How changing root system architecture can help tackle a reduction in soil phosphate (P) levels for better plant P acquisition.

The readily available global rock phosphate (P) reserves may run out within the next 50-130 years, causing soils to have a reduced P concentration which will affect plant P uptake. Using a combination of mathematical modelling and experimental data, we investigated potential plant-based options for optimizing crop P uptake in reduced soil P environments. By varying the P concentration within a well-mixed agricultural soil, for high and low P (35.5-12.5 mg L(-1) respectively using Olsen's P index), we investigated branching distributions within a wheat root system that maximize P uptake. Changing the root branching distribution from linear (evenly spaced branches) to strongly exponential (a greater number of branches at the top of the soil) improves P uptake by 142% for low-P soils when root mass is kept constant between simulations. This causes the roots to emerge earlier and mimics topsoil foraging. Manipulating root branching patterns, to maximize P uptake, is not enough on its own to overcome the drop in soil P from high to low P. Further mechanisms have to be considered to fully understand the impact of P reduction on plant development.

Early experience with the bioabsorbable anal fistula plug.

PURPOSE: Management of anal fistula represents a balance between curing the condition and maintaining anal continence. Recent reports of the results of the porcine anal fistula plug have demonstrated excellent fistula healing rates without reporting significant complications. METHODS: The outcome of patients who underwent treatment for anal fistula with the Surgisis anal plug was retrospectively reviewed. RESULTS: Twenty patients were treated; three underwent concomitant anal advancement flap at the time of plug placement. Seventeen patients had a trans-sphincteric fistula, and three had an anoperineal fistula. Ten patients had previously undergone failed surgical therapy to cure their fistula, including anal advancement flap in four, muscle interposition flap in two, fistulotomy in two, and cutting seton placement in two. Mean follow-up was 7.4 months. Only 4 of 17 (24%) patients treated with the plug alone had closure of their fistula. Acute postoperative sepsis was seen in 5 of 17 (29%) patients treated with the plug alone. Four developed perianal abscesses that required incision and drainage, and one intersphincteric abscess was treated with antibiotics. Two of the patients who underwent concomitant anal advancement flaps and plug placement healed successfully. CONCLUSIONS: Contrary to other published series, the use of the Surgisis anal plug was associated with a low rate of fistula healing and a high incidence of perianal sepsis. The addition of a transanal advancement flap to the procedure may improve success rates.

Endometriosis-associated invasive adenocarcinoma involving the rectum in a postmenopausal female: report of a case.

Sampson first reported a case of malignant transformation of endometriosis to adenocarcinoma in 1925. We present a case of such transformation occurring in a postmenopausal female 22 years after total abdominal hysterectomy and bilateral salpingo-oophorectomy. This case demonstrates histologic progression from endometriosis to complex hyperplasia with cytologic atypia, and ultimately to invasive endometrioid adenocarcinoma involving the rectum. Aggressive surgical extirpation of all visible colorectal endometriosis for patients with advanced disease is recommended.

Identification and characterization of segments 3 and 4 of the ISAV genome.

Infectious Salmon Anaemia is a serious disease of farmed Atlantic Salmon on three continents. The disease causes severe anaemia and haemorrphagic liver necrosis, and carries major economic consequences for affected areas. Nevertheless, the causative agent, a novel orthomyxo-like Virus (Infectious Salmon Anaemia Virus - ISAV), is only partially characterized at the molecular level. We report the isolation and characterization of two novel ISAV segments at the genomic and proteomic levels. These segments are the third and fourth largest of the (ISAV) genome and may code for a nucleocapsid protein (NP) and a polymerase (PA). Western blot analysis using an ISAV polyclonal antibody identified one of these novel proteins as being the major tissue antigen. We discuss the implications of our findings for vaccine development and surveillance of Infectious Salmon Anaemia.

Ulcer associated cell lineage glands expressing trefoil peptide genes are induced by chronic ulceration in ileal pouch mucosa.

BACKGROUND: Chronic ulcerative conditions in the gastrointestinal tract result in the appearance of the ulcer associated cell lineage (UACL). The glands of this new cell lineage secrete epidermal growth factor, transforming growth factor alpha, and the trefoil factor family (TFF) peptides, which are known to participate in repair processes. Pouchitis is the most frequent complication of ileal pouch-anal anastomosis. AIM: Our aim was to determine whether the mucosal ulceration present in pouchitis can induce the development of UACL glands. METHODS: Biopsies from ileal pouches with pouchitis (n=10), healthy pouches (n=5), and normal terminal ileum (n=5) were studied. Expression of TFF mRNA was assessed by in situ hybridisation. TFF1 and TFF2 proteins were localised by immunochemistry. RESULTS: UACL glands containing TFF1 and TFF2 were observed in six patients with pouchitis. In some glands, there was TFF3 mRNA as has been reported for Crohn's UACL. None of the biopsies from ileal reservoirs without pouchitis showed UACL glands (p<0.05). Neither TFF1 nor TFF2 expression was detected in ileal reservoirs without pouchitis. CONCLUSION: UACL glands arise de novo in ileal pouch mucosa of patients with pouchitis and express all three TFF peptide genes. Chronic inflammation alone, present in healthy pouches, is not enough to stimulate the growth of the UACL, and additional stimuli consequent on ulceration may be needed.

Isolated visceral angioedema: an underdiagnosed complication of ACE inhibitors?

Angiotensin-converting enzyme (ACE) inhibitors are known to cause potentially fatal peripheral angioedema in some patients. ACE inhibitors may also cause isolated visceral angioedema, a rarely reported complication. This article describes 2 patients who experienced this complication. Both patients came to medical attention with episodes of recurrent abdominal symptoms that had occurred while taking ACE inhibitors for hypertension. Each patient had undergone surgical procedures for symptoms that persisted after surgery and were ultimately relieved with cessation of their ACE inhibitors. These cases call attention to what may be an underappreciated cause of abdominal pain in patients presenting to emergency departments.

Disposable plastic liners for a colostomy appliance: a controlled trial and follow-up survey of convenience, satisfaction, and costs.

PURPOSE: The effectiveness of a disposable liner designed for a 2-piece colostomy appliance pouch was evaluated. DESIGN: Randomized, crossover trial with follow-up surveys. SETTING AND SUBJECTS: Nineteen participants were recruited from the Mayo Clinic in Scottsdale, Arizona, and the surrounding community. INSTRUMENTS: A Daily Colostomy Care Evaluation Record and tally sheet of times for ostomy care were designed by the authors. METHODS: Participants, acting as their own controls, were randomly assigned to use either an unlined or a lined appliance for 9 days. On day 10, participants switched to the opposite regimen, which was maintained through day 18. They recorded the time required for daily colostomy care and perceptions of the lined and unlined appliances. The volume of ostomy supplies and cost were recorded at baseline, 1, 3, and 5 to 9 months after the initial trial. RESULTS: Odor, bother, perceived severity of leakage, and partner acceptance were better with unlined than lined appliances. Half of the participants were using a liner > or =75% of the time 3 months after the trial. There was no difference in cost when lined versus unlined ostomy systems were compared. Participants who chose to use the liners indicated high satisfaction. Problems noted included an inadequate seal with the liner (58%), inadequate liner size (16%), retention of flatus by the liner (11%), and difficulty removing the full liner (11%). CONCLUSIONS: The study supports recommending liners to patients who have a modest amount of fecal output or flatus. However, patients who are unable to manipulate the seal or have a large output volume are unlikely to find the liners a convenience. Satisfaction with the liners was sufficient to warrant investigation and design of a lined device with an improved design, greater capacity, and tighter seal.

Application of DNA vaccine technology to aquaculture.

The aquaculture industry needs to augment its global production and efficiency to meet the increasing consumer needs for fish and shellfish products. Unfortunately, infectious diseases have been a major impediment to the development and profitability of fish farms. While vaccines offer the most efficient way to control infectious pathogens, current products have only been successful against some diseases. These are mostly bacterial, and there are still several important diseases, mainly of viral and parasitic origin, for which no prophylactic treatment exists. DNA vaccines, compared to traditional antigen vaccines, have several practical and immunological advantages that make them very attractive for the aquaculture industry. The early success of DNA vaccines in animal models was very encouraging, but fish are unique in many aspects, and findings with other classes of vertebrate, namely mammals and birds, do not necessarily apply to aquatic animals. However, more recent studies with reporter genes showed that fish cells efficiently express foreign proteins encoded by eukaryotic expression vectors. A piscine-specific backbone vector might eventually improve immune responses to DNA vaccines, but there is already strong direct evidence for the induction of protective immunity with currently available plasmids. Immune responses to plasmid DNA injected intramuscularly (IM) into fish are characterized by the production of antibodies, which have been shown to be neutralizing in two different viral disease models. There is also indirect evidence suggesting the induction of cell-mediated immunity. Despite this evidence, immune responses to DNA vaccines have only been poorly characterized in fish because of the limited knowledge of the piscine immune system, and the small number of studies on the subject. Apart from optimizing the efficiency of DNA vaccines, other important issues, such as safety and production cost will be determinants for the potential application of this technology in commercial fish farms. Alternative methods of administration will also have to be developed for small fish and low-valued species, for which IM injection is not practical and/or cost effective.

Intramuscular injection of DNA vaccines in fish.

The DNA-based immunization technology has only been applied to fish very recently. Though a preliminary study showing reporter gene expression in fish muscles was published in 1991 (1), the first demonstration of an immune response to plasmid-encoded antigen was not reported until five years later (2). Thus, relatively little is known about the administration methods, immunological responses, and protective efficacy of DNA vaccines in aquatic animals. In some instances, results obtained with other classes of vertebrates (mammals and birds) can be applied directly to fish, but because of physiological, immunological and structural differences between these animals, this is not necessarily true. For example, it was shown recently that short specific DNA sequences (CpG motifs), in a particular nucleotide context, act as immunostimulants (3,4). No study has been reported yet assessing these immunostimulatory sequences in fish, but it would be unlikely that the same sequences are effective in all animal species (Weeratna et al., this volume).

Genetic vaccination of rainbow trout against viral haemorrhagic septicaemia virus: small amounts of plasmid DNA protect against a heterologous serotype.

Viral haemorrhagic septicaemia (VHS) is known as one of the most important diseases in cultured rainbow trout in Europe. An efficient vaccine is highly desirable, but so far only limited success has been obtained with traditional products based on killed or attenuated virus. Genetic immunization with a plasmid vector containing the VHS virus glycoprotein gene under the control of a cytomegalovirus promoter has recently been shown to induce high levels of protection against the homologous virus isolate. Expressed glycoprotein could be detected immunohistochemically in fish muscle and about 70% of the vaccinated animals had neutralizing antibodies in their serum. To further evaluate the potential of the DNA vaccine technology for prophylaxis of VHS, a vaccination trial including lower doses of DNA and different virus isolates was performed. Eight weeks after injection, rainbow trout were challenged by immersion with the homologous virus isolate or with a serologically different isolate. Cumulative mortalities demonstrated that even the lowest dose of DNA tested (0.1 microg per fish) induced protective immunity against both virus isolates. Virus neutralization tests in cell culture indicated that trout sera neutralized VHS virus isolates independently of serotypes defined with mammalian mono- and polyclonal antibodies. No protection was observed following vaccination with a plasmid construct carrying the VHS virus nucleocapsid-protein gene.

Femoral hernia: a complication of laparoscopic pelvic lymphadenectomy after groin node dissection.

Groin node dissection was done in an 80-year-old woman who had bilateral groin metastasis from squamous cell carcinoma of the vulva. After this procedure, laparoscopic pelvic lymphadenectomy was performed because of bilaterally positive groin nodes. Postoperatively, a strangulated femoral hernia occurred.

Basidiobolomycosis: an unusual fungal infection mimicking inflammatory bowel disease.

Basidiobolus ranarum is a fungus belonging to the Entomophthoraceae family and is mainly associated with subcutaneous soft tissue infection. The disease is usually characterized by an insidious onset of massive induration of the subcutaneous tissue involving the limbs, trunk, or buttocks. Most cases of basidiobolomycosis have been reported from Africa, South America, and tropical Asia. Visceral involvement is extremely rare. Only 4 cases with involvement of the gastrointestinal tract, including 1 fatal case originating in the United States, have been well documented in the English-language literature. This case report describes the first successfully treated patient residing in the United States who had B. ranarum infection involving the gastrointestinal tract.

Strain variability and localization of important epitopes on the major structural protein (VP2) of infectious pancreatic necrosis virus.

Infectious pancreatic necrosis virus (IPNV), a birnavirus, is an important pathogen in fish farms. Analyses of viral proteins showed that VP2 is the major structural and immunogenic polypeptide of the virus. All neutralizing monoclonal antibodies (mAbs) against IPNV are specific to VP2 and bind to continuous or discontinuous epitopes. In order to determine which parts of the protein are involved in antigenic variations, five IPNV strains were sequenced over the VP2 coding region. Comparison of the sequences obtained with three previously published strains revealed a central variable domain (positions 183 to 335) which encompasses two hydrophilic hypervariable segments. Viral mutants which escaped neutralization were then selected with anti-VP2 mAbs directed against discontinuous epitopes. Sequencing of three mutants revealed a single amino acid mismatch in each of them. All of these substitutions occurred in the hypervariable segments, suggesting that these regions are involved in the formation of a discontinuous epitope. Finally, expression of different truncated VP2s in Escherichia coli allowed localization of the binding site for neutralizing mAbs which recognize continuous epitopes. One of these mAbs bound to the region adjacent to the C-terminus of the variable domain of VP2, while two others reacted with the central and C-terminal parts of the variable domain. No antibody reacted with the N-terminus of VP2. These results suggest that the variable domain of VP2 and the 20 adjacent amino acids of the conserved C-terminal part are the most important in inducing an immune response for the protection of animals.

Characterization of the small open reading frame on genome segment A of infectious pancreatic necrosis virus.

The genome of infectious pancreatic necrosis virus (IPNV) is composed of two segments of dsRNA. The larger segment contains a small ORF partly overlapping the 5' end of the polyprotein reading frame. Yet very little is known about this possible new gene, which presumably codes for a 17 kDa polypeptide (VP5). The region of the viral genome which encompasses the small ORF was reverse-transcribed and amplified by PCR before cloning and sequencing. Analysis of the sequences obtained from five different virus strains revealed that the small ORF is not found on one of them, and that it is truncated on two others. Moreover, the deduced amino acid sequences did not appear to be well conserved. Despite the large variations between IPNV strains at the genomic level, all predicted VP5 are arginine-rich basic polypeptides. To verify whether the small ORF is translated into protein in fish cells, the 17 kDa polypeptide of the VR-299 strain was expressed as fusion protein in a prokaryotic expression vector and used to produce a specific antiserum. This antiserum reacted with concentrated virus in an immunodot assay indicating that VP5 is synthesized in infected cells, but probably only in small quantities. When tested with 12 other IPNV strains, results were less conclusive than those obtained with strain VR-299. Nevertheless, three of the 12 viruses gave a clearly negative signal in the immunodot assay, suggesting that possibly more than one viral strain lacks the small ORF.

Evidence of a major neutralizable conformational epitope region on VP2 of infectious pancreatic necrosis virus.

A collection of neutralizing monoclonal antibodies (MAbs) produced against the LWVRT 60.1, Jasper and N1 strains of infectious pancreatic necrosis virus (IPNV) were selected for the analysis of VP2 epitopes. Previous characterization of the LW and JA MAbs allowed the identification of continuous and discontinuous epitopes but the topological localization of these sites remained obscure. The ability of these MAbs to differentiate individual epitopes was evaluated by additivity and competition assays using antigen-coated plates and by surface plasmon resonance (SPR), an automated biosensor system that is able to retain the conformation integrity of proteins. IPNV-neutralizing MAbs defined a major, conformational-dependent and immunodominant area where continuous epitopes represent portions of a larger discontinuous epitope. Moreover, weakly neutralizing MAbs could interact with internal sites, located within the foldings of the polypeptide chain. Anti-VP2 MAbs prepared against the European serotype N1 recognized and competed for epitopes present on the North American strain LWVRT 60.1 and Jasper. Attempts to establish the proximity of VP2 and VP3 epitopes have been made by SPR. Results indicate that these major structural proteins do not overlap in the virion.

Ten-year experience with a basic technical skills and perioperative management workshop for first-year residents.

Teaching technical skills is one of the most crucial tasks of the academic surgeon. The 10-year experience with a psychomotor skills laboratory at the Department of Surgery of the Université de Montréal is reported. Since 1983, first-year trainees were freed of hospital duties for "a week of surgical techniques" to develop their basic surgical technique and perioperative skills. Cognitive and practical sessions were designed for two groups of 10 residents. Teaching videos, suture boards, biologic substitutes, animal laboratory, round table discussions and formal lectures were the techniques used. Cognitive sessions were designed to provide information on instrumentation, adequate preoperative preparation, general organization of the operating room, intensive care and endoscopy units. The surgical procedures were approved by the local animal ethics committee. The program helped residents achieve surgical dexterity in a less stressful and more controlled manner than in the operating room. Close relationships of the trainees with their peers and teachers were established early helped to improve the operating environment. This program helps junior residents understand the complex world of the operating room and reduces the operative risks related to technique.

[Dilatation enteroplasty for obstructive Crohn disease. Experience of the University of Montreal]. / L'entéroplastie d'élargissement pour maladie de Crohn obstructive. Expérience de l'Université de Montréal.

Multiple small bowel resections for obstructive symptoms caused by Crohn's disease can lead to a short bowel and malabsorption. Preservation of intestinal length is possible by the use of strictureplasty. Between August 1983 and March 1993, ninety strictureplasties were performed in 25 patients. They were 13 males and 12 females with a mean age of 37 years. Fourteen (56%) previously had small bowel resection for Crohn's disease. A mean number of 4.3 strictureplasties per patient were performed. Concomitant resection of bowel with active disease was performed in 18 patients (72%). In this series, no perioperative death occurred and one patient developed an enterocutaneous fistula. The overall complication rate was 8%. Postoperatively, 18 patients (72%) were completely relieved of symptoms, 6 were improved (24%) and one became worst (4%). After a 27 month follow-up period, the symptoms recurred in 13 patients (52%); three had no treatment, 7 had medical treatment and 3 required reoperation (12%). Our results support the safety and the use of strictureplasty for stenotic bowel lesions associated with Crohn's disease.

Necrotic stenosis of the right colon secondary to acute pancreatitis.

The authors report the case of a 52-year-old man who had stenosis and necrosis of the right colon secondary to acute pancreatitis. The right colon is a very uncommon location for this complication. The site of the stenosis was documented by contrast enema examination and computed tomography. Although conservative management is usually advocated for the initial management of this complication, laparotomy was necessary when the patient's condition failed to improve with conservative therapy. Colonic necrosis was found at laparotomy, and a partial colectomy was carried out, followed later by ileocolic reanastomosis. The authors emphasize the diagnostic and treatment options for this entity.

Antigenic characterization of serogroup 'A' of infectious pancreatic necrosis virus with three panels of monoclonal antibodies.

Monoclonal antibodies (MAbs) were produced against three serotypes of infectious pancreatic necrosis virus (IPNV): A1 (LWVRT 60-1, U.S.A.), A2 (d'Honnincthun, France) and A9 (Jasper, Canada). Each panel of MAbs (identified as LW, HF and JA) was analysed by ELISA with the 10 proposed serotypes of IPNV and their specificity defined by immunoprecipitation and Western immunoblotting analysis. A first group of MAbs, directed against the outer capsid protein VP2, reacted with linear or conformational epitopes. A second group of MAbs, directed against the internal protein VP3, reacted with linear epitopes. There was no relationship between the neutralizing property of anti-VP2 MAb and the configuration of the epitope that it recognized. The MAbs were used for antigenic characterization of serogroup A. Each panel of MAbs showed a characteristic pattern of reactivity. The European HF series was predominantly cross-reactive and detected conserved epitopes among the 10 serotypes for both VP2 and VP3. The North American LW and JA series identified a group of conserved epitopes on VP3 and new specific epitopes on VP2 and VP3. The higher variability observed for VP2 in comparison with VP3 is one example of how external pressures may promote natural selection of those epitopes required for virus survival. Our results are consistent with an ancestral relationship of the European to the North American strains, the latter having developed new antigenic determinants upon evolution in their new geographical location.

Comparison of amino acid sequences deduced from a cDNA fragment obtained from infectious pancreatic necrosis virus (IPNV) strains of different serotypes.

Infectious pancreatic necrosis is an important viral disease of salmonid fish reared in hatchery. Its etiological agent, IPNV, showed a high degree of antigenic heterogeneity. Up to 10 serotypes and 2 serogroups were proposed. Yet, very little is known about genomic variations among viruses of different origin. In order to investigate these variations, a 310-bp cDNA fragment was prepared from 17 IPNV strains by reverse transcription of the viral genome and amplification by the polymerase chain reaction. These fragments were then cloned and sequenced. Comparison of the 17 sequences obtained with 3 previously published ones, at the amino acid level, showed that serologically related viruses are highly homologous (over 96% homology) but some strains which were reported to belong to different serotypes also appeared closely related. Thus, only three major groups, clearly distinct from each other, could be formed. Apart from this, a search for the exact cleavage site of the unprocessed polyprotein of IPNV was done since the amplified fragment used for sequencing was localized at the junction between two polypeptides of the virus, pVP2 and NS. No obvious sequence or dipeptide appeared conserved in all birnaviruses.