bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular analysis of microbial community structure in an arsenite‐oxidizing acidic thermal spring
Authors: Jackson Colin R. , Langner Heiko W. , Donahoe‐Christiansen Jessica , Inskeep William P. , McDermott Timothy R.
Published: March 2003

Electron microscopy (EM), denaturing gradient gel electrophoresis (DGGE) and 16S rDNA sequencing were used to examine the structure and diversity of microbial mats present in an acid‐sulphate–chloride (pH 3.1) thermal (58–62°C) spring in Norris Basin, Yellowstone National Park, WY, USA, exhibiting rapid rates of arsenite oxidation. Initial visual assessments, scanning EM and geochemical measurements revealed the presence of three distinct mat types. Analysis of 16S rDNA fragments with DGGE confirmed the presence of different bacterial and archaeal communities within these zones. Changes in the microbial community appeared to coincide with arsenite oxidation activity. Phylogenetic analysis of 1400 bp 16S rDNA sequences revealed that clone libraries prepared from both arsenic redox active and inactive bacterial communities were dominated by sequences phylogenetically related to Hydrogenobacter acidophilus and Desulphurella sp. The appearance of archaeal 16S rDNA sequences coincided with the start of arsenite oxidation, and sequences were obtained showing affiliation with both Crenarchaeota and Euryarchaeota. The majority of archaeal sequences were most similar to sequences obtained from marine hydrothermal vents and other acidic hot springs, although the level of similarity was typically just 90%. Arsenite oxidation in this system may result from the activities of these unknown archaeal taxa and/or the previously unreported arsenic redox activity of H. acidophilus‐ or Desulphurella‐like organisms. If the latter, arsenite oxidation must be inhibited in the initial high‐sulphide zone of the spring, where no change in the distribution of arsenite versus arsenate was observed.
Riboflavin, overproduced during sporulation of Ashbya gossypii, protects its hyaline spores against ultraviolet light
Authors: Stahmann K.‐Peter , Arst Herbert N. , Althöfer Henning , Revuelta José Luis , Monschau Nicole , Schlüpen Christina , Gätgens Cornelia , Wiesenburg Andreas , Schlösser Thomas
Published: March 2003

Riboflavin (vitamin B2), essential in tiny amounts as a precursor for oxidoreductase coenzymes, is a yellow pigment. Although it causes cytotoxicity via photoinduced damage of macromolecules, several microorganisms are striking overproducers. A question, unanswered for decades, is whether riboflavin overproducers can benefit from this property. Here, we report an ultraviolet (UV) protective effect of riboflavin. The spores of Ashbya gossypii, a riboflavin‐overproducing fungus, are more sensitive to UV than those of Aspergillus nidulans. The addition of riboflavin to suspensions improves the UV resistance of both spore types. Interestingly, we show that regulation of sporulation and riboflavin overproduction in A. gossypii are linked. In batch culture, both were elevated when growth ceased. At constant growth rates, obtained in a chemostat culture, neither was elevated. Supplementation of cultures by cAMP, a known stress signal, negatively affected sporulation as well as riboflavin overproduction, establishing a second, independent argument for the linkage.
A spontaneous mutant of microcystin biosynthesis: genetic characterization and effect on Daphnia
Authors: Kaebernick Melanie , Rohrlack Thomas , Christoffersen Kirsten , Neilan Brett A.
Published: March 2003

Microcystis aeruginosa strain MRC is unique in its' possession of the mcyA‐J gene cluster, which encodes microcystin synthetase, but its' inability to produce microcystins. M. aeruginosa strain MRD is genetically identical to MRC at numerous genomic loci examined, but produces a variety of microcystins, mainly with the amino acid tyrosine in the molecule. Zooplankton studies with Daphnia galeata and D. pulicaria, using the mutant (MRC) and its' wild type (MRD), showed for the first time that microcystins other than microcystin‐LR can be responsible for the poisoning of Daphnia by Microcystis. Regardless of microcystin content, both Daphnia exhibited significantly reduced ingestion rates when fed with either strain of M. aeruginosa compared with the green alga Scenedesmus acutus. A disruption of the molting process in both Daphnia spp. was noted when these species were fed with MRC cells. Such symptoms on Daphnia have not been previously reported for cyanobacteria and may point to a bioactive compound, other than microcystin, which inhibits the hardening of protein–chitin complexes in Daphnia.
The regulation of biofilm development by quorum sensing in Aeromonas hydrophila
Authors: Lynch Martin J. , Swift Simon , Kirke David F. , Keevil C. William , Dodd Christine E. R. , Williams Paul
Published: March 2003

Aeromonas hydrophila is an opportunistic Gram‐negative pathogen that readily attaches to stainless steel to produce a thin biofilm with a complex 3D structure covering 40–50% of the available surface and producing large microcolonies. As A. hydrophila possesses an N‐acylhomoserine lactone (AHL)‐dependent quorum‐sensing system based on the ahyRI locus, the presence of the AhyI protein and C4‐HSL within the biofilm phase was first established by Western blot and AHL biosensor analysis respectively. The ability of the A. hydrophila AH‐1 N strain to form biofilms in a continuous‐flow chamber was compared with isogenic ahyI and ahyR mutants. The ahyI mutant, which cannot produce C4‐HSL, failed to form a mature biofilm. In addition, the viable count of biofilm, but not planktonic phase ahyI mutants, was significantly lower that the parent or ahyR mutant. This defect in the differentiation of the ahyI mutant biofilm could be partially restored by the addition of exogenous C4‐HSL. A mutation in ahyR increased coverage of the available surface to around 80% with no obvious effect upon biofilm microcolony formation. These data support a role for AHL‐dependent quorum sensing in A. hydrophila biofilm development. Exposure of the A. hydrophila AH‐1N biofilm to N‐(3‐oxodecanoyl)homoserine lactone, which inhibits exoprotease production in planktonic cells, however, had no effect on biofilm formation or architecture within the continuous‐flow chamber.
Analysis of the Pseudomonas aeruginosa oprD gene from clinical and environmental isolates
Authors: Pirnay Jean‐Paul , Vos Daniel De , Mossialos Dimitris , Vanderkelen Alain , Cornelis Pierre , Zizi Martin
Published: March 2003

Genomes are constantly evolving. Our report highlights the wide mutational diversity of clinical as well as environmental isolates, compared with the laboratory strain(s), through the systematic genetic analysis of a chromosomal porin gene (oprD) in relation to a specific antibiotic resistance. Mutational inactivation of the oprD gene is associated with carbapenem resistance in Pseudomonas aeruginosa. The sequence of the oprD gene of 55 Pseudomonas aeruginosa natural isolates obtained from across the world – from sources as diverse as patients and rhizospheres – was analysed. A microscale mosaic structure for this gene – resulting from multiple intra‐ and possibly interspecies recombinational events – is reported. An array of independent and seemingly fast‐occurring defective oprD mutations were found, none of which had been described before. A burn wound isolate demonstrated unusually high overall sequence variability typical of mutator strains. We also present evidence for the existence of OprD homologues in other fluorescent pseudomonads.
Enrichment versus biofilm culture: a functional and phylogenetic comparison of polycyclic aromatic hydrocarbon‐degrading microbial communities
Authors: Stach James E. M. , Burns Richard G.
Published: March 2003

The effect that culture methods have on the diversity of degradative microbial communities is not well understood. We compared conventional batch enrichment with a biofilm culture method for the isolation of polycyclic aromatic hydrocarbon (PAH)‐degrading microbial communities from a PAH‐contaminated soil. The two methods were assessed by comparing: (i) the diversity of culturable bacteria; (ii) the diversity of PAH‐catabolic genes in isolated bacteria; (iii) the inter‐ and intraspecific diversity of active PAH‐catabolic gene classes; (iv) the diversity of bacteria present in 16S rRNA gene libraries generated from RNA extracted from the two communities and soil; and (v) the estimated diversity of active bacteria in the soil and culture systems. Single‐strand conformation polymorphism analysis showed that the biofilm culture yielded 36 bacterial and two fungal species compared with 12 bacterial species from the enrichment culture. Application of accumulation and non‐parametric estimators to clone libraries generated from 16S rRNA confirmed that the biofilm community contained greater diversity. Sequencing of clones showed that only species from the Proteobacteria were active in the enrichment culture, and that these species were expressing an identical nahAc‐like naphthalene
dioxygenase. 16S rRNA clones generated from the biofilm community indicated that
species from the Cytophaga/Flavobacterium, high G+C bacteria and Proteobacteria were
active at the time of sampling, expressing cndA‐, nahAc‐ and phnAc‐like naphthalene dioxygenases. The diversity of active species in the biofilm culture system closely matched that in the PAH‐contaminated source soil. The results of this study showed that biofilm culture methods are more appropriate for the study of community‐level interactions in PAH‐degrading microbial communities. The study also indicated that cultivation of microbial communities on solid media might be the primary source of bias in the recovery of diverse species.
Phylogenetic 16S rRNA analysis reveals the presence of complex and partly unknown bacterial communities in Tito Bustillo cave, Spain, and on its Palaeolithic paintings
Authors: Schabereiter‐Gurtner Claudia , Saiz‐Jimenez Cesareo , Piñar Guadalupe , Lubitz Werner , Rölleke Sabine
Published: March 2003

Tito Bustillo cave (Ribadesella, Spain) contains valuable Palaeolithic paintings, which date back 15 000–20 000 years. Since 1969, the cave has been open to the public. Rock wall surfaces, spelaeothems and soils are covered by apparent biofilms of phototrophic microorganisms, which develop under artificial lighting. In addition, rock surfaces present conspicuous bacterial growth in the form of round colonies of different colours and about 1–2 mm in diameter. Even the famous Paintings Panel shows some evident microbial growth. In the present study, bacterial communities on the paintings and on the rock surfaces near the paintings were analysed by culture‐independent techniques, including polymerase chain reaction (PCR) amplification of bacterial 16S rRNA genes (16S rDNA), phylogenetic sequence analyses and genetic community fingerprinting by denaturing gradient gel electrophoresis (DGGE). DGGE fingerprints showed complex bacterial community patterns. Forty‐one clones matching DGGE bands of the community fingerprints were sequenced, representing about 39% of DNA fragments in the DGGE patterns. Phylogenetic sequence analyses revealed a high number of phylogenetically novel 16S rDNA sequence types and a high diversity of putatively chemotrophic and heterotrophic bacteria. Sequences were phylogenetically most closely related to the Proteobacteria (20 clones), green non‐sulphur bacteria (three clones), Planctomycetales order (one clone), Cytophaga–Flexibacter– Bacteroides division (one clone) and the Actinobacteria (four clones). Furthermore, we report the presence of members of the Acidobacterium division (12 clones) in a karstic hypogean environment. Members of this phylum have not so far been detected in these particular environments.
Characterization of the bacterial consortium associated with black band disease in coral using molecular microbiological techniques
Authors: Cooney Rory P. , Pantos Olga , Tissier Martin D. A. Le , Barer Michael R. , O´Donnell Anthony G. , Bythell John C
Published: March 2003

The bacterial community associated with black band disease (BBD) of the scleractinian corals Diploria strigosa, Montastrea annularis and Colpophyllia natans was examined using culture‐independent techniques. Two complementary molecular screening techniques of 16S rDNA genes [amplified 16S ribosomal DNA restriction analysis (ARDRA) of clone libraries and denaturing gradient gel electrophoresis (DGGE)] were used to give a comprehensive characterization of the community. Findings support previous studies indicating low bacterial abundance and diversity associated with healthy corals. A single cyanobacterial ribotype was present in all the diseased samples, but this was not the same as that identified from Phormidium corallyticum culture isolated from BBD. The study confirms the presence of Desulfovibrio spp. and sulphate‐reducing bacteria that have previously been associated with the BBD consortium. However, the species varied between diseased coral samples. We found no evidence of bacteria from terrestrial, freshwater or human sources in any of the samples. We report the presence of previously unrecognized potential pathogens [a Cytophaga sp. and an α‐proteobacterium identified as the aetiological agent of juvenile oyster disease (JOD)] that were consistently present in all the diseased coral samples. The molecular biological approach described here gives an increasingly comprehensive and more precise picture of the bacterial population associated with BBD. To understand the pathogenesis of BBD, our attention should be focused on the pervasive ribotypes identified in this study (the Cyanobacterium sp., the Cytophaga sp. and the JOD pathogen).
Estimation of methanotroph abundance in a freshwater lake sediment
Authors: Costello Andria M. , Auman Ann J. , Macalady Jennifer L. , Scow Kate M. , Lidstrom Mary E.
Published: March 2003

The numbers of methane‐oxidizing bacteria (methanotrophs) in the sediments of Lake Washington were estimated using three culture‐independent methods. Quantitative slot‐blot hybridizations were performed with type I and type II methanotroph‐specific probes. These data were compared to data from quantitative hybridizations using a pmoA‐specific probe and a eubacterial probe. From the combined hybridi‐zation data, the methanotroph population in Lake Washington was estimated to be 3.6 × 108–7.4 × 108 cells/g dry weight. Methanotroph community structure and number were also investigated using polar lipid fatty acid (PLFA) analysis. Analysis of biomarker PLFAs characteristic of both type I (16:1ω8) and type II (18:1ω8) methanotrophs was used to estimate the abundance of these bacteria in Lake Washington sediments. From the PLFA data, the methanotroph population in Lake Washington was estimated to be 7.1 × 108–9.4 × 109 cells/g dry weight. As a third method of quantitation, we calculated the methanotroph population using the total methane oxidation rate for whole cells in Lake Washington sediment to be 1.3 × 108–1.2 × 109 cells/g dry weight. The three independent estimates of the number of methanotrophs in Lake Washington sediment agree within a two‐ to fourfold range. These data suggest that the three techniques used in this study detect the functionally significant population of methanotrophs in Lake Washington. Furthermore, these techniques will be useful for obtaining estimates of methanotroph abundance in additional environments.
Recovery of novel bacterial diversity from a forested wetland impacted by reject coal
Authors: Brofft Jennifer E. , McArthur J. Vaun , Shimkets Lawrence J.
Published: March 2003

Sulphide mineral mining together with improperly contained sulphur‐rich coal represents a significant environmental problem caused by leaching of toxic material. The Savannah River Site's D‐area harbours a 22‐year‐old exposed reject coal pile (RCP) from which acidic, metal rich, saline runoff has impacted an adjacent forested wetland. In order to assess the bacterial community composition of this region, composite sediment samples were collected at three points along a contamination gradient (high, middle and no contamination) and processed for generation of bacterial and archaeal 16S rDNA clone libraries. Little sequence overlap occurred between the contaminated (RCP samples) and unimpacted sites, indicating that the majority of 16S rDNAs retrieved from the former represent organisms selected by the acidic runoff. Archaeal diversity within the RCP samples consisted mainly of sequences related to the genus Thermoplasma and to sequences of a novel type. Bacterial RCP libraries contained 16S rRNA genes related to isolates (Acidiphilium sp., Acidobacterium capsulatum, Ferromicrobium acidophilium and Leptospirillum ferrooxidans) and environmental clones previously retrieved from acidic habitats, including ones phylogenetically associated with organisms capable of sulphur and iron metabolism. These libraries also exhibited particularly novel 16S rDNA types not retrieved from other acid mine drainage habitats, indicating that significant diversity remains to be detected in acid mine drainage‐type systems.
Holy water fonts are reservoirs of pathogenic bacteria
Authors: Jurado V. , Ortiz‐Martinez A. , Gonzalez‐delValle M. , Hermosin B. , Saiz‐Jimenez C.
Published: March 2003

The holy water fonts from the churches of Seville, Spain have a strong bacterial contamination. Coliforms, Enterobacteriaceae and other pathogenic bacteria are widely represented in the fonts investigated. Thirty out of the 37 different species isolated from holy waters are known human pathogens. The high bacterial contamination is related to human skin transmission and, probably, to misuse of the water.
Label‐free detection of 16S ribosomal RNA hybridization on reusable DNA arrays using surface plasmon resonance imaging
Authors: Nelson Bryce P. , Liles Mark R. , Frederick Kendra B. , Corn Robert M. , Goodman Robert M.
Published: March 2003

In this paper, we describe the detection of bacterial cell‐extracted 16S ribosomal RNA (rRNA) using an emerging technology, surface plasmon resonance (SPR) imaging of DNA arrays. Surface plasmon resonance enables detection of molecular interactions on surfaces in response to changes in the index of refraction, therefore eliminating the need for a fluorescent or radioactive label. A variation of the more common SPR techniques, SPR imaging enables detection from multiple probes in a reusable array format. The arrays developed here contain DNA probes (15–21 bases) designed to be complementary to 16S rRNA gene sequences of Escherichia coli and Bacillus subtilis as well as to a highly conserved sequence found in rRNAs from most members of the domain Bacteria. We report species‐specific hybridization of cell‐extracted total RNA and in vitro transcribed 16S rRNA to oligonucleotide probes on SPR arrays. We tested multiple probe sequences for each species, and found that success or failure of hybridization was dependent upon probe position in the 16S rRNA molecule. It was also determined that one of the probes intended to bind 16S rRNA also bound an unknown protein. The amount of binding to these probes was quantified with SPR imaging. A detection limit of 2 µg ml−1 was determined for fragmented E. coli total cellular RNA under the experimental conditions used. These results indicate the feasibility of using SPR imaging for 16S rRNA identification and encourage further development of this method for direct detection of other RNA molecules.
Molecular diversity and characterization of nitrite reductase gene fragments (nirK and nirS) from nitrate‐ and uranium‐contaminated groundwater
Authors: Yan Tingfen , Fields Matthew W. , Wu Liyou , Zu Yuangang , Tiedje James M. , Zhou Jizhong
Published: March 2003

Nitrate‐contaminated groundwater samples were analysed for nirK and nirS gene diversity. The samples differed with respect to nitrate, uranium, heavy metals, organic carbon content, pH and dissolved oxygen levels. A total of 958 nirK and 1162 nirS clones were screened by restriction fragment length polymorphism (RFLP) analysis: 48 and 143 distinct nirK and nirS clones, respectively, were obtained. A single dominant nirK restriction pattern was observed for all six samples and was 83% identical to the Hyphomicrobium zavarzinii nirK gene. A dominant nirS pattern was observed for four of the samples, including the background sample, and was 95% identical to the nirS of Alcaligenes faecalis. Diversity indices for nirK and nirS sequences were not related to any single geochemical characteristic, but results suggested that the diversity of nirK genes was inversely proportional to the diversity of nirS. Principal component analysis (PCA) of the sites based on geochemistry grouped the samples by low, moderate and high nitrate but PCA of the unique operational taxonomic units (OTUs) distributions grouped the samples differently. Many of the sequences were not closely related to previously observed genes and some phylogenetically related sequences were obtained from similar samples. The results indicated that the contaminated groundwater contained novel nirK and nirS sequences, functional diversity of both genes changed in relation to the contaminant gradient, but the nirK and nirS functional diversity was affected differently.
Prediction of colonoscopic yield of neoplasia
Authors: Sarela  , Russell  , Windsor  , O’Riordain  , Guillou
Published: March 2003

Objective

To identify criteria which may predict yield of neoplasia at colonoscopy.

Patients and methods

Clinicopathological characteristics of patients undergoing colonoscopy for either surveillance for neoplasia or investigation of colorectal symptoms were reviewed. Logistic regression was used to analyse risks for detection of adenoma and carcinoma.

Results

A total of 493 consecutive colonoscopies was reviewed. In the surveillance group, risk for detection of adenoma was two‐fold greater in the elderly (>65 years), in male patients and in those with a previous history of adenoma as opposed to carcinoma. In symptomatic patients, risk for detection of any neoplasm was three‐fold greater in the elderly but was independent of gender and presence or absence of rectal bleeding.

Conclusion

These data support a case for prioritization of elderly patients for colonoscopy. The value of surveillance colonoscopy in preventing colorectal cancer appears greater in patients with a previous history of adenoma as opposed to carcinoma. Strict selection of patients with non‐bleeding symptoms may result in a colonoscopic yield of neoplasia comparable to that in patients with rectal bleeding.
Interstitial cells of Cajal in slow transit constipation and megabowel
Authors: Hagger  , Finlayson  , Kumar
Published: March 2003

Objective

Disordered gut motor activity is a feature of patients with chronic idiopathic constipation. Interstitial cells of Cajal (ICC) are thought to modulate gut motility. The aim of this study was to test the hypothesis that there is an abnormality of the density of distribution of ICC in slow transit constipation and megabowel.

Patients and methods

ICC were identified by immunohistochemistry using an anti‐c‐kit antibody. Six patients (slow transit constipation n=3; megabowel n=3) were compared with normal controls. The density of distribution of ICC was assessed in the longitudinal and circular muscle layers, and in the intermuscular plane of the colon. Statistical analysis was performed using Fisher’s exact test and χ2 test.

Results

No consistent pattern of difference in the density of ICC could be identified between the constipated and control groups.

Conclusion

The density of ICC in the constipated patients was not significantly different from normal colon. The results in these patients suggest that if ICC have a role in the causation of slow transit idiopathic constipation or megabowel then an abnormality of function rather than distribution is implicated.
Artificial bowel sphincter (ABS) for severe faecal incontinence: a clinical and manometric study
Authors: Dodi  , Melega  , Masin  , Infantino  , Cavallari  , Lise
Published: March 2003

Objective

As experience with artificial sphincters for severe faecal incontinence is still limited, the authors’ aim was to report on the outcome following implantation of the ABS in their series.

Patients and methods

Eight women (mean age 56 years, range 48–64 years) with severe faecal incontinence refractory to conservative treatment underwent ABS implantation. This condition was idiopathic in six of the patients, due to trauma in one and due to malformation in the remaining one. The mean preoperative score for incontinence (AMS classification) was 96.2 (range 70–108). Two of the patients had rectal prolapse and three anterior colpocele.

Results

Two patients had post‐operative infection requiring implant removal. In the six other patients (mean follow up 10.5 months, range 4–23 months) the mean incontinence score was 19.4 (range 0–61). Continence to solid stools was achieved in all six patients, although one complained of occasional episodes of incontinence to liquid stools and another of episodes of soiling; none had intolerance to the device, which functioned satisfactorily.

Conclusion

Our findings indicate that the ABS implant is well tolerated and may be a valid option in the treatment of severe incontinence, even in the presence of complex pelvic disorders, although the risk of infection must always be borne in mind. Studies on larger series with longer follow ups are required to confirm these preliminary findings.
Effect of acute changes in sacral nerve stimulation amplitude on anorectal function in faecal incontinence
Authors: Malouf A. J. , Kamm M. A. , Nicholls R. J.
Published: March 2003

Objective

Sacral nerve stimulation improves faecal continence. Preliminary evidence suggests that the effect may be mediated via altered rectal and anal smooth muscle activity, as well as facilitation of external sphincter contraction. Clinical benefit however, appears unrelated to whether stimulation amplitude is above or below that required to produce threshold perineal sensation. Formal evaluation of the effect of different levels of stimulation has not been undertaken. This study aimed to assess the effect of varying stimulation amplitude on pelvic floor motor and sensory function in patients permanently implanted for faecal incontinence.

Patients and methods

Three female patients with passive faecal incontinence secondary to internal sphincter weakness, rendered continent with a permanently implanted sacral nerve stimulating electrode and pulse generator a mean of 19 months previously, were assessed. Patients underwent a series of anorectal physiological tests whilst stimulating amplitude was altered but all other stimulation parameters were kept constant. Baseline studies were initially performed at the stimulation amplitude providing continence over recent months for individual patients. Amplitude was then initially reduced, and then increased, in increments of 0.2 V, initially down to zero, and then to the maximal tolerated stimulation amplitude, at which pain was felt. Anorectal physiological testing was repeated 10 min after adjustment to each new amplitude of stimulation.

Results

Procedures were well tolerated by all patients. There were no significant differences in any of the physiological variables measured dependent upon intensity of stimulation between zero and the maximum tolerated stimulation. The recto‐anal inhibitory reflex was unaltered in the one patient in whom it was demonstrable prior to stimulation.

Conclusion

Acute changes in stimulation amplitude alone do not produce acute measurable differences in standard anorectal physiological variables. The clinical benefits of sacral nerve stimulation for faecal incontinence are not mediated primarily by improvement in anal canal pressures or alteration of anorectal sensation. Trials of different stimulation parameters over weeks or days may be necessary to demonstrate other functional differences.
Intestinal spirochetosis: clinicopathological features with review of the literature
Authors: Alsaigh N. , Fogt F.
Published: March 2003

Objective

The purpose of this study is to evaluate the clinical presentation of patients with intestinal spirochetosis, as it is has not been well described in the literature.

Methods

We studied 15 patients with colonic biopsies that showed spirochetosis. The study group consisted of 11 males and 4 females, 10 of the males were heterosexual and one was homosexual. None of these patients were clinically immunocompromized. A colonoscopy was performed for evaluation of different symptoms. The histological diagnosis of spirochetosis was made on H&E examination and confirmed by Giemsa and/or Steiner stain. There was no evidence of associated active or any specific colitis in any of the cases. The control group consisted of 30 patients, 16 males and 14 females that were matched for age and clinical indications for obtaining a colonic biopsy.

Results

Colonic mucosa with prominent brush border‐like surface colonized with large amounts of spirochetes was noted in all 15 cases in the study group and in none of 30 cases in the control group. The clinical presentation in patients with spirochetosis was compared to the control group. Of the spirochetosis patients 86% presented with some form of clinical symptoms compared with 13% of controls. These symptoms included chronic watery diarrhoea in 40% spirochetosis patients vs 5% in controls; a change in bowel habit was present in 33% of spirochetosis patients vs 3.3% in controls. The endoscopic appearance in spirochetosis patients was reported as normal in six patients, `polyoid' in seven patients, erythematous in one patient and `lesion' in one patient.

Conclusion

These findings suggest that colonic spirochetosis affects a heterogenous group of patients, the majority of whom presented with gastrointestinal symptoms. The variable clinical findings may be related to the infecting organism and the condition may not be harmless in all patients.
Diagnostic lessons learnt from a series of enterovesical fistulae
Authors: Daniels I. R. , Bekdash B. , Scott H. J. , Marks C. G. , Donaldson D. R.
Published: March 2003

Objective  An enterovesical fistula (EVF) is an uncommon condition requiring careful and sometimes extensive preoperative investigation. Our experience over a 10‐year period has been reviewed with emphasis on the diagnostic investigations performed.

Patients and method  Forty‐two patients (30 male) have been studied. Presenting symptoms, diagnostic investigations, and subsequent treatment have been reviewed.

Results  The site of the fistulae were; 37 colonic, 2 rectal, and 3 ileal. The commonest presenting symptoms were; pneumaturia 75%, faecaluria 63% and urinary tract infections 57%. The positivity rate of the investigations performed were; cystoscopy 89%, urine cytology 86%, barium enema 65%, computerized tomography (CT) scanning 55%, IVP 35%, and cystography 27.5%. The causes of the fistula were; diverticular disease 71%, carcinoma 20%, Crohn's disease 7%, and radiotherapy 2%.

Conclusions  We recommend cystoscopy and urine cytology for faecal material as the first‐line investigations in all patients with a suspected enterovesical fistulae. CT scanning and barium enema should not be first line investigations but may be performed subsequently to help determine the aetiology and planning of surgery.
Rectal flap advancement – a simple and effective approach for the treatment of rectourethral fistula
Authors: Dreznik Z. , Alper D. , Vishne T. H. , Ramadan E.
Published: March 2003

Objective  Rectourethral fistula is a rare complication of prostatic surgery and other pelvic procedures. We report our experience of surgical repair of using a rectal advancement flap.

Patients  Three patients with rectourethral fistula following prostatic surgery were treated. Two patients had an anterior partial thickness of rectal flap advancement via a trans‐anal approach without urinary or faecal diversion. In one patient a rectal flap repair was performed through a posterior transsphincteric approach following urinary and faecal diversion.

Results  No significant postoperative complications occured. Healing was successful in each patient and faecal and urinary continence was normal.

Conclusion  Transanal rectal advancement flap is a simple and effective technique for the treatment of a rectourethral fistula with no need for urinary or faecal diversion.
A prospective audit of stomas‐analysis of risk factors and complications and their management
Authors: Arumugam P. J. , Bevan L. , Macdonald L. , Watkins A. J. , Morgan A. R. , Beynon J. , Carr N. D.
Published: March 2003

Aim  To prospectively audit stomas and to determine the nature and rate of complications and their relationship with various risk factors and their management.

Materials and methods  The study was performed prospectively on 97 consecutive patients who had stomas formed between January 2000 to August 2000. Patients were followed up for one year. Risk factors including age, body mass index (BMI), preoperative siting, contour of the abdominal wall, smoking, grade of operating surgeon, emergency or elective procedure, diabetes, type of stoma and suture material used were noted. The type of surgery, and indications for surgery were also recorded. The complications were documented by two qualified stoma nurses and a photographic record taken. Statistical analysis comprising both univariate and multivariate methods, was performed by SPSS 10.

Results  The mean age was 65 years (standard deviation 16.01, range 16–99) and mean body mass index was 24.5 (standard deviation 4.66, range 15–37). Forty‐nine of 97 (50.5%) stomas developed one or more complications. Twenty‐three patients experienced retraction, 18 had stomas sited in a skin crease, 16 had early and 12 had late skin excoriation, 12 had detachments and a further 12 had parastomal hernia. Eleven further stoma complications were noted including prolapse, necrosis, ischaemia and sloughing. None of the risk factors achieved statistical significance when analysed against the overall complication rate. However, when the risk factors were analysed against individual complications using univariate logistic regression, a high body mass index was associated with more retractions (P = 0.003), early skin excoriation (P = 0.036) and poor siting (stoma in crease) occurred more commonly in emergencies (P = 0.022). Diabetes was associated with late skin excoriation (P = 0.02). Multivariate logistic regressions confirmed an independent association of body mass index, diabetes and emergency surgery with complications. Forty‐five of 49 patients who had complications needed some conservative management such as a convexity appliance. Four patients needed refashioning.

Conclusion  Body mass index, diabetes and emergency surgery were the significant risk factors identified in our study. Overall complications compare favourably with other series. We found that preoperative siting by stoma nurses and the grade of operating surgeon did not affect the outcome.
A b3‐adrenergic agonist increases muscle GLUT1/GLUT4 ratio, and regulates liver glucose utilization in diabetic rats*
Authors: Milagro F. I. , Gómez‐Ambrosi J. , Forga L. , Martínez J. A.
Published: March 2003

Aim: Previous studies have reported that β3‐adrenergic agonists reduce plasma glucose levels in situations of hyperglycaemia and diabetes in rodents. Nevertheless, the mechanisms still remain unclear. In this context Trecadrine®, a novel compound with affinity for β3‐adrenergic receptors, has been tested in alloxan‐diabetic rats for its potential use as an anti‐diabetic drug, but also to elucidate the role of muscle/liver glucose utilization in the process.

Methods and results: Daily oral administration (1 mg/kg) to alloxan‐diabetic Wistar rats (n = 10) for 4 days caused a significant reduction in plasma glucose levels (from 15.0 to 8.3 mmol/l) with no apparent effects on insulin secretion. Furthermore, Trecadrine® administration tended to normalize glucose storage (estimated by measuring glucokinase activity) and output (by measuring glucose‐6‐phosphatase activity) in the liver of diabetic animals. On the other hand, Trecadrine® administration for 4 days resulted in an increase in GLUT1 gene expression in gastrocnemius muscle as compared to insulin‐dependent glucose transporter GLUT4. Furthermore, a significant stimulation of 2‐deoxy‐
d‐glucose uptake in extensor digitorum longus muscle and, in a lesser degree, in gastrocnemius, but not in soleus muscle and in white adipose tissue, occurs.

Conclusions: Trecadrine® reduces glucose output from the liver, thus thus contributing to the reduction of plasma glucose levels to achieve the values of control rats. Furthermore, Trecadrine® administration stimulates glucose uptake in skeletal muscle, especially in those muscles with predominant glycolytic fast‐twitched fibres, apparently by a direct non‐insulin‐dependent mechanism, involving a relative increase in the content of GLUT1 in the plasma membrane as compared with GLUT4. In conclusion, Trecadrine® shows a potent hypoglycaemic effect in the alloxan‐induced model of diabetes in rats by decreasing hepatic glucose output and improving muscle glucose uptake.
Unfavourable impact of growth hormone (GH) discontinuation on body composition and cholesterol profiles after the completion of height growth in GH‐deficient young adults
Authors: Kohno H. , Ueyama N. , Honda S.
Published: March 2003

Aim: Growth hormone (GH) plays an important role in the regulation of body composition and metabolism. GH deficiency is associated with obesity and hypercholesterolemia, which respond to GH treatment. In this study we evaluated changes in body composition and cholesterol profiles after discontinuation of GH therapy to assess atherogenic risk factors in GH‐deficient patients.

Methods: We studied 18 male patients with GH deficiency 17–20 years of age at the time of discontinuing GH therapy. Body composition and cholesterol were measured 6 months before discontinuation of GH therapy with a weekly dose of 0.5 IU/kg (≈ 0.19 mg/kg), and immediately, 2 months, and 6 months after the end of GH therapy.

Results: Two months after termination of GH therapy the percentage of body fat and fat mass increased from 7.4% to 9.4% and from 3.8 kg to 5.0 kg, respectively, and remained high thereafter. Lean body mass decreased gradually, but the change was not significant. Lean body mass : fat mass ratio decreased from 14.7 at termination of GH therapy to 10.9 at the end of study. Total cholesterol (TC) showed a significant linear increase from 156 mg/dl immediately after discontinuation to 169 mg/dl 6 months after discontinuation of GH, whereas high‐density lipoprotein cholesterol (HDLC) showed no change during the study. The TC to HDLC ratio showed a slight but insignificant trend toward an increase. There were no significant changes in any variables during the last 6 months of GH therapy.

Conclusion: GH therapy in patients with GH deficiency can reduce risk factors for obesity‐related diseases and atherosclerosis. These beneficial effects are reversed after discontinuation of GH therapy. Further long‐term studies of the effects of the GH withdrawal on lipid profiles, adiposity and life expectancy must be performed.
Comparative efficacy study of atorvastatin vs. simvastatin, pravastatin, lovastatin and placebo in type 2 diabetic patients with hypercholesterolaemia
Authors: Gentile S. , Turco S. , Guarino G. , Sasso C. F. , Amodio M. , Magliano P. , Salvatore T. , Corigliano G. , Agrusta M. , De Simone G. , Gaeta I. , Oliviero B. , Torella R.
Published: March 2003

Although there is little information from primary or secondary prevention trials on cholesterol‐lowering medication in diabetic patients, the reduction of elevated cholesterol is widely recommended for this group. The American Diabetes Association (ADA) recommends drug therapy in diabetic patients if low density lipoprotein (LDL)‐cholesterol remains at > 130 mg/dl, or > 100 mg/dl in patients with macroangiopathy, after dietary intervention. When cholesterol‐lowering medication is indicated, the choice of the drug must take into account the other lipid abnormalities that are often present and the need to maintain optimal glycaemic control. In the present study we compared the efficacy and safety of the novel HMG‐CoA reductase inhibitor atorvastatin at the dose of 10 mg/day with simvastatin , lovastatin and pravastatin at doses of 10, 20 and 20 mg/day, respectively, and placebo, in type 2 diabetic patients with moderate elevation of LDL‐cholesterol with or without elevation of triglycerides. All the quoted agents are enzyme inhibitors effective in lowering LDL‐cholesterol in humans. The efficacy endpoints were the mean per cent changes in plasma LDL‐cholesterol (primary), total cholesterol, triglycerides, and high‐density lipoprotein (HDL)‐cholesterol concentrations from baseline to the end of treatment (24 weeks). Atorvastatin at a dose of 10 mg/day produced: (1) a significant reduction in LDL‐cholesterol (− 37%) in comparison with equivalent doses of simvastatin

(− 26%), pravastatin (− 23%), lovastatin (− 21%), and placebo (− 1%); (2) HDL‐cholesterol increases (7.4%) comparable to or greater than those obtained with simvastatin (7.1%), pravastatin (3.2%), lovastatin (7.21%), and placebo (− 0.5%); (3) a significantly greater reduction in total cholesterol (− 29%) than that obtained with simvastatin (− 21%), pravastain (− 16%), lovastatin (− 18%), and placebo (1%); and (4) a significantly greater reduction in triglycerides than that obtained with all the other drugs and placebo. In all treatment groups no significant variation in fibrinogen concentration was observed. All reductase inhibitors studied had similar levels of tolerance. There were no incidents of persistent elevations of serum aminotransferases or myositis.
Effect of treatment with acarbose and insulin in patients with non‐insulin‐dependent diabetes mellitus associated with non‐alcoholic liver cirrhosis
Authors: Gentile S , Turco S , Guarino G , Oliviero B , Annunziata S , Cozzolino D , Sasso F. C , Turco A , Salvatore T , Torella R
Published: March 2003

Summary

Aim

Non‐insulin‐dependent diabetes mellitus (type 2 diabetes) not responding to dietary treatment alone in patients with non‐alcoholic liver cirrhosis is characterized by high postprandial hyperglycaemia. The control of postprandial hyperglycaemia in such patients, is generally achieved by the means of progressively higher doses of insulin, with an increasing risk of hypoglycaemia in the late postprandial period. The aim of this study was to evaluate the use of acarbose for the control of postprandial hyperglycaemia in 100 patients with well‐compensated liver cirrhosis and type 2 diabetes treated with insulin.

Methods

The study was double blind with randomization of treatments into acarbose (52 patients) vs. placebo (48 patients) with parallel branches over a period of 28 weeks.

Results

All patients tolerated the treatments well and no significant variations in liver function tests were observed (< 5% vs. pretreatment). A significant reduction of several parameters was observed only after acarbose treatment: fasting glycaemia (173 ± 28 vs. 146 ± 19 mg/dl; p < 0.01), postprandial glycaemia (230 ± 24 vs. 148 ± 20 mg/dl; p < 0.01), mean glycaemia (206 ± 20 vs. 136 ± 13 mg/dl; p < 0.01), mean variation (180 ± 14 vs. 51 ± 10 mg/dl; p < 0.01), HbA1c (8.9 ± 0.8 vs. 7.2 ± 0.5; p < 0.05), C‐peptide 2 h after a standard meal (4.5 ± 1.9 vs. 2.8 ± 1.7 ng/ml; p < 0.05), whereas the parameters did not change significantly after the placebo. After acarbose treatment a significant increase of intestinal voiding/week (+ 116% vs. + 10%; p < 0.01) and a parallel reduction of blood ammonia levels (− 52 ± 9% vs. − 9 ± 5%; P < 0.01) were observed.

Conclusions

The results clearly document the good tolerability and the absence of toxic effects of acarbose on liver, due to the lack of both intestinal absorption and hepatic metabolism of the drug at doses in the therapeutic range. In fact, acarbose increases the peristalsis movements of the gut, stimulates the proliferation of the saccarolytic bacteria and simultaneously reduces the proliferation of proteolytic bacteria, thus resulting active in the reduction of blood ammonia levels. These effects of acarbose may be advantageously exploited in the treatment of type 2 diabetic patients with well‐compensated non‐alcholic liver cirrhosis.
Comparison of adipose tissue changes following administration of rosiglitazone in the dog and rat
Authors: Toseland C. D. N. , Campbell S. , Francis I. , Bugelski P. J. , Mehdi N.
Published: March 2003

Rosiglitazone (BRL‐49653‐C), a thiazolidinedione, is a potent agonist for the nuclear hormone receptor peroxisome proliferator‐activated receptor gamma (PPARγ). Thiazolidinediones have been reported to induce adipocyte differentiation in vitro and there is limited data on their effects in vivo. The objective of this study was to compare the effects of rosiglitazone on adipocyte differentiation between dogs and rats. Morphological (light and ultrastructural) and morphometric evaluations were conducted on perirenal adipose tissue from dogs that have been treated for 1 month with 0.4, 5, 60 mg/kg/day and rats treated for the same period with 80 mg/kg/day. There was a dose‐related change in the phenotype of white adipose tissue in dogs, reflected by an increase in nuclear numerical density (up to threefold) and cytoplasmic area fraction (up to 2.1‐fold). In addition, there was an enlargement of the nuclei and a reduction in the size of the white adipocyte lipid vacuoles. Ultrastructural changes included an increase in the number of mitochondria per adipocyte. In the rat, similar changes were seen in nuclear numerical density (1.5‐fold increase) and cytoplasmic area fraction (2.2‐fold increase). There were also increased numbers of mitochondria per cell in white adipocytes giving them similar numbers of mitochondria to brown adipocytes. In the brown adipocytes, there was a reduction in cytoplasmic area fraction with a corresponding increase in the size of the lipid filled vacuoles in other words there was a converging of the phenotypes of the white and brown adipose tissues.
Effects of the Magenstrasse and Mill operation for obesity on plasma leptin and insulin resistance
Authors: Carmichael A. R. , Johnston D. , King R. F. G. J. , Sue‐Ling H. M.
Published: March 2003

Background  We evaluated the effect of the Magenstrasse and Mill (M & M) operation–a new form of non‐banded vertical gastroplasty–on weight loss, plasma leptin levels and insulin resistance.

Methods  Fasting plasma glucose, leptin and insulin levels were measured in 12 normal controls, 39 morbidly obese patients and 39 patients a median 3 years after the M & M procedure. Insulin resistance was calculated by the homeostasis model insulin resistance index.

Results  Body mass index mean (s.d.) decreased significantly (p < 0.0001), from 48(7) to 33(5) kg/m2, after the M & M procedure. Fasting plasma leptin concentration in the morbidly obese group was 37.9(15.4) ng/ml, significantly (p < 0.0001) higher than the control group (12.2(8.4)) and the M & M group (19.1(12.7)) ng/ml. Fasting plasma insulin concentrations were also significantly (p < 0.0001) higher in the morbidly obese group compared with than in the M & M group or in the control group: 35.5(22.3) mU/l, 15.5(7.1) mU/l and 13.6(3.4) mU/l, respectively. Insulin resistance was 9.6(7.2) in the morbidly obese group and 3.5(1.9) in the M & M group (p < 0.0001).

Conclusion  This is one of the first studies to show that the decrease in insulin resistance after weight loss achieved by anti‐obesity surgery is associated with significantly lower levels of plasma leptin.