Reprogramming hMSCs morphology with silicon/porous silicon geometric micro-patterns.

Geometric micro-patterned surfaces of silicon combined with porous silicon (Si/PSi) have been manufactured to study the behaviour of human Mesenchymal Stem Cells (hMSCs). These micro-patterns consist of regular silicon hexagons surrounded by spaced columns of silicon equilateral triangles separated by PSi. The results show that, at an early culture stage, the hMSCs resemble quiescent cells on the central hexagons with centered nuclei and actin/ß-catenin and a microtubules network denoting cell adhesion. After 2 days, hMSCs adapted their morphology and cytoskeleton proteins from cell-cell dominant interactions at the center of the hexagonal surface. This was followed by an intermediate zone with some external actin fibres/ß-catenin interactions and an outer zone where the dominant interactions are cell-silicon. Cells move into silicon columns to divide, migrate and communicate. Furthermore, results show that Runx2 and vitamin D receptors, both specific transcription factors for skeleton-derived cells, are expressed in cells grown on micropatterned silicon under all observed circumstances. On the other hand, non-phenotypic alterations are under cell growth and migration on Si/PSi substrates. The former consideration strongly supports the use of micro-patterned silicon surfaces to address pending questions about the mechanisms of human bone biogenesis/pathogenesis and the study of bone scaffolds.

Long-term effects of ciprofloxacin treatment on the gastrointestinal and oropharyngeal microbiome are more pronounced after longer antibiotic courses.

BACKGROUND: Urinary tract infections (UTIs) are one of the main reasons for antibiotic prescriptions in primary care. Recent studies demonstrate similar clinical outcomes with short vs. long antibiotics courses. The aim of this study was to investigate the differential collateral effect of ciprofloxacin treatment duration on the gastrointestinal and oropharyngeal microbiome in patients presenting with uncomplicated UTI to primary care practices in Switzerland, Belgium and Poland. METHODS: Stool and oropharyngeal samples were obtained from 36 treated patients and 14 controls at the beginning of antibiotic therapy, end of therapy and one month after the end of therapy. Samples underwent shotgun metagenomics. RESULTS: At the end of therapy, patients treated with both short (≤7 days) and long (>7 days) ciprofloxacin courses showed similar changes in the gastrointestinal microbiome compared to non-treated controls. After one month, most changes in patients receiving short courses were reversed; however, long courses led to increased abundance of the genera Roseburia, Faecalicatena and Escherichia. Changes in the oropharynx were minor and reversed to baseline levels within one month. Ciprofloxacin resistance encoding mutations in gyrA/B and parC/E reads were observed in both short and long treatment groups but decreased to baseline levels after one month. An increased abundance of resistance genes was observed in the gastrointestinal microbiome after longer treatment, and correlated to increased prevalence of aminoglycoside, ß-lactam, sulphonamide, and tetracycline resistance genes. CONCLUSION: Collateral effects on the gastrointestinal community, including an increased prevalence of antimicrobial resistance genes, persists for up to at least one month following longer ciprofloxacin therapy. These data support the use of shorter antimicrobial treatment duration.

Association of hyperglycaemia with hospital mortality in nondiabetic COVID-19 patients: A cohort study.

OBJECTIVE: Diabetes is a known risk factor for mortality in Coronavirus disease 2019 (COVID-19) patients. Our objective was to identify prevalence of hyperglycaemia in COVID-19 patients with and without prior diabetes and quantify its association with COVID-19 disease course. RESEARCH DESIGN AND METHODS: This observational cohort study included all consecutive COVID-19 patients admitted to John H Stroger Jr. Hospital, Chicago, IL from March 15, 2020 to May 3, 2020 and followed till May 15, 2020. The primary outcome was hospital mortality, and the studied predictor was hyperglycaemia [any blood glucose ≥7.78 mmol/L (140 mg/dL) during hospitalization]. RESULTS: Of the 403 COVID-19 patients studied, 51 (12.7%) died; 335 (83.1%) were discharged while 17 (4%) were still in hospital. Hyperglycaemia occurred in 228 (56.6%) patients; 83 of these hyperglycaemic patients (36.4%) had no prior history of diabetes. Compared to the reference group no-diabetes/no-hyperglycaemia patients the no-diabetes/hyperglycaemia patients showed higher mortality [1.8% versus 20.5%, adjusted odds ratio 21.94 (95% confidence interval 4.04-119.0), P < 0.001]; improved prediction of death (P = 0.01) and faster progression to death (P < 0.01). Hyperglycaemia within the first 24 and 48 h was also significantly associated with mortality (odds ratio 2.15 and 3.31, respectively). CONCLUSIONS: Hyperglycaemia without prior diabetes was common (20.6% of hospitalized COVID-19 patients) and was associated with an increased risk of and faster progression to death. Development of hyperglycaemia in COVID-19 patients who do not have diabetes is an early indicator of progressive disease.

Life-style factors associated with overweight and obesity among Spanish adults.

OBJECTIVES: To assess the relationship between life styles and eating habits with the overweight and obesity prevalence in a Spanish adult population. METHODS: A population-based, cross-sectional study conducted on 2640 subjects older than 15 years, in Cádiz (Spain). Surveys were conducted in subjects' homes to obtain life styles, eating habits, and anthropometric data. Logistic regression has been used to study the association between the life style variables and overweight and obesity. RESULTS: Prevalence of overweight and obesity in Cadiz is 37% and 17%, respectively; higher in males and increases with age. BMI has an inverse relationship with educational level (PR = 2.3, 1.57-2.38). The highest levels of obesity are associated with daily alcohol consumption (PR = 1.39, 1.29-1.50), greater consumption of television,and sedentary pursuit (PR 1.5, 1.07-1.24). A lower prevalence of obesity is observed among those with active physical activity (10.9% vs 21.6%), with differences between sex. Following a slimming diet is more frequent in the obese and in women but dedicate more hours than men to passive activities. In men is greater the consumption of alcohol, high energy foods and snacks. Overweight and obesity is associated with the male sex (OR = 3.35 2.75-4.07), high consumption of alcohol (OR = 1.38 1.03-1.86) and watching television (OR = 1.52 1.11-2.07), and foods likes bread and cereals (OR = 1.47 1.13-1.91). Exercise activities is a protective factor (OR = 0.76 0.63-0.98). CONCLUSIONS: Life styles factors associated with overweight and obesity present different patterns in men and women and is necessary to understand them to identify areas for behavioural intervention in overweight and obesity patients.

Audit of cataract surgery in Cadiz: visual outcomes and complications. / Auditoría de la cirugía de catarata senil en Cádiz: resultados visuales y complicaciones.

OBJECTIVE: To publish the outcomes and complications of age-related cataract surgery in Cadiz (Spain). Due to the lack of national audits, a comparison was made between the results obtained here and those of the most recent European audit, EUREQUO (2013), and the British audit RCOphth NOD (2015). METHODS: A prospective, longitudinal, before-after study of 312 patients undergoing cataract surgery in the University Hospitals of Puerta del Mar and Puerto Real (Cadiz), in 2013-14. Outcome measurements included sociodemographic characteristics, visual acuity (VA), symptoms secondary to cataract, ocular comorbidity, waiting time, expertise of surgeon (consultant vs. trainee), rate and type of surgical complications. RESULTS: The median age at surgery was 73.92±7.31. Almost all (98.3%) of patients at consultation had a VA ≥0.60logMAR, with a mean pre-surgical VA of 1.01logMAR (0.92-1.10). There was a 6.7% complication rate, with 3.8% posterior capsule ruptures and 2.8% corneal decompensations. No cases of endophthalmitis occurred. The mean post-operative VA was 0.28logMAR (0.22-0.33). More than three-quarters (78.8%) of cases achieved a post-operative VA ≤0.3logMAR, and 27.6% of cases achieved a VA ≤0.0logMAR. CONCLUSIONS: Our success rate was inferior to the EUREQUO and RCOphth NOD studies, with the percentage of patients acquiring a postoperative VA ≤0.3logMAR being 98% and 89%, respectively. However, the populations were not comparable. It is hoped that this study will encourage other public hospitals in Spain to undertake audits and share their results, in order to provide a tool for constructive criticism and quality improvement initiatives.

Hybrid titania-aminosilane platforms evaluated with human mesenchymal stem cells.

The properties of hybrid aminopropyltriethoxysilane-tetraisopropylorthotitanate (APTS-TIPT) platforms prepared by a sol-gel route have been explored, and their biocompatibility was assayed after culture of human mesenchymal stem cells (hMSCs). The organic content of this material was observed to be preferably surface-oriented as indicated by microanalytical techniques. Furthermore, the surface showed characteristic amino-silane bands when explored by Raman spectroscopy as well as indications of silane and titanate condensation. Surface activity of the amino groups was probed by ultraviolet-visible spectroscopy imine derivatization and chemical force spectroscopy, showing a pH-dependent surface charge-induced potential. hMSCs cultured onto these surfaces showed relevant differences with respect to their behavior on gelatin-coated glass plates. Even if with a lower proliferative rate than controls, the cells develop long cytosolic prolongations in osteogenic differentiation medium, thus, supporting the idea of an APTS-TIPT stimulated process.

Direct laser writing of nanorough cell microbarriers on anatase/Si and graphite/Si.

The formation of hierarchical structures consisting of microstripe barriers decorated with nanorough ablated materials prepared by direct laser writing is described. Linear features of circa 25µm width and 12µm height are achieved on amorphous and crystalline titania and graphitic carbon films deposited on silicon. Ablated protrusions build up barriers decorated by nanoscale Si-film reconstructions, as indicated by EDX maps and micro-Raman spectroscopy. Wettability tests show a dramatic change in water contact angle, which leads to almost full wetting after irradiation, irrespective of the original film composition. Fluorescence microscopy images of human mesenchymal stem cells cultured on 1D and 2D structures demonstrate the short term biocompatibility of the ablated surfaces. It is shown that cells adhere, extend and polarize on feature edges, independently of the type of surface, thus suggesting that the created nanoroughness is at the origin of the antifouling behavior. In particular, irradiated anatase and graphite surfaces demonstrate an increased performance of crystalline films for the creation of cell guiding and trapping devices. The results suggest that such laser processing of films may serve as a time-and-cost-efficient method for the design of few-cells analytical surfaces.

Surface micro- and nano-texturing of stainless steel by femtosecond laser for the control of cell migration.

The precise control over the interaction between cells and the surface of materials plays a crucial role in optimizing the integration of implanted biomaterials. In this regard, material surface with controlled topographic features at the micro- and nano-scales has been proved to affect the overall cell behavior and therefore the final osseointegration of implants. Within this context, femtosecond (fs) laser micro/nano machining technology was used in this work to modify the surface structure of stainless steel aiming at controlling cell adhesion and migration. The experimental results show that cells tend to attach and preferentially align to the laser-induced nanopatterns oriented in a specific direction. Accordingly, the laser-based fabrication method here described constitutes a simple, clean, and scalable technique which allows a precise control of the surface nano-patterning process and, subsequently, enables the control of cell adhesion, migration, and polarization. Moreover, since our surface-patterning approach does not involve any chemical treatments and is performed in a single step process, it could in principle be applied to most metallic materials.

Characteristics of eating disorders in a university hospital-based Spanish population.

OBJECTIVE: To describe the personal and family antecedents and clinical characteristics of patients with eating disorders (EDs) in a population of the south of Spain; to analyse the influence of lifestyles, family functioning, socioeconomic status (SES), and psychological characteristics in these processes. DESIGN: A university-based case-control study. SETTING: University Hospital (Andalusia, Spain). SUBJECTS: A total of 120 patients with EDs and 240 controls. INTERVENTIONS: SCOFF, EDI, APGAR family, and SES questionnaires. RESULTS: In all, 67.5% of patients presented anorexia (AN), 15% bulimia (BN), and 17.5% mixed forms. EDs emerged at around 18-20 y (95% CI 17.9-19.8). Factors associated with EDs are psychiatric conditions (depression OR: 4.16, anxiety OR: 4.59), more frequent use of medication (OR: 2.26), dietary fibre (OR: 2.59), and laxatives (OR: 3.47). Toxics consumption, sport activity, SES, and family antecedents of pathology are not associated with EDs. An inverse relationship was found between family functioning and the scores in various subscales of the EDI. CONCLUSIONS: Eating disorders in Andalusia (Spain) are influenced significantly more by psychological, family, and cultural factors than by social factors.

Prolactin (PRL)-PRL receptor system increases cell proliferation involving JNK (c-Jun amino terminal kinase) and AP-1 activation: inhibition by glucocorticoids.

PRL receptor (PRLR) signal transduction supports PRL-induced growth/differentiation processes. While PRL is known to activate Jak2-Stat5 (signal transducer and activator of transcription 5) signaling pathway, the mechanism by which cell proliferation is stimulated is less known. We show that PRL induces proliferation of bovine mammary gland epithelial cells and AP-1 site activation. Using PRLR mutants and the PRLR short form, we have found that both homodimerization of PRLR wild type and the integrity of box-1 and C-distal tyrosine of PRLR intracellular domain are needed in PRL-induced proliferation and AP-1 activation. The effect of PRL has been assayed in the presence of dexamethasone (Dex), insulin, and alone. We found that Dex negatively regulates PRL-induced proliferation and AP-1 site activation. We demonstrate that PRL exerts activation of AP-1 transcriptional complex, and the mechanism by which this activation is produced is also studied. We show that PRL induces an increase in the c-Jun content of AP-1 transcriptional complexes. The PRL-induced c-Jun of AP-1 transcriptional complex diminishes in the presence of Dex in a dose-dependent manner. Dex inhibition was reversed by the higher concentration of PRL added to cells. Despite the fact that the regulation of the AP-1 site is complex, we found that PRL activates the c-Jun amino terminal kinase (JNK), while glucocorticoid prevents this JNK activation. These data support a regulation of cellular growth by PRL-PRLR system by increasing AP-1 transcriptional complex activity via JNK activation. JNK activation can be repressed by glucocorticoid in a DNA-binding-independent manner.

Prolactin receptor is associated with c-src kinase in rat liver.

The mechanism of action of the pituitary hormone PRL was studied in hepatocytes of lactating rats. PRL receptor immune complexes obtained from liver lysates have an associated tyrosine kinase activity. The tyrosine kinase has been identified in isolated hepatocytes as pp60c-src. Incubation of hepatocytes with PRL induces the association of PRL receptor with pp60c-src and the resultant stimulation of its tyrosine kinase activity. Furthermore, PRL stimulates the gene expression of c-fos, c-jun, and c-src. All of these findings support the idea that the pp60c-src tyrosine kinase participates in the early steps of the PRL intracellular signaling that promotes cell growth in liver cells.

The short form of the prolactin (PRL) receptor silences PRL induction of the beta-casein gene promoter.

The PRL receptor (PRLR) is a member of the cytokine receptor superfamily. Rats and mice express two forms of PRLR, short (SPRLR) and long (LPRLR), which differ in the length and sequence of their cytoplasmic domains. We have analyzed the ability of each form of rat PRLR to transduce lactogenic signals in a bovine mammary gland epithelial cell line. The rat PRLR forms were expressed and detected by RT-PCR, indirect immunofluorescence, and cell surface ligand binding. When the biological activity of each form of PRLR was assessed by transient transfection, we found that the long form was able to activate the beta-casein gene promoter and that the short form was inactive. Interestingly, the coexpression of both forms of PRLR resulted in a block of PRL signal to the milk protein gene promoter as a function of the concentration of the SPRLR. Similar results were obtained when LPRLR was coexpressed with totally or partially inactive tyrosine mutants of either the Nb2 form or the LPRLR form. Thus, these results suggest that the SPRLR form has at least one clear biological function, i.e. to silence lactogenic signals and to contribute to a differential and acute PRL effect in rat tissues. Furthermore, the data derived from coexpression of LPRLR and PRLR mutants confirm a crucial role of the C-terminal tyrosine residue in lactogenic signaling and the dimerization of PRLRs.

Regulation of expression of the messenger ribonucleic acid encoding the cytosolic form of phosphoenolpyruvate carboxykinase in liver and small intestine of lactating rats.

The content of P-enolpyruvate carboxykinase enzyme mRNA (mRNA(PEPCK)) in the liver and small intestine changes in a coordinate way at various stages of pregnancy, lactation, and weaning periods of rats. On the ninth day of lactation, the accumulation of mRNA(PEPCK) in the liver and small intestine was 82% and 152%, respectively, compared with that in starved control rats. After 18 h of induced weaning, both tissues presented residual levels of mRNA(PEPCK). However, after 60 h of induced weaning, the accumulation of mRNA(PEPCK) increased to 60% in the liver and 76% in the small intestine compared with that in starved control rats. Adrenalectomy and bromocriptine-induced hypoprolactinemia decreased the content of this mRNA in the liver of lactating rats, while diabetes increased it. PEPCK gene transcription, determined in isolated nuclei, was 2.4-fold higher in the liver of lactating rats than in hypoprolactinemic animals, but 3.7-fold lower than that in starved animals. These results suggest that the mRNA(PEPCK) accumulation observed in the liver of lactating rats must be due to an increase in both transcription rate and messenger stabilization. PRL added to primary culture of hepatocytes obtained from lactating rats caused a dose-dependent increase in the level of mRNA(PEPCK) and mRNAc-myc. Therefore, the high PEPCK activity reported during lactation is due to increased amounts of mRNA(PEPCK), which, in turn, is due to a coordinated response at transcriptional and posttranscriptional levels, where PRL seems to play an important role.

Prolactin increases cytosolic free calcium concentration in hepatocytes of lactating rats.

PRL at a physiological concentration (10(-8) M) produced a very rapid and transient increase in 45Ca efflux in freshly isolated hepatocytes, which reached the highest value within 5 min and returned to baseline level after 20 min. PRL-induced 45Ca2+ efflux resulted in a loss of 15% of total cell calcium, which was similar to that found in vasopressin-treated cells. However, in contrast with the PRL effect, 45Ca2+ efflux induced by vasopressin was sustained. We demonstrate by using two different approaches, glycogen phosphorylase-a activation and direct cytosolic calcium concentration [( Ca2+]i) measurements, that PRL elicits a [Ca2+]i increase. The treatment of hepatic cells with PRL caused a 4-fold stimulation in glycogen phosphorylase-alpha activity after 2 min of PRL addition. Direct [Ca2+]i determination in fluo-3-loaded hepatocytes showed a 11% increase after 5 min of PRL addition. Similar data were observed in hepatocytes stimulated either with vasopressin (10(-7) M) or calcium ionophore A23187 (200 nM). The increase in [Ca2+]i promoted by PRL was independent of extracellular calcium or voltage-operated calcium channels. The data demonstrate that calcium is involved in the intracellular signaling of PRL in liver cells and that PRL initiates its action by a Ca2+ mobilization from the intracellular stores.

Transgenic mice expressing bovine GH develop arthritic disorder and self-antibodies.

We observed disability of movement in 6-month-old transgenic mice expressing the fusion gene coding for the bovine GH (bGH) under the transcriptional control of phosphoenolpyruvate carboxykinase promoter (PEPCK-bGH). Histological study of the knee joint showed altered synovial and tibial articular cartilage tissues. In the cartilage the following observations were made: (i) generalized loss of the normal zonal structure and presence of clefts, and (ii) profound alterations in chondrocyte growth/differentiation processes consistent with hypertrophy. The synovial tissue showed a reduced number of adipocytes, and a significant thickening of synovial lining tissue and pannus. These findings indicate that transgenic mice suffer damage to diarthritic joints with osteoarthritic appearance. As changes in synovial membrane in osteoarthritis are almost indistinguishable from those seen in inflammatory arthritis, we determined the potential correlation with an immunological disorder. Serological determination of self-antibodies measured as a function of age and sex showed anti-nuclear, anti-single-stranded DNA, anti-double-stranded DNA and anti-70K antibodies, and an altered immunoglobulin typing. These results suggest that transgenic mice expressing bGH develop an arthritic process which is correlated with an immune disorder. The results also indicate that these mice are a suitable animal model to study the specific role of GH-driven processes in immune cells and arthritis.

Biological evaluation of aerosol-gel-derived hydroxyapatite coatings with human mesenchymal stem cells.

The bioactive properties of hydroxyapatite (HAP) are evaluated for applications involving the enhancement of biocompatible prostheses by seeding human pluripotent mesenchymal stem cells (MSCs). The in vitro response of human MSCs seeded on aerosol-gel HAP coatings is addressed in this work. The processing of the HAP coatings has been carried out by the aerosol-gel technique using calcium nitrate and triethylphosphate as starting precursors. The characterization of the coatings was carried out by using transmission electron microscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, energy disperse X-ray microanalysis, and surface force microscopy, which confirmed the high performance of the HAP coatings. In vitro tests show that human MSCs adhere to aerosol-gel-derived HAP coatings and show proliferation signals on these surfaces.

Detection and hormonal regulation of the mRNA for cytosolic phosphoenolpyruvate carboxykinase in rat lung.

We have studied the presence of the messenger RNA (mRNA) for the cytosolic enzyme, phosphoenolpyruvate carboxykinase (PEPCK), in rat lung by Northern blot hybridization to a complementary DNA (cDNA) probe. Lung from normal rats contained substantial amounts of this mRNA, although its relative concentration was approximately six times lower than in liver. Fasting produced an eightfold increase in the content of the enzyme mRNA in lung, which could be reverted to normal values by glucose refeeding. Induced diabetes also resulted in a sevenfold increase of the levels of PEPCK mRNA in lung. Dexamethasone, thyroid hormone, dibutyryl cyclic adenosine monophosphate (cAMP), histamine, and serotonin also induced important accumulations of the enzyme mRNA without affecting the concentration of beta-tubulin mRNA measured as reference. Thus, the PEPCK gene appears to be regulated in a similar manner in lung and liver. The results suggest that PEPCK may be involved in lung metabolism in starvation, diabetes, and other specific hormonal situations.

Epidemiological study of the influence of family and socioeconomic status in disorders of eating behaviour.

OBJECTIVE: To analyse the differences in family functioning and socioeconomic status between subjects with disorders of eating behaviour and the healthy population, considering the possible relationship of these factors with the psychic characteristics of patients, with consumption of various substances, and with sexual practices. DESIGN: Case-control study. SETTING: 'Puerta del Mar' University Hospital (Andalusia, Spain). SUBJECTS: Conducted on a sample of 120 patients with AN and BN, and 240 controls with an identical distribution by age and sex. INTERVENTIONS: SCOFF, eating disorder inventory (EDI), Apgar family and socioeconomic questionnaires are utilised. RESULTS: Patients with disorders of eating behaviour present greater family dysfunctioning than controls; among cases, this difference is greater in the acute forms, but there are no differences between recent situations or crises due to previous episodes. Family dysfunction is associated with higher scores of multiple subscales of the EDI, which is corroborated on analysing each of the Apgar parameters independently. Family functioning is not associated with other variables such as breast-feeding or consumption of toxic substances. Socioeconomic status does not differentiate cases from controls, or acute situations from evolving ones, or new episodes from other crisis episodes, although differences may be found in the psychic manifestations according to social class. CONCLUSIONS: It is confirmed that family functioning has an influence in these types of disorder, in their evolution and in the psychic characteristics of the patients, without any evidence being found of a relationship between these disorders and socioeconomic status.

Expression of CCAAT/enhancer-binding protein-beta (C/EBPbeta) and CHOP in the murine growth plate. Two possible key modulators of chondrocyte differentiation.

Our aim was to evaluate the expression of transcription factors CCAAT/enhancer-binding protein-beta (C/EBPbeta) and C/EBP-homologous protein (CHOP) in the growth plate. Proximal tibial epiphyseal growth plates from ten 15-day-old Wistar rats were used. Additionally, anti-proliferating cell nuclear antigen (PCNA), anti-5-bromo-2'-deoxyuridine (BrdU) immunostaining, terminal transferase dUTP nick end-labelling (TUNEL) and nucleolar organiser region-associated proteins (AgNOR) techniques were peformed. The histological morphology of the growth plate from C/EBPbeta knock-out mice was also analysed. The normal growth plate showed that C/EBPbeta and CHOP factors are expressed both in the germinative/ upper proliferative and in the lower proliferative zones. Furthermore, BdrU+ and PCNA+ cells were present exclusively in the germinative and proliferative zones, while TUNEL+ and AgNOR+ cells were seen in all three zones of the growth plate. Acellular areas, hypocellularity, the increase in cell death and anomalies in the architecture of the cell columns were observed in the growth plates of C/EBPbeta (-/-) knockout mice. We suggest that C/EBPbeta and CHOP transcription factors may be key modulators participating in the chondrocyte differentiation process in the growth plate.

[Injury rate and incidence of accidents with biological risk among infirmary students]. / Accidentalidad e incidencia de accidentes biológicos de riesgo en estudiantes de enfermería.

BACKGROUND: A study of the incidence and characteristics of biological accidents among infirmary students during their practicals at the hospital. MATERIAL AND METHOD: A retrospective study carried out at five centres by means of two questionnaires, one on the duration of the training and the rate of accidents and the other on the characteristics, precautions and ports exposure behaviour. RESULTS: Out of 397 students, 70,5% had accidents at a rate of 64% (CI 95%, 59-68). Of these, 15% were accidents with biological risk, the majority being jabs (39%) and splashes (32,5%). It is worth note that 49,2% occurred while putting away the material and 58% in the absence of any individual protective measures. One out of 8 accidents implied a biological risk. CONCLUSIONS: A very high rate of accidents was observed with important deficiencies in security.