a face-to-face meeting between health personnel and a trained external expert. Six months after, each Centre repeated the data collection (POST phase), specular to the PRE.

RESULTS

A total of 5200 medical charts were analysed. Pain was documented in 37.5% of the patients. After the educational intervention, the intensity of pain was appropriately assessed in a higher percentage of patients (77.4% vs. 47.8%, p = 0.0001), and it was more frequently monitored during hospitalisation. Qualitative definition of pain (pathogenesis, duration, etc.) increased in POST phase (75.4% vs. 62.7%, p = 0.0001). A 73.3% increase in the use of strong opioids was detected following educational programme.

CONCLUSIONS

Pain affects 4 out of 10 patients hospitalised in IM. According to our large real-world study, to implement a standardised one-shot educational programme may persistently improve the attitude of health personnel towards the characterisation and management of pain.

Cytotoxicity of halogenated benzenes and its relationship with logP

The in vitro toxicity of a series of environmentally relevant halobenzenes was tested using a Chinese hamster lung fibroblast cell line and its relationship with the logarithm of octanol/water partition coefficient (logP) was investigated. Since we wanted to study the direct biological activity of the parent substances, we have used the V-79 cell line that does not express phase I metabolic activities. Moreover, because of the available knowledge on the substances, we decided to perform the colony-forming ability test (CFA) and to analyse the DNA damage by a cytofluorimetric assay. To identify the concentration range at which the toxic effect could be detected, a prescreen with the neutral red assay has been performed. All the substances tested were positive in the CFA, but, according to the concentration values inhibiting this activity by 50%, they can be divided into two groups of differing toxicity. The FACScan analysis shows for the majority of the halobenzenes a clear hypodiploid peak. A good correlation between values describing the concentration that inhibits CFA by 50% and logP was found, indicating that it depends on the hydrophobic properties of the compounds and that logP is a suitable descriptor.

Choice and standardization of test protocols in cytotoxicology: A multicentre approach

A major problem that interferes with the introduction of in vitro tests for toxicological risk assessment is that of defining reliable standardized protocols. This issue was approached in the present study with an interlaboratory comparison of three cytotoxicity assays detecting chemical toxicity as impairment of cell viability in confluent cultures, reduction of colony forming ability, and inhibition of cell proliferation over 3 days of treatment. The study was performed using V79 cells, which are unable to activate indirectly-acting xenobiotics, and six chemicals with different mechanisms of action: two antioxidants (butylated hydroxyanisole and butylated hydroxytoluene), an inhibitor of protein synthesis (cycloheximide), an alkylating agent requiring metabolic activation (cyclophosphamide), an uncoupler of oxidative phosphorylation (dinitrophenol), and a genotoxic metal salt (potassium dichromate). The three tests produced the same rank of relative toxic potency for the tested chemicals, based on LC(50) values. The cell viability test appeared to be the most suited for the screening of unknown chemicals, given its simplicity and better reproducibility.

Functional alterations induced by the food contaminant furazolidone on the human tumoral intestinal cell line Caco-2

Caco-2 cells, which are derived from a human colon carcinoma and are able to differentiate in culture, have been used to study the effect of furazolidone (FZ), a chemical belonging to the nitrofuran family which is frequently used for the prevention of animal infections. Its potentially toxic residues could remain in some food products of animal origin and affect human health. Toxicity has been measured by different parameters, either in undifferentiated cells (day 7 of culture), or on differentiated cells (day 21 of culture). Our results indicate that FZ may seriously affect the proliferating portion of the intestinal mucosa, while the differentiated cells appear to be more resistant. However, the slight effect recorded on the aspecific and specific functions of the differentiated cells may suggest that the specialized portion of the intestine can also be compromised by the drug. Caco 2 cells seem a good model for a deeper investigation of the mechanism involved in the toxic action of FZ.

Opioid-related bowel dysfunction: prevalence and identification of predictive factors in a large sample of Italian patients on chronic treatment

BACKGROUND AND OBJECTIVES

Opioid-bowel dysfunction (OBD) is a broad range of symptoms potentially associated with opioid therapy. This prospective, multicentric study assesses the prevalence of OBD in patients on analgesic therapy for the treatment of pain from any cause and identifies the factors associated with the onset of this side effect.

MATERIALS AND METHODS

Consecutive patients aged > 18 years, on analgesic treatment with opioids, non-steroidal anti-inflammatory drugs (NSAIDs) or other therapies for chronic pain of any aetiology were included in the study. The association of OBD with gender, age, pain aetiology and analgesic treatment was analyzed by multivariate analysis and logistic analysis.

RESULTS

In total, 2324 patients were included in the study. The prevalence of OBD symptoms was 63.5%, despite that the wide majority of patients (89.5%) were receiving laxatives. OBD symptoms were judged as directly correlated with analgesic therapy in 85.1% of cases. The highest prevalence of constipation was reported with morphine, whereas the lowest was observed in patients on oxycodone CR and buprenorphine TTS. Statistical analysis showed that patients on opioids have a higher likelihood of experiencing OBD symptoms than those on NSAIDs or other treatments (66.2% vs 37.0%), and this probability is even higher in those with cancer-related pain (69.3%). Female gender and age > 70 years also appeared as risk factors. The logistic analysis indicated that cancer-related pain, increased age and the use of fentanyl are positive predictors of the presence of OBD, whereas the administration of oxycodone CR was associated with a decreased incidence of these symptoms.

DISCUSSION

Even with the limitation of any observational experience, this study suggests, for the first time, the existence of some factors predictive of the onset of OBD symptoms in patients on analgesic treatment. Moreover, different opioids seem to be associated with a different risk of experiencing these symptoms.

The management of constipation in palliative care: clinical practice recommendations

Constipation is one of the most common problems in patients receiving palliative care and can cause extreme suffering and discomfort. The aims of this study are to raise awareness of constipation in palliative care, provide clear, practical guidance on management and encourage further research in the area. A pan-European working group of physicians and nurses with significant experience in the management of constipation in palliative care met to evaluate the published evidence and produce these clinical practice recommendations. Four potentially relevant publications were identified, highlighting a lack of clear, practical guidance on the assessment, diagnosis and management of constipation in palliative care patients. Given the limited data available, our recommendations are based on expert clinical opinion, relevant research findings from other settings and best practice from the countries represented. Palliative care patients are at a high risk of constipation, and while general principles of prevention should be followed, pharmacological treatment is often necessary. The combination of a softener and stimulant laxative is generally recommended, and the choice of laxatives should be made on an individual basis. The current evidence base is poor and further research is required on many aspects of the assessment, diagnosis and management of constipation in palliative care.

Safety assessment of food-contact paper and board using a battery of short-term toxicity tests: European union BIOSAFEPAPER project

An European Union (EU)-funded project QLK1-CT-2001-00930 (BIOSAFEPAPER) involves the development, validation and intercalibration of a short-term battery of toxicological tests for the safety assessment of food-contact paper and board. Dissemination of the results to industry, legislators (e.g. DG Consumer Protection, DG Enterprises, DG Research), standardization bodies such as CEN, and consumers will create an agreed risk evaluation procedure. The project involves pre-normative research in order to establish a set of in-vitro cytotoxicity and genotoxicity tests that will be easily adaptable to food-contact fibre-based materials and have endpoints relevant to consumer safety, including sub-lethal cellular events. These tests will be performed on samples representing actual migration conditions from food-contact paper and board with respect to different foodstuffs, and should form an experimental basis for scientifically sound recommendations for a harmonized system of risk evaluation and product testing.

The Caco-2 cell line as a model of the intestinal barrier: influence of cell and culture-related factors on Caco-2 cell functional characteristics

The human intestinal Caco-2 cell line has been extensively used over the last twenty years as a model of the intestinal barrier. The parental cell line, originally obtained from a human colon adenocarcinoma, undergoes in culture a process of spontaneous differentiation that leads to the formation of a monolayer of cells, expressing several morphological and functional characteristics of the mature enterocyte. Culture-related conditions were shown to influence the expression of these characteristics, in part due to the intrinsic heterogeneity of the parental cell line, leading to selection of sub-populations of cells becoming prominent in the culture. In addition, several clonal cell lines have been isolated from the parental line, exhibiting in general a more homogeneous expression of differentiation traits, while not always expressing all characteristics of the parental line. Culture-related conditions, as well as the different Caco-2 cell lines utilized in different laboratories, often make it extremely difficult to compare results in the literature. This review is aimed at summarizing recent, or previously unreviewed, data from the literature on the effects of culture-related factors and the influence of line sub-types (parental vs. different clonal lines) on the expression of differentiation traits important for the use of Caco-2 cells as a model of the absorptive and defensive properties of the intestinal mucosa. Since the use of Caco-2 cells has grown exponentially in recent years, it is particularly important to highlight these methodological aspects in order to promote the standardization and optimisation of this intestinal model.

Absorption of Fumonisin B1 and aminopentol on an in vitro model of intestinal epithelium; the role of P-glycoprotein

The aim of the present paper is to evaluate the absorption of fumonisin B1 and its principal metabolite, aminopentol on a human intestinal model, Caco-2 cells, cultured on semi-permeable inserts, that reproduces the two different intestinal compartments: luminal (apical) and serosal (basolateral) side. Following separate exposure in apical and in basolateral compartments, aminopentol passage through the cell layer (in particular from basolateral to apical direction) was shown, while it was not observed for the parent compound. The different aminopentol distribution between the two compartments of the culture system, and its variation in presence of verapamil or probenecid (P-gp and MRP inhibitors respectively), strongly suggests the involvement of P-glycoprotein in the influx/efflux mechanisms of aminopentol in the intestinal cells, reducing its oral bioavailability.

Toxicology investigations with cell culture systems: 20 years after

From almost 20 years the "in vitro" model has gained a wide ground in toxicological investigation, providing advanced tools, reliable protocols, mechanistic information. These advancements have been done thanks to different approaches, addressed at improving chemical testing and validating procedures, at exploring the cellular and molecular basis of toxicity, at studying the modifications that xenobiotics undergo in the cellular environment. In this review the most advanced cellular models, the mechanisms of cell death, the techniques to monitor gene activation, following chemical exposure, is highlighted. Moreover the more recent in vitro models to approach the biotransformation issue will be presented.

Evaluation of Fumonisin B(1) and its metabolites absorption and toxicity on intestinal cells line Caco-2

The aim of the present paper is to investigate intestinal absorption and toxicity of Fumonisin B(1) (FB(1)) and its partially (PHFB(1) and PHFB(2)) and totally hydrolyzed (HFB(1)) metabolites, using the human intestinal cell line Caco-2, a very well known in vitro model of intestinal epithelium for absorption and metabolism studies. Caco-2 cells were treated for 48 h with several toxin concentrations (in the range of 1-138 microM). At the end of exposure period, no significant variation on cell viability has been observed with all chemicals tested, either in undifferentiated cells or in differentiated ones, suggesting a poor toxicity of these mycotoxins for intestinal cells. In any case, FB(1) appears the most active in this respect. For which concerns the cellular absorption, FB(1), PHFB(1) and PHFB(2) are never detected into Caco-2 cells. On the contrary, a dose-dependent absorption of HFB(1) has been observed in differentiated cells, which express enzymatic and metabolic characteristics of mature enterocytes. Thus HFB(1), losing the tricarballylic acid chain, is more bioavailable than FB(1) on intestinal cell, supporting the hypothesis that in risk evaluation of fumonisins exposure its metabolites are also relevant.

In vitro toxicology methods: impact on regulation from technical and scientific advancements

The impressive advancement of technologies in biomedical research, and particularly in the area of in vitro experimental models, has opened up new possibilities related to co-cultures, micromass or stem cell cultures. Engineered cells to study specific targets and/or mechanisms are also available. Moreover, a very subtle approach in the study of toxicological effects is represented by the very recent genomics and proteomics techniques. New mechanistically based methods could be established from all these approaches, which, once validated, could enter the regulatory procedure. So far, in toxicology, only a few in vitro tests are accepted for regulatory purposes, such as those related to corrosion, phototoxicity and absorption. Many others are in the pre-validation or validation phase. An area where in vitro tests play a key role is the genetic toxicology. In this context, the most recent testing strategies and test methods will be presented, with particular attention to the recently updated guidelines for food additives by the EU Scientific Committee on Food. An improvement in the implementation of validated methods could arise from a better coordination on the matter at national and international levels, the harmonisation of different legislations, and a strict control of the national rules in order to make them up-to-date with respect to validated methods.

Identification and coupling to adenylate cyclase of three different [(3)H]CGP 12177 binding sites in Caco-2 cell membranes

In the present investigation the identification of beta -adrenoceptor (beta -ARs) subtypes in the Caco-2 cell line was performed using radiometric assays. beta -ARs were measured using increasing concentrations of the highly specific beta -AR antagonist (-)[(3)H]CGP 12177 (0.06-4 nM), whereas the beta(1)- and beta(2)-AR subtypes discriminated through selective binding assays using the highly selective unlabelled antagonists CGP 20712A and ICI 118551. Atypical beta -ARs were measured using an incubation system formed by higher concentrations (0.6-20 nM) of (-)[(3)H]CGP 12177. beta - Atypical binding site concentrations (69 +/- 5 fmol mg ml(-1)of membrane protein) were higher than beta(1)-ARs (7 +/- 1) and beta(2)-ARs (24 +/- 2), respectively. The different beta -AR subtype affinities were characterized by binding inhibition experiments and the adrenergic agonists displaced the radioligand from its specific binding sites in the following order of potency: isoproterenol > clenbuterol > dobutamine > SR 58611A; for antagonists the order of potency was: propranolol approximately = ICI118551 approximately = CGP20712A. For atypical beta -ARs the order was: SR 58611A > clenbuterol > dobutamine > isoproterenol for agonists and propranolol > CGP 20712A > ICI 118551 for antagonists. As far as in vitro functional studies are concerned, beta -AR subtypes were shown to be coupled to adenylyl cyclase as their stimulation produced cAMP in an amount significantly higher than basal values. cAMP production after stimulation with dobutamine, clenbuterol, isoproterenol, and SR 58611A was measured using a cAMP radioassay kit. The order of efficacy suggested that the stimulation of beta(2)-ARs was the most effective in inducing the activation of cell signalling mechanisms. The identification of functional beta -ARs in a cancer cell line represents the first step in the study of the possible adrenergic control of cellular activities (e.g. proliferation and/or differentiation), which could suggest the use of this cancer cell line as a model for the study of cell activity or possibly new therapeutic strategies.

Nitric oxide production in Caco-2 cells exposed to different inducers, inhibitors and natural toxins

The involvement of the NO pathway in several intestinal inflammatory diseases is under investigation. In vitro models may provide a useful approach to better characterise this pathway at the cellular level. For this purpose, we have used Caco-2 cells, which are able to spontaneously differentiate in long-term culture to small intestine enterocytes. The effect of different NO pathway inducers [gamma-interferon (IFN-gamma) and phorbol myristate acetate (PMA)] has been studied. Our results demonstrate that Caco-2 cells constitutively express NOS at very low levels, while the induction with PMA+IFN-gamma triggers the expression of the inducible isoform with a stronger effect starting from day 14 of differentiation. The use of specific inhibitors of gene expression, at transcriptional and translational level, suggests that new synthesis of iNOS mRNA is required, through direct activation of the gene or new synthesis of transcription-required factors, as indicated by CHX inhibition. The morphological alteration induced by PMA+IFN-gamma is reversed by iNOS inhibitor, suggesting that the NO pathway may be involved in the cytoskeletal alterations. The DSP toxins, OA and DTX-1, induce NO production at levels corresponding to their different toxicity, previously detected in Caco-2 cells.

Apoptosis evaluation in epithelial cells exposed to different chemicals: relevance of floating cells

The recent increase in understanding of cell death has promoted new approaches in toxicological studies, mainly those dealing with in vitro systems where the evaluation of cell death has been the most widely adopted end-point in measuring the effects of chemical toxicants. The aim of this study was to investigate the possibility of improving the traditional cytotoxicity test protocols in order to produce more specific information on the type of cell death induced by exposure to toxicants. In particular, we characterized the mode of cell death in an established epithelial cell line, HEp-2 cells, which is frequently used in cytotoxicity testing owing to its easy handling and standardization of culture conditions. Reference chemicals for apoptosis and necrosis were selected as controls, together with other molecules that have been shown, in preliminary studies, to induce various morphological and structural modifications in relation to cell death. The results obtained show that: (a) the floating fraction of treated cells gives the clearest picture of the necrotic/apoptotic distribution; (b) morphological analysis is crucial for characterization of apoptosis; (c) more than one cytotoxic end-point is necessary to clearly identify the type of cell death.

Evidence for cytochrome P4501A2-mediated protein covalent binding of thiabendazole and for its passive intestinal transport: use of human and rabbit derived cells

Thiabendazole (TBZ), an anthelmintic and fungicide benzimidazole, was recently demonstrated to be extensively metabolized by cytochrome P450 (CYP) 1A2 in man and rabbit, yielding 5-hydroxythiabendazole (5OH-TBZ), the major metabolite furtherly conjugated, and two minor unidentified metabolites (M1 and M2). In this study, exposure of rabbit and human cells to 14C-TBZ was also shown to be associated with the appearance of radioactivity irreversibly bound to proteins. The nature of CYP isoforms involved in this covalent binding was investigated by using cultured rabbit hepatocytes treated or not with various CYP inducers (CYP1A1/2 by beta-naphthoflavone, CYP2B4 by phenobarbital, CYP3A6 by rifampicine, CYP4A by clofibrate) and human liver and bronchial CYP-expressing cells. The covalent binding to proteins was particularly increased in beta-naphthoflavone-treated rabbit cells (2- to 4-fold over control) and human cells expressing CYP1A2 (22- to 42-fold over control). Thus, CYP1A2 is a major isoenzyme involved in the formation of TBZ-derived residues bound to protein. Furthermore, according to the good correlation between covalent binding and M1 or 5OH-TBZ production, TBZ would be firstly metabolized to 5OH-TBZ and subsequently converted to a chemically reactive metabolic intermediate binding to proteins. This metabolic activation could take place preferentially in liver and lung, the main biotransformation organs, rather than in intestines where TBZ was shown to be not metabolized. Moreover, TBZ was rapidly transported by passive diffusion through the human intestinal cells by comparison with the protein-bound residues which were not able to cross the intestinal barrier. Consequently, the absence of toxicity measured in intestines could be related to the low degree of TBZ metabolism and the lack of absorption of protein adducts. Nevertheless, caution is necessary in the use of TBZ concurrently with other drugs able to regulate CYP1A2, particularly in respect to liver and lung tissues, recognised as sites of covalent-binding.

[Epidural spinal stimulation in the treatment of refractory angina pectoris. Its clinical efficacy, complications and long-term mortality. An Italian multicenter retrospective study]

BACKGROUND

Spinal cord stimulation has been used for many years in the treatment of refractory angina pectoris. Its anti-anginal and anti-ischemic effect has been well documented in several studies, but the long-term efficacy, safety and survival rate are not well known. The aim of this study was to carry out a retrospective analysis of a series of patients from the Italian Multicenter Registry, the data of which were collected in five centers, by means of a questionnaire.

METHODS

One hundred and thirty patients (83 males, 47 females, mean age 74.8 +/- 9.8 years) were submitted to spinal cord stimulator implantation for refractory angina pectoris in the period 1988-1995 and controlled during a mean follow-up of 31.4 +/- 25.9 months. A previous myocardial infarction had already occurred in 69.3% of patients, whereas in 67.6% multivessel coronary artery disease was documented. A left ventricular dysfunction (ejection fraction < 0.40) was present in 34% of patients; bypass surgery and coronary angioplasty were performed in 49.6% and in 27% of patients respectively. In 96.3% of cases revascularization procedures were not advisable.

RESULTS

A complete follow-up of 116 patients (89.2%) was available. The spinal cord stimulator induced a significant reduction in NYHA functional class from 2.5 +/- 1.2 to 1.5 +/- 0.9 (p < 0.01). During the follow-up 41 patients (35.3%) died, and in 14.2% a new acute myocardial infarction developed. The total percentage of minor spinal cord stimulation-related complications was 6.8%. No major complications occurred. The annual total mortality rate was 6.5%, whereas the cardiac mortality rate was 5%. Compared to the survivors, patients who died showed a higher incidence of left ventricular dysfunction, previous myocardial infarction and bypass surgery at implantation.

CONCLUSIONS

In our experience, spinal cord stimulation is an effective therapy in patients affected by refractory angina pectoris and who cannot undergo revascularization procedure. The complication rate is low, with the total and cardiac mortality showing a trend as that reported for patients with similar coronary disease.

Metabolism of furazolidone: alternative pathways and modes of toxicity in different cell lines

1. The metabolism and cytotoxicity of the antimicrobial nitrofuran drug furazolidone have been studied in Caco-2, HEp-2 and V79 cell lines. Free radical production, metabolite pattern, formation of bound residues, inhibition of cellular replication and protection by the antioxidant glutathione were compared for the three cell lines. 2. All three cell lines produced the same nitro-anion radical with similar kinetics. Little further metabolic breakdown was observed in V79 cells, whereas Caco-2 and HEp-2 cells showed extensive degradation of furazolidone, but with different end patterns. 3. Under hypoxic conditions, the colony-forming ability was extensively impaired in HEp-2 cells whereas the other two cell lines were less affected, suggesting that irreversible damage to DNA occurred prevalently in HEp-2 cells. In V79 cells the absence of oxygen caused a 25-fold increase in the formation of protein-bound residues. 4. Brief exposure to furazolidone caused a 50% loss of endogenous glutathione in Caco-2 cells, but no loss could be detected in V79 and HEp-2 cells. Consistently, when glutathione was depleted by buthionine-[S,R]-sulphoximine (BSO) and diethylmaleate (DEM) treatment, the viability of V79 and HEp-2 cells was minimally affected by furazolidone, whereas that of Caco-2 cells was substantially reduced. 5. It is concluded that the cytotoxicity of furazolidone in these cell lines can be exerted by a number of different mechanisms, possibly related to different metabolic pathways. The cytotoxicity of nitrofuran drugs, therefore, cannot be ascribed to a single toxic intermediate, but in Caco-2 cells furazolidone is extensively metabolized and detoxified by GSH, in V79 is only partially activated and then bound to proteins, whereas in HEp-2, once activated, may react with DNA.

Toxicity of selected plant volatiles in microbial and mammalian short-term assays

In this study, several short-term microbial and mammalian in vitro assays were used to evaluate cytotoxicity and genotoxicity of four plant volatiles showing antifungal activity: cinnamaldehyde, carvacrol, thymol and S(+)-carvone. All inhibited viability and proliferation of Hep-2 cells in a dose-dependent manner. IC50 ranged from 0.3 mM (cinnamaldehyde) to 0.7 mM (thymol) in viability tests and from 0.2 mM (carvacrol) to 0.9 mM (carvone) in the proliferation test. The morphological analysis suggested an involvement of apoptosis in the cases of carvone, carvacrol and cinnamaldehyde. At nontoxic doses, carvacrol and thymol increased the number of revertants in the Ames test by 1.5-1.7 times, regardless of metabolic activation. In the SOS-chromotest, none of the four plant volatiles caused DNA damage at non-toxic doses. In the DNA repair test, a marked dose-dependent differential toxicity was observed with carvone and, to a lesser extent, with cinnamaldehyde, while with thymol and carvacrol, this effect was less pronounced. In conclusion, the considered in vitro cytotoxicity assays have shown to be sensitive enough to highlight a variety of toxic effects at the cellular level, which can be rather different between chemically closely related compounds, such as isomers.

Evaluation of the use of two human cell lines for okadaic acid and DTX-1 determination by cytotoxicity assays and damage characterization

Two human cell lines have been used, HEp-2 and (de)differentiated Caco-2, derived from a larynx and a colon carcinoma, respectively, with the aim of evaluating and characterizing the cytotoxicity of okadaic acid (OA) and related toxins. Effects of OA and dinophysistoxin-1 (DTX-1) on cell viability (neutral red uptake) and on cell morphology/cytoskeleton structure have been observed in both cell lines, though at different time exposures and with different concentrations. The morphological alteration was detected earlier than the viability inhibition in HEp-2 cells with both toxins and in Caco-2 cells with DTX-1. HEp-2 cells have shown to be more sensitive than the intestinal cell line and thus possibly suitable for screening of contaminated samples, while Caco-2 cells could be used for further investigating the possible mechanisms involved in diarrhoeic shellfish poisoning (DSP) toxins.

A contribution to safety assessment of veterinary drug residues: in vitro/ex vivo studies on the intestinal toxicity and transport of covalently bound residues

1. The gastrointestinal fate of protein-bound residues of the model compound furazolidone (FZD) was investigated in vitro and ex vivo. Protein-bound residues were generated in rat liver microsomes, isolated by solvent extraction and digested with 0.5% hydrochloric acid and Pronase E. 2. During digestion, 3-amino-2-oxazolidinone (AOZ), the side chain of furazolidone, was partly released from bound residues. 3. The absorption of free AOZ and digested protein-bound residues was tested in isolated perfused rat gut segments (IPGS) and in the intestinal cell line Caco-2. Free AOZ was transfered both in the IPGS model and in Caco-2 monolayer cultures, while no indications for passage of bound residues were obtained. 4. No acute toxicity of AOZ or digested food residues respectively was observed in gut segments and Caco-2 cells at concentrations that were substantially above maximum residue levels to be expected in food of animal origin after administration of therapeutic doses. 5. The results demonstrate that digestive processes can alter the chemical nature of drug residues and yield degradation products that may be bioavailable for the consumer. Thus, the covalent binding of xenobiotics to macromolecular tissue constituents cannot necessarily be regarded as an irreversible endpoint of residue bioavailability and toxicity.

[Ethical problems of research on medical-assisted reproduction]

Research in the field of assisted reproduction technologies (ART) is today very active internationally and is aimed both at improving success chances of already consolidated techniques (in fact these chances are still considerably low), and at elaborating new methods like ICSI (intracytoplasmic sperm injection), oocyte cryoconservation, ovary tissue cultures. Some other techniques, connected to ART, are here considered, like preimplantation diagnosis, early sex determination, gene therapy in utero and cloning. All these subjects of research are here briefly mentioned in relation to the ethical debate which they have stirred or which they should stir according to the authors. These debates are in part mirrored in the different legislations.

Characterization of furazolidone apical-related effects to human polarized intestinal cells

In studying the effects of furazolidone (FZ) on the human intestinal Caco-2 cell line grown on microporous membrane, we have previously demonstrated a higher toxicity when the compound was administered at the apical (AP) side than at the basolateral (BL) side. Moreover, we have also shown the production, in the intact cells, of a nitroanion radical from FZ by a cytochrome c P450 reductase. The aim of the present study was to investigate which specific cell structures and functions are involved in the observed domain-related toxicity. The relevance of alterations in integrity and selective properties of the intestinal barrier as first-pass site for ingested molecules is also discussed. We have confirmed that, as expected, the Caco-2 cells are protected from FZ injury by a specific inhibitor of the cytochrome c P450 reductase, and we have shown that this protection is more active on the apical side of the cells. In sublethal conditions, FZ causes increased permeability to 3H-mannitol and, to a different extent, to 3H-inulin. Again the effect is higher when the cells are apically exposed. We have thus examined the tight junctions morphology: a disruption of the apical perijunctional actin-bound cytoskeleton was detected by rhodamine-phalloidin staining and microtubule disorganization by antitubulin fluoresceinated antibodies. Again, the effect was more evident when the cells were apically treated with FZ. Preferential transport and accumulation of the compound by active transport mechanisms could be excluded, since transport of FZ was linear and no intracellular accumulation was detected either from the AP and or the BL sides. All together these results may suggest that the AP formation of the active metabolite and its possible reactivity with SH groups of perijunctional microfilaments could be responsible of the higher FZ apical toxicity. This study shows that polarized differentiated cells are very interesting in vitro models to investigate specific cellular domains as targets of toxic effects and to detect subtle changes that may be induced, in absence of cell death, in specialized epithelial layers.

Efficacy and safety of permanent cardiac DDD pacing with contemporaneous double spinal cord stimulation

Spinal cord stimulation (SCS) is currently used to treat peripheral vascular disease (PVD) and refractory angina pectoris not amenable to revascularization. In a case of contemporaneous SCS implant and permanent cardiac pacemaker (PPM), if multipolar electrodes are used it is possible to avoid any interference between the systems. We describe the case of a patient with a DDD pacemaker, in whom two bipolar SCSs were implanted at different times: one to control refractory angina pectoris and the other for PVD. No interference between the three systems has been observed.

[Epidural spinal cord stimulation in the treatment of refractory angina pectoris. Mechanisms of action, clinical results and current indications]

The spinal cord stimulation (SCS) is an antalgic technique which has been used since 1967 for the treatment of several painful syndromes. More recently it was employed in cardiology to treat refractory angina, not suitable for revascularization. Despite the fact that published results on this subject have reported small, non-homogeneous series, and that the mechanisms of action are not completely understood, we can affirm according to the analysis of the literature and our own experience that SCS causes improvement in quality of life, reduction in frequency of angina attacks and reduced consumption of rapid-action nitrates. There is also evidence that electrical stimulation has a definite anti-ischemic effect, as revealed by increased work capacity, improved lactate metabolism and reduced downward slope of ST segment at comparable maximum work load. In expert hands SCS implantation is associated with relatively low frequency of complications, whose incidence is greatly reduced if the main contraindications are respected, particularly in patients receiving anticoagulants or with an infection.

In vitro toxicity and formation of early conjugates in Caco-2 cell line treated with clenbuterol, salbutamol and isoxsuprine

Caco-2, human intestinal cell line able to differentiate in long-term culture, has been used to assess the cytotoxicity of the beta-agonists clenbuterol, salbutamol and isoxsuprine, also used at high doses to obtain lean meat in food producing animals, and to investigate the eventual in vitro formation of early conjugates of these compounds. For this purpose, the cells have been characterized for the activity of UDP-glucuronyltransferase, which is present and increases in the differentiated cells, and for the beta-receptors' binding characteristics, which are those of beta 1 and beta 2 subtypes. Isoxsuprine was shown to be the most toxic, followed by clenbuterol and salbutamol. Conjugates have been observed after incubation of the cells both with the lowest isoxsuprine and the highest salbutamol concentrations. No conjugates were detected in the case of clenbuterol.

Furaltadone cytotoxicity on three cell lines in the presence or absence of DMSO: comparison with furazolidone

Nitrofuran drugs have been studied on cellular systems in order to develop in vitro tests for safety assessment of food contaminants. In the present study we have tested furaltadone on three cell lines (HEp-2, Caco-2 and V79), using the same toxicity endpoints as in a previous study with furazolidone, namely cell viability and growth, colony-forming ability, LDH release, and O2 consumption. One of the aims of this investigation was to compare the two compounds in order to determine whether our models are able to discriminate among structurally related molecules. The other aim was to study the influence of the solvent used on the observed toxicity, because furaltadone is soluble both in water and in DMSO. The results show that the three cell lines used as differently affected by the two compounds, and that, at least in the case of furaltadone, the solvent is not relevant for the observed toxicity.

N-[5-nitro-2-furfurylidene]-3-amino-2-oxazolidinone activation by the human intestinal cell line Caco-2 monitored through noninvasive electron spin resonance spectroscopy

The pathways participating in the metabolism of the nitrofuran antimicrobial drug N-[5-nitro-2-furfurylidene]-3-amino-2-oxazolidinone (furazolidone) in intact cells were investigated in the human intestinal cell line Caco-2. One-electron reduction of furazolidone led to the formation of a free radical intermediate that could be monitored in dense cell suspensions by noninvasive electron spin resonance spectroscopy. The effects of enzyme inhibitors on the kinetics of radical production and decay were used to estimate the relative contribution of different enzymes to the reductive activation of the drug. Although many enzymes are known to reduce nitrofurans in vitro (e.g., xanthine oxidase, aldehyde oxidase, DT-diaphorase, mitochondrial redox chain components), their contributions were insignificant in living Caco-2 cells. The first reducing equivalent required for the formation of the nitroanion derivative of furazolidone appeared to be provided essentially by the microsomal cytochrome P450 reductase. This was confirmed through studies of the NADPH-dependent radical formation by microsomes. Differentiated Caco-2 cells, an established enterocyte model, showed only modestly increased radical formation and the same enzyme-specificity pattern as undifferentiated cells. Consistently, only a small increase in P450 reductase activity was found in differentiated cells, in contrast to the 10-fold increase seen in typical differentiation marker enzymes. With the electron spin resonance method that we describe, it is possible to distinguish between sites of bioactivation of redox active drugs in intact cells.

[Epidural electrostimulation in the treatment of refractory angina pectoris in elderly patients: preliminary results]

The spinal cord stimulation is an antalgic technique which has been used since 1967 for the treatment of several painful syndromes. More recently it was employed in the cardiology field to treat refractory angina, not suitable for revascularization. We applied spinal cord stimulation as alternative therapy in 7 clients older than 70 years who, for different reasons, could not undergo revascularization. We obtained good short- and long-term clinical results, without complications. On the basis of our preliminary experience with this technique in a small group of elderly patients and after a critical review of the literature, we conclude that spinal cord stimulation can be used without significant risks, in elderly patients with refractory angina pectoris.

Established cell lines for safety assessment of food contaminants: differing furazolidone toxicity to V 79, HEp-2 and Caco-2 cells

In vitro models, preferentially derived from human tissues, may be valuable tools to study the biotransformation and toxicity of compounds that may be present as residues in food products. Such residues may represent a risk to human health, and therefore call for increased testing. Three established cell lines were used to study the toxic effect of furazolidone (FZ), a widely used veterinary drug: HEp-2 cells, derived from a human larynx carcinoma, previously used in toxicity screening of several compounds; Caco-2 cells, derived from a human colon adenocarcinoma, able to differentiate partially in culture, and V 79, a fibroblast cell line derived from Chinese hamster lung, widely used to assess direct toxicants. Various toxicity parameters were used, primarily dealing with cell death and cell proliferation. In all cell lines FZ at a concentration of 5 micrograms/ml caused a marked decrease in cell viability and especially in cell proliferation. Inhibition of DNA synthesis has also been observed, even if at higher concentrations. However, only in V 79 cells was the decrease in cell number accompanied by a marked increase in lactate dehydrogenase leakage due to membrane damage. Moreover, the surviving V 79 cells, after removal of FZ, fully recovered from the effect of the drug, as shown by their full capacity to attach to dishes and to form colonies. Surviving cells of the other two cell lines showed much poorer colony-forming ability. Exposure of Caco-2 cells and, to a lesser extent, HEp-2 cells, caused a marked increase in oxygen consumption, that possibly was due to redox cycling of the initially formed radical nitro anion. Biotransformation of the drug by all three cell lines was accompanied by the formation of protein-bound metabolites, HEp-2 being the most active cells. The toxic effects recorded show that cell lines provide a sensitive system in toxicity assessment. Moreover, it may be suggested that a battery of cell lines, including some of human origin, as well as a battery of endpoints, may be of help in addressing further specific mechanistic investigations.

[2 unusual cases of fibrous polyp of the upper urinary tract (reported occasionally)]

Two rare cases (occasional reports) of fibrous polyp of the ureter and kidney pelvis are described. The symptomatology not significant, and the surgical diagnosis and surgical treatment of these lesions is discussed. The ureterorenoscopy is suggested in the follow-up of these neoformation, but when possible the diagnosis and a correct therapeutic approach is recommended.

Technical and clinical problems in patients with simultaneous implantation of a cardiac pacemaker and spinal cord stimulator

Spinal cord stimulators are used to relieve pain associated with peripheral ischemia and angina pectoris. In patients with both permanent pacemaker (PPM) and a spinal cord stimulator (SCS), electromagnetic signals from the SCS may inhibit the PPM. A bipolar PPM configuration is preferred to minimize myopotential or electromagnetic interference but patients have safely had unipolar devices implanted. We report ten patients (six males and four females; median age 73.3 years) with both a SCS and a PPM implanted between 1987-1991. Intermittent interference with one PPM (Ela Medical Model Opus 3001) was noted after an increase in the output voltage of the SCS for continued clinical efficacy. Inhibition was output voltage dependent, and reversion to the noise mode was frequency dependent. Sensitivity to both could be managed by changing the pacemaker sensitivity. Interference with pacemaker function occurred if the SCS output was set above a voltage and pulse duration which resulted in a product of these values above 1.9-2 mVs. Seven VVI, one VDD, and two DDD PPM had been implanted. In five patients both PPM and SCS were unipolar. In two patients the SCS was bipolar and the PPM unipolar, in two patients a bipolar PPM was associated with a bipolar SCS and with one patient, a unipolar SCS. Multiprogrammable and/or bipolar PPMs should be implanted in a patient with a SCS to allow reprogramming of the PPM and to minimize the risk of inter-device interference. Inhibition of the PPM may occur at different SCS stimulation frequencies. The frequency at which inhibition occurs varies with different models of implanted pacemaker.

Studies of cytotoxicity and metabolic competence with the rat intestinal cell line IEC-17

The characterization of metabolic activity of intestinal cells in culture may be of particular interest for the study of the effects of food additives and contaminants which, ingested through the diet, are absorbed primarily by the gut mucosa. IEC-17 cell line is derived from the intestine of newborn rat and has been shown to be competent for the metabolism of xenobiotics (Quaroni and Isselbacher, 1981), and to keep some degree of differentiation also in in vitro conditions. Our studies indicate that the xenobiotic metabolic activity of this cell line, as shown by measurement of 7-ethoxycoumarin (7-EC), can be induced by beta-naphthoflavone (NF) and not by phenobarbital (PB) and only at late subculturing stages, suggesting these cells undergo some kind of maturation in vitro. Induction of xenobiotic metabolism by beta-naphthoflavone seems also to elicit the toxicity of 9,10-dimethyl-1,2-benzathracene (DBA) but not that one of cyclophosphamide (CPA).

Expression and synthesis of fibronectin and laminin by an intestinal epithelial cell line

An intestinal epithelial cell line (IEC-17), undergoing a process of progressive morphological differentiation, was analysed for expression and synthesis of the extracellular matrix glycoproteins, fibronectin (FN) and laminin (LM). FN and LM cell surface expression was detected by immunoelectron microscopy, while intracytoplasmic accumulation was shown by immunofluorescence. 35S-methionine metabolic labelling was also performed to demonstrate FN and LM synthesis by IEC-17. We have compared two different maturation stages of the cell culture and have found that either early epithelial monolayer cells or later multistratified organoid structure cells expressed and produced large amounts of both proteins. These results indicate that FN and LM are constantly present during the process of IEC-17 organoid maturation: we can hypothesize that the two proteins act as mediators of cell to cell and cell to substrate adhesion interactions and, probably, have an active regulatory role in the process of intestinal epithelial cell differentiation.

Cytotoxic effects of wheat gliadin-derived peptides

The peptic-tryptic-cotazym (PTC) digest, obtained from bread wheat gliadin by simulating in vivo protein digestion, was more active than the PTC-digest of durum wheat gliadin in reversibly inhibiting HEp-2 cell proliferation and in increasing cellular acid phosphatase. Colony-forming ability of the cells was not affected by treatment with both bread or durum wheat gliadin peptides. The peptic-tryptic (PT) digest of bread wheat gliadin also showed agglutinating activity of HEp-2 cells.

Effects of gliadin-derived peptides from bread and durum wheats on in vitro cultures of human cell lines. Implications for coeliac disease pathogenesis

A peptic-tryptic-cotazym digest, obtained from bread (hexaploid) wheat gliadins under experimental conditions mimicking in vivo protein digestion, was found to reduce in vitro viability of human embryo (MRC-5) and tumor cell (Hep-2) lines. Time of onset and extent of cytotoxic effects were largely dependent on initial peptide concentrations in the culture medium. The presence of 2% fetal calf serum was capable of delaying, but not of preventing, the onset of cytotoxic effects only in MRC-5 cultures. A peptic-tryptic-cotazim digest obtained from durum (tetraploid) wheat gliadins and tested under identical conditions did not show any cytotoxic activity on MRC-5 and Hep-2 cell lines. These results indicate that cell systems are useful to investigate pathogenetic mechanisms of coeliac disease (gluten-dependent enteropathy).