Recent developments and prospects of sustainable remediation treatments for major contaminants in soil: A review.

Rapid industrialisation and urbanisation are contributing to the entry of emerging contaminants into the environment, posing a significant threat to soil health and quality. Therefore, several remediation technologies have been investigated and tested at a field scale to address the issue. However, these remediation technologies face challenges related to cost-effectiveness, environmental concerns, secondary pollution due to the generation of by-products, long-term pollution leaching risks, and social acceptance. Overcoming these constraints necessitates the implementation of sustainable remediation methodologies that prioritise approaches with minimal environmental ramifications and the most substantial net social and economic advantages. Hence, this review delves into diverse contaminants that threaten soil health and quality. Moreover, it outlines the research imperatives for advancing innovative remediation techniques and effective management strategies to tackle this concern. The review discusses a remediation treatment train approach that encourages resource recovery, strengthens the circular economy, and employs a Life Cycle Assessment (LCA) framework to assess the environmental impacts of different remediation strategies. Additionally, the study explores mechanisms to integrate sustainability principles into soil remediation practices. It underscores the necessity for a comprehensive and systematic approach that takes into account the economic, social, and environmental consequences of remediation methodologies in the development of sustainable solutions.

A geo-chemo-mechanical study of a highly polluted marine system (Taranto, Italy) for the enhancement of the conceptual site model.

The paper presents the results of the analysis of the geo-chemo-mechanical data gathered through an innovative multidisciplinary investigation campaign in the Mar Piccolo basin, a heavily polluted marine bay aside the town of Taranto (Southern Italy). The basin is part of an area declared at high environmental risk by the Italian government. The cutting-edge approach to the environmental characterization of the site was promoted by the Special Commissioner for urgent measures of reclamation, environmental improvements and redevelopment of Taranto and involved experts from several research fields, who cooperated to gather a new insight into the origin, distribution, mobility and fate of the contaminants within the basin. The investigation campaign was designed to implement advanced research methodologies and testing strategies. Differently from traditional investigation campaigns, aimed solely at the assessment of the contamination state within sediments lying in the top layers, the new campaign provided an interpretation of the geo-chemo-mechanical properties and state of the sediments forming the deposit at the seafloor. The integrated, multidisciplinary and holistic approach, that considered geotechnical engineering, electrical and electronical engineering, geological, sedimentological, mineralogical, hydraulic engineering, hydrological, chemical, geochemical, biological fields, supported a comprehensive understanding of the influence of the contamination on the hydro-mechanical properties of the sediments, which need to be accounted for in the selection and design of the risk mitigation measures. The findings of the research represent the input ingredients of the conceptual model of the site, premise to model the evolutionary contamination scenarios within the basin, of guidance for the environmental risk management. The study testifies the importance of the cooperative approach among researchers of different fields to fulfil the interpretation of complex polluted eco-systems.

Neoadjuvant chemotherapy in locally advanced colon cancer: a systematic review.

BACKGROUND: Preoperative or neoadjuvant chemotherapy (NAC) has emerged as a novel alternative to treat locally advanced colon cancer (LACC), as in other gastrointestinal malignancies. However, evidence of its efficacy and safety has not yet been gathered in the literature. The aim of the present study was to perform an extensive review of the scientific evidence for NAC in patients with LACC. METHODS: PubMed, EMBASE, MEDLINE and Cochrane Library were searched for a systematic review of the literature from 2010 to 2019. Six eligible studies were included, with a total of 27,937 patients, 1232 of them (4.4%) treated with NAC. There were only one randomized controlled trial, three phase II non-randomized single arm studies and two retrospective studies. RESULTS: The baseline computed tomography scan showed that most of patients had a T3 tumor. The completion rate of the planned neoadjuvant treatment ranged from 52.5 to 93.8%. Between 97.2 and 100% of patients had the scheduled surgery. The median tumor volume reduction after NAC ranged from 62.5 to 63.7%. The anastomotic leak rate in the NAC group ranged from 0 to 7%, with no cases of postoperative mortality. There was major pathological tumor regression in 4-34.7% of cases. Between 84 and 100% of NAC patients had R0-surgery. Survival after NAC seems to be encouraging although significant improvement has only been proven in T4b tumours. CONCLUSIONS: According to our systematic review, the NAC may be a safe and effective emerging therapeutic alternative for treating LACC. This approach, which is still being tested, increases the reliance on accurate radiological staging.

Experimental investigations and numerical modelling of in-situ reactive caps for PAH contaminated marine sediments.

The present study compared numerical modelling and experimental investigations to evaluate the effectiveness of in-situ reactive capping for marine sediments contaminated by polycyclic aromatic hydrocarbons (PAHs). As a case study, sediment samples from Mar Piccolo (Italy) were analyzed and experiments were undertaken using batch columns. Two types of capping amendments were tested: AquaGate® + 5 % of powdered activated carbon (AG PAC) and Organoclay Reactive Core Mat (OC RCM). The column tests were carried out for 20 days, obtaining a short-term PAH distribution for three cases analysed, which compared the application of the two caps with no intervention. In parallel, in order to evaluate the intervention long term efficacy, an ad-hoc multilayered model predicting PAH concentrations into the sediments and the overlying water column was developed and validated with the experimental results. Both capping systems considerably reduced PAH concentrations in the overlying water, with the highest performance seen in AG PAC for benzo[a]pyrene (99 %) and anthracene (72 %); results also confirmed in the model predictions. In addition, the numerical simulations indicated a good efficiency of both caps over time, obtaining PAH values below the threshold limit in the long term. Although further experiments need to be developed accounting for multiple contamination competitiveness.

Dietary inflammatory index and mortality: a cohort longitudinal study in a Mediterranean area.

BACKGROUND: Higher Dietary Inflammatory Index (DII®) scores are associated with increased morbidity and mortality. However, little is known about the effects of DII on mortality in Mediterranean countries. Therefore, in the present study, we aimed to investigate the potential association between DII scores and overall, cancer and cardiovascular disease (CVD) mortality in people living in a Mediterranean area. METHODS: DII scores were calculated using a validated food-frequency questionnaire. DII scores were then categorised into tertiles. Mortality was ascertained via death certificates. The association between DII scores with overall and cause-specific mortality was assessed via a multivariable Cox's regression analysis and reported as hazard ratios (HRs) with their 95% confidence intervals (CIs). RESULTS: The study included 1565 participants (mean age 65.5 years; females 44.7%). After a median follow-up of 12 years (2005-2017), 366 (23.4%) participants died. After adjusting for 17 potential confounders, people with higher DII scores had an increased risk of death compared to those in the lowest (most anti-inflammatory) tertile (HR = 1.38; 95% CI = 1.04-1.82 for the second tertile; HR = 1.38; 95% CI = 1.03-1.86 for the third tertile). Each 1 SD increase in DII score increased the risk of death by 13%. No association was found between DII scores and cancer or CVD death when considered separately. CONCLUSIONS: Higher DII scores were associated with a significantly higher mortality risk, whereas the association with cause-specific mortality was less clear. These findings highlight the potential importance of diet in modulating inflammation and preventing death.

Potato Consumption Is not Associated with Higher Risk of Mortality: A Longitudinal Study among Southern Italian Older Adults.

OBJECTIVE: The consumption of potatoes is increasing worldwide, but few studies have assessed the association between potato consumption and mortality, particularly in Mediterranean countries. We therefore investigated whether potato consumption is associated with higher risk of death in a large cohort of people living in South Italy. DESIGN: Longitudinal. SETTING: Community-dwelling. MEASUREMENTS: 2,442 participants coming from MICOL and NUTRIHEP studies aged more than 50 years at baseline were followed-up for 11 years. Dietary intake was assessed by means of a Food Frequency Questionnaire. Potato consumption was categorized in quintiles according to their daily consumption (< 3.95, 3.96-8.55, 8.56-15.67, 15.68-22.0, and > 22.0 g/day). Mortality was ascertained through validated cases of death. The association between potato consumption and mortality was assessed through Cox's regression models, adjusted for potential confounders, and reporting the data as hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: The 2,442 eligible participants were prevalently males (54.6%) and aged a mean of 64.3±9.3 years. During the 11-year follow-up, 396 (=16.2%) participants died. After adjusting for 12 potential baseline confounders, and taking those with the lowest consumption of potatoes as the reference group, participants with the highest consumption of potatoes did not have an increased overall mortality risk (HR=0.75; 95%CI: 0.53-1.07). Modelling the potato consumption as continuous (i.e. as increase in 10 g/day) did not substantially change our findings (fully-adjusted HR=0.93; 95%CI: 0.84-1.02). CONCLUSION: Overall potato consumption was not associated with higher risk of death in older people living in a Mediterranean area. Future studies are warranted to elucidate the role of potato consumption on all-cause and cause-specific mortality.

In situ remediation of contaminated marinesediment: an overview.

Sediment tends to accumulate inorganic and persistent hydrophobic organic contaminants representing one of the main sinks and sources of pollution. Generally, contaminated sediment poses medium- and long-term risks to humans and ecosystem health; dredging activities or natural resuspension phenomena (i.e., strongly adverse weather conditions) can remobilize pollution releasing it into the water column. Thus, ex situ traditional remediation activities (i.e., dredging) can be hazardous compared to in situ techniques that try to keep to a minimum sediment mobilization, unless dredging is compulsory to reach a desired bathymetric level. We reviewed in situ physico-chemical (i.e., active mixing and thin capping, solidification/stabilization, chemical oxidation, dechlorination, electrokinetic separation, and sediment flushing) and bio-assisted treatments, including hybrid solutions (i.e., nanocomposite reactive capping, bioreactive capping, microbial electrochemical technologies). We found that significant gaps still remain into the knowledge about the application of in situ contaminated sediment remediation techniques from the technical and the practical viewpoint. Only activated carbon-based technologies are well developed and currently applied with several available case studies. The environmental implication of in situ remediation technologies was only shortly investigated on a long-term basis after its application, so it is not clear how they can really perform.

Has serum CA 125 assay at the time of relapse a prognostic relevance for patients with recurrent ovarian carcinoma after primary cytoreduction and platinum- and paclitaxel-based chemotherapy?

PURPOSE OF INVESTIGATION: To correlate serum CA125 at relapse with survival in ovarian cancer patients who achieved a complete response after primary cytoreduction and paclitaxel- and platinum-based chemotherapy. MATERIALS AND METHODS: The study was conducted in 104 patients. RESULTS: The 25%, 50%, and 75% quantiles of CA125 levels at relapse were 46, 118, and 190 U/ml. By log-rank test, survival after recurrence was related to consolidation treatment (p = 0.046), platinum-free interval (PFI) (p < 0.000005), number of recurrence sites (p = 0.03), treatment at recurrence (p = 0.002), and serum CA125 taking 118 U/ml as cut-off (p = 0.013). On multivariate analysis, consolidation treatment (p = 0.007), PFI (p = 0.0001), treatment at recurrence (p = 0.01), and serum CA125 taking 118 U/ml as cut-off (p = 0.04) were independent prognostic variables for survival. CONCLUSIONS: Serum CA125 at relapse was an independent prognostic variable. Patients with serum CA125 > 118 U/m had 1.943 higher risk of death than those with lower antigen value.

Drug screening on Hutchinson Gilford progeria pluripotent stem cells reveals aminopyrimidines as new modulators of farnesylation.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by a dramatic appearance of premature aging. HGPS is due to a single-base substitution in exon 11 of the LMNA gene (c.1824C>T) leading to the production of a toxic form of the prelamin A protein called progerin. Because farnesylation process had been shown to control progerin toxicity, in this study we have developed a screening method permitting to identify new pharmacological inhibitors of farnesylation. For this, we have used the unique potential of pluripotent stem cells to have access to an unlimited and relevant biological resource and test 21,608 small molecules. This study identified several compounds, called monoaminopyrimidines, which target two key enzymes of the farnesylation process, farnesyl pyrophosphate synthase and farnesyl transferase, and rescue in vitro phenotypes associated with HGPS. Our results opens up new therapeutic possibilities for the treatment of HGPS by identifying a new family of protein farnesylation inhibitors, and which may also be applicable to cancers and diseases associated with mutations that involve farnesylated proteins.

Tumor-induced alterations in lipid metabolism.

Alterations of lipid metabolism have been increasingly recognized as a hallmark of cancer cells. Cancer cells esterify fatty acids predominantly to phospholipids, an essential component of cell membranes. The main pathway along which proliferating cells gain lipids for membrane synthesis is the endogenous mevalonate pathway. Increased synthesis of mevalonate and mevalonate-derived isoprenoids supports increased cell proliferation through activating growth-regulatory proteins and oncoproteins and promoting DNA synthesis. The importance of a better knowledge of metabolic changes in lipogenic enzymes pathways, as well as of the role of each biochemical pathway in carcinogenesis, provides the rationale for in-depth study of the oncogenic signaling important for the initiation and progression of tumors. The dependence of tumor cells on a dysregulated lipid metabolism suggests that the proteins involved in this process may be excellent chemotherapeutic targets for cancer treatment. Here, we confirm the vital link between lipogenesis and cell proliferation, and our recent findings suggest that nutritional intervention is an effective and safe way to reduce cell proliferation in experimental models of carcinogenesis. The olive oil diet significantly reduces the protein activities of lipogenic enzymes associated with cell growth. The use of natural dietary components could potentially assist in the management of subjects with metabolic disorders-related tumors.

Reduced fructosamine-3-kinase activity and its mRNA in human distal colorectal carcinoma.

Fructosamine-3-Kinase (FN3K) is an enzyme phosphorilating fructoselysine (FL) residues on glycated proteins, resulting in the production of protein-bound FL-3-phosphate. The pathological role of the non-enzymatic modification of proteins by reducing sugars has become increasingly evident in various types of disorders, including the cancer. In this study, our aim was to study FN3K enzyme activity, as well as its mRNA in human colorectal cancer (CRC). Thirty consecutive CRC patients undergoing surgery of the colon were enrolled in the study. FN3K enzymatic activity and gene expression were analyzed using a radiometric assay and quantitative RT-PCR, respectively. FN3K is a functionally active enzyme in human colon tissue, without significant differences between normal mucosa and cancer. The mean level of FN3K mRNA was significantly lower in cancer than in the corresponding normal colorectal mucosa The colorectal tumors located on the left side showed lower levels of both enzymatic activity and mRNA FN3K than tumors located in the right side of colon. This paper is the first studying FN3K enzyme activity in human CRC, showing a significant relationship between enzymatic activity, its mRNA and tumor side.

Association between cannabinoid type-1 receptor polymorphism and body mass index in a southern Italian population.

CONTEXT: Endocannabinoids control food intake via both central and peripheral mechanisms, and cannabinoid type-1 receptor (CB1) modulates lipogenesis in primary adipocyte cell cultures and in animal models of obesity. OBJECTIVES: We aimed to evaluate, at the population level, the frequency of a genetic polymorphism of CB1 and to study its correlation with body mass index. DESIGN, SETTING AND PARTICIPANTS: Healthy subjects from a population survey carried out in southern Italy examined in 1992-1993 and older than 65 years (n=419, M=237, F=182) were divided into quintiles by body mass index (BMI). Two hundred and ten subjects were randomly sampled from the first, third and fifth quintile of BMI (BMI, respectively: 16.2-23.8=normal, 26.7-28.4=overweight, 31.6-49.7=obese) to reach a total of 70 per quintile. Their serum and white cells from the biological bank were used to measure the genotype and the blood variables for the study. MEASUREMENTS: Anthropometric parameters, blood pressure, serum glucose and lipid levels were measured with standard methods; genotyping for the CB1 1359G/A polymorphism was performed using multiplex PCR. Statistical methods included chi2 for trend, binomial and multinomial multiple logistic regression to model BMI on the genotype, controlling for potential confounders. RESULTS: We found a clear trend of increasing relative frequency of the CB1 wild-type genotype with the increase of BMI (P=0.03) and, using a multiple logistic regression model, wild-type genotype, female gender, age, glycaemia and triglycerides were directly associated with both overweight (third quintile of BMI) and obesity (fifth quintile of BMI). CONCLUSIONS: Although performed in a limited number of subjects, our results show that the presence of the CB1 polymorphic allele was significantly associated with a lower BMI.

Polyamine biosynthesis in relation to K-ras and p-53 mutations in colorectal carcinoma.

BACKGROUND: Polyamines are important polycations found in high concentrations in gastrointestinal neoplasms, and ornithine decarboxylase is the key enzyme in their biosynthesis. Also genes with oncogenic potential (e.g. K-ras and p53) contribute to neoplastic transformation by modifying normal cellular proliferation and differentiation. Our aim was to evaluate the ornithine decarboxylase activity and polyamine levels in samples of colorectal carcinoma and uninvolved surrounding mucosa from 86 patients (52 men and 34 women) showing different patterns of K-ras/p53 mutations. METHODS: Polyamines were evaluated by high performance liquid chromatography. Ornithine decarboxylase activity was determined using the radiometric method. K-ras and p53 mutations were investigated by PCR followed by restriction fragment length polymorphism (PCR-RFLP) and single strand conformational polymorphism (PCR-SSCP), respectively. Multiple linear regression analysis was used to analyse relationships among polyamine biosynthesis, clinical-pathological variables and K-ras/p53 mutations. RESULTS: ODC activity and polyamine levels were significantly higher in neoplastic samples than in normal surrounding mucosa. K-ras codon 12 mutation was found in 25/86 patients (29.1%) and p53 gene mutation in 41/86 (47.7%). Polyamine biosynthesis was significantly higher in cancers showing K-ras mutation, either with or without p53 mutation [K-ras(+)/p53(-) and K-ras(+)/p53(+)], compared to samples with K-ras wild type [K-ras(-)/p53(-) and K-ras(-)/p53(+)]. Multiple linear regression analysis confirmed this finding. CONCLUSIONS: The present study provides evidence of a close relationship between K-ras mutation and polyamine biosynthesis in human colorectal carcinoma in a way that is largely p53 independent. In addition, our data support the hypothesis of different pathways in colorectal tumorigenesis reflecting different combinations of biochemical parameters and genetic alterations.

A new phosphate-selective sorbent for the Rem Nut process. Laboratory investigation and field experience at a medium size wastewater treatment plant.

P-control technologies for municipal wastewater are essentially based on "destructive" methods, that lead to formation of concentrated solid-phases (sludge), usually disposed-off in controlled landfills. Ion exchange, as a "non-destructive" technology, allows for selective removal and simultaneous recovery of pollutants, which can be recycled to the same and/or related productive lines. In this context, the REM NUT process removes nutrient species (HPO4 = , NH4+, K+) present in biologically oxidised municipal effluents and recovers them in the form of struvites (MgNH4PO4; MgKPO4), premium quality slow release fertilisers. The main limitation to the extensive application of this ion exchange based process is the non-availability of selective exchangers for specific removal of nutrient species. This paper illustrates laboratory investigation and pilot scale development of a so-called "P-driven" modified REM NUT scheme based on a new phosphate-selective sorbent developed at Lehigh University, PA, USA.

Increased farnesyltransferase activity in human colorectal cancer: relationship with clinicopathological features and K-ras mutation.

BACKGROUND: The enzyme farnesyltransferase has emerged as an important target for anti-cancer therapies. Farnesyltransferase inhibitors have been introduced in clinical trials of subjects with colorectal cancer. We investigated Farnesyltransferase activity, beta-subunit Farnesyltransferase protein expression and its mRNA in patients with colorectal cancer and its relationship with clinicopathological features and K-ras mutation. METHODS: Farnesyltransferase activity was determined by Farnesyltransferase [3H] SPA enzyme assay. Beta-subunit Farnesyltransferase protein expression was investigated by Western blotting and its mRNA by reverse transcriptase-polymerase chain reaction. K-ras mutation was detected by polymerase chain reaction amplification and restriction enzyme analysis. Multiple linear regression analysis was used to analyse relationships among age, sex, site of tumour, Dukes' stage, histological differentiation, K-ras mutation and Farnesyltransferase activity in normal mucosa and cancer. RESULTS: The levels of Farnesyltransferase activity and beta-subunit Farnesyltransferase protein expression were significantly higher in cancer than in normal mucosa. Moreover, tumours located on the right side, with mucinous histological differentiation and with K-ras mutation showed higher levels of Farnesyltransferase activity. CONCLUSIONS: Our findings suggest that Farnesyltransferase activity may be a potential marker of tumourigenicity. The differences in Farnesyltransferase activity in relation to histological grading, tumour location and K-ras mutation described here may constitute a starting point for investigating the causes of this variation within the large bowel.

Demonstration of a direct stimulatory effect of bile salts on rat colonic epithelial cell proliferation.

BACKGROUND: Despite the clear demonstration that an increase in faecal bile salt concentration can augment colonocyte proliferation, it is still controversial whether bile salts act on these cells as direct mitogens or by inducing a damage-related proliferative response. The goal of this study was to define the mechanism mediating the proliferative effect of bile salts on rat colonocytes. METHODS: Faecal bile salt concentration was increased by feeding rats on diets enriched with either bile salts or fats. Colonic mucosa proliferating cell nuclear antigen (PCNA) expression, histology and apoptosis, and faecal water cytolytic activity were evaluated to assess proliferation and direct or indirect signs of mucosal damage. RESULTS: Compared to standard diet, chenodeoxycholate-, deoxycholate- and fat-enriched diets produced a significant increase in both faecal water total bile salt concentration (46.0 versus 124.1, 145.9 and 498.5 micromol/L, respectively) and percentage of PCNA-positive nuclei (30.5, versus 37.7, 33.9 and 47.1, respectively) that appeared significantly correlated (r = 0.8; P < 0.001). Chenodeoxycholate and deoxycholate fed animals showed colonic mucosa histology and faecal water cytolytic activity similar to controls, with a significantly reduced apoptotic index. Rats fed on high fat diet, however, showed a mild inflammatory infiltrate associated with an increased apoptosis and faecal water cytolytic activity, all conditions not apparently determined by the increased faecal water total bile salt concentration. CONCLUSIONS: The results obtained in this study demonstrate that bile salts act as direct mitogens on colonic epithelial cells.

Oestrogen receptors and microsatellite instability in colorectal carcinoma patients.

About 10-15% of sporadic colorectal cancers show microsatellite instability (MIN), a mutator phenotype of mismatch repair genes. It seems that oestrogens may inhibit the pathway to colorectal carcinoma which involves a mismatch repair deficiency. Oestrogen receptorial status was evaluated in the neoplastic tissue and uninvolved surrounding mucosa of 17 MIN-positive and 33 MIN-negative tumours using an immunoenzymatic assay. MIN status was examined using the polymerase chain reaction and specific microsatellite markers. MIN was significantly associated with very low levels of oestrogen receptor in tumour tissue. Our findings suggest that MIN-positive tumours might lose a possible oestrogenic modulation mechanism.

Low density lipoprotein receptor and mRNA expression in human colorectal cancer.

BACKGROUND: We have previously show that, 63.3% of colorectal cancers did not express the Low Density Lipoprotein Receptor (LDLR). We now report the findings of a study on the expression of LDLR and its mRNA in neoplastic tissue specimens of human colorectal cancer (CRC), carried out to verify whether the absence of the LDLR in these tumours is reflected by the absence of its transcript. MATERIALS AND METHODS: 32 patients (10 females and 22 males) operated for CRC were included in the study. The LDLR levels were evaluated by immunoenzymatic assay. The LDLR-mRNA, reverse-transcribed and then amplified by polymerase chain reaction, was detected by chromatography. RESULTS: The LDLR protein was present in 12 out of the 32 patients. LDLR-mRNA expression was detected in 17 out of the 32 patients. The absence of the LDLR protein was reflected by the absence of its transcript in 13 out of the 20 tumours; The LDLR mRNA levels were significantly higher in the tumours that did not expres LDLR. CONCLUSION: The variable expression of the LDLR protein and LDLR mRNA in CRC detected in this study suggests the possibility that different therapeutic strategies may be indicated for these tumours.

K-ras and p53 mutations in DNA extracted from colonic epithelial cells exfoliated in faeces of patients with colorectal cancer.

BACKGROUND: Exfoliated colonic epithelial cells in faeces provide a source of human DNA which may be analysed for the presence of tumour-induced modification. AIM: In the present study we investigated K-ras and p53 mutations in faeces of patients with colorectal carcinoma, to verify whether analysis of these mutations might identify a high percentage of patients with colorectal cancer. PATIENTS AND METHODS: Faeces, tumour and normal mucosa samples were taken from 26 patients. Polymerase chain reaction amplification and restriction enzyme analysis were performed to detect K-ras mutations; p53 gene mutations were identified by using polymerase chain reaction amplification and single strand conformation polymorphism. RESULTS: We were able to amplify the K-ras gene and exons 5-9 of the p53 gene in 100% of the faecal samples studied. K-ras and p53 gene mutations were detected in faeces in 26.9% and 50% of the cases, respectively. The two mutations were present together in 5 out of 26 patients. There was full agreement between the K-ras and p53 pattern observed in faecal DNA and that in tumour tissue DNA. CONCLUSIONS: Application of K-ras and p53 mutation gene analysis in the faeces may have clinical applications in the future. Since this genetic analysis is able to detect only 57.7% of patients with colorectal cancer, the study of other genes involved in colorectal carcinogenesis is necessary.

Use of macroporous polypropylene filter to allow identification of bacteria by PCR in human fecal samples.

The detection of pathogenic bacteria directly in human fecal specimens by PCR, requires removal of PCR-inhibitory substances. To investigate whether five different macroporous filters (polypropylene, nylon, polyester, polyethylene, fluorocarbon) could retain polysaccharides, major PCR inhibitors, an in vitro model and human fecal samples were used. The in vitro model consisted of Xanthum gum solutions (3 mg/ml PBS), a bacterial polysaccharide, to which Helicobacter pylori cells were added. Fecal samples from healthy volunteers were spiked with H. pylori and Mycobacterium paratuberculosis cells. Polysaccharide concentrations were significantly reduced only by the polypropylene but not by the other filters. Accordingly, both Xanthum gum solutions and spiked fecal specimens became PCR positive only after filtration with the polypropylene filter. We conclude that this filter can be used to prepare a bacterial DNA template suitable for PCR analysis from human feces.