Brain tumor diagnostic model and dietary effect based on extracellular vesicle microbiome data in serum

The human microbiome has been recently associated with human health and disease. Brain tumors (BTs) are a particularly difficult condition to directly link to the microbiome, as microorganisms cannot generally cross the blood–brain barrier (BBB). However, some nanosized extracellular vesicles (EVs) released from microorganisms can cross the BBB and enter the brain. Therefore, we conducted metagenomic analysis of microbial EVs in both serum (152 BT patients and 198 healthy controls (HC)) and brain tissue (5 BT patients and 5 HC) samples based on the V3–V4 regions of 16S rDNA. We then developed diagnostic models through logistic regression and machine learning algorithms using serum EV metagenomic data to assess the ability of various dietary supplements to reduce BT risk in vivo. Models incorporating the stepwise method and the linear discriminant analysis effect size (LEfSe) method yielded 12 and 29 significant genera as potential biomarkers, respectively. Models using the selected biomarkers yielded areas under the curves (AUCs) >0.93, and the model using machine learning resulted in an AUC of 0.99. In addition, Dialister and [Eubacterium] rectale were significantly lower in both blood and tissue samples of BT patients than in those of HCs. In vivo tests showed that BT risk was decreased through the addition of sorghum, brown rice oil, and garlic but conversely increased by the addition of bellflower and pear. In conclusion, serum EV metagenomics shows promise as a rich data source for highly accurate detection of BT risk, and several foods have potential for mitigating BT risk.

The gut microbiome affects brain health via tiny packets of microbial metabolites called extracellular vesicles (EVs) that are small enough to pass through the blood–brain barrier. The brain was thought to be sheltered from the microbiome’s effect on health by this barrier, which blocks microbes from entering the brain via the blood. Yoon-Keun Kim at MD Healthcare Inc. and Sun Ha Paek at Seoul National University, both in Seoul, South Korea, and co-workers compared the EVs in the blood of brain cancer patients and healthy individuals, and found the two groups harbored different types of microbes. Feeding mice brown rice oil, sorghum, and garlic markedly shifted their EV profiles towards those of the healthy microbiome. These results provide a foundation for investigating new methods for brain cancer risk assessment and dietary interventions to reduce that risk.

Diagnostic Models for Atopic Dermatitis Based on Serum Microbial Extracellular Vesicle Metagenomic Analysis: A Pilot Study

PURPOSE

Associations between a wide variety of diseases and the microbiome have been extensively verified. Recently, there has been a rising interest in the role the microbiome plays in atopic dermatitis (AD). Furthermore, metagenomic analysis of microbe-derived extracellular vesicles (EVs) has revealed the importance and relevance of microbial EVs in human health.

METHODS

We compared the diversity and proportion of microbial EVs in the sera of 24 AD patients and 49 healthy controls, and developed a diagnostic model. After separating microbial EVs from serum, we specifically targeted the V3-V4 hypervariable regions of the 16S rDNA gene for amplification and subsequent sequencing.

RESULTS

Alpha and beta diversity between controls and AD patients both differed, but only the difference in beta diversity was significant. Proteobacteria, Firmicutes, and Bacteroidetes were the dominant phyla in healthy controls and AD patients, accounting for over 85% of the total serum bacterial EVs. Also, Proteobacteria, Firmicutes, Actinobacteria, Verrucomicrobia, and Cyanobacteria relative abundances were significantly different between the AD and control groups. At the genus level, the proportions of Escherichia-Shigella, Acinetobacter, Pseudomonas, and Enterococcus were drastically altered between the AD and control groups. AD diagnostic models developed using biomarkers selected on the basis of linear discriminant analysis effect size from the class to genus levels all yielded area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy of value 1.00.

CONCLUSIONS

In summary, microbial EVs demonstrated the potential in their use as novel biomarkers for AD diagnosis. Therefore, future work should investigate larger case and control groups with cross-sectional or longitudinal clinical data to explore the utility and validity of serum microbiota EV-based AD diagnosis.

Is Cutibacterium (previously Propionibacterium) acnes a potential pathogenic factor in the aetiology of the skin disease progressive macular hypomelanosis?

Progressive macular hypomelanosis (PMH) is a skin condition that normally causes symmetrically distributed hypopigmented macules on the front and back of the trunk, but rarely the face. To date, the pathophysiology of the condition is not well understood, but a role for the anaerobic skin bacterium Cutibacterium (previously Propionibacterium) acnes in the development of the disease has been proposed due to its sole presence within lesional, but not normal peri-lesional, skin. The success of antimicrobials in the treatment of PMH also provides circumstantial evidence that this association may be causal, although this is still to be proven. More recent culture and metagenomic typing studies indicate that strains of C. acnes subsp. elongatum (type III) may be important in the aetiology of the condition, which would help to explain why PMH does not normally affect the face since such strains are rarely present there, and why no association between this condition and acne vulgaris is found; acne appears to primarily involve type IA₁ strains from C. acnes subsp. acnes (type I). In this review, we summarize current knowledge on the relationship between C. acnes and PMH, and re-examine previous challenges to the view that the bacterium plays a role in the condition against the backdrop of newly emerged data.

Bariatric/Metabolic Surgery Induces Noticeable Changes of Microbiota and Their Secreting Extracellular Vesicle Composition in the Gut

INTRODUCTION

Microbial ecology is reported to be an important regulator of energy homeostasis and glucose metabolism. Microbes secrete extracellular vesicles (EVs) during their proliferation and death to communicate with other cells. To investigate the roles of gut microbiota in glucose metabolism, we analyzed serial changes of gut microbe and microbial EV composition before and after bariatric/metabolic surgery (BMS).

METHODS

Twenty-eight Wistar rats were fed on high-fat diet (HFD) to induce obesity and diabetes. Five of them compared with 5 rats fed on regular chow diet (RCD). Among the remaining 23 rats, Roux-en-Y gastric bypass (RYGB) (n = 10), sleeve gastrectomy (SG) (n = 10), or sham operation (n = 3) was randomly performed. Gut microbiota and EVs from fecal samples were analyzed by 16S rDNA amplicon sequencing.

RESULTS

The present study showed that microbial diversity was decreased in HFD-fed rats versus RCD-fed rats. In addition, BMS reversed glucose intolerance and microbial richness which were induced by HFD. In terms of microbiota and microbial EV composition, both RYGB and SG enhance the composition of phyla Proteobacteria, Verrucomicrobia, and their secreting EVs, but decrease phylum Firmicutes and its EVs. We tried to demonstrate specific genera showed a significant compositional difference in obesity/diabetes-induced rats compared with normal rats and then restored similarly toward normal rats' level after BMS. At the genus level, Lactococcus, Ruminococcus, Dorea in Firmicutes(p), Psychrobacter in Proteobacteria(p), and Akkermansia in Verrucomicrobia(p) fit these conditions after BMS.

CONCLUSION

We suggest that these genera are the candidates contributing to obesity and diabetes improvement mechanism after BMS.

Lactobacillus paracasei-derived extracellular vesicles attenuate the intestinal inflammatory response by augmenting the endoplasmic reticulum stress pathway

Lactobacillus paracasei is a major probiotic and is well known for its anti-inflammatory properties. Thus, we investigated the effects of L. paracasei-derived extracellular vesicles (LpEVs) on LPS-induced inflammation in HT29 human colorectal cancer cells and dextran sulfate sodium (DSS)-induced colitis in C57BL/6 mice. ER stress inhibitors (salubrinal or 4-PBA) or CHOP siRNA were utilized to investigate the relationship between LpEV-induced endoplasmic reticulum (ER) stress and the inhibitory effect of LpEVs against LPS-induced inflammation. DSS (2%) was administered to male C57BL/6 mice to induce inflammatory bowel disease, and disease activity was measured by determining colon length, disease activity index, and survival ratio. In in vitro experiments, LpEVs reduced the expression of the LPS-induced pro-inflammatory cytokines IL-1α, IL-1β, IL-2, and TNFα and increased the expression of the anti-inflammatory cytokines IL-10 and TGFβ. LpEVs reduced LPS-induced inflammation in HT29 cells and decreased the activation of inflammation-associated proteins, such as COX-2, iNOS and NFκB, as well as nitric oxide. In in vivo mouse experiments, the oral administration of LpEVs also protected against DSS-induced colitis by reducing weight loss, maintaining colon length, and decreasing the disease activity index (DAI). In addition, LpEVs induced the expression of endoplasmic reticulum (ER) stress-associated proteins, while the inhibition of these proteins blocked the anti-inflammatory effects of LpEVs in LPS-treated HT29 cells, restoring the pro-inflammatory effects of LPS. This study found that LpEVs attenuate LPS-induced inflammation in the intestine through ER stress activation. Our results suggest that LpEVs have a significant effect in maintaining colorectal homeostasis in inflammation-mediated pathogenesis.

Tiny vesicles released by a bacterial species found in the human gut can reduce symptoms of inflammatory bowel disease (IBD) and prevent disease progression. People with IBD have a decreased abundance of Lactobacilli bacteria in their gut, creating an imbalance that perpetuates the disease. Replenishment of this bacteria may become a valuable therapy. Chang Mo Moon at Ewha Womans University, Yoon-Keun Kim at MD Healthcare, both in Seoul, South Korea, and co-workers demonstrated how extracellular vesicles (EVs) released by Lactobacilli paracasei can actively prevent bowel inflammation. These EVs contain a mixture of proteins, nucleic acids and other biomolecules. The team administered EV to cultured human colorectal cancer cells and to mice with induced colitis. The EVs decreased pro-inflammatory protein activity and boosted levels of protective cellular membrane proteins via augmenting ER stress pathway.

The impact of bacteria-derived ultrafine dust particles on pulmonary diseases

The relationship between ambient particulate matter exposure and health has been well established. Ultrafine particles (UFP) with a diameter of 100 nm or less are known to increase pulmonary disease risk. Biological factors in dust containing UFP can cause severe inflammatory reactions. Pulmonary diseases develop primarily as a result of chronic inflammation caused by immune dysfunction. Thus, this review focuses on the adverse pulmonary effects of biological UFP, principally lipopolysaccharide (LPS), and bacterial extracellular vesicles (EVs), in indoor dust and the pathophysiological mechanisms involved in the development of chronic pulmonary diseases. The impact of LPS-induced pulmonary inflammation is based primarily on the amount of inhaled LPS. When relatively low levels of LPS are inhaled, a cascade of immune responses leads to Th2 cell induction, and IL-5 and IL-13 released by Th2 cells contributes to asthma development. Conversely, exposure to high levels of LPS induces a Th17 cell response, leading to increased production of IL-17, which is associated with asthma, COPD, and lung cancer incidence. Responses to bacterial EV exposure can similarly be broadly divided based on whether one of two mechanisms, either intracellular or extracellular, is activated, which depends on the type of the parent cell. Extracellular bacteria-derived EVs can cause neutrophilic inflammation via Th17 cell induction, which is associated with asthma, emphysema, COPD, and lung cancer. On the other hand, intracellular bacteria-derived EVs lead to mononuclear inflammation via Th1 cell induction, which increases the risk of emphysema. In conclusion, future measures should focus on the overall reduction of LPS sources in addition to the improvement of the balance of inhaled bacterial EVs in the indoor environment to minimize pulmonary disease risk.

Lung Disease Diagnostic Model Through IgG Sensitization to Microbial Extracellular Vesicles

Purpose

Recently, there has been a rise in the interest to understand the composition of indoor dust due to its association with lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) and lung cancer. Furthermore, it has been found that bacterial extracellular vesicles (EVs) within indoor dust particles can induce pulmonary inflammation, suggesting that these might play a role in lung disease.

Methods

We performed microbiome analysis of indoor dust EVs isolated from mattresses in apartments and hospitals. We developed diagnostic models based on the bacterial EVs antibodies detected in serum samples via enzyme-linked immunosorbent assay (ELISA) in this analysis.

Results

Proteobacteria was the most abundant bacterial EV taxa observed at the phylum level while Pseudomonas, Enterobacteriaceae (f) and Acinetobacter were the most prominent organisms at the genus level, followed by Staphylococcus. Based on the microbiome analysis, serum anti-bacterial EV immunoglobulin G (IgG), IgG1 and IgG4 were analyzed using ELISA with EV antibodies that targeted Staphylococcus aureus, Acinetobacter baumannii, Enterobacter cloacae and Pseudomonas aeruginosa. The levels of anti-bacterial EV antibodies were found to be significantly higher in patients with asthma, COPD and lung cancer compared to the healthy control group. We then developed a diagnostic model through logistic regression of antibodies that showed significant differences between groups with smoking history as a covariate. Four different variable selection methods were compared to construct an optimal diagnostic model with area under the curves ranging from 0.72 to 0.81.

Conclusions

The results of this study suggest that ELISA-based analysis of anti-bacterial EV antibodies titers can be used as a diagnostic tool for lung disease. The present findings provide insights into the pathogenesis of lung disease as well as a foundation for developing a novel diagnostic methodology that synergizes microbial EV metagenomics and immune assays.

Development of a colorectal cancer diagnostic model and dietary risk assessment through gut microbiome analysis

Colorectal cancer (CRC) is the third most common form of cancer and poses a critical public health threat due to the global spread of westernized diets high in meat, cholesterol, and fat. Although the link between diet and colorectal cancer has been well established, the mediating role of the gut microbiota remains elusive. In this study, we sought to elucidate the connection between the gut microbiota, diet, and CRC through metagenomic analysis of bacteria isolated from the stool of CRC (n = 89) and healthy (n = 161) subjects. This analysis yielded a dozen genera that were significantly altered in CRC patients, including increased Bacteroides, Fusobacterium, Dorea, and Porphyromonas prevalence and diminished Pseudomonas, Prevotella, Acinetobacter, and Catenibacterium carriage. Based on these altered genera, we developed two novel CRC diagnostic models through stepwise selection and a simplified model using two increased and two decreased genera. As both models yielded strong AUC values above 0.8, the simplified model was applied to assess diet-based CRC risk in mice. Mice fed a westernized high-fat diet (HFD) showed greater CRC risk than mice fed a regular chow diet. Furthermore, we found that nonglutinous rice, glutinous rice, and sorghum consumption reduced CRC risk in HFD-fed mice. Collectively, these findings support the critical mediating role of the gut microbiota in diet-induced CRC risk as well as the potential of dietary grain intake to reduce microbiota-associated CRC risk. Further study is required to validate the diagnostic prediction models developed in this study as well as the preventive potential of grain consumption to reduce CRC risk.

Microbe-derived extracellular vesicles as a smart drug delivery system

The human microbiome is known to play an essential role in influencing host health. Extracellular vesicles (EVs) have also been reported to act on a variety of signaling pathways, distally transport cellular components such as proteins, lipids, and nucleic acid, and have immunomodulatory effects. Here we shall review the current understanding of the intersectionality of the human microbiome and EVs in the emerging field of microbiota-derived EVs and their pharmacological potential. Microbes secrete several classes of EVs: outer membrane vesicles (OMVs), membrane vesicles (MVs), and apoptotic bodies. EV biogenesis is unique to each cell and regulated by sophisticated signaling pathways. EVs are primarily composed of lipids, proteins, nucleic acids, and recent evidence suggests they may also carry metabolites. These components interact with host cells and control various cellular processes by transferring their constituents. The pharmacological potential of microbiomederived EVs as vaccine candidates, biomarkers, and a smart drug delivery system is a promising area of future research. Therefore, it is necessary to elucidate in detail the mechanisms of microbiome-derived EV action in host health in a multi-disciplinary manner.

Quantifying multiple sclerosis pathology in post mortem spinal cord using MRI

Multiple sclerosis (MS) is a common inflammatory, demyelinating and degenerative disease of the central nervous system. The majority of people with MS present with symptoms due to spinal cord damage, and in more advanced MS a clinical syndrome resembling that of progressive myelopathy is not uncommon. Significant efforts have been undertaken to predict MS-related disability based on short-term observations, for example, the spinal cord cross-sectional area measured using MRI. The histo-pathological correlates of spinal cord MRI changes in MS are incompletely understood, however a surge of interest in tissue microstructure has recently led to new approaches to improve the precision with which MRI indices relate to underlying tissue features, such as myelin content, neurite density and orientation, among others. Quantitative MRI techniques including T₁ and T₂, magnetisation transfer (MT) and a number of diffusion-derived indices have all been successfully applied to post mortem MS spinal cord. Combining advanced quantification of histological features with quantitative - particularly diffusion-based - MRI techniques provide a new platform for high-quality MR/pathology data generation. To more accurately quantify grey matter pathology in the MS spinal cord, a key driver of physical disability in advanced MS, remains an important challenge of microstructural imaging.

Bile salt hydrolase-mediated inhibitory effect of Bacteroides ovatus on growth of Clostridium difficile

Clostridium difficile infection (CDI) is one of the most common nosocomial infections. Dysbiosis of the gut microbiota due to consumption of antibiotics is a major contributor to CDI. Recently, fecal microbiota transplantation (FMT) has been applied to treat CDI. However, FMT has important limitations including uncontrolled exposure to pathogens and standardization issues. Therefore, it is necessary to evaluate alternative treatment methods, such as bacteriotherapy, as well as the mechanism through which beneficial bacteria inhibit the growth of C. difficile. Here, we report bile acid-mediated inhibition of C. difficile by Bacteroides strains which can produce bile salt hydrolase (BSH). Bacteroides strains are not commonly used to treat CDI; however, as they comprise a large proportion of the intestinal microbiota, they can contribute to bile acid-mediated inhibition of C. difficile. The inhibitory effect on C. difficile growth increased with increasing bile acid concentration in the presence of Bacteroides ovatus SNUG 40239. Furthermore, this inhibitory effect on C. difficile growth was significantly attenuated when bile acid availability was reduced by cholestyramine, a bile acid sequestrant. The findings of this study are important due to the discovery of a new bacterial strain that in the presence of available bile acids inhibits growth of C. difficile. These results will facilitate development of novel bacteriotherapy strategies to control CDI.

Antisepsis of the skin before spinal surgery with povidone iodine-alcohol followed by chlorhexidine gluconate-alcohol versus povidone iodine-alcohol applied twice for the prevention of contamination of the wound by bacteria: a randomised controlled trial

AIMS

The aim of this study was to determine whether the sequential application of povidone iodine-alcohol (PVI) followed by chlorhexidine gluconate-alcohol (CHG) would reduce surgical wound contamination to a greater extent than PVI applied twice in patients undergoing spinal surgery.

PATIENTS AND METHODS

A single-centre, interventional, two arm, parallel group randomised controlled trial was undertaken, involving 407 patients who underwent elective spinal surgery. For 203 patients, the skin was disinfected before surgery using PVI (10% [w/w (1% w/w available iodine)] in 95% industrial denatured alcohol, povidone iodine; Videne Alcoholic Tincture) twice, and for 204 patients using PVI once followed by CHG (2% [w/v] chlorhexidine gluconate in 70% [v/v] isopropyl alcohol; Chloraprep with tint). The primary outcome measure was contamination of the wound determined by aerobic and anaerobic bacterial growth from samples taken after disinfection.

RESULTS

The detection of viable bacteria in any one of the samples taken after disinfection (culture-positive) was significantly lower in the group treated with both PVI and CHG than in the group treated with PVI alone (59 (29.1%) versus 85 (41.7%), p = 0.009; odds ratio 0.574; 95% confidence interval, 0.380 to 0.866).

CONCLUSIONS

Antisepsis of the skin with the sequential application of PVI and CHG more effectively reduces the contamination of a surgical wound than PVI alone. Cite this article: Bone Joint J 2017;99-B:1354-65.

Intra- and inter-observer reproducibility of CINtec® PLUS in ThinPrep® cytology preparations

BACKGROUND

This study evaluated the intra- and inter-observer reproducibility of the dual-stain biomarker, CINtec^® PLUS cytology in ThinPrep^® specimens, for improved specificity in the detection of cervical disease in women testing human papillomavirus (HPV) positive.

METHODS

A total of 972 cases of HPV-positive women from a triage and primary HPV screening population were selected from an ongoing study evaluating the clinical performance of CINtec^® PLUS cytology. For reproducibility analyses, three cytotechnologists rescreened sets of slides which they had previously reported themselves and which were previously reported by each of the other cytotechnologists. The original results of slides previously screened by each of the three cytotechnologists were also compared with the results of an expert reference evaluator.

RESULTS

Intra- and inter-observer agreement for paired evaluations between reviewers ranged from 82.8% to 94.9% (kappa 0.65-0.91) and 89.2% to 93% (kappa 0.83-0.88), respectively. Reproducibility analyses between the cytotechnologists and the reference evaluator revealed agreements ranging from 95.5% to 98% (kappa 0.89-0.96).

CONCLUSION

Evaluation of the dual-stain biomarker showed a high level of agreement across all evaluators suggesting that CINtec^® PLUS cytology will perform well in the hands of cytotechnologists and pathologist reviewers and could be introduced into cellular pathology laboratories that employ ThinPrep^® LBC with a minimum effort.

HPV16 and HPV18 genotyping triage in young women with borderline cytology or mild dyskaryosis: effect of age on genotype-specific risk of high-grade CIN

OBJECTIVE

Human papillomavirus (HPV) triage of borderline cytology or mild dyskaryosis is limited by the higher prevalence of HPV in women with these findings relative to those with high-grade cervical intraepithelial neoplasia (≥CIN2). This is particularly relevant in young women in whom HPV prevalence is discernible. In a previous analysis of HPV triage and colposcopy outcomes in Northern Ireland, we revealed a substantial amount of prevalent high-grade disease in women below 30 years of age. We explored the role of genotyping for HPV16/HPV18 in this population by assessing the risk of high-grade lesions associated with these genotypes and the effect of age on type-specific risk.

METHODS

Of the 866 women eligible for HPV triage, those who tested positive for HPV were referred to colposcopy. The relative risk of ≥CIN2 for HPV16, HPV18 and non-HPV16/18 high-risk genotype positivity was determined for cobas(®) HPV Test-positive results.

RESULTS

The relative risk of high-grade CIN was significantly greater in women infected with HPV16 and/or HPV18 compared with non-HPV16/18 infections, regardless of age (2.23 and 0.45, respectively). In women under 30 years of age, HPV16-associated risk of ≥CIN2 was significantly greater than that of HPV18 and the non-HPV16/18 genotypes (1.74 versus 1.03 and 0.58, respectively). In women aged ≥30 years, HPV18 infection presented the greatest risk of ≥CIN2 (3.03). The relative risk of ≥CIN2 associated with non-HPV16/18 genotypes was lower (range, 0.32-0.58) for both age groups.

CONCLUSION

This analysis demonstrates the value of genotyping for HPV16/HPV18 and age stratification to improve the specificity of HPV triage and to tailor management relative to the risk of high-grade CIN and cancer.

Association of airway cathepsin B and S with inflammation in cystic fibrosis

Irreversible tissue damage within the cystic fibrosis (CF) lung is mediated by proteolytic enzymes during an inflammatory response. Serine proteinases, in particular neutrophil elastase (NE), have been implicated however, members of the cysteine proteinase family may also be involved. The aim of this study was to determine cathepsin B and S levels in cystic fibrosis (CF) sputum and to assess any relationship to recognized markers of inflammation such as sputum NE, interleukin-8 (IL-8), tumor necrosis factor alpha (TNF-alpha), urine TNF receptor 1 (TNFr1), plasma IL-6, and serum C-reactive protein (CRP). Proteinase activities were measured in the sputum of 36 clinically stable CF patients using spectrophotometric and fluorogenic assays. Immunoblots were also used to confirm enzyme activity data. All other parameters were measured by ELISA. Patients had a mean age of 27.2 (8.2) years, FEV. of 1.6 (0.79) L and BMI of 20.7 (2.8). Both cathepsin B and S activities were detected in all samples, with mean concentrations of 18.0 (13.5) microg/ml and 1.6 (0.88) microg/ml, respectively and were found to correlate not only with each other but with NE, TNF-alpha and IL-8 (in all cases . < 0.05). Airway cathepsin B further correlated with circulatory IL-6 and CRP however, no relationship for either cathepsin was observed with urine TNFr1. This data indicates that cathepsin B and S may have important roles in the pathophysiology of CF lung disease and could have potential as markers of inflammation in future studies.

Biofilm formation by bacteria isolated from retrieved failed prosthetic hip implants in an in vitro model of hip arthroplasty antibiotic prophylaxis

Bacterial infection primarily with Staphylococcus spp. and Propionibacterium acnes remains a significant complication following total hip replacement. In this in vitro study, we investigated the efficacy of gentamicin loading of bone cement and pre- and postoperative administration of cefuroxime in the prevention of biofilm formation by clinical isolates. High and low initial inocula, representative of the number of bacteria that may be present at the operative site as a result of overt infection and skin contamination, respectively, were used. When a high initial inoculum was used, gentamicin loading of the cement did not prevent biofilm formation by the 10 Staphylococcus spp. and the 10 P. acnes isolates tested. Similarly, the use of cefuroxime in the fluid phase with gentamicin-loaded cement did not prevent biofilm formation by four Staphylococcus spp. and four P. acnes isolates tested. However, when a low bacterial inoculum was used, a combination of both gentamicin-loaded cement and cefuroxime prevented biofilm formation by these eight isolates. Our results indicate that this antibiotic combination may protect against infection after intra-operative challenge with bacteria present in low numbers as a result of contamination from the skin but would not protect against bacteria present in high numbers as a result of overt infection of an existing implant.

Gastrointestinal transit in the common brushtail possum measured by gamma scintigraphy

This paper reports an example of the application of pharmaceutical technology to wildlife management, specifically the design of an oral delivery system for the common brushtail possum in New Zealand. Designing an oral delivery system requires a knowledge of the time taken for particulates to reach target sites within the gastrointestinal tract (GIT). The transit time for fluid and indigestible particles of two different size ranges was determined in the common brushtail possum (Trichosurus vulpecula). Technetium-labelled (99mTc) anion exchange resin particles (75-125 or 500-700 microm diameter) or solution (99mTc-labelled diethylenetriamine pentaacetic acid, 99mTc-DTPA) was administered orally. At predetermined times after dosing (3, 6, 12, 24 or 32 h), the distribution of radioactivity throughout excised gastrointestinal tracts was determined by gamma scintigraphy. The transit profile was similar for the three formulations investigated. Unlike other closely related hindgut fermenting marsupials, there was no evidence to support the presence of a colonic separating mechanism in the common brushtail possum. Gastrointestinal transit was independent of body mass, gender and time of day that the dose is given. To target the hindgut for oral delivery of protein and peptide biocontrol agents, the formulation would need to protect the bioactive for approximately 12 h prior to release.

Application of pharmaceutical drug delivery for biological control of the common brushtail possum in New Zealand: a review

The common brushtail possum (Trichosurus vulpecula) is the most significant vertebrate pest in New Zealand, being a major ecological threat to the indigenous biodiversity and an economic threat as a vector for bovine tuberculosis. Novel and effective strategies to reduce the population of T. vulpecula are needed urgently. Several biocontrol agents are currently being assessed and from research to date it is likely that the biocontrol agents will be peptide or protein molecules. It is not possible to administer such biocontrol agents alone because they would be degraded rapidly in the animal, especially if delivered orally. Technologies used in the pharmaceutical industry to design efficacious drug-delivery systems for humans and animals can be applied to the design of delivery systems for biocontrol agents used in wildlife management, although there are some unique challenges that must be overcome.

A morphometric study of the gastrointestinal tract of the common brushtail possum in southern New Zealand

The length and mass of sections of the gastrointestinal (GI) tract is reported for common brushtail possums (Trichosurus vulpecula) captured in the Otago region of New Zealand (n = 41). The pH of digesta (n = 12) and of the mucosal surface was also determined for specific sections of the GI tract of fed (n = 5) and fasted (n = 5) animals. Inter-animal variability in some morphometric characteristics was influenced by gender, live body mass, fur colour and time spent in captivity. Feeding significantly reduced the pH of the mucosal surface in the caecum only. GI tract morphology of T. vulpecula from southern New Zealand differs from that reported for Australian specimens, with average mass of the caecum in individuals from Otago being less than that of Australian specimens. Such differences in GI tract morphology may be due to improved diet quality in New Zealand compared with Australia.

Prevalence and clonality of Burkholderia cepacia complex genomovars in UK patients with cystic fibrosis referred for lung transplantation

BACKGROUND

It has previously been reported that patients infected with Burkholderia cenocepacia (genomovar III) before lung transplantation have a poorer outcome than those with other B. cepacia complex infections.

METHODS

An extensive study was conducted to determine the prevalence and clonality of B. cepacia complex genomovars isolated from patients referred for transplant assessment between 1989 to the present and, where appropriate, whether strain type was related to transplant outcome.

RESULTS

Isolates from 29 patients were identified as B. cepacia complex organisms by molecular analysis. Thirteen patients (45%) were infected with the highly transmissible ET-12 strain of B. cenocepacia recA lineage III-A, while all remaining patients were infected with genetically unique B. cenocepacia, B. multivorans, and B. vietnamiensis strains. All previously reported deaths following transplantation were associated with ET-12 infection.

CONCLUSIONS

The ET-12 strain is the predominant cause of B. cenocepacia infections in patients with cystic fibrosis referred to our pulmonary transplant centre and is associated with poor transplant outcomes using standard treatment regimens.

Clinical outcome of Burkholderia cepacia complex infection in cystic fibrosis adults

BACKGROUND

The Burkholderia cepacia complex (BCC) is one of the most important groups of organisms infecting cystic fibrosis (CF) patients. The aim of the study was to examine how infection with BCC affects clinical outcome.

METHODS

Nineteen CF adults infected with BCC and 19 controls infected with Pseudomonas aeruginosa were studied over a 4-year period. The best forced expiratory volume in 1 s (FEV(1)) and body mass index (BMI) for each year were recorded and annual rate of decline calculated.

RESULTS

The BCC infected group displayed a significantly greater reduction of FEV(1) and BMI compared to the P. aeruginosa infected group (p=0.001 and p=0.009, respectively). Sixteen patients infected with a single Burkholderia cenocepacia strain had a significantly greater rate of FEV(1) decline compared to those infected with Burkholderia multivorans (n=3) or P. aeruginosa (p=0.01 and p<0.0001, respectively). The rate of BMI decline was significantly greater in patients infected with B. cenocepacia compared to those with P. aeruginosa (p=0.007), but not significantly different in those with B. multivorans (p=0.29).

CONCLUSION

BCC infection is associated with an accelerated decline in pulmonary function and BMI. Infection with a single B. cenocepacia strain was associated with a more rapid decline in lung function than those infected with either B. multivorans or P. aeruginosa.

Inflammatory markers in cystic fibrosis patients with transmissiblePseudomonas aeruginosa

Chronic Pseudomonas aeruginosa infection in cystic fibrosis (CF) leads to a damaging host inflammatory response. There are an increasing number of reports of P. aeruginosa cross-infection at CF centres. The clinical significance of acquisition of a transmissible strain for patients who already harbour P. aeruginosa is unclear. In this study, levels of inflammatory markers in clinically stable adult CF patients who harbour transmissible and sporadic strains of P. aeruginosa have been compared. Patients with CF and chronic P. aeruginosa infection were grouped into those who harbour a transmissible P. aeruginosa and those who harbour their own sporadic strains. Total white cell and differential counts, sputum neutrophil elastase (NE), interleukin (IL)-8, tumour necrosis factor (TNF)-alpha, plasma IL-6 and NE/alpha1-antitrypsin complexes, serum C-reactive protein, and urine TNF receptor 1 were all measured in clinically stable patients 4-6 weeks following completion of intravenous antibiotic therapy. The two groups (both n=20) were well matched for per cent predicted forced expiratory volume in one second, per cent predicted forced vital capacity and body mass index. There were no significant differences in levels of white cell counts or inflammatory markers between the two groups. At times of clinical stability, cystic fibrosis patients infected with transmissible Pseudomonas aeruginosa do not have a heightened inflammatory response above that of those harbouring sporadic strains.

Autoantibodies to malondialdehyde-modified low-density lipoprotein in patients with angiographically confirmed coronary artery disease

Oxidised low-density lipoprotein (LDL) has physicochemical properties that are pivotal in atherosclerotic plaque formation. As a consequence, antioxidant regimens may prove an important therapy in the prevention and treatment of cardiovascular disease. Since oxidised LDL is immunogenic, the aims of our study were to measure serum IgG titres to malondialdehyde-modified LDL (MDA-LDL) in patients with coronary artery disease (CAD) and control subjects and assess their potential as a clinical marker for coronary atherosclerosis and, consequently, antioxidant intervention. Serum IgG titres to MDA-LDL were measured in patients with angiographically confirmed CAD (n = 40) and aged-matched controls (n = 40) by enzyme-linked immunosorbant assay (ELISA). Titres were calculated and expressed as both the difference and the ratio of blanked absorbance units (AU) for IgG binding to MDA-LDL and native LDL. For the control population, median IgG titres were 0.26 AU (interquartile range (IQR) 0.20-0.46 AU) and 5.34 (IQR 3.40-8.58), respectively, while the patient population had median IgG titres of 0.30 AU (IQR 0.20-0.47 AU) and 5.08 (IQR 3.30-9.66), respectively. Both sets of calculated titre values were not significantly different between the two groups (P = 0.60 and 0.82, respectively). In conclusion, this study could not establish any significant association between circulating autoantibody titres to MDA-LDL and coronary atherosclerosis. Therefore, the diagnostic value of autoantibodies to oxidised LDL remains unclear.

PCR-based detection and identification of Burkholderia cepacia complex pathogens in sputum from cystic fibrosis patients

PCR amplification of the recA gene followed by restriction fragment length polymorphism (RFLP) analysis was investigated for the rapid detection and identification of Burkholderia cepacia complex genomovars directly from sputum. Successful amplification of the B. cepacia complex recA gene from cystic fibrosis (CF) patient sputum samples containing B. cepacia genomovar I, Burkholderia multivorans, B. cepacia genomovar III, Burkholderia stabilis, and Burkholderia vietnamiensis was demonstrated. In addition, the genomovar identifications determined directly from sputum were the same as those obtained after selective culturing. Sensitivity experiments revealed that recA-based PCR could reliably detect B. cepacia complex organisms to concentrations of 10(6) CFU g of sputum(-1). To fully assess the diagnostic value of the method, sputum samples from 100 CF patients were screened for B. cepacia complex infection by selective culturing and recA-based PCR. Selective culturing identified 19 samples with presumptive B. cepacia complex infection, which was corroborated by phenotypic analyses. Of the culture-positive sputum samples, 17 were also detected directly by recA-based PCR, while 2 samples were negative. The isolates cultured from both recA-negative sputum samples were subsequently identified as Burkholderia gladioli. RFLP analysis of the recA amplicons revealed 2 patients (12%) infected with B. multivorans, 11 patients (65%) infected with B. cepacia genomovar III-A, and 4 patients (23%) infected with B. cepacia genomovar III-B. These results demonstrate the potential of recA-based PCR-RFLP analysis for the rapid detection and identification of B. cepacia complex genomovars directly from sputum. Where the sensitivity of the assay proves a limitation, sputum samples can be analyzed by selective culturing followed by recA-based analysis of the isolate.

Burkholderia cepacia complex genomovars and pulmonary transplantation outcomes in patients with cystic fibrosis

Burkholderia cepacia is a group of organisms that comprises seven genotypically distinct species (B cepacia genomovars I-VII), which are collectively known as the B cepacia complex. Preoperative infection with B cepacia is associated with a poor prognosis in lung transplant recipients with cystic fibrosis. Many centres do not, therefore, offer transplants to these individuals. Our aim was to ascertain whether or not post-transplant mortality is affected by pretransplant genomovar status. We studied archived isolates with PCR-based methods, and recorded excessive mortality in patients infected with B cepacia genomovar III, but not in those infected with other genomovars.

A study of the anti-invasive properties of N-alpha-phthalimidomethyl-ketomethylene tripeptide-based metalloprotease inhibitors

We have developed matrix metalloprotease (MMP) inhibitors based on synthetic peptides incorporating a non-cleavable peptide-bond isostere at the site of the putative scissile bond. These inhibitors, N-alpha-phthaloyl-Gly-psi(CO-CH2)-Leu-Tyr-Ala-NH2 (Pht-G-CH2-LYA-NH2) and N-alpha-phthaloyl-Gly-psi(CO-CH2)-Leu-Tic-Ala-NH2 (Pht-G-CH2-LTcA-NH2) were kinetically evaluated against the type IV collagenases, gelatinase A (MMP-2) and B (MMP-9), and compared with an exactly analogous chelating-based inhibitor, N-alpha-mercaptoacetyl-Leu-Tyr-Ala-NH2 (HSCH2CO-LYA-NH2). The peptide inhibitors were also tested for their anti-invasive effects on breast carcinoma cell lines using a modification of the Boyden chamber assay. Gelatin zymography was utilized to identify gelatinolytic activities present in media removed from cultured breast cancer cells. Of the two N-alpha-phthalimidomethyl-ketomethylene peptide-based inhibitors, Pht-G-CH2-LYA-NH2 proved the more effective inhibitor of MMP-2 and MMP-9 (Ki 34.27 and 45.75 microM, respectively). However, when tested against two breast cancer cell lines, T47D and MDA-MB-231, both inhibitors were able to effectively reduce tumour cell invasion through a type IV collagen matrix by up to 91.2%. Of particular interest was the observation that Pht-G-CH2-LYA-NH2 was the most potent inhibitor of invasion by the highly aggressive MDA-MB-231 cells, despite the cells' relative lack of active secreted metalloprotease activity. The results obtained from this kinetic and anti-invasive analysis of the new inhibitors suggest that compounds incorporating the N-alpha-phthalimidomethyl-ketomethylene peptide-bond isostere may have potential for development as new agents with anti-metastatic properties.

Inhibition of Escherichia coli glucosamine synthetase by novel electrophilic analogues of glutamine--comparison with 6-diazo-5-oxo-norleucine

A series of electrophilic glutamine analogues based on 6-diazo-5-oxo-norleucine has been prepared, using novel synthetic routes, and evaluated as inhibitors of Escherichia coli glucosamine synthetase. The gamma-dimethylsulphonium salt analogue of glutamine was found to be one of the most potent inactivators of this enzyme yet reported, with an apparent second order rate constant (k2/Ki) of 3.5 x 10(5) M(-1) min(-1).

Vibrational directionality in the southern green stink bug, Nezara viridula (L.), is mediated by female song

We tested the hypothesis that male southern green stink bugs, Nezara viridula (L.), use substrate-borne songs to locate females. We recorded the responses of bugs on plants to the vibrations caused by a prerecorded female song and by an artificial sound. The female song caused males to walk, to respond with the calling and courtship songs and to approach the source of the song with characteristic search behaviour at junctions between branches on the plants. At a junction, a searching male stopped, stretched his legs and antennae and compared the vibratory signals on the two branches, with different combinations of legs and antennae. The males then left the junction and approached the source of the vibration. Males located the loudspeaker significantly more frequently in the presence than in the absence of vibratory stimuli on cyperus, Cyperus alternifolius L., and beans, Phaseolus vulgaris L. Vibrational directionality was also elicited by artificial pure tones whose spectral and temporal parameters were similar to those of natural female song. Females showed no reaction to vibratory stimulation and no vibrational directionality. We discuss possible mechanisms underlying vibrational directionality in the light of expected signal changes during transmission through plants. Copyright 1999 The Association for the Study of Animal Behaviour.

The effect of intravenous lidoflazine on whole blood-induced basilar artery contraction. An in vivo study

Lidoflazine, a piperazine derivative of known selectivity for vascular smooth muscle, was evaluated as a possible agent for prophylaxis of cerebral vascular contraction induced by subarachnoid perfusion with whole blood. Previous studies from this laboratory have indicated its efficacy in preventing basilar artery contraction induced by serotonin. The animals treated with a subarachnoid perfusion of whole blood had a mean 30% reduction in vessel diameter over the control value. Groups that were treated with 0.5 mg/kg of lidoflazine and 1.0 mg/kg of lidoflazine and then perfused with whole blood in the subarachnoid space had reductions in control diameter of 2.8% and 6.8%, respectively. One group treated with 2.0 mg/kg of lidoflazine and then perfused with whole blood actually had an increase in diameter of 6.8% over the control value. Lidoflazine, when administered intravenously at a slow rate, will not adversely lower systemic blood pressure and can prevent the contraction of cerebral vessels when the stimulus for contraction is whole blood within the subarachnoid space.