bluuebunny/crossref_metadata_2025 huggingface dataset:
Affinity towards maternal odour and offspring dispersal in the common lizard
Authors: Léna J.P. , De Fraipont M. , Clobert J.
Published: March 2003

Kin competition is known to strongly influence the spacing behaviour of juveniles in the common lizard, a species which is only weakly social and has no parental care. We examined whether variation in offspring dispersal propensity was associated with variation in their ability to discriminate odours of their mothers versus unknown females. We caught pregnant females in two populations and reared them in the laboratory until parturition. Just after birth, we recorded the juvenile response to the odour of either their mother or an unrelated female. Mothers and offspring were then released at the mother’s last capture point, and juvenile movement was monitored by recapture for 2 years. Philopatric individuals were more attracted to the odour of their mother and more repulsed by the odour of an unrelated female than dispersers. In this species, ability to discriminate maternal cues appears to be implied in the spacing behaviour of juveniles. Since juvenile males and females reacted in the same way, the main role of mother discrimination is likely to be the avoidance of kin competition by promoting juvenile dispersal. This does not necessary require mother discrimination to imply mother recognition, or not to be implied in other functions such as inbreeding avoidance. Further research is needed to clarify these points. We suggest that context‐dependent kin discrimination may be involved in the spacing behaviour of a large number of species, even for those species where other social functions for kin discrimination have been proposed.
Contrasting alternative hypotheses about rodent cycles by translating them into parameterized models
Authors: Turchin Peter , Hanski Ilkka
Published: March 2003

Ecologists working on population cycles of arvicoline (microtine) rodents consider three ecological mechanisms as the most likely explanations of this long‐standing puzzle in population ecology: maternal effects, interaction with specialist predators, and interaction with the food supply. Each of these hypotheses has now been translated into parameterized models, and has been shown to be capable of generating second‐order oscillations (that is, population cycles driven by delayed density dependence). This development places us in a unique situation for population ecology. We can now practice “strong inference” by explicitly and quantitatively comparing the predictions of the three rival hypotheses with data. In this review, we contrast the ability of each hypothesis to explain various empirically observed features of rodent cycles, with a particular emphasis on the well‐studied case of Microtus agrestis and other small rodents in Fennoscandia (Finland, Sweden and Norway). Our conclusion is that the current evidence best supports the predation hypothesis.
The allometry of flower size dimorphism in dioecious Dombeya species on La Réunion
Authors: Humeau Laurence , Thompson John D.
Published: March 2003

In this paper we examine whether variation in male and female flower size follows an allometric relation for 10 dioecious species in the genus Dombeya endemic to La Réunion. Male flowers are significantly larger than female flowers and the degree of dimorphism varies significantly across species. There is a significant allometric relationship between male and female flower size: as mean flower size decreases the degree of flower size dimorphism increases. This is the first study to document an allometric relationship between male and female flower size in unisexual plants. We discuss this allometric relationship in relation to two characteristics frequently observed in dioecious flowers: flower size dimorphism is common in unisexual plants and dioecious species often have smaller flowers than hermaphrodites.
Investigations in commonness and rarity: a comparative analysis of co‐occurring, congeneric Mexican trees
Authors: Kelly Colleen K. , Smith Helena Banyard , Buckley Yvonne M. , Carter Rebecca , Franco Miguel , Johnson William , Jones Tim , May Ben , Ishiwara Rubèn Pèrez , Pèrez‐Jimènez Alfredo , Magallanes Arturo Solis , Steers Helen , Waterman Caroline
Published: March 2003

Population size distributions were examined for 12 species of trees co‐occurring at Chamela Biological Station in Jalisco, Mexico. Species had been selected as congeneric pairs and trios similar in gross morphology and ecology in order better to identify correlates of relative abundance. Rarer species were found unanimously to have more irregular distributions of individuals among size classes than more common species when distributions were compared to a smooth, descending curve constructed from population mean stem diameters (an exponential distribution). Examination among species of patterns of deviation from these corresponding smooth distributions indicates that the most reasonably inferred cause for the observed pattern is consistent differences in degree of fluctuation in recruitment into adult size classes. These results thereby suggest a demographic difference between locally rarer and more common species that may be generally associated with observed differences in relative abundance and indicate a focus for management of rarity in forest trees.
Experimental evidence that competition between stickleback species favours adaptive character divergence
Authors: Gray Suzanne M. , Robinson Beren W.
Published: March 2003

The ecological character displacement hypothesis assumes that the effects of interspecific resource competition cause divergent selection to favour phenotypes that exploit non‐shared resources. This model predicts that interspecific competition declines with increased divergence. Direct tests of this decline are rare despite much comparative evidence for character displacement. We tested this prediction using a pair of divergent brook sticklebacks. Brook sticklebacks sympatric with ninespine sticklebacks have diverged from local allopatric brook populations, and so the two types of brook sticklebacks potentially represent pre‐ and post‐displacement forms. We used enclosures placed in a lake to compare short‐term fitness (growth) of sympatric (post‐displacement) and allopatric (pre‐displacement) brook forms in the presence and absence of ninespine sticklebacks. Brook sticklebacks grew less in the presence vs. absence of ninespine sticklebacks, indicating that interspecific competition occurred. As expected, allopatric brook forms had lower growth than sympatric forms when ninespine sticklebacks were present. This result suggests that ecological character displacement has occurred.
The scent of food and defence: green leaf volatiles and toluquinone as sex attractant mediate mate finding in the European cockchafer Melolontha melolontha
Authors: Reinecke Andreas , Ruther Joachim , Hilker Monika
Published: March 2003

Mate finding in the European cockchafer, Melolontha melolontha, has been investigated in the field. Our data suggest that mainly males show flight activity at dusk. In a landing cage bioassay, male cockchafers preferred cages baited with females over cages baited with males. Gas chromatographic analysis of beetle extracts with electronantennographic detection revealed the presence of electrophysiologically active compounds, among them toluquinone. In funnel trap bioassays none of these compounds was attractive towards males per se. A mixture of green leaf volatiles (GLV) mimicking the bouquet of mechanically damaged leaves was highly attractive to M. melolontha males. The attractiveness of the same GLV mixture was synergistically enhanced when toluquinone was added to the lure. GLV attract males to damaged leaves. Toluquinone as a sex pheromone indicates the presence of conspecific females and synergistically enhances the attractiveness of GLV.
Evidence that the fungus cultured by leaf‐cutting ants does not metabolize cellulose
Authors: Abril Adriana B. , Bucher Enrique H.
Published: March 2003

Leaf‐cutting ants are a very specialized group of ants that cultivate fungus gardens in their nests, from which they obtain food. The current opinion is that the fungus cultivated by leaf‐cutting ants digests cellulose. Here we reassess the cellulose‐degrading capability of the fungus by using two complementary approaches tested in four Attini species (genera Atta and Acromyrmex): (1) ability of fungus to grow in cellulose; and (2) lignin/cellulose ratio in the refuse material dumped outside the nest, as an indicator of cellulose consumption. We found that (1) the fungus did not grow in cellulose, and (2) the lignin/cellulose ratio was much lower in the ants' refuse than in material digested by cellulose‐digesting organisms, such as brown‐rot fungus, termites, and ruminant mammals. This evidence strongly suggests the inability of the fungus to degrade cellulose. Therefore, the fungus–ant symbiosis and the ecological role of leaf‐cutting ants need to be reconsidered.
Complex networks: two ways to be robust?
Authors: Melián Carlos J. , Bascompte Jordi
Published: March 2003

Recent studies of biological networks have focused on the distribution of the number of links per node. However, the connectivity distribution does not uncover all the complexity of their topology. Here, we analyse the relation between the connectivity of a species and the average connectivity of its nearest neighbours in three of the most resolved community food webs. We compare the pattern arising with the one recently reported for protein networks and for a simple null model of a random network. Whereas two highly connected nodes are unlikely to be connected between each other in protein networks, the reverse happens in food webs. We discuss this difference in organization in relation to the robustness of biological networks to different types of perturbation.
Mating signal partitioning in multi‐species assemblages: a null model test using frogs
Authors: Chek Andrew A. , Bogart James P. , Lougheed Stephen C.
Published: March 2003

Abstract Competitive partitioning of ‘community’ signal space has long been suggested to underlie diversification of mating signals. Selection or competitive exclusion is expected to reduce overlap of signals, minimizing destructive interference or reducing mismating. We used null models backed by simulation of type I and II error rates to test for evidence of structuring within 11 frog advertisement call assemblages. Within three assemblages, we found significant over‐dispersion and regularity‐of‐spacing in dominant frequency and in pulse rate, consistent with a signal interference hypothesis and signal confusion hypothesis, respectively. Observed partitioning could represent signal evolution or could result from selection on assemblage composition. Most assemblages showed no acoustic partitioning possibly because: (i) partitioning is more readily apparent in female preference, calling times or sites, rather than call attributes; (ii) assemblages have not yet accommodated recently arrived species, or are compositionally unstable so that acoustic accommodation cannot occur; and (iii) evidence of partitioning is only likely where the acoustic space is densely packed.
13C/12C isotope fractionation of aromatic hydrocarbons during microbial degradation
Authors: Meckenstock Rainer U. , Morasch Barbara , Warthmann Rolf , Schink Bernhard , Annweiler Eva , Michaelis Walter , Richnow Hans H.
Published: March 2003

The influence of microbial degradation on the 13C/12C isotope composition of aromatic hydrocarbons is presented using toluene as a model compound. Four different toluene‐degrading bacterial strains grown in batch culture with oxygen, nitrate, ferric iron or sulphate as electron acceptors were studied as representatives of different environmental redox conditions potentially prevailing in contaminated aquifers. The biological degradation induced isotope shifts in the residual, non‐degraded toluene fraction and the kinetic isotope fractionation factors αC for toluene degradation by Pseudomonas putida (1.0026 ± 0.00017), Thauera aromatica (1.0017 ± 0.00015), Geobacter metallireducens (1.0018 ± 0.00029) and the sulphate‐reducing strain TRM1 (1.0017 ± 0.00016) were in the same range for all four species, although they use at least two different degradation pathways. A similar 13C/12C isotope fractionation factor (αC = 1.0015 ± 0.00015) was observed in situ in a non‐sterile soil column in which toluene was degraded under sulphate‐reducing conditions. No carbon isotope shifts resulting from soil–hydrocarbon interactions were observed in a non‐degrading soil column control with aquifer material under the same conditions. The results imply that microbial degradation of toluene can produce a 13C/12C isotope fractionation in the residual hydrocarbon fraction under different environmental conditions.
Tomato seed and root exudate sugars: composition, utilization by Pseudomonas biocontrol strains and role in rhizosphere colonization
Authors: Lugtenberg Ben J. J. , Kravchenko Lev V. , Simons Marco
Published: March 2003

The role of tomato seed and root exudate sugars as nutrients for Pseudomonas biocontrol bacteria was studied. To this end, the major exudate sugars of tomato seeds, seedlings and roots were identified and quantified using high‐performance liquid chromatographic (HPLC) analysis. Glucose, fructose and maltose were present in all studied growth stages of the plant, but the ratios of these sugars were strongly dependent on the developmental stage. In order to study the putative role of exudate sugar utilization in rhizosphere colonization, two approaches were adopted. First, after co‐inoculation on germinated tomato seeds, the root‐colonizing ability of the efficient root‐colonizing P. fluorescens strain WCS365 in a gnotobiotic quartz sand–plant nutrient solution system was compared with that of other Pseudomonas biocontrol strains. No correlation was observed between the colonizing ability of a strain and its ability to use the major exudate sugars as the only carbon and energy source. Secondly, a Tn5lacZ mutant of P. fluorescens strain WCS365, strain PCL1083, was isolated, which is impaired in its ability to grow on simple sugars, including those found in exudate. The mutation appeared to reside in zwf, which encodes glucose‐6‐phosphate dehydrogenase. The mutant grows as well as the parental strain on other media, including tomato root exudate. After inoculation of germinated sterile tomato seeds, the mutant cells reached the same population levels at the root tip as the wild‐type strain, both alone and in competition, indicating that the ability to use exudate sugars does not play a major role in tomato root colonization, despite the fact that sugars have often been reported to represent the major exudate carbon source. This conclusion is supported by the observation that the growth of mutant PCL1083 in vitro is inhibited by glucose, a major exudate sugar, at a concentration of 0.001%, which indicates that the glucose concentration in the tomato rhizosphere is very low.
Co‐evolution between Frankia populations and host plants in the family Casuarinaceae and consequent patterns of global dispersal
Authors: Simonet Pascal , Navarro Elisabeth , Rouvier Carole , Reddell Paul , Zimpfer Jeff , Dommergues Yvon , Bardin René , Combarro Pilar , Hamelin Jérôme , Domenach Anne‐Marie , Gourbière François , Prin Yves , Dawson Jeffrey O. , Normand Philippe
Published: March 2003

Symbioses between the root nodule‐forming, nitrogen‐fixing actinomycete Frankia and its angiospermous host plants are important in the nitrogen economies of numerous terrestrial ecosystems. Molecular characterization of Frankia strains using polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analyses of the 16S rRNA‐ITS gene and of the nifD–nifK spacer was conducted directly on root nodules collected worldwide from Casuarina and Allocasuarina trees. In their native habitats in Australia, host species contained seven distinctive sets of Frankia in seven different molecular phylogenetic groups. Where Casuarina and Allocasuarina trees are newly planted outside Australia, they do not normally nodulate unless Frankia is introduced with the host seedling. Nodules from Casuarina trees introduced outside Australia over the last two centuries were found to contain Frankia from only one of the seven phylogenetic groups associated with the host genus Casuarina in Australia. The phylogenetic group of Frankia found in Casuarina and Allocasuarina trees introduced outside Australia is the only group that has yielded isolates in pure culture, suggesting a greater ability to survive independently of a host. Furthermore, the Frankia species in this group are able to nodulate a wider range of host species than those in the other six groups. In baiting studies, Casuarina spp. are compatible with more Frankia microsymbiont groups than Allocasuarina host spp. adapted to drier soil conditions, and C. equisetifolia has broader microsymbiont compatibility than other Casuarina spp. Some Frankia associated with the nodular rhizosphere and rhizoplan, but not with the nodular tissue, of Australian hosts were able to nodulate cosmopolitan Myrica plants that have broad microsymbiont compatibility and, hence, are a potential host of Casuarinaceae‐infective Frankia outside the hosts' native range. The results are consistent with the idea that Frankia symbiotic promiscuity and ease of isolation on organic substrates, suggesting saprophytic potential, are associated with increased microsymbiont ability to disperse and adapt to diverse new environments, and that both genetics and environment determine a host's nodular microsymbiont.
A novel haloarchaeal‐related lineage is widely distributed in deep oceanic regions
Authors: López‐García Purificación , Moreira David , López‐López Arantxa , Rodríguez‐Valera Francisco
Published: March 2003

During our study of the 16S rRNA gene sequence‐based archaeal diversity of a deep‐sea site located at a 3000 m depth at the Antarctic Polar Front, we detected several phylotypes ascribed to already known Group II and III Euryarchaeota, and a cluster of distinct sequences that branched off at the base of haloarchaea. The position of this lineage (marine Group IV) was very robust using distance (neighbour‐joining) and maximum‐likelihood methods. Subsequently, we designed specific primers for the detection of this archaeal group in other marine environments using polymerase chain reaction amplification and sequence comparison. Group IV archaea were found in the Antarctic area (across a gradient from the Southern ocean to the South Atlantic), and also in North Atlantic and Mediterranean waters. In all oceanic locations, Group IV archaea were never detected in surface waters, but were vertically distributed in the deepest part of the water column.
Evidence for anaerobic syntrophic acetate oxidation during methane production in the profundal sediment of subtropical Lake Kinneret (Israel)
Authors: Nüsslein Bernhard , Chin Kuk‐Jeong , Eckert Werner , Conrad Ralf
Published: March 2003

Methane production was measured in samples of the profundal sediment from Lake Kinneret. Production rates of CH4 were higher at 30°C than at the in situ temperature of 15°C and were higher in the top 5 cm layer than below. Turnover of [2‐14C]‐acetate resulted in the production of 14CH4 and 14CO2 with turnover times of < 42 min. However, < 30% of the added radioactivity was converted to gaseous products, indicating that only part of the acetate pool was microbially available. The calculated acetate turnover rates were sufficient to account for total CH4 production, indicating that CH4 was produced exclusively from acetate. This conclusion was confirmed by inhibition of methanogens with chloroform, which resulted in an almost stoichiometric accumulation of acetate. However, a large percentage (30–60%) of [2‐14C]‐acetate was converted to 14CO2, despite lack of reducible sulphate or other oxidants in the sediment. Anoxic preincubation of the sediment did not result in reduced production of 14CO2. Therefore, part of the acetate must have been oxidized rather than methanogenically cleaved. Conversion of [14C]‐bicarbonate to 14CH4 indicated that 30–50% of total CH4 production originated from reduction of CO2. To reconcile the relatively high contribution of H2/CO2‐dependent methanogenesis with the relatively high oxidative conversion of acetate, we assume that part of the acetate was used syntrophically by consortia of acetate‐oxidizing bacteria and H2/CO2‐using methanogens. This conclusion is supported by favourable thermodynamic conditions for syntrophic acetate oxidation under in situ conditions and complete inhibition of [2‐14C]‐acetate turnover at high H2 partial pressures. Further evidence to support this conclusion comes from the analysis of the structure of the archaeal community. Terminal restriction fragment length polymorphism (T‐RFLP) and partial sequence analysis of the SSU rRNA genes amplified from DNA extracts of the sediment showed Methanomicrobiaceae as the dominant methanogenic group, whereas acetoclastic methanogens could not be detected.
β‐Glucose 1‐phosphate‐interconverting enzymes in maltose‐ and trehalose‐fermenting lactic acid bacteria
Authors: Andersson Ulrika , Rådström Peter
Published: March 2003

Maltose and trehalose catabolic pathways are linked through their common enzyme, β‐phosphoglucomutase, and metabolite, β‐glucose 1‐phosphate, in Lactococcus lactis. Maltose is degraded by the concerted action of maltose phosphorylase and β‐phosphoglucomutase, whereas trehalose is assimilated by a novel pathway, including the recently discovered enzyme, trehalose 6‐phosphate phosphorylase, and β‐phosphoglucomutase. In the present study, 40 strains of lactic acid bacteria were investigated for utilization of metabolic reactions involving β‐glucose 1‐phosphate. All genera of the low G+C content lactic acid bacteria belonging to the clostridial subbranch of Gram‐positive bacteria were represented in the study. The strains, which fermented maltose or trehalose, were investigated for β‐phosphoglucomutase, maltose phosphorylase and trehalose 6‐phosphate phosphorylase activity, as indications of maltose and trehalose catabolic pathways involving β‐glucose 1‐phosphate interconversions. Eighty per cent of all strains fermented maltose and, of these strains, 63% were shown to use a maltose phosphorylase/β‐ phosphoglucomutase pathway. One‐third of the strains fermenting trehalose were found to harbour trehalose 6‐phosphate phosphorylase activity, and these were also shown to possess β‐phosphoglucomutase activity. Mainly L. lactis and Enterococcus faecalis strains were found to harbour the novel trehalose 6‐phosphate phosphorylase/β‐phosphoglucomutase pathway. As lower β‐glucose 1‐phosphate interconverting enzyme activities were observed in the majority of glucose‐cultivated lactic acid bacteria, glucose was suggested to repress the synthesis of these enzymes in most strains. Thus, metabolic reactions involving the β‐anomer of glucose 1‐phosphate are frequently found in both maltose‐ and trehalose‐utilizing lactic acid bacteria.
Microenvironments and microbial community structure in sediments
Authors: Tankéré S. P. C. , Bourne D. G. , Muller F. L. L. , Torsvik V.
Published: March 2003

The aim of this study was to explore the potential of a combined chemical and microbiological approach as part of a study of organic carbon oxidation processes in sediments. An assessment of microbiological diversity using molecular techniques was carried out in combination with high resolution chemical measurements at the sediment–water interface of a coastal lagoon affected by eutrophication in autumn 2000. There was a 0.2 mm overlap between the O2 and H2S profiles. pH showed a maximum just above the sediment–water interface coinciding with an oxygen maximum, suggesting photosynthetic activity, and a minimum coinciding with the O2–H2S interface. The redox potential was high in bottom water and surface sediment, reflecting the presence of oxygen and oxides, and reached low values after a step‐wise decrease at −18 mm. Reduction of Fe occurred within the biofilm at the O2–H2S interface and was mostly due to reduction by H2S. The elevated concentrations of dissolved Mn in the oxic water may have been caused either by in situ production within organic aggregates or lateral water flow from sites nearby at which Mn2+ diffuses out of the sediment. Sequences related to sulphur chemolitotrophs were retrieved from the biofilm samples, which is consistent with the small overlap between O2 and H2S observed in this biofilm. Although the resolution of techniques used was different, sequencing results were consistent with chemical data in delineating the same horizons according to redox, pH or ecological properties.
Pilonidal sinus: experience with the Limberg flap
Authors: Tekin
Published: March 2003

A personal series of 162 patients with chronic pilonidal disease was treated by rhombic excision and Limberg transposition flap. Each sinus was totally excised and covered primarily by a fasciocutaneous Limberg flap. Full primary healing was obtained in 161 out of 162 patients. One patient had ischaemia which resulted in necrosis of the flap tips that healed later with a scar. Minor infection occurred in 12 patients (7%). The average hospital stay was 4.2 days, and no patient remained in hospital more than 12 days. The mean follow‐up period was 18 months, and three recurrences (2%) have occurred. Surgery for pilonidal sinus should not only eradicate the presenting sinus formation but should also aim to eliminate factors that predispose to formation of another sinus. This can be achieved using a Limberg flap which reduces the depth of the cleft and ensures that all parts of the wound and all suture holes are away from the midline.
Anorectal dysfunction following low anterior resection for rectal carcinoma: a comparison between handsewn and stapled anastomosis
Authors: Jiang  , Lin
Published: March 2003

Sphincter‐saving resection for rectal carcinoma is frequently accompanied by anorectal dysfunction (increased stool frequency and varying degrees of faecal incontinence). Although numerous reports regarding this dysfunction have been published, the exact mechanism is still controversial. The purpose of the present study was to compare the functional results of low anterior resection (LAR) for rectal carcinoma following handsewn and stapled anastomosis. The patients with rectal carcinoma were divided into two groups: LAR with handsewn anastomosis (HS) (n = 15), and LAR with stapled EEA (U.S. Surgical Corporation) anastomosis (EEA) (n = 16; four with 28 mm stapler, 12 with 31 mm stapler). Sixteen patients with carcinoma of sigmoid colon who received high anterior resection (HAR) were taken as the control group. Anorectal functional study was performed preoperatively and post‐operatively at 1 week and another after 6 months, whereas routine clinical assessment was carried out preoperatively and 6 months post‐operatively. The post‐operative maximal resting pressure was significantly reduced in both HS and EEA groups, while a tendency to recovery was observed in the HS and 28 mm stapler group 6 months later. A significant decrease in rectal capacity was noted in the EEA group. The return of rectoanal inhibitory reflex was observed in 67% of the HS group and 37.5% of the EEA group. Although clinically increased stool frequency was experienced in both HS and EEA groups, continence was significantly worse in the EEA group. LAR for rectal carcinoma results in impaired anorectal function, which might present clinically with increased stool frequency and minor faecal soiling. The former may be due partially to reduced neorectal capacity, while the latter may be due to internal anal sphincter dysfunction, possibly because of damage to innervation.
Endoluminal stenting for relief of colonic obstruction is safe and effective
Authors: Cole  , Boorman  , Osman  , Sathananthan  , Parker
Published: March 2003

Objective

The aim of this study was to investigate the outcome of endoluminal stenting in the management of patients presenting with acute large bowel obstruction.

Patients and methods

Twenty‐eight consecutive patients presenting to one consultant surgeon with large bowel obstruction were considered for the procedure.

Results

Twenty‐four patients were successfully treated using this modality, which is to date the largest series in the UK. We discuss the complications encountered in detail and discuss the cost effectiveness of this procedure.

Conclusion

Endoluminal stenting is safe and effective, and cost effective for palliation. We advocate a multicentre randomized prospective trial of best practice emergency surgery vs endoluminal stenting and subsequent elective surgery for large bowel obstruction.
5‐amino‐salicylate in the management of inflammatory bowel disease
Authors: Makins R. J. , Cowan R. E.
Published: March 2003

The role of aminosalicylates in the treatment of idiopathic bowel disease is reviewed, with emphasis on how the different formulations can be used in different clinical manifestations. Although not fully understood, the possible mechanisms of action of these agents are discussed and their adverse reactions noted. Their use in clinical practice, both in acute disease and in remission, is outlined with particular reference to the different delivery characteristics of the aminosalicylates, thus allowing their use according to the distribution of the disease. Finally, benefits that might come from maintenance therapy, including possible reduction in post‐operative recurrence of Crohn’s disease and the risk of colorectal cancer are mentioned.
Rectal excision with coloanal anastomosis for superficial distal third rectal cancer: Survival and local recurrence
Authors: Gamagami R. A. , Liagre A. , Istvan G. , Muhammad S. , Moossa A. R. , Lazorthes F.
Published: March 2003

Objective

Appropriate surgical treatment of distal third rectal cancer limited to bowel wall (i.e. T1 or T2) in medically operable patients is controversial. Transanal excision can deprive some patients of accurate pathological staging, prognosis and cure. In contrast abdominoperineal resection has considerable practical and psychosocial problems largely related to a permanent colostomy. We hypothesize that superficial distal rectal tumours can be effectively treated with rectal excision and coloanal anastomosis.

Subjects and methods

Prospective oncological study of 80 patients with distal third superficial rectal carcinomas treated by complete rectal excision with coloananl anastomosis from December 1977 to January 1993 was carried out. The resected specimens were examined for depth of spread and number of histologically positive nodes. The actuarial local recurrence and survival rates for superficial node‐negative and node‐positive tumours were analysed independently.

Results

Seventy‐eight patients had complete postoperative assessment. Thirty‐one percent had received low‐dose preoperative neo‐adjuvant radiotherapy (3500 rads). Mean follow‐up time in all patients was 70 months on average. The lymph node involvement rate for T1 and T2 tumours was 12.5 and 15.6%, respectively. The local recurrence rates for patients with (T1/T2) N0 and (T1/T2) N1 were 1.5 and 16.7%, respectively, and the five year actuarial survival rates were 96.6 and 90%, respectively. The overall local recurrence was 3.8% with five‐year actuarial survival of 95.8%.

Conclusions

Lymph node involvement in superficial tumours is not rare. Rectal excision with coloanal anastomosis results in a high cure rate especially for node‐positive superficial tumours. This treatment strategy avoids the psychological trauma of colostomy following abdominoperineal resection and the potential risk of undertreatment by local excision.
The results of total mesorectal excision for rectal carcinoma in a district general hospital before the era of surgical specialization
Authors: Saha S. , Booth M. I. , Dehn T. C. B.
Published: March 2003

Objective

To evaluate the results of rectal cancer surgery performed by a gastrointestinal surgeon in a district general hospital prior to the introduction of specialization, and to compare these to the targets set by the Royal College of Surgeons for specialist units.

Methods

Data collection in 73 consecutive patients (prospective in 53) undergoing elective excisional surgery (sphincter conserving in 77%) for rectal cancer. While adjuvant radio/chemotherapy and pathological assessment evolved over the study period, a standardized surgical technique (total mesorectal excision) was used in all patients.

Results

Observed (and recommended) outcome measures were operative mortality 4.1% (<5), anastomotic leak 6.2% (<8), wound infection 2.7% (< 10), pelvic recurrence after curative resection 9.6% (< 10). Temporary defunctioning stomas were used in 32/48 (66.7%) of patients. Other complications, currently without recommended outcomes, were erectile dysfunction (13%), stoma related (7.1%) urinary retention (4.1%), urinary incontinence (2.7%) and benign anastomotic stricture (2.7%).

Conclusion

All treatment outcome criteria were met. Trained gastrointestinal surgeons outside the setting of a specialist unit can achieve good results with acceptable complication rates.
Effects of lanreotide on the healing of small bowel anastomoses following obstructive ileus in rats
Authors: Demetriades H. , Kanellos I. , Mantzoros I. , Kalfadis S. , Galovatsea K. , Zaraboukas T. , Betsis D.
Published: March 2003

Purpose

Lanreotide, a long‐acting somatostatin analogue, inhibits intestinal, bile and pancreatic secretions and decreases intestinal motility. The purpose of this experimental study was to evaluate the effects of lanreotide on the healing of intestinal anastomoses following small bowel obstruction.

Methods

Two groups of 16 Wistar rats (average weight 310 g) were used. Basal diameters of ileus were measured prior to the ligation of the bowel, 15 cm from the ileocecal valve. Luminal fluid was also withdrawn proximal to the obstructed bowel for sodium and potassium analysis. Lanreotide was administered intramuscularly in a single dose (5.4 mg/kg) in the first group, while the same volume of saline was used in the control group. 48 h later rats were re‐operated upon. Diameters of the obstructed segments were measured, and luminal fluid of the obstructed bowel was withdrawn and sodium and potassium levels were measured. A segment of 1 cm of the obstructed bowel was resected and end‐to‐end intestinal anastomosis was performed. Rats were sacrificed on day 7 following the second operation. Anastomoses were examined macroscopically and resected including a 2.5 cm of small bowel on either side. Bursting pressures were measured and the specimens were send for histological examination.

Results

The diameter of obstructed bowel increased significantly in both groups. The increase was more prominent in the control group (P < 0.001). Total luminal electrolyte contents for sodium and potassium were stastistically higher in the control group compared to the lanreotide group (P < 0.001). Adhesion formation was more extensive in the control group. Bursting pressures were significantly higher in the lanreotide group compared to the control group (P=0.003). Histological examination of anastomoses showed a more profound inflammatory reaction in the control group compared to the lanreotide group while microscopical healing of the anastomoses was almost the same in both groups.

Conclusions

Lanreotide administration in rats with small bowel obstruction decreases significantly distension and electrolyte losses and seems to improve strength of small bowel anastomoses.
Total anorectal reconstruction with an artificial bowel sphincter: Report of five cases with a minimum follow‐up of 6 months
Authors: Romano G. , La Torre F. , Cutini G. , Bianco F. , Esposito P.
Published: March 2003

Background The artificial bowel sphincter (Acticon ABS – American Medical Systems, Minneapolis, MN, USA) has been proposed as a treatment for patients with faecal incontinence. The good results achieved with this procedure encouraged us to utilize this device for reconstruction of patients who previously underwent an abdominoperineal resection (APR).

Method Between 1999 and 2000 we implanted the ABS in five patients undergoing an APR. One patient was male and four female, the mean age was 51.3 years. Three patients had been operated on for rectal cancer, one for rectal agenesia and one for a giant benign tumour of the pelvis.

Results The length of follow up ranged from 6 to 22 months. Manometry assessed a basal pressure with the ABS cuff inflated between 58 and 62.2 mmHg. All but one achieved a good grade of continence with a Wexner score range between 3 and 9. A certain degree of impaired evacuation occurred in two patients but, with adequate training, this improved and did not affect patient satisfaction.

Conclusion The ABS is a good option for reconstruction of patients previously treated with an APR. As compared to electrostimulated graciloplasty the ABS technique seems to be easier to perform and more acceptable for the patients, although the cost of the device is still high.
A 5‐cm colonic J pouch colo‐anal reconstruction following anterior resection for low rectal cancer results in acceptable evacuation and continence in the long term
Authors: Amin A. I. , Hallböök O. , Lee A. J. , Sexton R. , Moran B. J. , Heald R. J.
Published: March 2003

Background  Optimal treatment for low rectal cancer is total mesorectal excision, with most patients suitable for low colo‐rectal or colo‐anal anastomosis. A colon pouch has early functional benefits, although long‐term function, especially evacuation, might mitigate against its routine use. The aim of this study was to assess evacuation and continence in patients with a colon pouch, and to examine the impact of possible risk factors.

Methods  In 1998, all 102 surviving patients with a colon pouch, whose stoma had been closed for more than one year, were sent a postal questionnaire. A composite incontinence score was calculated from questions on urgency, use of a pad, incontinence of gas, liquid or faeces; and a composite evacuation score from questions on medication taken to evacuate, straining, the need and number of times returned to evacuate.

Results  The response rate was 90% (50 M, 42 F), with a median age of 68 years (IQR 60–78) and median follow‐up of 2.6 years (IQR 1.7–3.9). The anastomosis was 3 cm or less from the anus in 45/92 (49%), and incontinence scores were worse in this group (P = 0.001). There were significantly higher incontinence scores in females (P = 0.014). Age, preoperative radiotherapy, part of colon used for anastomosis, postoperative leak and length of follow‐up had no demonstrable effect on either score.

Conclusion  Gender and anastomotic height were the only variables which influenced incontinence. Ninety percent of patients reported that their bowel function did not affect their overall wellbeing, and none would have preferred to have a stoma.
Impact of insulin lispro on HbA1c values in insulin pump users
Authors: Garg S. K. , Anderson J. H. , Gerard L. A. , Mackenzie T. A. , Gottlieb P. A. , Jennings M. K. , Chase H. P.
Published: March 2003

SUMMARY

Aim  To compare the therapeutic efficacy of the short‐acting insulin analogue insulin lispro (Humalog®) with that of buffered regular human insulin (Velosulin®) in patients on insulin pump therapy.

Patients and Methods  Sixty‐two (45 women and 17 men) young patients with type 1 diabetes using insulin pump therapy were compared while using buffered regular human insulin for a mean ± s.e.m. of 20.1 ± 1.2 months or insulin lispro for a mean ± s.e.m. of 19.7 ± 0.5 months.

The initial mean ± s.e.m. age and duration of diabetes were 29.1 ± 0.9 and 17.7 ± 0.9 years, respectively. The mean HbA1c values, basal insulin dosages, premeal insulin dosages and number of low blood sugars were recorded during treatment with both insulins.

Results  Mean ± s.e.m. HbA1c values were significantly lower (p < 0.001; paired Wilcoxon t‐test) during insulin lispro treatment (7.4 ± 0.1%) as compared to treatment with buffered regular human insulin (7.9 ± 0.1%). Total units of insulin (mean ± s.e.m.)/kg/day was significantly (p = 0.03) lower (0.61 ± 0.02) during the insulin lispro treatment period as compared to the buffered regular human insulin treated period (0.65 ± 0.03). Total mean ± s.e.m. (U/kg/day) of basal insulin administered per day was higher when patients received insulin lispro treatment (0.44 ± 0.02 vs. 0.42 ± 0.01 for buffered regular human insulin treated period; p = 0.002). The pre‐meal insulin boluses (mean ± s.e.m.) for the two treatment groups were significantly different with less insulin required for the insulin lispro treatment period for all three meals (p < 0.001, t‐test). The number of mild/moderate and severe hypoglycaemic episodes were similar in the two groups.

Conclusion  We conclude that use of insulin lispro in pump therapy significantly lowers HbA1c values in comparison to therapy with buffered regular human insulin insulin without increasing hypoglycaemic episodes.
Physiological responses during hypoglycaemia induced by regular human insulin or a novel human analogue, insulin glargine
Authors: Dagogo‐Jack S. , Askari H. , Morrill B. , Lehner L. L. , Kim B. , Sha X.
Published: March 2003

SUMMARY

Aim  Glargine, a product of recombinant technology, has different structural and physico‐chemical properties compared with native human insulin. We determined whether such differences are associated with alterations in the responses to hypoglycaemia induced by glargine.

Methods  Nineteen adults (six healthy and 13 with type 1 diabetes) underwent a 5‐h hyperinsulinaemic (2 mU/kg/min−1) stepped hypoglycaemic clamps (hourly targets of 4.7, 4.2, 3.6, 3.1 and 2.5 mmol/l, respectively) on two occasions using intravenous infusion of regular human insulin or glargine, in random sequence. Hypoglycaemic symptoms, counter‐regulatory hormones and glucose disposal rates were assessed at intervals throughout the clamps. A 1‐week ‘wash out’ period was observed between studies.

Results  The peak total symptoms scores (mean ± s.e.m.) at nadir blood glucose (2.5 mmol/l) were 18.83 ± 2.68 (healthy) and 17.46 ± 3.62 (diabetic) during regular insulin, and 18.50 ± 3.20 (healthy) and 19.08 ± 3.83 (diabetic) during glargine infusion. The peak epinephrine levels during hypoglycaemia were 767.8 ± 140.4 pg/ml (regular insulin) and 608.8 ± 129.9 pg/ml (glargine) among healthy subjects, and 332.5 ± 54.8 pg/ml (regular insulin) and 321.8 ± 67.4 pg/ml (glargine) in diabetic patients. Diabetic patients had blunted glucagon responses during hypoglycaemia with either insulin. Both insulins also elicited similar rates of glucose disposal.

Conclusions  We conclude that insulin glargine and regular human insulin elicit comparable symptomatic and counter‐regulatory hormonal responses during hypoglycaemia in healthy or diabetic subjects, and induce similar rates of glucose disposal. Since glargine is designed for subcutaneous (s.c.) use, it is possible (though unlikely) that our findings obtained using an intravenous protocol could differ from responses to hypoglycaemia induced by the s.c. route.
Differential effects of short and long duration insulinotropic agents on meal‐related glucose excursions
Authors: De Souza C. J. , Russo P. , Lozito R. , Dunning B. E.
Published: March 2003

SUMMARY

Aim  Abnormal β‐cell function, characterized as the inability of the β‐cell to mount a rapid secretory response to glucose, is a well‐established pathology of type 2 diabetes mellitus. These studies were designed to demonstrate the importance of early insulin release on the control of meal‐induced glucose excursions by capitalizing on the significant pharmacodynamic differences between several oral insulin secreting agents.

Methods  Male Sprague Dawley fitted with indwelling jugular cannulas were used to compare the pharmacodynamic profiles of nateglinide (Nateg), glipizide (Glip) and repaglinide (Repag) through frequent blood samples following the administration of these compounds via oral gavage. In similar animals which were pretrained to consume their daily food intake in two discrete 45‐min meals, the effects of compound induced changes in pre‐meal, meal and post‐meal insulin profiles on glycaemic control were assessed through frequent blood sampling following the administration of these compounds 10 min prior to a 30‐min meal.

Results  There were significant pharmacodynamics differences between the three oral agents tested and the time to elicit peak insulin secretory responses increased from Nateg (4 min) to Repag (10 min) to Glip (45 min). During the meal tolerance test, glibenclamide did not increase pre‐meal insulin levels and glucose excursions paralleled those in the control. Conversely, the other three agents, at doses that produced hypoglycaemic responses of similar magnitude, all increased early insulin release (ΔAUC(‐15 to 3 min) = 0.5 ± 0.01, 1.6 ± 0.4, 3.6 ± 0.0, 1.2 ± 0.1 and 1.73 ± 0.4 nmol/min, for control, Nateg at 60 and 120 mg/kg, Glip and Repag, respectively) and curbed glucose excursions during the meal at varying rates and degrees (ΔAUC(0−30 min) = 39 ± 6, 8 ± 7, 5 ± 7, − 1 ± 8 and − 3 ± 8 mmol/min for control, Nateg at 60 and 120 mg/kg, Glip and Repag, respectively). However, unlike Nateg, the longer duration of action of Repag and Glip elicited sustained post‐meal relative hypoglycaemia.

Conclusion  These data support the impact of early and rapid insulin release in the control of prandial and post‐meal glycaemia and demonstrate that a short anticipatory burst of insulin, restricted to the beginning of a meal, provides a clear metabolic advantage and prevents post‐meal hypoglycaemic episodes when compared to a greater but reactive insulin exposure that follows a meal‐induced increase in glucose excursion.
Influence of a combination of herbs on appetite suppression and weight loss in rats
Authors: Talpur N. A. , Echard B. W. , Manohar V. , Preuss H. G.
Published: March 2003

SUMMARY

Aim  We evaluated the ability of a Chinese herbal formulation previously associated with weight loss to influence appetite and weight loss in a carefully controlled laboratory study performed on rats. As a secondary gain, results with this herbal formulation were compared with those from a commonly available phenylpropanolamine (PPA) compound.

Design  Eight rats were placed in each arm of a three‐arm study, a total of 24 rats. All rats were gavaged with a 2‐ml fluid volume containing no addition (control) or the two test substances (combined herbs or PPA) for the first 4 days of the week over 6 consecutive weeks; no gavages were given over weekends. Rats in the two‐test groups were given a relatively low dose of the test substance for 3 weeks, followed by a higher dose over the next 3‐week periods. Food and water intake were measured for 24‐h periods over the ensuing week days. The average daily values for food and water intake for an individual rat were calculated on the basis of collected data over each 3‐week period. The mean values for each rat obtained over the low‐ and high‐dose periods comprised results from averaging at least 10 measurements.

Results  Average daily food intake was decreased only with the herbal formulation, not the PPA compound at the low and high doses. Both the PPA compound and the herbal formulation lowered water intake significantly at the low and high doses. Rats ingesting the herbal formulation at the lower dose had statistically significant lower daily body weight changes over the 3 weeks than those ingesting the PPA compound. At the higher dose, body weight changes for both agents were significantly less than the control, but not significantly different from each other. No evidence of toxicity was seen in the blood chemistries or after histopathological examination.

Conclusions  Data collected on rats suggest that the herbal formulation examined might be a useful and safe combination to overcome the overweight state and obesity.