Shared attention in virtual immersive reality enhances electrophysiological correlates of implicit sensory learning

Shared attention effects on learning and memory demonstrate that experiences are amplified when we are not alone. Virtual reality poses new challenges to the study of co-presence. Above all, is coattending together with someone else's avatar in an immersive VR setting comparable with shared experiences at a neural processing level? In the present study we investigate shared attention effects in VR for the first time. We recorded mismatch negativities (MMN) during an auditory roving paradigm, a well-known index of implicit perceptual learning. EEG responses to deviant and standard sounds were registered while subjects were alone (Solo condition) or together (Other condition) with a virtual avatar (Virtual scenario) or physically present confederate (Physical scenario). We found an overall main effect of co-presence on MMN revealed by a point-by-point 2 × 2 ANOVA, thereby replicating previous studies on physical co-presence. Additionally, we found no significant interaction between the scenario (Physical vs. Virtual) and co-presence (Solo vs. Other). Our results indicate that virtual immersive co-presence mimics physical co-presence.

The aesthetic valve: how aesthetic appreciation may switch emotional states from anxiety to curiosity

Pursuing new knowledge in the entropic environment is pivotal for survival. However, dealing with uncertainty is a costly challenge for the agent surrounded by the stochastic sensory world, giving rise to different epistemic emotions, such as curiosity and anxiety. We recently proposed that aesthetic appreciation may have the role of associating pleasant feedback with the update of predictive representations. According to this idea, aesthetic appreciation and its associated rewarding feeling could drive people to seek new knowledge over anxiety. However, the relationship between aesthetic appreciation, curiosity, and anxiety has been still under-examined in the literature. Here, we explore the relationship between these epistemic emotions in a series of three experiments. In study 1, we examined whether music-induced aesthetic appreciation would influence curiosity in a gambling task. In studies 2a and 2b, we explore the relationship between music-induced aesthetic appreciation and anxiety state. Overall, aesthetic appreciation promoted curiosity-driven behaviour while it was negatively associated with anxiety. These results were consistent with the idea that aesthetic appreciation could act as a 'valve', prompting the individual to perceive curiosity (i.e. to consider novelty as a valuable opportunity to acquire new knowledge) rather than anxiety (i.e. to consider novelty as a risk to be avoided). This article is part of the theme issue 'Art, aesthetics and predictive processing: theoretical and empirical perspectives'.

The HELLP syndrome: clinical issues and surgical management. A Case Experience

AIM

This study aims to challenge the current know-how in patients with spontaneous rupture of a liver hematoma, to differentiate amongst patients requiring such specific surgical therapy and avoiding mistakes during surgical operations, in order to terminate pregnancy with beneficial effects on the mother and fetus.

MATERIALS AND METHODS

In a emergency scenario we admitted a 37-year-old woman at 35+4 weeks of gestation for emergency cesarean section after the onset of right hypochondrium pain. A diagnosis of hemoperitoneum and severe preeclampsia with liver and splenic bleeding was done and managed with packing of hepatic and splenic hematomas and according to her haemo-dynamic clinical conditions, done in different time.

RESULTS

A diagnosis of hemoperitoneum and severe pre-eclampsia with liver and splenic bleeding was done and managed it with 3 xypho-pubic-laparatomy in different time with haemostatic packing.

DISCUSSION

In this case report, the patient underwent an emergency caesarean section and was managed with packing of hepatic and splenic hematomas and according to her haemodynamic clinical conditions was operated in different time. The choice of laparotomy and hepatic packing has proved to be a viable option in patients with unstable vital signs and is feasible even in limited resource settings.

CONCLUSION

Short interval between diagnosis and management may enhance the feto-maternal survival rate and prevent further morbidity or mortality. The choice of laparotomy and hepatic packing has proved to be a viable option in patients with unstable vital signs and is feasible even in limited resource settings.

KEY WORDS

HELLP syndrome, Liver hematoma rupture, Packing.

Physical but not virtual presence of others potentiates implicit and explicit learning

E-learning activities are becoming more and more common. Whilst it is well known that the physical presence of others motivates individuals to engage in perceptual and learning tasks, systematic investigations comparing the effects of physical and virtual co-presence of others on knowledge acquisition are still scarce. Here we investigate the effects of physical and virtual co-presence of others on explicit and implicit learning. In Experiment 1 (discovery sample), retrieval accuracy in a spatial memory task and EEG indexes (mismatch negativity-MMN) of implicit perceptual learning were recorded when participants were alone or in presence of another individual. In Experiment 2 (replicating sample), we added a "virtual" condition, where the same tasks were performed during a video-conference call. In both experiments, MMN was demonstrated to encode for perceptual learning as revealed by the significant correlation with Bayesian Surprise (a consolidated information-theoretic index of Bayesian learning). Furthermore, In Experiments 1 and 2 physical co-presence systematically ameliorated memorization performances and increased MMN indexes related to implicit learning. These positive effects were absent in the virtual condition, thus suggesting that only physical, but not virtual co-presence is effective in potentiating learning dynamics.

Nice and easy: Mismatch negativity responses reveal a significant correlation between aesthetic appreciation and perceptual learning

Neurocomputational models of cognition have framed aesthetic appreciation within the domain of knowledge acquisition and learning, suggesting that aesthetic appreciation might be considered as a hedonic feedback on successful perceptual learning dynamics. Such hypothesis, however, has never been empirically demonstrated yet. In order to investigate the relationship between aesthetic appreciation and learning, we measured the EEG mismatch negativity (MMN) response to more or less appreciated musical intervals, which is considered as a reliable index of perceptual learning. To this end, we measured the MMN to frequency (Hz) standard and frequency deviant musical intervals (Experiment 1) while participants were asked to judge their beauty. For each single stimulus, we also computed an information-theoretic index of perceptual learning (Bayesian surprise). We found that more appreciated musical intervals were associated with a larger MMN responses, which, in turn, correlated with trial-by-trial fluctuations in Bayesian surprise (Experiment 1). Coherently with previous results, Bayesian surprise was also found to correlate with slower RTs in a detection task of the same stimuli, evidencing that motor behavior is inhibited in presence of surprising sensory states triggering perceptual learning (Experiment 2). Our results provide empirical evidence of the existence of a positive correlation between aesthetic appreciation and EEG indexes of perceptual learning. We argue that the sense of beauty might have evolved to signal the nervous system new sensory knowledge acquisition and motivate the individual to search for informationally profitable stimuli. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Laparoscopic appendectomy as an index procedure for surgical trainees: clinical outcomes and learning curve

Surgical training is essential to maintain safety standards in healthcare. The aim of this study is to evaluate learning curves and short-term postoperative outcomes of laparoscopic appendectomy (LA) performed by trainees (TRN) and attendings (ATT). The present study included the medical records of patients with acute appendicitis who underwent a fully LA in our department between January 2013 and December 2018. Cases were divided into trainees (TRN and ATT groups based on the experience of the operating surgeon. The primary outcome measures were 30-day morbidity and mortality. Preoperative patients' clinical characteristics, intraoperative findings, operative times, and postoperative hospitalization were compared. Operative times were used to extrapolate learning curves and evaluate the effects of changes in faculty using CUSUM charts. A propensity score matching analysis was performed to reduce differences between cohorts regarding both preoperative characteristics and intraoperative findings. A total of 1173 patients undergoing LA for acute appendicitis were included, of whom 521 (45%) in the TRN group and 652 (55%) in the ATT group. No significant differences were found between the two groups in terms of complication rates, operative times and length of hospital stay. However, CUSUM chart analysis showed decreased operating times in the TRN group. Operative times improved more quickly for advanced cases. The results of this study indicate that LA can be performed by trainees without detrimental effects on clinical outcomes, procedural safety, and operative times. However, the learning curve is longer than previously acknowledged.

A contingent assessment of the structural and governance characteristics of interconnected dyads in multitier supply chains

Purpose

The purpose of this paper is to examine the buyer–supplier exchange dynamic in terms of the influence of product and market contingencies on the interfirm connectivity, governance and exchange performance of interconnected dyads in multitier supply chains (MSCs).

Design/methodology/approach

Using an inductive approach, the authors analyzed the supply network of a high-end motorcycle manufacturer (OEM). Four sets of “interconnected dyads” constituting four embedded units of analysis were considered, each involving the OEM, its tier 1 and corresponding tier 2 suppliers. These interconnected dyads representing four strategic components and their sub-components offer contrasts in terms of product and market contingencies.

Findings

This analysis reveals that product and market contingencies influence patterns of dependence among firms. These in turn impact interfirm connectivity (i.e. structural characteristic), and the degree of contract formalization, collaboration and concentration of decision-making power (i.e. governance characteristics) in the interconnected dyads. The authors also found that structural and governance aspects can have mutual influence, leading to satisfactory or unsatisfactory outcomes. Propositions synthesizing the relationships among the constructs are developed.

Research limitations/implications

The constructs and their underlying relationships need to be further refined if we are to devise hypotheses and validate them at a large-scale empirical level.

Originality/value

This is one of the first studies to explore the influence of business contingencies on the complex buyer–supplier exchange dynamic in MSCs having a “beyond the dyad” perspective. The authors address why and how various types of interconnectivity are developed, and how the interplay among interfirm dependence, connectivity and governance influences the suppliers’ performance in the MSCs.

Optical particle counter data collected in two inhabited sites close to an industrial hot spot during a three months survey

Data on this paper describe the monitoring of different size ranges of particulate matter on dwellings positioned close to an integral cycle steel plant. Data were collected by eight channel (PM_0.3, PM_0.5, PM_0.7, PM₁, PM₂, PM₃, PM₅, PM₁₀) optical particle counters positioned in two sites. The data were recorded as counts-per-minute for every size channel in a three months survey from June to September 2015. Basic statistical elaboration and boxplot graphs as well as raw data are included. The data are related to “Characterization of variability of air particulate matter size profiles recorded by Optical Particle Counters near a complex emissive source by use of Self-Organizing Map algorithm” Licen et al.,2019, in which a statistical elaboration by Self-Organizing Map algorithm is proposed.

Motivations of manufacturing reshoring: an interpretative framework

Purpose

– The purpose of this paper is to present a framework for the analysis of reshoring. The framework is then applied to analyze motivations for reshoring, as they emerge from extant literature and from new evidence collected.

Design/methodology/approach

– The authors start by formulating a literature-grounded definition of reshoring and reviewing some key theoretical approaches for international manufacturing location. In light of these theories, the authors then propose an interpretative framework for the analysis of reshoring motivations. Finally, the authors provide new evidence on this phenomenon, by presenting the findings of an extensive data collection of reshoring cases built on secondary data.

Findings

– The authors show that a vast array of single drivers of reshoring can be extracted from extant literature; however, the interpretative framework eventually highlights four main typologies of reshoring motivations, thus allowing for a more sound comprehension of why the phenomenon happens. The empirical investigation proves also useful in comparing the relative importance of these motivations, as it reveals that value-driven and country-specific motivations prevail over efficiency-driven and firm-specific ones, respectively.

Research limitations/implications

– The study is based on the analyses of secondary data extracted from newspapers and magazine sources. Some motivations (and especially those that configure a “correction of a previous erroneous decision”) could have been underestimated. In addition, certain industries (e.g. clothing and footwear), certain countries (USA and China), and certain firms (large companies and MNCs) could have more visibility to the media. Another possible limitation is due to the fact that the classification work inherently implied some discretion and individual judgment. The authors however spent considerable efforts in cross-validating the assessments through extensive discussion within the research team.

Originality/value

– This is the first paper that summarizes the motivations of the rising reshoring phenomenon and interprets them based on an original theory-derived classification framework.

Bioaccumulation of polycyclic aromatic hydrocarbons and survival of earthworms (Eisenia andrei) exposed to biochar amended soils

Biochar has a charcoal polycyclic aromatic structure which allows its long half-life in soil, making it an ideal tool for C sequestration and for adsorption of organic pollutants, but at the same time raises concerns about possible adverse impacts on soil biota. Two biochars were tested under laboratory-controlled conditions on Eisenia andrei earthworms: a biochar produced at low temperature from wine tree cuttings (WTB) and a commercial low tar hardwood lump charcoal (HLB). The avoidance test (48-h exposure) showed that earthworms avoid biochar-treated soil with rates higher than 16 t ha(-1) for HLB and 64 t ha(-1) for WTB. After 42 days, toxic effects on earthworms were observed even at application rates (100 t ha(-1)) that are generally considered beneficial for most crops. The concentration of HLB and WTB required to kill half of earthworms' population (LC50; 95% confidence limits) in the synthetic OECD soil was 338 and 580 t ha(-1), respectively. Accumulation of polycyclic aromatic hydrocarbons (PAH) in earthworms exposed to the two biochar types at 100 t ha(-1) was tested in two soils of different texture. In biochar-treated soils, the average earthworm survival rates were about 64% in the sandy and 78% clay-loam soils. PAH accumulation was larger in the sandy soil and largest in soils amended with HLB. PAH with less than four rings were preferentially scavenged from the soil by biochars, and this behaviour may mask that of the more dangerous components (i.e. four to five rings), which are preferentially accumulated. Earthworms can accumulate PAH as a consequence of exposure to biochar-treated soils and transfer them along the food chain. Soil type and biochar quality are both relevant in determining PAH transfer.

Integrative population pharmacokinetic and pharmacodynamic dose finding approach of the new camptothecin compound namitecan (ST1968)

AIMS

Namitecan is a new camptothecan compound undergoing early clinical development. This study was initiated to build an integrated pharmacokinetic (PK) and pharmacodynamic (PD) population model of namitecan to guide future clinical development.

METHODS

Plasma concentration-time data, neutrophils and thrombocytes were pooled from two phase 1 studies in 90 patients with advanced solid tumours, receiving namitecan as a 2 h infusion on days 1 and 8 every 3 weeks (D1,8) (n = 34), once every 3 weeks (D1) (n = 29) and on 3 consecutive days (D1-3) (n = 27). A linear three compartment PK model was coupled to a semiphysiological PD-model for neutrophils and thrombocytes. Data simulations were used to interrogate various dosing regimens and give dosing recommendations.

RESULTS

Clearance was estimated to be 0.15 l h(-1), with a long terminal half-life of 48 h. Body surface area was not associated with clearance, supporting flat-dosing of namitecan. A significant and clinically relevant association was found between namitecan area under the concentration-time curve (AUC) and the percentage drop of neutrophils (r(2) = 0.51, P < 10(-4)) or thrombocytes (r(2) = 0.49, P < 10(-4)). With a target for haematological dose-limiting toxicity of <20%, the recommended dose was defined as 12.5 mg for the D1,8 regimen, 23 mg for the once every 3 week regimen and 7 mg for the D1-3 regimen.

CONCLUSION

This is the first integrated population PK-PD analysis of the new hydrophilic topoisomerase I inhibitor namitecan, that is currently undergoing early clinical development. A distinct relationship was found between drug exposure and haematological toxicity, supporting flat-dosing once every 3 weeks as the most adequate dosing regimen.

Validation of a food frequency questionnaire to assess food group intake by pregnant women

BACKGROUND

Previous studies conducted among pregnant women to test the accuracy of food frequency questionnaires (FFQ) for estimating food group intake were restricted to one specific trimester of pregnancy. The present study aimed to validate a FFQ for assessing the intake of food groups throughout pregnancy.

METHODS

In total, 75 adult pregnant Brazilian women were evaluated. Dietary intake was assessed by the FFQ (completed at the third trimester of pregnancy) and by three 24-h dietary recalls; one in each trimester of pregnancy.

RESULTS

The food items were classified into 20 groups. Adequate deatenuatted Pearson correlation coefficients (>0.4) were observed for the intake of bread/cake, butter/margarine; milk/dairy products; soft drinks/artificial juices; coffee/tea; and pastries/sandwiches. The FFQ served poorly for estimating fruit and vegetable intake. A high percentage (>70%) of women were classified into the same or adjacent quartiles for estimates of cookies/crackers, butter/margarine, milk/dairy products, fruit juices, soft drinks/artificial juices, coffee/tea, roots, rice, beans, meat/chicken/sausages, fried foods, fish, eggs, sweets/sugars, and pastries/sandwiches. Nevertheless, the agreement of joint classification between the dietary methods was mostly into adjacent quartiles, rather than in the same quartile, and low values of kappa were found.

CONCLUSIONS

The data reported in the present study suggest that the FFQ might not be an appropriate dietary method for evaluating food group intake throughout pregnancy. The joint classification between methods by categories of intake of food groups was mostly into adjacent quartiles, which could lead to attenuated associations when investigating diet-disease relationships during pregnancy.

Isolation and Metabolic Characterization of a Pseudomonas stutzeri Mutant Able To Grow on the Three Isomers of Xylene

From an o-xylene-degrading Pseudomonas stutzeri strain (OX1), we previously isolated mutant M1, which had acquired the ability to grow on m-xylene and p-xylene but lost the ability to utilize the ortho isomer. From M1 cultures we have now isolated a revertant strain (R1) which grows on o-xylene and retains the ability to grow with the meta and para isomers regardless of the selective pressure applied. In P. stutzeri R1, o-xylene is degraded through two successive monooxygenations of the aromatic ring, while m-xylene and p-xylene catabolism proceeds through the progressive oxidation of a methyl substituent, although unquantifiable amounts of these two substrates are transformed into the corresponding dimethylphenols, which are not utilized for further growth. The two catabolic pathways are inducible by all three xylene isomers.

The reversed clock drawing test phenomenon in Alzheimer's disease: A perfusion SPECT study

AIM

To unveil a brain single photon emission computed tomography (SPECT) pattern in Alzheimer's disease (AD) patients, showing a reversed clock drawing test (CDT) phenomenon.

PATIENTS AND METHODS

Among 1,005 consecutive subjects, 9 AD patients who drew a reversed CDT (AD-R) underwent SPECT, which was analysed (SPM2) versus a group of 10 AD patients performing the CDT correctly (AD+) and versus 15 controls (CTR). Brain SPECT in 11 AD patients who mistook the CDT in a common way (AD-) was compared with AD+ and CTR groups.

RESULTS

Relative hypoperfusion was found in AD-R versus CTR in right medial frontal, parahippocampal and subcallosal gyri, and in left insula and superior temporal gyrus. Hypoperfusion was found in AD-R versus AD+ in the right uncus, superior temporal and parahippocampal gyri. In the AD- versus CTR comparison, hypoperfusion was found in left hippocampus, parahippocampal gyrus and superior parietal lobule. In AD-R versus AD+ and CTR merged together, the analysis showed hypoperfusion in the right parahippocampus, medial frontal gyrus, superior temporal gyrus and uncus, in the left insula and superior temporal gyrus.

CONCLUSION

Fronto-temporal dysfunction, especially in the right hemisphere, plays a role in the reversed CDT phenomenon in AD patients, whereas matched AD patients mistaking the CDT in a common way show left posterior temporo-parietal hypoperfusion.

Phase II of oral gimatecan in patients with recurrent epithelial ovarian, fallopian tube or peritoneal cancer, previously treated with platinum and taxanes

BACKGROUND

A prospective phase II study was conducted to evaluate the efficacy and toxicity of oral gimatecan in patients with recurrent epithelial ovarian, fallopian tube or peritoneal cancer.

PATIENTS AND METHODS

Patients had a maximum of three prior chemotherapy lines with no more than two prior platinum-containing regimens and a progression-free interval after the last dose of platinum <12 months. A total dose of 4 mg/m(2)/cycle (0.8 mg/m(2)/day from day 1 to day 5) was administered, repeated every 28 days.

RESULTS

From June 2005 to December 2005, 69 assessable patients were enrolled. The best overall response to study treatment by combined CA-125 and RECIST criteria was partial response in 17 patients (24.6%) and disease stabilization in 22 patients (31.9%). The median time to progression and overall survival were 3.8 and 16.2 months, respectively. A total of 312 cycles were administered. Neutropenia grade 4 and thrombocytopenia grade 4 occurred in 17.4% and 7.2% of patients, respectively. Diarrhea grade 4 was never observed. Asthenia and fatigue were reported by 36.2% and 18.8% of patients, but were all grade 2 or less.

CONCLUSION

Gimatecan is a new active agent in previously treated ovarian cancer with myelosuppression as main toxicity.

Clinical development of namitecan (ST1968), a novel camptothecin derivative with high antitumor activity: Phase I clinical data

2570

Background: Namitecan is a new water-soluble camptothecin analogue which showed high antitumor activity in preclinical models. Aim of this trial was to determine safety, PK profile and activity in adult patients with advanced solid tumors. Methods: The dose escalation started at 2.5 mg i.v. on days 1 and 8 of a 21 day cycle (D1, D8 Q21D) and increased according to 3+3 cohort design depending on the observed toxicity. Dose limiting toxicity (DLT) definitions were: ANC <0.5x109/L for >5 days; PLT ≥ Grade 3 (CTC V3); grade ≥2 liver/renal toxicity not recovered by D22; any non-hematologic toxicity ≥ Grade 3; D8 dose skipping due to toxicity. Maximum tolerated dose (MTD) and recommended dose (RD) were the primary end-points. Blood and urine samples were collected at cycle 1 for PK evaluation. Results: 31 pts (11 endometrial ca., 5 CRC, 5 ovarian ca., 2 NSCLC, 8 other) have been included, with 6 dose levels evaluated (2.5; 5; 10; 15; 17.5 and 20 mg). 17.5 mg was introduced later when 2/7 DLTs at 20 mg were observed (ANC G4>5days, one with D8 skipping). At 17.5mg 2/4 pts experienced DLTs (ANC G4; D8 skipped). Uncomplicated neutropenia and thrombocytopenia were the most relevant G3/4 hematological toxicities. Other toxicities were mild or moderate asthenia, fatigue and alopecia. The MTD was defined at 17.5 mg and the RD was 15 mg. Stable disease ≥ 6 cycles was recorded in 6 pts (2 stable diseases ≥ 10 cycles). PK was linear and data suggest an entero-hepatic recirculation. No metabolites were found in plasma and the product resulted poorly excreted into urine. Conclusions: The MTD and RD of D1, D8 Q21D schedule have been identified. The study will continue with the evaluation of MTD and RD of a single administration per cycle (D1 Q21D), to optimize the schedule of treatment.

[Table: see text]

Is PM(10) mass measurement a reliable index for air quality assessment? An environmental study in a geographical area of north-eastern Italy

The aim of this study was to measure the concentration of some metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Ti) in PM(10) samples collected in one urban and one industrial site and to assess that PM(10) total mass measurement may be not sufficient as air quality index due to its complex composition. Metals were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and differential pulsed anodic stripping voltammetry (DPASV). The measured concentrations were used to calculate the content of metals in the PM(10) total mass, and to estimate the enrichment factors and the correlations between PM(10), metal concentrations and meteorological data for the two sites. The mean PM10 concentration during the sampling period in the urban site exceeded the annual European Union (EU) standard (40 microg/m(3)) and, for some sampling days, the daily EU standard (50 microg/m(3)) was also exceeded. In opposite, both EU standards were never exceeded in the industrial site. The overall metal content was nearly double in the industrial site compared to the urban one, and the mean Ni concentration exceeded the EU annual limit value (10 ng/m(3)). The metals with the highest enrichment factor were Cd, Cu, Ni and Pb for both sites, suggesting a dominant anthropogenic source for these metals. Metal concentrations were very low and typical of rural background during Christmas holidays, when factories were closed. PM(10) total mass measurement is not a sufficient air quality index since the metal content of PM(10) is not related to its total mass, especially in sites with industrial activities. This measurement should be associated with the analysis of toxic metals.

Comparison of self-organizing maps classification approach with cluster and principal components analysis for large environmental data sets

Three classification techniques (loading and score projections based on principal components analysis (PCA), cluster analysis (CA) and self-organizing maps (SOM)) were applied to a large environmental data set of chemical indicators of river water quality. The study was carried out by using long-term water quality monitoring data. The advantages of SOM algorithm and its classification and visualization ability for large environmental data sets are stressed. The results obtained allowed detecting natural clusters of monitoring locations with similar water quality type and identifying important discriminant variables responsible for the clustering. SOM clustering allows simultaneous observation of both spatial and temporal changes in water quality. The chemometric approach revealed different patterns of monitoring sites conditionally named "tributary", "urban", "rural" or "background". This objective separation could lead to an optimization of river monitoring nets and to a better tracing natural and anthropogenic changes along the river stream.

A phase II trial of the novel oral camptothecin gimatecan (G) in women with anthracycline (A) and taxane (T) pre-treated advanced breast cancer

662

Background: Gimatecan (G) is a new oral camptothecin with a favourable therapeutic index in several tumor xenograft models and with documented antitumor activity in breast, endometrial and NSCLC cancer in Phase I. A Phase II trial was implemented to determine the antitumor activity of G in women with pre-treated metastatic breast cancer (MBC). Methods: A Simon 2-step design was used: patients with MBC who failed A & T were eligible. Treatment failure was defined as disease progressing after receiving both A and T (adjuvant or metastatic setting). All patients had ECOG 0–1. Baseline neuropathy > gr 1 or CNS metastases were criteria of exclusion. G was administered for 5 days every week on weeks 1 & 2 q4weeks at 4–5 mg/m2 total dose per cycle. Results: To date, 21 patients have received 67 cycles of G (median 3); 18 are evaluable for the 1st step analysis. Median age was 53 years (range, 32–70), all had received A & T prior treatment. The initial dose of 5 mg/m2 was reduced to 4 mg/m2 after treating the first 7 cases due to hematological toxicity (thrombocytopenia G3 30% and neutropenia G3–4 40%) that prevented the planned monthly retreatment. The toxicity at 4 mg/m2 included thrombocytopenia (% of cycles with any grade: 36%, G3 9%); neutropenia (G3 18%), diarrhea (1 case), nausea (81%, G3 18%), vomiting (G1 18%), and asthenia (G1 36%). To date, three confirmed partial responses (PR) lasting respectively 5.5, 5.7+, and 9.4+ months and two unconfirmed PR were observed in visceral and nodal sites. Accrual into step 2 is proceeding. Conclusions: Gimatecan at a dose of 4 mg/m2 is well tolerated and active. The antitumor activity of 27% observed in the first step of the study is unusual for camptothecins and prompted to continue to the second step and complete the ongoing enrolment of 43 patients overall.

[Table: see text]

Penetration of benzene, toluene and xylenes contained in gasolines through human abdominal skin in vitro

Few studies are available in literature on the risk for humans from skin exposure to gasolines. This work is focused on the in vitro skin penetration of benzene (carcinogenic substance), toluene and xylenes. We examined three commercial gasolines using the Franz diffusion cells and human abdominal full thickness skin. Gasoline composition was determined using a multi-dimensional gas chromatographic (MDGC) technique. Aromatic compounds into the receptor fluid, consisting of saline solution were quantitated by a gas chromatography technique equipped with a flame ionization detector (GC-FID) and coupled with a headspace-solid phase micro extraction system (HS-SPME). Among the three substances, benzene showed the highest average apparent permeability coefficient (K(p)=43.8x10(-5)cmh(-1)) compared to toluene (K(p)=6.48x10(-5)cmh(-1)) and xylenes (K(p)=0.84x10(-5)cmh(-1)). This value could be explained by the lower boiling point and higher water solubility of benzene. Lag times were about 1h for benzene and 2h for toluene and xylenes. Averaged total recoveries in the receptor fluid were 0.43% of dose for benzene, 0.06% for toluene and 0.008% for xylenes. A statistical significative difference (Student's t-test, P<0.05) between the fluxes calculated for the three gasolines are noted only for xylene and for toluene between gasolines #1 (richer in aromatic compounds) and #3. The obtained apparent permeability coefficient are useful for determining the permeability of these aromatics components from gasolines of a different composition. Hands exposure risk, calculated using RfD and RfC as defined by US EPA, is critical for benzene. The risk of skin permeation of gasoline, and, in particular, of benzene, should be better evaluated for those workers who have a large potential for exposure. Adequate personal protective equipment should be used in the high exposure jobs, mainly for hands and forearms.

Validation of counter propagation neural network models for predictive toxicology according to the OECD principles: a case study

The OECD has proposed five principles for validation of QSAR models used for regulatory purposes. Here we present a case study investigating how these principles can be applied to models based on Kohonen and counter propagation neural networks. The study is based on a counter propagation network model that has been built using toxicity data in fish fathead minnow for 541 compounds. The study demonstrates that most, if not all, of the OECD criteria may be met when modeling using this neural network approach.

An airlift biofilm reactor for the biodegradation of phenol by Pseudomonas stutzeri OX1

Phenol bioconversion by Pseudomonas stutzeri OX1 using either free or immobilized cells was investigated with the aim of searching for optimal operating conditions of a continuous bioconversion process. The study was developed by analyzing: (a) free-cell growth and products of phenol bioconversion by batch cultures of P. stutzeri; (b) growth of P. stutzeri cells immobilized on carrier particles; (c) bioconversion of phenol-bearing liquid streams and the establishment and growth of an active bacterial biofilm during continuous operation of an internal-loop airlift bioreactor. We have confirmed that free Pseudomonas cultures are able to transform phenol through the classical meta pathway for the degradation of aromatic molecules. Data indicate that bacterial growth is substrate-inhibited, with a limiting phenol concentration of about 600 mg/L. Immobilization tests revealed that a stable bacterial biofilm can be formed on various types of solid carriers (silica sand, tuff, and activated carbon), but not on alumina. Entrapment in alginate beads also proved to be effective for P. stutzeri immobilization. Continuous bioconversion of phenol-bearing liquid streams was successfully obtained in a biofilm reactor operated in the internal-circulation airlift mode. Phenol conversion exceeded 95%. Biofilm formation and growth during continuous operation of the airlift bioreactor were quantitatively and qualitatively assessed.

BBR 3438, a novel 9-aza-anthrapyrazole, in patients with advanced gastric cancer: A phase II study group trial of the central European Society of Anticancer-Drug Research (CESAR)

BBR 3438, a member of the 9-aza-anthrapyrazole family designed to decrease anthracycline dependent cardiotoxicity and to improve efficacy provided high in vivo activity in gastric carcinoma xenograft models. The present study was carried out to assess the efficacy and safety of BBR 3438 applied at a dose of 50 mg/m(2) four-weekly as an 1-hour infusion to pretreated patients with gastric cancer. Twenty-seven patients received at least one administration of BBR 3438. Lymph nodes and liver were the most common sites of metastases. A total of 94 cycles were administered (median 2, range 1-6). The main toxicity consisted of (worst per patient [%]; NCIC CTC grades 1/2/3/4) neutropenia 7/7/19/52 (one case of febrile neutropenia), stomatitis 15/19/4/-, nausea 22/26/7/-, vomiting 19/7/7/-, alopecia 15/33/-/-. Neutrophil nadir (520/mul) was reached after a median 15 days. The median time to recovery to < or = grade 1 neutropenia was 13.5 days. The median average cumulative dose of BBR 3438 was 166.8 mg, and the median dose intensity was 48.8 mg/m(2). Left ventricular ejection function (LVEF) was monitored with multiple-gated angiography (MUGA). Median LVEF values at baseline and at the end of cycle 2 were 67.5% and 65%, respectively, and no patient showed a relevant decrease of LVEF. In 25 patients evaluable for response no remission was observed. Four patients (16%) had stable disease. Median time to progression was 51 days, median overall survival was 64 days. In all, the feasibility and tolerability of BBR 3438 applied 4-weekly at a dose of 50 mg/m(2) was confirmed and neither relevant LVEF decreases nor hints of cardiac toxicity were observed. In terms of antitumor activity, BBR 3438 was found to be ineffective in the treatment of gastric cancer.

Application of counterpropagation artificial neural network for modelling properties of fish antibiotics

The present study focuses on fish antibiotics which are an important group of pharmaceuticals used in fish farming to treat infections and, until recently, most of them have been exposed to the environment with very little attention. Information about the environmental behaviour and the description of the environmental fate of medical substances are difficult or expensive to obtain. The experimental information in terms of properties is reported when available, in other cases, it is estimated by standard tools as those provided by the United States Environmental Protection Agency EPISuite software and by custom quantitative structure-activity relationship (QSAR) applications. In this study, a QSAR screening of 15 fish antibiotics and 132 xenobiotic molecules was performed with two aims: (i) to develop a model for the estimation of octanol--water partition coefficient (logP) and (ii) to estimate the relative binding affinity to oestrogen receptor (log RBA) using a model constructed on the activities of 132 xenobiotic compounds. The custom models are based on constitutional, topological, electrostatic and quantum chemical descriptors computed by the CODESSA software. Kohonen neural networks (self organising maps) were used to study similarity between the considered chemicals while counter-propagation artificial neural networks were used to estimate the properties.

Structure-Mutagenicity Study of 12 Trimethylimidazopyridine Isomers Using Orbital Energies and “Spectrum-like Representation” As Descriptors

The set of 12 trimethylimidazopyridine isomers with mutagenic potency toward two strains of Salmonella was treated in this study. Ten isomers with known mutagenic properties were taken to build the models. Fifteen molecular orbital energies, or a "spectrum-like" representation of 3D structures, were taken as descriptors. As modeling techniques the multiple linear regression and the counter propagation neural network were applied. Models were tested with the recall ability test and the leave-one-out cross-validation tests. For two isomers, which have not been synthesized yet, we report predicted values for both mutagenic potencies obtained with different models. The best models were found when unoccupied molecular orbital energies are among the descriptors.

Response of bacterial community during bioremediation of an oil-polluted soil

AIM

To study the response of the bacterial community to bioremediation of a soil with an aged contamination of crude oil.

METHODS AND RESULTS

The bacterial community in laboratory soil columns during a 72-day biostimulation treatment was followed by analysing the number of total cultivable hydrocarbon-degrading bacteria, soil respiratory activity and the 16S-23S rDNA internal transcribed spacer homoduplex heteroduplex polymorphisms (ITS-HHP) of total soil bacterial DNA. ITS-HHP permits an estimate of both length and sequence polymorphism in a 16S-23S rDNA spacer population, using to advantage the homoduplex and heteroduplex fragments that are generated during PCR. The treatment, made by air sparging and biostimulation with a mineral nutrient and surfactant solution, resulted in a 39.5% decrease of the total hydrocarbon content. Within 4 days of treatment onset the bacterial community underwent a first phase of activation that led to a substantial increase in the observable diversity. Subsequently, after a 12-day period of stability, another activation phase was observed with further shifts of the community structure and an increase in the abundance and diversity of catechol-2,3-dioxygenase (C23O) genes.

CONCLUSIONS

The overall data suggest an important contribution of uncultivable bacteria to the soil bioremediation, since, during the second activation phase, the increases of the respiratory activity, bacterial diversity and C23O gene abundance and diversity were not accompanied by a corresponding increase of the cultivable bacteria number.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study shows that successive phases of activation of bacterial populations occur during a bioremediation treatment of oil-polluted soil.

Levels of cadmium and zinc in hepatopancreas of reared Mytilus galloprovincialis from the Gulf of Trieste (Italy)

Cadmium and zinc concentrations were determined in hepatopancreatic tissues of Mytilus galloprovincialis, reared in three non-contaminated hatcheries of the Gulf of Trieste (Northern Adriatic Sea). Mussels were collected in 13 sampling exits with monthly frequency for verifying possible seasonal variations. Freeze dried hepatopancreatic tissues were dissolved by nitric acid procedure using a microwave system; analysis of Zn and Cd followed by AAS technique. Metal concentrations were below the critical values for mollusc soft tissues, but xenobiotic cadmium had values requiring monitoring attention. Cadmium and zinc showed moderate variations along the months, with a slight winter maximum followed by a summer pre-spawning minimum, matching the seasonal trends of temperature/salinity. The estuarine site appears to have the best quality of the examined area in terms of metal contents. The results can constitute a guideline for the water quality in the Northern Adriatic Sea, and permit comparisons with the quality of other areas of the Mediterranean Sea.

New insights into the activation of o-xylene biodegradation in Pseudomonas stutzeri OX1 by pathway substrates

The regulation of the tou operon of Pseudomonas stutzeri OX1, for degradation of toluene and o-xylene via phenolic intermediates, has been faithfully reconstructed in vitro with purified proteins. The set-up included the prokaryotic enhancer-binding protein TouR, the sigma54-dependent PToMO promoter and the sigma54-containing RNA polymerase. With this system we prove that direct binding of 2-methylphenol (o-cresol) to TouR is the only regulatory step for activation of PToMO in response to aromatic effectors, thereby ruling out the involvement of other factors or a need for protein processing. In addition, we found that while TouR failed entirely to activate PToMO in the absence of inducers, the protein had per se a very significant ATPase activity, which was only moderately increased by o-cresol addition. The results presented here support the view that TouR-like proteins are particularly suitable as evolutionary assets to endow recently evolved pathways for the degradation of environmental pollutants with an optimal degree of transcriptional regulation.

Case study of groundwater pollution in a critical area of the Southern-Friuli exposed to agricultural and landfill pressures

Groundwater of the Southern-Friuli displays high levels of agricultural pollutants, such as nitrates and triazinic herbicides not only in the surficial layers, but also in the deeper ones, below 150 m. Some wells of the district of Gonars was monitored. The examined waters, used for irrigation but also for drinkable use, are exposed to environmental risk due to both agricultural practices and presence of many waste disposal sites. Heavy metals, nitrates and triazinic herbicides were measured in samples taken at four wells in three periods having different rain conditions. We found that groundwater quality is affected mainly by agricultural practices: nitrates and triazines are present at levels very near as well as superior to the maximum concentration allowable by Italian law. These agricultural contaminants have similar levels at all sampled sites: no difference was detected between dry periods and rain ones. Heavy metal contents are negligible in all cases; this fact suggests that ion-exchange, sorbing and complexing properties of the soils hinder the way of the metal leachates towards underlying groundwater. Zinc constitutes an exception; it is found at levels near or superior to the maximum allowable concentration (CMA), and the highest contents are observed in rain periods; different sites display different zinc levels, suggesting that this metal could have various point sources. Nitrates fertilisers were found in all sites at similar levels, very near to CMA (50 mg/L). Triazines are specific herbicides for corn growing, highly diffused here: their use in recent years is forbidden by Italian law, but the presence in groundwater of parent triazines and metabolites is a persistent problem of this area. The Italian law indicates a CMA of 0.10 microgram/L for the sum of atrazine and desethylatrazine, but we found that desethylatrazine by itself exceeds largely CMA in all sites.

Tetrachloroethylene, trichloroethylene, and chlorinated phenols induce toluene-o-xylene monooxygenase activity in Pseudomonas stutzeri OX1

Pseudomonas stutzeri OX1 naphthalene-oxidation activity is induced 3.0-fold by tetrachloroethylene (PCE) and 3.1-fold by trichloroethylene (TCE) at 100 microM. With the mutant P. stutzeri M1, which does not express toluene-o-xylene monooxygenase (ToMO, product of the tou operon), no naphthalene-oxidation activity induction by PCE and TCE was found; hence, PCE and TCE induce ToMO of P. stutzeri OX1. The chlorinated phenols 2-, 3-, and 4-chlorophenol induced ToMO expression 0.58-, 0.23- and 0.37-fold, respectively, compared to the direct inducer of the pathway, o-cresol. Using P. putida PaW340 (pPP4062, pFP3028), which has the tou promoter fused to the reporter catechol-2,3-dioxygenase, and the regulator gene touR, it was determined that the tou promoter was induced directly 5.7-, 7.1-, and 5.1-fold for 2-, 3-, and 4-chlorophenol, respectively (compared to an 8.8-fold induction with o-cresol). In addition, it was found that TCE and PCE do not directly induce the tou pathway and that components other than the tou structural and regulatory genes are necessary for induction. Gas chromatography results also showed that 100 microM TCE induced its own degradation (8-9%) in 16 h in P. stutzeri OX1, and all of the stoichiometric chloride from the degraded TCE was detected in solution.

Metal contents in tench otoliths: relationships to the aquatic environment

A monitoring of the quality of waters was attempted determining metal accumulation in target organs as otoliths of freshwater fish. Tenchs of age ranging between 2 and 10 years were sampled in three different canals receiving wastewater from industrial, agricultural and urban activities. Metal contents were determined in both lapilli and asterisci otoliths, using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Analytical data are reported for minor metals and for some trace metals. Al, Fe and Zn have contents depending on the environment where the fish has lived, while Na, K, Ca and Sr contents are insensitive to the different aquatic habitat. Considering the two types of otolith separately, lapilli display a different affinity for trace metals (Al, Fe and Zn), while in asterisci this affinity is matched only for zinc. The high affinity of zinc for both types of otoliths suggests using this metal for discriminating the fresh waters by checking its accumulation in otoliths, as well as correlating this accumulation with age of the fish: a negative power curve equation is proposed. Since highest concentrations are found in individuals of 2-3 yr., it is advisable to use this fish for such environmental studies.

Aerobic degradation of mixtures of tetrachloroethylene, trichloroethylene, dichloroethylenes, and vinyl chloride by toluene-o-xylene monooxygenase of Pseudomonas stutzeri OX1

A recombinant strain of Escherichia coli (JM109/pBZ1260) expressing constitutively toluene-o-xylene monooxygenase (ToMO) of Pseudomonas stutzeri OX1 degraded binary mixtures (100 microM each) of tetrachloroethylene (PCE) with either trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis-dichloroethylene (cis-DCE), trans-1,2-dichloroethylene (trans-DCE), or vinyl chloride (VC). PCE degradation was 8-20% for these binary mixtures, while TCE and trans-DCE with PCE were degraded at 19%, 1,1-DCE at 37%, cis-DCE at 97%, and VC at 27%. The host P. stutzeri OXI was also found to degrade binary mixtures of PCE/TCE, PCE/cis-DCE, and PCE/VC when induced with toluene. Degradation of quaternary mixtures of PCE/TCE/trans-DCE/VC and PCE/TCE/cis-DCE/VC by JM109/pBZ1260 were also investigated as well as mixtures of PCE/TCE/trans-DCE/1,1-DCE/cis-DCE/VC; when all the chlorinated compounds were present, the best degradation occurred with 24-51% removal of each. For these degradation reactions, 39-85% of the stoichiometric chloride expected from complete degradation of the chlorinated ethenes was detected. The time course of PCE/TCE/1,1-DCE degradation was also measured for a mixture of 8, 17, and 6 microM, respectively; initial degradation rates were 0.015, 0.023. and 0.029 nmol/min x mg protein, respectively. This indicates that for the first time an aerobic enzyme can degrade mixtures of all chlorinated ethenes, including the once--so it was believed-completely recalcitrant PCE.

Organization and regulation of meta cleavage pathway genes for toluene and o-xylene derivative degradation in Pseudomonas stutzeri OX1

Pseudomonas stutzeri OX1 meta pathway genes for toluene and o-xylene catabolism were analyzed, and loci encoding phenol hydroxylase, catechol 2,3-dioxygenase, 2-hydroxymuconate semialdehyde dehydrogenase, and 2-hydroxymuconate semialdehyde hydrolase were mapped. Phenol hydroxylase converted a broad range of substrates, as it was also able to transform the nongrowth substrates 2,4-dimethylphenol and 2,5-dimethylphenol into 3,5-dimethylcatechol and 3,6-dimethylcatechol, respectively, which, however, were not cleaved by catechol 2,3-dioxygenase. The identified gene cluster displayed a gene order similar to that of the Pseudomonas sp. strain CF600 dmp operon for phenol catabolism and was found to be coregulated by the tou operon activator TouR. A hypothesis about the evolution of the toluene and o-xylene catabolic pathway in P. stutzeri OX1 is discussed.

Evolution of catabolic pathways and metabolic versatility in Pseudomonas stutzeri OX1

Pseudomonas stutzeri OX1 is able to degrade toluene and ortho-xylene via the direct oxygenation of the aromatic ring. The genetic studies carried out suggest that the genes coding for the monooxygenase involved in the early steps of this catabolic route have been acquired by gene transfer. P stutzeri OX1 is also potentially able to utilize meta- and para-xylene as growth substrates. These two isomers are metabolized through a different pathway (TOL pathway). Both catabolic routes can be activated or inactivated by means of genomic rearrangements. The relevance of such recombination mechanisms in the evolution and the adaptability of P. stutzeri is discussed.

Conformational analysis of putative regulatory subunit D of the toluene/o-xylene-monooxygenase complex from Pseudomonas stutzeri OX1

A gene cluster isolated from Pseudomonas stutzeri OX1 genomic DNA and containing six ORFs codes for toluene/o-xylene-monooxygenase. The putative regulatory D subunit was expressed in Escherichia coli and purified. Its protein sequence was verified by mass spectrometry mapping and found to be identical to the sequence predicted on the basis of the DNA sequence. The surface topology of subunit D in solution was probed by limited proteolysis carried out under strictly controlled conditions using several proteases as proteolytic probes. The same experiments were carried out on the homologous P2 component of the multicomponent phenol hydroxylase from Pseudomonas putida CF600. The proteolytic fragments released from both proteins in their native state were analyzed by electrospray mass spectrometry, and the preferential cleavage sites were assessed. The results indicated that despite the relatively high similarity between the sequences of the two proteins, some differences in the distribution of preferential proteolytic cleavages were detected, and a much higher conformational flexibility of subunit D was inferred. Moreover, automatic modeling of subunit D was attempted, based on the known three-dimensional structure of P2. Our results indicate that, at least in this case, standard modeling procedures based on automatic alignment on the structure of P2 fail to produce a model consistent with limited proteolysis experimental data. Thus, it is our opinion that reliable techniques such as limited proteolysis can be employed to test three-dimensional models and highlight problems in automatic model building.

Aerobic degradation of tetrachloroethylene by toluene-o-xylene monooxygenase of Pseudomonas stutzeri OX1

Tetrachloroethylene (PCE) is thought to have no natural source, so it is one of the most difficult contaminants to degrade biologically. This common groundwater pollutant was thought completely nonbiodegradable in the presence of oxygen. Here we report that the wastewater bacterium Pseudomonas stutzeri OX1 degrades aerobically 0. 56 micromol of 2.0 micromol PCE in 21 h (Vmax approximately 2.5 nmol min(-1) mg(-1) protein and KM approximately 34 microM). These results were corroborated by the generation of 0.48 micromol of the degradation product, chloride ions. This degradation was confirmed to be a result of expression of toluene-o-xylene monooxygenase (ToMO) by P. stutzeri OX1, since cloning and expressing this enzyme in Escherichia coli led to the aerobic degradation of 0.19 micromol of 2.0 micromol PCE and the generation of stoichiometric amounts of chloride. In addition, PCE induces formation of ToMO, which leads to its own degradation in P. stutzeri OX1. Degradation intermediates reduce the growth rate of this strain by 27%.