Antimicrobial effects of Melaleuca alternifolia (tea tree) essential oil against biofilm-forming multidrug-resistant cystic fibrosis-associated Pseudomonas aeruginosa as a single agent and in combination with commonly nebulized antibiotics.

Broth microdilution assays were used to determine minimum inhibitory concentrations (MICs) and fractional inhibitory concentration indices (FICIs) of tea tree oil (TTO), tobramycin, colistin and aztreonam (ATM) against clinical cystic fibrosis-associated Pseudomonas aeruginosa (CFPA) isolates (n = 20). The minimum biofilm eradication concentration (MBEC) and fractional biofilm eradication concentration index (FBECI) were also determined using a similar microbroth dilution checkerboard assay, with biofilms formed using the MBEC device® . TTO was effective at lower concentrations against multidrug-resistant (MDR) CFPA isolates (n = 3) in a biofilm compared to in a planktonic state (MBEC 18·7-fold lower than MIC). CFPA within biofilm was less susceptible to ATM, colistin and tobramycin compared to planktonic cells (MBEC 6·3-fold, 9·3-fold, and 2·1-fold higher than MIC respectively). All combinations of essential oil and antibiotic showed indifferent relationships (FICI 0·52-1·72) when tested against planktonic MDR CFPA isolates (n = 5). Against CFPA isolates (n = 3) in biofilm, combinations of TTO/aztreonam and TTO/colistin showed indifferent relationships (mean FBECI 0·85 and 0·60 respectively), whereas TTO/tobramycin showed a synergistic relationship (mean FBECI 0·42). The antibiofilm properties of TTO and the synergistic relationship seen between TTO and tobramycin against CFPA in vitro make inhaled TTO a promising candidate as a potential therapeutic agent.

Comparison of perinatal outcomes between spontaneous vs. commissioned cycles in gestational carriers for single and same-sex male intended parents.

PURPOSE: To determine whether gestational carrier (GC) in vitro fertilization (IVF) cycles (commissioned cycles) for same-sex or single male intended parents have an increased incidence of adverse perinatal outcomes compared with spontaneous cycles in the same GCs. DESIGN: GC singleton pregnancies were identified from a database of 895 commissioned cycles from a large fertility center. Of these, 78 commissioned cycles met inclusion and exclusion criteria and were compared with 71 spontaneous cycles by the same GCs. The primary outcome was the composite score for adverse perinatal outcomes. Secondary outcomes included mode of delivery, birthweight, and gestational age. Chi-square test of association and Mann-Whitney U tests were used to compare categorical and continuous variables between the cohorts, respectively. Logistic and linear regressions controlling for GC age were constructed to determine the influence of GC cycle type on adverse perinatal outcomes. RESULTS: Commissioned cycles were significantly associated with adverse perinatal outcomes (25.6% vs. 9.9%; p = 0.02) and lower average gestational age (38.7 ± 1.5 vs. 39.4 ± 0.9; p < 0.001) compared with spontaneous cycles. Commissioned cycle increased the likelihood of adverse perinatal outcomes (OR 3.3; p = 0.03) and was a significant independent predictor of a lower average gestational age (ß = 0.897; p < 0.001). There were no significant differences in the incidence of vaginal deliveries or cesarean sections between commissioned and spontaneous cycles. CONCLUSIONS: Commissioned cycles confer a greater incidence of composite perinatal complications and were independently associated with a lower average gestational age when compared with spontaneous pregnancies carried by the same GC despite a confirmed healthy uterine environment, sperm samples, and donor oocytes.

Wave intensity analysis of maternal arterial stiffness: augmentation index and pulse wave velocity in pregnancies complicated by diabetes or hypertension.

PURPOSE: The aim of our study was to compare the maternal arterial stiffness in pregnant women with diabetic disease, hypertension and those with normal pregnancies. METHODS: A cross-sectional study was performed involving 65 pregnant women with diabetic disease (DD group), 26 pregnant women with hypertension (RR group) and 448 women with normal pregnancies (control group). The augmentation index (AIx) and the pulse wave velocity (PWV) of the right carotid artery were assessed using non-invasive sonographic wave intensity analysis. Furthermore, the reliability of the measurements was evaluated in 21 healthy women. RESULTS: Compared with the controls, the AIx and PWV were increased in the DD group [11.0 (interquartile range, IQR 7.3, 15.2) vs. 5.7 (IQR 2.4, 9.3), P < 0.001; 5.7 (IQR 5.1, 6.4) vs. 5.2 (IQR 4.6, 6.1), P = 0.001; respectively] and the RR group [9.3 (IQR 6.6, 11.5) vs. 5.7 (IQR 2.4, 9.3), P < 0.001; 7.1 (6.3, 7.9) vs. 5.2 (IQR 4.6, 6.1), P < 0.001; respectively]. The intraclass and interclass correlation coefficients were good to excellent for the AIx (ICC: 0.91, P < 0.001 and 0.74, P < 0.002; respectively) and PWV measurements (ICC: 0.71, P < 0.004 and 0.70, P < 0.005; respectively). CONCLUSION: Pregnancies complicated by diabetic disease or hypertension are associated with increased maternal arterial stiffness. The importance of wave intensity analysis needs to be verified and larger studies are needed to establish both normal and cutoff values that may be relevant for clinical decisions.

Natural products show diverse mechanisms of action against Clostridium difficile.

AIMS: To investigate the mechanisms of action of natural products with bactericidal (cinnamon root powder, peppermint oil, trans-cinnamaldehyde, menthol and zingerone) or bacteriostatic (fresh garlic bulb extract, garlic clove powder, Leptospermum honey and allicin) activity against two Clostridium difficile strains. METHODS AND RESULTS: Bactericidal products significantly reduced intracellular ATP after 1 h (P ≤ 0·01), quantified using the BacTiter-Glo reagent, and damaged the cell membrane, shown by the leakage of both 260-nm-absorbing materials and protein, and the uptake of propidium iodide. Bacteriolysis was not observed, determined by measuring optical density of treated cell suspensions at 620-nm. The effect of three bacteriostatic products on protein synthesis was quantified using an Escherichia coli S30 extract system, with Leptospermum honey (16% w/v) showing significant inhibition (P < 0·01). Lastly, no products showed elevated minimum inhibitory concentrations against antimicrobial-resistant C. difficile, determined by broth microdilution. CONCLUSIONS: Cytoplasmic membrane damage was identified as a mechanism of action that may contribute to the activity of several natural products against C. difficile. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes the possible mechanisms of action of natural products against C. difficile, yet the efficacy in vivo to be determined.

"Just like a natural man": The B.D. styles of Gertrude "Ma" Rainey and Bessie Smith.

This article pays homage to the antique term "B.D. (bulldyke) Woman" of the 1920s and 1930s, at a moment when the rise of a universal queer subject threatens to erase specific lesbian histories. Characterized by an aggressive stance and an enormousness that confronts rather than merely protests, Black B.D. artists "stole" both masculinity and White privilege to accumulate power and cultural capital. B.D. is therefore a multilayered response to sexism, racism, and homophobia. This performance style is a product of outrage at the oppressive conditions that marked the legacy of slavery, to which B.D. blues must be viewed as a response rather than a more static sexual aesthetic style belonging to lesbian women. Such masculine bravado in Black women disrupted gender/sex alignments and notions of cisnormativity embedded in African American communities. In order to think through this historical legacy, I perform close readings of song lyrics performed by Gertrude "Ma" Rainey and Bessie Smith. The rejection of oppressive conditions occurs most acutely through the theme of travelling in songs that decenter racialized and heteronormative conceptions of home. Through this theme, Rainey and Smith expanded the phallic possibilities of their time period, and for the 2010s, these artists tamper with our staid notions of what gender, sex, and sexuality have meant in the past.

Effects of natural products on several stages of the spore cycle of Clostridium difficile in vitro.

AIMS: To investigate the effect of natural products on the spore cycle of Clostridium difficile in vitro. METHODS AND RESULTS: Twenty-two natural products were investigated using four C. difficile strains. Effects on sporulation, determined using microscopy and a conventional spore recovery assay, showed that fresh onion bulb extract (6·3% v v-1 ) and coconut oil (8% v v-1 ) inhibited sporulation in all four isolates by 66-86% and 51-88%, respectively, compared to untreated controls. Fresh ginger rhizome extract (25% v v-1 ) was also inhibitory, although to a lesser extent. Using a standard spore germination and outgrowth assay, germination was unaffected by the 22 products, whereas outgrowth was significantly reduced by artichoke extract (18·8 mg ml-1 ), fresh onion bulb extract (25% v v-1 ), Leptospermum honeys (8% w v-1 ) and allicin (75 mg ml-1 ; P < 0·01). Sporicidal activity, investigated using a standard plate recovery assay, was minimal. CONCLUSIONS: Three of the 22 natural products (13%) showed inhibitory effects on sporulation of C. difficile and six products (27%) reduced vegetative outgrowth of C. difficile. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows the potential of natural products to inhibit different stages of C. difficile sporulation and encourages further investigation in this field.

Cumulative Effect of an Antimicrobial Stewardship and Rapid Diagnostic Testing Bundle on Early Streamlining of Antimicrobial Therapy in Gram-Negative Bloodstream Infections.

The use of rapid diagnostic tests (RDTs) enhances antimicrobial stewardship program (ASP) interventions in optimization of antimicrobial therapy. This quasi-experimental cohort study evaluated the combined impact of an ASP/RDT bundle on the appropriateness of empirical antimicrobial therapy (EAT) and time to de-escalation of broad-spectrum antimicrobial agents (BSAA) in Gram-negative bloodstream infections (GNBSI). The ASP/RDT bundle consisted of system-wide GNBSI treatment guidelines, prospective stewardship monitoring, and sequential introduction of two RDTs, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and the FilmArray blood culture identification (BCID) panel. The preintervention period was January 2010 through December 2013, and the postintervention period followed from January 2014 through June 2015. The postintervention period was conducted in two phases; phase 1 followed the introduction of MALDI-TOF MS, and phase 2 followed the introduction of the FilmArray BCID panel. The interventions resulted in significantly improved appropriateness of EAT (95% versus 91%; P = 0.02). Significant reductions in median time to de-escalation from combination antimicrobial therapy (2.8 versus 1.5 days), antipseudomonal beta-lactams (4.0 versus 2.5 days), and carbapenems (4.0 versus 2.5 days) were observed in the postintervention compared to the preintervention period (P < 0.001 for all). The reduction in median time to de-escalation from combination therapy (1.0 versus 2.0 days; P = 0.03) and antipseudomonal beta-lactams (2.2 versus 2.7 days; P = 0.04) was further augmented during phase 2 compared to phase 1 of the postintervention period. Implementation of an antimicrobial stewardship program and RDT intervention bundle in a multihospital health care system is associated with improved appropriateness of EAT for GNBSI and decreased utilization of BSAA through early de-escalation.

Antimicrobial activity of natural products against Clostridium difficile in vitro.

AIMS: To investigate the antimicrobial activity of various natural products against Clostridium difficile in vitro. METHODS AND RESULTS: The antibacterial activity of 20 natural products was determined by the agar well diffusion and broth microdilution assays against four C. difficile strains, three comparator organisms and four gastrointestinal commensal organisms. Of the raw natural products, garlic juice had the highest activity. The most active processed products were peppermint oil and the four pure compounds trans-cinnamaldehyde, allicin, menthol and zingerone. Furthermore, Bacteroides species had similar susceptibility to C. difficile to most natural products; however, Lactobacillus casei was less susceptible. The combined effect of natural products with vancomycin or metronidazole was determined using the conventional checkerboard titration method and the fractional inhibitory concentration index was calculated. The results showed a possible synergism between trans-cinnamaldehyde and vancomycin and partial synergy between trans-cinnamaldehyde and metronidazole. CONCLUSIONS: The study indicates a range of antimicrobial activity of natural products against C. difficile and suggests that they may be useful as alternative or complementary treatments for C. difficile infection (CDI), particularly as most are able to be given orally. SIGNIFICANCE AND IMPACT OF THE STUDY: This study encourages further investigation of natural products for treatment of CDI.

Outcome of fetuses with gastroschisis after modification of prenatal management strategies : Prenatal management and outcome of gastroschisis.

PURPOSE: To improve the outcome of fetuses with gastrochisis several studies evaluated prenatal predictors. But there are different guidelines established and therefore the prenatal care is not standardized. With our study we wanted to evaluate the outcome of fetuses with gastroschisis after modification of prenatal management strategies at the Department of Obstetrics and Gynecology of the University Hospital Münster. METHODS: In this explorative retrospective study of 39 fetuses with gastroschisis, we compare the clinical outcome between two management groups. In the first group (group 1, n = 14) prenatal indication for delivery was confirmed by a subjective evaluation of the small bowel diameter and the wall thickness without established cut-off values for these parameters. In the second group (group 2, n = 25) certain limits for the small bowel diameter (25 mm) and the wall thickness (2.5 mm) were used for fetal surveillance. RESULTS: Noticeable differences between the two groups regarding birth weight, weight centile, arterial pH, small bowel diameter, wall thickness, adverse bowel condition and re-operations could not be observed. In group 2, delivery was earlier (p = 0.011), and a lower rate of prenatal complications was observed (p = 0.016). CONCLUSION: To avoid adverse prenatal complications we recommend the observation of fetuses with gastroschisis by sonographic monitoring of the small bowel diameter and the wall thickness.

Antimicrobial activity of honey from the stingless bee Trigona carbonaria determined by agar diffusion, agar dilution, broth microdilution and time-kill methodology.

AIMS: The aim of this study was to determine the spectrum of antimicrobial activity of 11 samples of stingless bee honey compared to medicinal, table and artificial honeys. METHODS AND RESULTS: Activity was assessed by agar diffusion, agar dilution, broth microdilution and time-kill viability assays. By agar dilution, minimum inhibitory concentration (MIC) ranges were 4% to >10% (w/v) for Gram-positive bacteria, 6% to >16% (w/v) for Gram-negative bacteria and 6% to >10% (w/v) for Candida spp. By broth microdilution, all organisms with the exception of Candida albicans and Candida glabrata were inhibited at 3 log for Pseudomonas aeruginosa and <1 log for C. albicans. Similar treatment with each control honey resulted in decreases of <1 log for all organisms. CONCLUSIONS: Stingless bee honey has broad-spectrum antibacterial activity although activity against Candida was limited. Stingless bee honey samples varied in activity and the basis for this remains to be determined. SIGNIFICANCE AND IMPACT OF THE STUDY: Stingless bee honey had similar activity to medicinal honey and may therefore have a role as a medicinal agent.

Water Sensitive Cities Index: A diagnostic tool to assess water sensitivity and guide management actions.

Cities are wrestling with the practical challenges of transitioning urban water services to become water sensitive; capable of enhancing liveability, sustainability, resilience and productivity in the face of climate change, rapid urbanisation, degraded ecosystems and ageing infrastructure. Indicators can be valuable for guiding actions for improvement, but there is not yet an established index that measures the full suite of attributes that constitute water sensitive performance. This paper therefore presents the Water Sensitive Cities (WSC) Index, a new benchmarking and diagnostic tool to assess the water sensitivity of a municipal or metropolitan city, set aspirational targets and inform management responses to improve water sensitive practices. Its 34 indicators are organised into seven goals: ensure good water sensitive governance, increase community capital, achieve equity of essential services, improve productivity and resource efficiency, improve ecological health, ensure quality urban spaces, and promote adaptive infrastructure. The WSC Index design as a quantitative framework based on qualitative rating descriptions and a participatory assessment methodology enables local contextual interpretations of the indicators, while maintaining a robust universal framework for city comparison and benchmarking. The paper demonstrates its application on three illustrative cases. Rapid uptake of the WSC Index in Australia highlights its value in helping stakeholders develop collective commitment and evidence-based priorities for action to accelerate their city's water sensitive transition. Early testing in cities in Asia and the Pacific has also showed the potential of the WSC Index internationally.

Water Sensitive Cities Index: A diagnostic tool to assess water sensitivity and guide management actions.

Cities are wrestling with the practical challenges of transitioning urban water services to become water sensitive; capable of enhancing liveability, sustainability, resilience and productivity in the face of climate change, rapid urbanisation, degraded ecosystems and ageing infrastructure. Indicators can be valuable for guiding actions for improvement, but there is not yet an established index that measures the full suite of attributes that constitute water sensitive performance. This paper therefore presents the Water Sensitive Cities (WSC) Index, a new benchmarking and diagnostic tool to assess the water sensitivity of a municipal or metropolitan city, set aspirational targets and inform management responses to improve water sensitive practices. Its 34 indicators are organised into seven goals: ensure good water sensitive governance, increase community capital, achieve equity of essential services, improve productivity and resource efficiency, improve ecological health, ensure quality urban spaces, and promote adaptive infrastructure. The WSC Index design is a quantitative framework based on qualitative rating descriptions and a participatory assessment methodology, enabling local contextual interpretations of the indicators while maintaining a robust universal framework for city comparison and benchmarking. The paper demonstrates its application on three illustrative cases. Rapid uptake of the WSC Index in Australia highlights its value in helping stakeholders develop collective commitment and evidence-based priorities for action to accelerate their city's water sensitive transition. Early testing in cities in Asia, the Pacific and South Africa has also showed the potential of the WSC Index internationally.

A review of the toxicity of Melaleuca alternifolia (tea tree) oil.

The essential oil of Melaleuca alternifolia, also known as tea tree or melaleuca oil, is widely available and has been investigated as an alternative antimicrobial, anti-inflammatory and anti-cancer agent. While these properties are increasingly well characterised, relatively limited data are available on the safety and toxicity of the oil. Anecdotal evidence from almost 80 years of use suggests that the topical use of the oil is relatively safe, and that adverse events are minor, self-limiting and occasional. Published data indicate that TTO is toxic if ingested in higher doses and can also cause skin irritation at higher concentrations. Allergic reactions to TTO occur in predisposed individuals and may be due to the various oxidation products that are formed by exposure of the oil to light and/or air. Adverse reactions may be minimised by avoiding ingestion, applying only diluted oil topically and using oil that has been stored correctly. Data from individual components suggest that TTO has the potential to be developmentally toxic if ingested at higher doses, however, TTO and its components are not genotoxic. The limited ecotoxicity data available indicate that TTO is toxic to some insect species but more studies are required.

Persistence and reactivation of human adenoviruses in the gastrointestinal tract.

Reactivation of persistent human adenoviruses (HAdVs) is associated with high morbidity and mortality in paediatric haematopoietic stem cell transplant (HSCT) recipients. Although invasive HAdV infections mainly arise from the gastrointestinal (GI) tract, the specific sites of HAdV persistence are not well characterised. We prospectively screened biopsies from 143 non-HSCT paediatric patients undergoing GI endoscopy and monitored serial stool specimens from 148 paediatric HSCT recipients for the presence of HAdV by real-time PCR. Persistence of HAdV in the GI tract was identified in 31% of children, with the highest prevalence in the terminal ileum. In situ hybridisation and immunohistochemistry identified HAdV persistence in lymphoid cells of the lamina propria, whereas biopsies from five transplant recipients revealed high numbers of replicating HAdV in intestinal epithelial cells. The prevalence of HAdV species, the frequencies of persistence in the GI tract and reactivations post transplant indicated a correlation of intestinal HAdV shedding pre-transplant with high risk of invasive infection. HAdV persistence in the GI tract is a likely origin of infectious complications in immunocompromised children. Intestinal lymphocytes represent a reservoir for HAdV persistence and reactivation, whereas the intestinal epithelium is the main site of viral proliferation preceding dissemination. The findings have important implications for assessing the risk of life-threatening invasive HAdV infections.

Effectiveness of hand-cleansing formulations containing tea tree oil assessed ex vivo on human skin and in vivo with volunteers using European standard EN 1499.

The efficacy of formulations containing tea tree oil (TTO) has been assessed in vitro in previous studies. Products that passed the European suspension test guidelines were investigated further in this study, in vivo with volunteers using the European handwashing method (EN 1499) and ex vivo using freshly excised human skin samples. The activity of 5% TTO in 0.001% Tween 80, in a hygienic skin wash (HSW) and in an alcoholic hygienic skin wash (AHSW) was investigated and compared with that of a non-medicated soft soap (SS, control). These formulations were assessed against Escherichia coli K12 as recommended by the European standard. In-vivo results showed that 5% TTO in Tween 80 and the AHSW were significantly more active than the SS after 1 min of handwashing. When assessed ex vivo, these two products were also significantly more active than the reference soap after 1 min of rubbing. Both methods showed that 5% TTO in Tween 80 was generally, although not always, more active than a handwash formulation, and that the AHSW was generally more active than the HSW, although this difference was not significant. The formulations tested, as well as the SS, were more active when assessed in vivo than ex-vivo against E. coli, although only the SS and the HSW were significantly more active in vivo. There appeared to be a pattern in the comparison between ex vivo and in vivo results. The antiseptics tested were, on average, 1.28+/-0.06 times more active when assessed in-vivo than when assessed ex vivo. Nevertheless, the main outcome of the European handwashing method is for the formulation tested to be significantly more active than the SS; both 5% TTO in Tween 80 and the AHSW achieved this both in-vivo and ex-vivo. TTO in Tween 80 and in formulations met the European in-vivo method requirements.

Assessment of the antibacterial activity of tea tree oil using the European EN 1276 and EN 12054 standard suspension tests.

The activity of tea tree oil (TTO) and TTO-containing products was investigated according to the EN 1276 and EN 12054 European suspension methods. The activity of different concentrations of TTO, a hygienic skin wash (HSW), an alcoholic hygienic skin wash (AHSW) and an alcoholic hand rub (AHR) was investigated. These formulations were assessed in perfect conditions with the EN 12054 test, and in perfect conditions as well as in the presence of interfering substances with the EN 1276 test, against Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli and Pseudomonas aeruginosa. With the latter test, the activity of the same formulations without TTO was also assessed as a control. With the EN 1276 test, the AHR achieved a >10(5)-fold reduction against all four test organisms within a 1-min contact time. The AHSW achieved a >or=10(5)-fold reduction against A. baumannii after a 1-min contact time and against S. aureus, E. coli and P. aeruginosa after a 5-min contact time. The efficacy of TTO appeared to be dependent on the formulation and the concentration tested, the concentration of interfering substances and, lastly, the organism tested. Nevertheless, 5% TTO achieved a >10(4)-fold reduction in P. aeruginosa cell numbers after a 5-min contact time in perfect conditions. TTO (5%) in 0.001% Tween 80 was significantly more active against E. coli and P. aeruginosa than against S. aureus and A. baumannii. With the EN 12054 test, after a 1-min contact time, 5% TTO in 0.001% Tween 80 and the AHSW achieved a >10(4)-fold reduction in E. coli and A. baumannii cell numbers, respectively, and the AHR achieved a >4 log10 reduction against all organisms tested. The formulations used in this study are now being tested using a novel ex vivo method as well as the in vivo European standard handwashing method EN 1499.

Treatment of acne with tea tree oil (melaleuca) products: a review of efficacy, tolerability and potential modes of action.

Over-the-counter acne treatments containing tea tree oil from the plant Melaleuca alternifolia are widely available, and evidence indicates that they are a common choice amongst those self-treating their acne. The aims of this review were to collate and evaluate the clinical evidence on the use of tea tree oil products for treating acne, to review safety and tolerability and to discuss the underlying modes of therapeutic action.

The pyrH gene of Lactococcus lactis subsp. cremoris encoding UMP kinase is transcribed as part of an operon including the frr1 gene encoding ribosomal recycling factor 1.

The pyrH gene of Lactococcus lactis subsp. cremoris MG1363, encoding UMP kinase, has been sequenced and cloned. It encodes a polypeptide of 239 amino acid residues (deduced molecular weight of 25951), which was shown to complement a temperature sensitive pyrH mutation in Escherichia coli, thus establishing the ability of the encoded protein to synthesize UDP. The pyrH gene in L. lactis is flanked downstream by frr1 encoding ribosomal recycling factor 1 and upstream by an open reading frame, orfA, of unknown function. The three genes were shown to constitute an operon transcribed in the direction orfA-pyrH-frr1 from a promoter immediately in front of orfA. This operon belongs to an evolutionary highly conserved gene cluster, since the organization of pyrH on the chromosomal level in L. lactis shows a high resemblance to that found in Bacillus subtilis as well as in Escherichia coli and several other prokaryotes

Advanced distal colonic lesions as predictors of advanced lesions in the proximal colon.

The characteristics of adenomas found during sigmoidoscopy have been suggested to predict synchronous adenomas in the proximal colon. Our aim was to examine whether the presence and characteristics of distal colonic lesions are associated with the presence and characteristics of lesions in the proximal colon. We performed a university hospital based case-control study with 3,268 consecutive subjects who received colonoscopy between January 1992 and December 1995. Subjects who had a history of colonic polyps, inflammatory bowel disease, intestinal resection, or had a contraindication against biopsies were excluded. Number size, and histologic characteristics of polyps in the distal and proximal colon were recorded. Advanced lesions were defined as neoplastic lesions with 1 or more of the following features: 1) > or = 1 cm diameter, and/or 2) villous histology, and/or 3) severe dysplasia or carcinoma, and/or 4) > or = 3 lesions. We found that 439 patients had neoplastic lesions in the distal colon only (61.3% with advanced lesions), 198 patients had lesions in the proximal colon only (55.1% advanced), and 197 had lesions in both the distal colon (74.6% advanced) and the proximal colon (55.8% advanced). Distal lesions were significantly more often advanced in patients with synchronous proximal lesions compared with patients with lesions in the distal colon only (odds ratio: 1.9; 95% confidence interval [CI]: 1.3-2.8; p < 0.001). The odds ratios for finding any neoplastic lesion in the proximal colon and an advanced proximal lesion, respectively, were 3.7 (2.6-5.3) (p < 0.001) and 2.2 (1.3-3.7) (p < 0.01) when a nonadvanced lesion was found in the distal colon, and 6.8 (5.3-8.7) (p < 0.001) and 6.7 (4.9-9.0) (p < 0.001) when an advanced lesion was found in the distal colon. Logistic regression analysis revealed number of distal polyps and villous histology as independent predictors of advanced lesions in the proximal colon; size and severe dysplasia were not independent predictors. In conclusion, characteristics of neoplastic lesions in the distal colon predict the presence and characteristics of lesions in the proximal colon.