Disease-induced chaos, coexistence, oscillations, and invasion failure in a competition-model with strong Allee effect

Biological invasions have impacts on diverse social, ecological, and economic issues. Among others, invasion success can be determined by epidemiological aspects, intraspecific dynamics as, e.g., Allee effects, and interspecific interactions as, e.g., competition. In this study, a process-based model describing competitive eco-epidemiological dynamics of two species, which are both subject to an Allee effect, is developed. Only one of the species can be infected by an infectious disease which is transmitted both, horizontally and vertically. The local dynamics of the disease-free competition model, the competition-free SI-model, and the full eco-epidemiological model are considered. In particular, it is shown that an outbreak of a disease is more likely in the absence of a competitor. Thus, competition and species richness can increase disease resistance of particular species in a community. The complete partial differential equation model is investigated both, analytically and numerically in order to determine possible impacts of the disease on the invasion dynamics. It is shown that in case of strong competition, invasion fronts are always slowed down or even reversed due to the infection for parameter regimes in which the invader is the stronger competitor in the absence of the disease while in case of weak competitive pressure, the dynamics are more complex. Besides slowing down of the invasion front, disease-induced chaos, coexistence (i.e., coexistence in a regime in which coexistence without disease would not be possible), and oscillations can occur. Furthermore, spatial spread can temporarily prevent an infected population from going extinct with potentially detrimental impacts for the resident. This happens via a (replicating) traveling pulse which pushes the competitor out of the domain. The results are discussed in order to enhance the understanding of mechanisms underlying biological invasions and to develop better management strategies for biological invasions as, e.g., selective infections.

Immunologische Studien am Omentum

Es wird über Experimente berichtet, die zum Ziel haben, die Reaktionen des Omentum majus der Maus auf einen primären antigenen Stimulus zu untersuchen. Dazu werden Tiere mit korpuskulären und löslichen Antigenen intraperitoneal immunisiert. In weiteren Versuchen wird das System in vitro nachgeahmt.

Nach Immunisierung werden die Omenten in Zeitabständen für eine Stde. mit 3H-Thymidin inkubiert. In allen Experimenten findet sich eine mitotische Aktivität der Mesothelzellen, die bei den Kontrollen und einer 20-proz. Glucoselösung nicht gefunden werden. Die Aktivität hat ein Maximum nach 24-48 Stunden. Dieser Teilungsbereitschaft geht die Phagozytose voraus. Die Beteiligung des Mesothels an der Immunantwort ist unseres Wissens neu und wirft verschiedene Fragen auf, die diskutiert werden.

Nach Abklingen der Teilungsaktivität am vierten Tag ist das Omentum zellreicher und enthält eine Vielzahl von „blastähnlichen“ Zellen. Diese „Immunoblasten“ treten in kleinen Gruppen auf. und sie werden nur bei den in vivo-Experimenten gefunden.

[Invasion of an intermediate predator: the dynamics of fish populations in the mathematical model of a trophic chain (as applied to the Syamozero lake)]

We present a mathematical model of the dynamics of a spatially heterogeneous predator-prey population system. A prototype of the model system is the Syamozero lake fish community. We study the impact of the invader, an intermediate predator, on the dynamics of the fish community. We show that the invasion can lead to the appearance of chaotic oscillations in the population density. We show also that different dynamical regimes resulting from the invasion, i.e., stationary, non-chaotic oscillatory and chaotic ones, can coexist. The "choice" of a specific regime therewith depends on the initial invader density. Our analysis of solutions of the mathematical models shows that the successful invasion of the alien species takes place solely in the absence of the competition between the invaders and the native species.

[Evolution of rotifer population dynamics in a heterogeneous habitat: mathematical modeling]

We present the results of mathematical modeling of a rotifer species inhabiting two coupled habitats with different environmental conditions. We use the modified Consensus model and show that the exchange between the habitats can lead to chaotization of originally regular plankton dynamics and synchronization of plankton biomass oscillations. As a result, the invasion of a chaotic regime takes place.

Analysis of the therapeutic efficacy of different doses of budesonide in patients with active Crohn's ileocolitis depending on disease activity and localization

BACKGROUND AND AIMS

The nonsystemic steroid budesonide has been used to treat active ileocecal and ileocolonic Crohn's disease (CD). This study investigated the optimal budesonide dose using a pH-dependent release formulation. The goal of treatment was the remission of CD (CDAI <150) within 6 weeks of treatment.

PATIENTS AND METHODS

The study was of randomized, double-blind, dose-finding design. Patients with active CD ileocolitis without steroid pretreatment were treated with 3x2 mg ( n=39), 3x3 mg ( n=33), or 3x6 mg ( n=32) oral pH-modified released budesonide daily.

RESULTS

The remission rates after 6 weeks were 36% with 3x2 mg, 55% with 3x3 mg, and 66% with 3x6 mg. Significantly more patients were in remission while treated with 3x6 mg than with 3x2 mg budesonide/day. Subgroup analyses revealed that patients with high disease activity (CDAI >/= 300) or ileocolonic disease with disease manifestation distal to the transverse colon responded better to the highest budesonide dose.

CONCLUSION

Oral pH-modified released budesonide shows a dose-dependent effectiveness in patients with active ileocolonic CD. In the majority of patients 9 mg budesonide per day is sufficient. However, in patients with highly active disease or ileal disease with distal colonic manifestation higher doses of budesonide could increase the therapeutic response

[Effect of the rate of phytoplankton growth on the spaced-time dynamics of plankton communities in an homogeneous environment]

We use a conceptual mathematical reaction-diffusion model to investigate the mechanisms of spatial structure formation and complex temporal dynamics of plankton in a heterogeneous environment. We take into account basic trophic interactions, namely, "prey-predator" interactions between phytoplankton, zooplankton, and fish in upper layers of natural waters. We consider plankton as a passive contaminant in turbulent waters. We show that plankton structure formation can result from the difference in phytoplankton growth rate in neighboring habitats. Phytoplankton and zooplankton biomass is shown to undergo both regular and chaotic oscillations. The fish predation rate substantially affects the spatial and temporal dynamics of plankton in a heterogeneous environment.

[Interdependence of plankton spatial distribution and plancton biomass temporal oscillations: mathematical simulation]

The dynamics of aquatic biological communities in a patchy environment is of great interest in respect to interrelations between phenomena at various spatial and time scales. To study the complex plankton dynamics in relation to variations of such a biologically essential parameter as the fish predation rate, we use a simple reaction-diffusion model of trophic interactions between phytoplankton, zooplankton, and fish. We suggest that plankton is distributed between two habitats one of which is fish-free due to hydrological inhomogeneity, while the other is fish-populated. We show that temporal variations in the fish predation rate do not violate the strong correspondence between the character of spatial distribution of plankton and changes of plankton biomass in time: regular temporal oscillations of plankton biomass correspond to large-scale plankton patches, while chaotic oscillations correspond to small-scale plankton patterns. As in the case of the constant fish predation rate, the chaotic plankton dynamics is characterized by coexistence of the chaotic attractor and limit cycle.

Fat composition may be a clue to explain the primary therapeutic effect of enteral nutrition in Crohn's disease: results of a double blind randomised multicentre European trial

BACKGROUND

Dietary fat has been suggested to determine the therapeutic effect of enteral diets in Crohn's disease.

AIM

To assess the efficacy of two whole protein based diets with different fat compositions (n6 polyunsaturated fatty acids v monounsaturated fatty acids) in inducing clinical remission in active Crohn's disease compared with steroids.

METHODS

Sixty two patients with active Crohn's disease were randomised to receive, for not more than 4 weeks: (a) a polymeric enteral diet containing 35 g of lipids per 1000 kcal, high in oleate (79%) and low in linoleate (6.5%) (PEN1), (b) an identical enteral diet except for the type of fat which was high in linoleate (45%) and low in oleate (28%) (PEN2), or (c) oral prednisone (1 mg/kg/day). Diets were double blindly administered. The steroid group received a conventional ward diet. Treatment failure was considered when remission was not achieved at week 4. Clinical activity and biological and nutritional parameters were monitored. Independent predictors of remission were identified by stepwise logistic regression analysis.

RESULTS

Overall remission rates (by intention to treat) were 20% (4/20) for PEN1, 52% (12/23) for PEN2, and 79% (15/19) for steroids (overall p=0.001; p<0.0005 steroids v PEN1, and p=0.056 PEN2 v PEN1). After excluding those patients who were non-compliant during the first week (per protocol analysis), remission rates were 27%, 63%, and 79%, respectively (p=0.008, steroids and PEN2 v PEN1). After adjusting for confounding variables, PEN1 remained significantly associated with a poor response.

CONCLUSION

The type of dietary fat may be of importance for the primary therapeutic effect of enteral nutrition in active Crohn's disease.

A new mesalazine foam enema (Claversal Foam) compared with a standard liquid enema in patients with active distal ulcerative colitis

BACKGROUND

Rectally administered mesalazine (5-aminosalicylic acid) is a recognized therapy for distal ulcerative colitis. It is frequently applied as a liquid enema. However, there are reasons (acceptability to the patient, more uniform topical dispersion and effective adhesion) to prefer a foam-based enema.

AIM

This study compared a foam enema (2 g mesalazine per day, Claversal Foam) with a standard liquid enema (4 g mesalazine per day, Salofalk enema).

METHODS

Patients with active distal ulcerative colitis, diagnosed according to standardized criteria, were treated for 4 weeks. The primary goal was clinical remission; endoscopic remission, histological changes, global assessment and standard safety measures were also analysed. A major subset of the patients also provided quality-of-life data.

RESULTS

Both foam and liquid enema gave good rates of clinical and endoscopic remission. The foam enema was shown to be as efficacious as the reference, even though the daily dose in the foam treatment contained only half as much active drug as in the reference treatment. Minor regional differences in efficacy were seen. The tolerabilities of the two formulations were comparable.

CONCLUSIONS

The foam enema offers a safe, efficacious and acceptable treatment for distal ulcerative colitis.

Low ileal interleukin 10 concentrations are predictive of endoscopic recurrence in patients with Crohn's disease

BACKGROUND

Endoscopic recurrence after surgery in Crohn's disease is frequent and unpredictable. Abnormal intestinal production of pro- (interleukin (IL)-1 beta, tumour necrosis factor alpha (TNF-alpha)) and anti- (IL-10) inflammatory cytokines has been associated with severe outcome in experimental models of colitis.

PATIENTS AND METHODS

We evaluated if ileal TNF-alpha, IL-1 beta, or IL-10 mRNA levels measured at the time of surgery predict endoscopic recurrence, and if ileal IL-10 levels are associated with particular IL-10 promoter alleles. Ileal biopsies were obtained peroperatively from the healthy neoileum of patients undergoing a right ileocolectomy for Crohn's disease. Mucosal TNF-alpha, IL-1 beta, and IL-10 mRNA levels were quantified by competitive polymerase chain reaction. A cut off value was determined using a receiver operating curve. IL-10.G promoter haplotypes were analysed using a polymorphic dinucleotide repeat in the IL-10 promoter region.

RESULTS

Three months after surgery, 53% of patients had endoscopic recurrence while 47% remained free of disease. The risk of endoscopic recurrence correlated with ileal IL-10 mRNA concentrations (r(2)=0.81). Endoscopic recurrence occurred more frequently in patients classified as low IL-10 producers than in those that were high producers (80% v 40%) (p=0.02). Patients with at least one of the two alleles G7-8 or G10-13 produced, respectively, higher (p=0.006) and lower (p=0.029) ileal IL-10 mRNA. The distribution of IL-10.G microsatellite genotypes was similar in patients with or without endoscopic recurrence.

CONCLUSION

Low ileal IL-10 mRNA concentration is a good marker of endoscopic recurrence in Crohn's disease but the distribution of IL-10.G haplotypes cannot predict the postoperative evolution of the disease.

Patchy environment as a factor of complex plankton dynamics

We study the role of the diffusive interaction in plankton dynamics in a patchy environment. We use a minimal reaction-diffusion model of the nutrient-plankton-fish food chain to simulate the diffusive interaction between fish-populated and fish-free habitats. We show that such interaction can give rise to spatiotemporal plankton patterns. The plankton dynamics depend on the fish predation rate and can exhibit both regular and chaotic behavior. We show that limit cycle and chaotic attractor coexist in the system. The entire basin of attraction of the limit cycles is found to be riddled with "holes" leading to the competitive chaotic attractors. The chaotic dynamics is typical of a wide range of the fish predation rates.

Interleukin 10 (Tenovil) in the prevention of postoperative recurrence of Crohn's disease

BACKGROUND AND AIMS

New lesions of Crohn's disease occur early after ileal or ileocolonic resection and ileocolonic anastomosis. We performed a double blind controlled trial to evaluate the safety and tolerance of recombinant human interleukin 10 (IL-10; Tenovil) in subjects operated on for Crohn's disease. We also assessed the effect of Tenovil in preventing endoscopic recurrence 12 weeks after surgery.

METHODS

Patients with Crohn's disease who underwent curative ileal or ileocolonic resection and primary anastomosis were randomised within two weeks after surgery to receive subcutaneous Tenovil 4 microg/kg once daily (QD) (n=22) or 8 microg/kg twice weekly (TIW) (n=21), or placebo (QD or TIW) (n=22). An ileocolonoscopy was performed after 12 weeks of treatment.

RESULTS

Compliance was excellent. The most frequently observed adverse events were mild and moderate in severity and equally distributed across treatment groups. Thirty seven patients in the pooled Tenovil group and 21 patients in the pooled placebo group were evaluable by endoscopy. At 12 weeks, 11 of 21 patients (52%) in the placebo group had recurrent lesions compared with 17 of 37 patients (46%) in the Tenovil group (ns). The incidence of severe endoscopic recurrence was similar in both groups (9%).

CONCLUSION

Tenovil treatment for 12 consecutive weeks in patients with Crohn's disease after intestinal resection was safe and well tolerated. No evidence of prevention of endoscopic recurrence of Crohn's disease by Tenovil was observed.

Absence of efficacy of subcutaneous antisense ICAM-1 treatment of chronic active Crohn's disease

BACKGROUND & AIMS

ISIS-2302, an antisense oligonucleotide directed against intercellular adhesion molecule 1, was effective in steroid refractory Crohn's disease in a pilot trial. The aim of this study was to investigate safety and efficacy of ISIS-2302 in chronic active Crohn's disease (CACD).

METHODS

A dose-interval, multicenter, placebo-controlled trial was conducted in 75 patients with steroid-refractory CACD (Crohn's Disease Activity Index [CDAI], 200-400). The primary endpoint was steroid-free remission (CDAI <150) at week 14.

RESULTS

Only 2 of 60 (3.3%) ISIS-2302-treated and no placebo patients reached the primary endpoint. Steroid-free remission at week 26 (secondary endpoint) was reached in 8 of 60 (13.3%) active treatment and 1 of 15 (6.7%) placebo patients. A greater proportion of ISIS-2302-treated than placebo patients achieved a steroid dose <10 mg/day at weeks 14 and 26 (48.3% vs. 33.3% and 55.0% vs. 40.0%, respectively, and a glucocorticoid dose of 0 mg [prednisone equivalent] at week 26 [23.3% vs. 6.7%, respectively]). Treatment with ISIS-2302 was safe. The most common side effects were injection site reactions in the active treatment group (23% in ISIS-2302-treated patients vs. none in placebo patients). No statistically significant differences in the frequency of side effects were detected between dose groups.

CONCLUSIONS

The trial did not prove clinical efficacy of ISIS-2302 based on the primary endpoint. Positive trends were observed in some of the secondary endpoints.

Wave of chaos: new mechanism of pattern formation in spatio-temporal population dynamics

The dynamics of a simple prey-predator system is described by a system of two reaction- diffusion equations with biologically reasonable non-linearities (logistic growth of the prey, Holling type II functional response of the predator). We show that, when the local kinetics of the system is oscillatory, for a wide class of initial conditions the evolution of the system leads to the formation of a non-stationary irregular pattern corresponding to spatio-temporal chaos. The chaotic pattern first appears inside a sub-domain of the system. This sub-domain then steadily grows with time and, finally, the chaotic pattern invades the whole space, displacing the regular pattern.

Biological factors underlying regularity and chaos in aquatic ecosystems: simple models of complex dynamics

This work is focused on the processes underlying the dynamics of spatially inhomogeneous plankton communities. We demonstrate that reaction-diffusion mathematical models are an appropriate tool for searching and understanding basic mechanisms of complex spatio-temporal plankton dynamics and fractal properties ofplanktivorous fish school walks

Chaos and regular dynamics in model multi-habitat plankton-fish communities

This work is focused on the role of diffusive interaction between separate habitats in a patchy environment in plankton pattern formation. We demonstrate that conceptual reaction-diffusion mathematical models constitute an appropriate tool for searching and understanding basic mechanisms of plankton pattern formation and complex spatio-temporal plankton dynamics

Switch from systemic steroids to budesonide in steroid dependent patients with inactive Crohn's disease

BACKGROUND

Steroid dependent patients with Crohn's disease are at high risk of developing glucocorticosteroid induced side effects.

AIMS

We evaluated the possibility of switching from systemic steroids to budesonide (Entocort) in prednisolone/prednisone dependent patients with inactive Crohn's disease affecting the ileum and/or ascending colon.

PATIENTS

Steroid dependent patients with a Crohn's disease activity index </=200 were included.

METHODS

In a double blind multicentre trial, 120 patients were randomly assigned to receive budesonide 6 mg once daily or placebo. Prednisolone was tapered to zero during the first 4-10 weeks and budesonide or placebo was given concomitantly and for a further 12 weeks. Relapse was defined as an index >200 and an increase of 60 points from baseline or withdrawal due to disease deterioration.

RESULTS

After one and 13 weeks without prednisolone, relapse rates were 17% and 32%, respectively, in the budesonide group, and 41% and 65% in the placebo group (95% confidence intervals for the difference in percentages -41%, -8% and -51%, -16%; p=0.004 and p<0.001, respectively). The number of glucocorticosteroid side effects was reduced by 50% by switching from prednisolone and was similar in the budesonide and placebo groups. Basal plasma cortisol increased in both groups.

CONCLUSIONS

The majority of patients with steroid dependent ileocaecal Crohn's disease may be switched to budesonide controlled ileal release capsules 6 mg without relapse, resulting in a sharp decrease in glucocorticosteroid side effects similar to placebo, and with an increase in plasma cortisol levels.

[The role of carnivorous zooplankton in dynamics of trophic interaction of fish and plankton]

A conceptual (minimal) model of the aquatic community is proposed, which includes phytoplankton, zooplankton, fish and fish larvae. It is shown that carnivorous zooplankton increases the system stability when the fish predation changes. As a result, the system collapse followed by algal bloom becomes less probable.

Motional instabilities in prey-predator systems

Differential fluxes can destabilize the locally stable stationary density distributions in interaction systems with diffusion, advection, and/or locomotion of chemical or biological species. By this method they can cause the formation of stationary or travelling spatial structures. Different scenarios of this general mechanism of spatio-temporal pattern formation in reaction-diffusion-advection systems will be demonstrated, using a simple two-species predator-prey system as an example model.

Attachment representation and cortisol response to the adult attachment interview in idiopathic spasmodic torticollis

OBJECTIVE

The study investigates individual differences in the mental representation of attachment and their impact on the cortisol response to psychosocial stress in idiopathic spasmodic torticollis (IST). It was hypothesized (a) that in IST insecure attachment is more prevalent than in a non-clinical control group and (b) that subjects with dismissing attachment respond with higher physiological arousal to a specific stimulus activating the attachment behavioural system than subjects with secure attachment.

METHOD

20 patients with IST and 20 healthy controls matched for age and sex underwent the Adult Attachment Interview, an hour-long, semiclinical interview on attachment experiences. During the interview salivary cortisol levels were monitored. The subjects' mental state with regard to attachment was classified using the attachment Q-sort method. Anxiety and depression were measured as potential covariates of the adrenocortical stress response.

RESULTS

Compared to the non-clinical group, dismissing attachment was strongly overrepresented in IST. In IST, but not in the healthy control group, dismissing attachment correlated with an elevated cortisol response to the interview.

CONCLUSION

In clinical, but not in non-clinical samples dismissing attachment may be associated with increased vulnerability to psychosocial stress. The factors contributing to this interaction are not yet fully elucidated.

[Dependence of the fish school movement and plankton special distribution on the phytoplankton growth rate]

In this paper we investigate the spontaneous emergence and the dynamics of patchiness in spatially distributed communities of plankton, which plays a key role in the matter rotation on earth. Patchiness is often supposed to be due to hydrodynamical factors (diffusion and advection). In contrast to this approach, we consider the formation of plankton patches as a result of interactions in the trophic chain nutrient--phytoplankton--zooplankton-fish. We present a mathematical model of such interactions, which combines a continuous description of the plankton spatio-temporal dynamics and a discrete description of the fish school movement. We show that the fish school can give rise to plankton patches. In turn, fish school walks are shown to depend on phytoplankton growth rate. We show also that the Hurst exponent characterizing the fish school movement in the diffusion approximation depends on phytoplankton growth rate.

Lack of clinical efficacy of additional factor XIII treatment in patients with steroid refractory colitis. The Factor XIII Study Group

Patients with active ulcerative colitis have decreased levels of factor XIII (FXIII) activity, which is important for woundhealing. Recent uncontrolled studies claimed a beneficial effect of Factor XIII on clinical symptoms of ulcerative colitis, in particular intestinal bleeding. The objective of this trial was to evaluate the benefits of additional FXIII treatment in steroid-refractory patients with ulcerative colitis in a prospective, double blind, placebo-controlled study. A total of 28 patients were enrolled between October 1994 and January 1997. Primary objective of this study was the time until cessation of visible intestinal bleeding with 14 days after the start of treatment. Patients were treated for ten days either by i.v. application of FXIII concentrate or by placebo. The analysis of the primary efficacy criterion, cessation of intestinal bleeding, by a planned interim analysis showed no significant differences between the treatment groups (p = 0.8). This resulted in the termination of the study. The same applied to the CAI score. No patient in both treatment groups reached remission according to the colo-/-sigmoidoscopy score. Due to the high number of patients (16 of 28) who had to be excluded from the per-protocol analysis (e.g. changes to the concomitant medication) only the intention-to-treat population was analyzed. Overall the study showed no beneficial effect of additional FXIII treatment on active steroid-refractory ulcerative colitis. These results do not confirm previous open label studies which had reported a significant improvement of clinical symptoms.

Anti-TNF antibody in Crohn's disease--status of information, comments and recommendations of an international working group

The chimeric anti-TNF antibody Remicade (Infliximab) has recently been approved for human use by the FDA and is now available on the market. Since there is considerable interest in this kind of treatment among patients with Crohn's disease, an international working group has summarized the presently available information about efficacy, side effects and possible problems of this treatment. Studies show that Remicade is effective in the treatment of active Crohn's disease, maintaining remission and fistulae. The working group does not see Infliximab as a first-line treatment for Crohn's disease. It may be used in active phase recurrent disease, chronic active disease and fistulae if standard treatment was not successful. For the surveillance special attention has to be given to the unknown malignancy rate of Infliximab. Infusion should be performed in an institution, routinely performing intravenous infusions and a two-hour surveillance of the patients should be guaranteed to recognize anaphylactic reactions or acute side effects. There is presently no information indication that the combination with immunosuppressants might increase risks or side effects of this treatment. Due to the limited information available the working group would prefer to use Remicade in studies only and recommends central collection and documentation of all data on efficacy and side effects for the next year.

Oral budesonide for prevention of postsurgical recurrence in Crohn's disease. The IOIBD Budesonide Study Group

BACKGROUND & AIMS

Prevention of postoperative recurrence after resection for Crohn's disease (CD) would be of great clinical benefit. The efficacy of oral budesonide for prevention of endoscopic recurrence was evaluated in patients undergoing resection for ileal or ileocecal CD.

METHODS

Sixty-three patients received budesonide and 66 received placebo in a double-blind, randomized trial with parallel groups. Ileocolonoscopy, including biopsy, was performed after 3 and 12 months. Indications for surgery were fibrostenosis (78 patients), disease activity (41), and other reasons (10).

RESULTS

The frequency of endoscopic recurrence did not differ between the groups at 3 and 12 months. In patients with disease activity as indication for surgery, the endoscopic recurrence rate at the anastomosis was lower in the budesonide group at 3 months, although not significantly (21% vs. 47%; P = 0.11), and at 12 months (32% vs. 65%; P = 0.047). There was no such difference with respect to fibrostenosis as indication for surgery. No differences in adverse event patterns were found between the two groups.

CONCLUSIONS

Oral budesonide, 6 mg daily, offered no benefit in prevention of endoscopic recurrence after surgery for ileal/ileocecal fibrostenotic CD but decreased the recurrence rate in patients who had undergone surgery for disease activity.

Budesonide prolongs time to relapse in ileal and ileocaecal Crohn's disease. A placebo controlled one year study

BACKGROUND AND AIMS

To evaluate the efficacy and safety of the topical corticosteroid budesonide, given in an oral controlled release formulation for maintenance of remission in patients with ileal and ileocaecal Crohn's disease (CD).

PATIENTS AND METHODS

Out of 176 patients with active CD who had achieved remission (CD activity index score < or = 150) after 10 weeks' treatment with either budesonide or prednisolone, 90 were randomised to continue with once daily treatment of 6 mg budesonide, or 3 mg budesonide or placebo for up to 12 months in a double blind, multicentre trial. Time to symptomatic relapse was calculated using Kaplan-Meier estimates. Morning plasma cortisol was measured at clinic visits and a corticotropin stimulation test was performed after three months of treatment.

RESULTS

Thirty two patients were allocated to the 6 mg budesonide group, 31 to the 3 mg group, and 27 to the placebo group. After three months, 19 per cent of the patients in the 6 mg group had relapsed, compared with 45 per cent in the 3 mg group and 44 per cent in the placebo group (p = 0.047). The corresponding results after 12 months was 59 per cent in the 6 mg budesonide group, 74 per cent in the 3 mg group, and 63 per cent in the placebo group (p = 0.44). The median time to relapse or discontinuation was 258 days in the 6 mg group, 139 days in the 3 mg group, and 92 days in the placebo group (p = 0.021). Mean morning plasma cortisol values increased from entry in all three groups with no statistically significant differences at 12 months. All 13 patients remaining in the placebo group after three months had a normal corticotropin stimulation response, compared with 18 of 23 patients in the 6 mg, and 19 of 21 in the 3 mg budesonide groups (p = 0.14). Acne and moon face were slightly more common in the budesonide groups.

CONCLUSION

6 mg budesonide once daily is significantly more efficacious than placebo in prolonging time to relapse in CD, and causes only minor systemic side effects.

A comparison of budesonide with prednisolone for active Crohn's disease

BACKGROUND

Patients with active Crohn's disease are often treated with corticosteroids, but the treatment has many side effects. Budesonide is a potent, well-absorbed corticosteroid, but because of a high rate of first-pass metabolism in the liver, its systemic bioavailability is low.

METHODS

We conducted a randomized, double-blind, 10-week trial comparing the efficacy and safety of an oral controlled-release form of budesonide with the efficacy and safety of prednisolone in 176 patients with active ileal or ileocecal Crohn's disease (88 patients in each treatment group). The dose of budesonide was 9 mg per day for eight weeks and then 6 mg per day for two weeks. The dose of prednisolone was 40 mg per day for two weeks, after which it was gradually reduced to 5 mg per day during the last week.

RESULTS

At 10 weeks, 53 percent of the patients treated with budesonide were in remission (defined as a score < or = 150 on the Crohn's disease activity index), as compared with 66 percent of those treated with prednisolone (P = 0.12). The mean score on the Crohn's disease activity index decreased from 275 to 175 in the budesonide group and from 279 to 136 in the prednisolone group (P = 0.001). Corticosteroid-associated side effects were significantly less common in the budesonide group (29 vs. 48 patients, P = 0.003). Two patients in the prednisolone group had serious complications (one had intestinal perforation and one an abdominal-wall fistula). The mean morning plasma cortisol concentration was significantly lower in the prednisolone group than in the budesonide group after 4 weeks (P < 0.001) and 8 weeks (P = 0.02) of therapy, but not after 10 weeks.

CONCLUSIONS

Among patients with active Crohn's disease, both controlled-release budesonide and prednisolone are effective in inducing remission. In this trial, prednisolone reduced scores on the Crohn's disease activity index more, whereas with budesonide there were fewer glucocorticoid-associated side effects and less suppression of pituitary-adrenal function.

Laser-assisted removal of a foreign body from the colon

An 81-year-old woman underwent a colonoscopy because of a sigmoiditis poorly responding to conservative therapy. A rod-shaped foreign body found in the sigma proved impossible to remove conventionally. Irradiation with a low laser energy caused the foreign body to break apart, after which its extraction was straightforward. The further clinical course was uncomplicated. In this case a partial sigmoidectomy would have been indicated had the laser-supported extraction not been successful. The authors suggest that a similar procedure could be helpful in the management of foreign bodies in the esophagus.

A randomised controlled trial to evaluate the effects of flumazenil after midazolam premedication in outpatients undergoing colonoscopy

The degree of sedation and amnesia, subjective assessment of awakening and side effects after intravenous injection of 3-4 mg midazolam and 1 mg flumazenil or placebo were studied directly after colonoscopy, and on the first and the eight day. A total of 91 patients were studied; 45 patients were given flumazenil and 46 patients a placebo. Five minutes after injection of the test drugs all 45 patients given flumazenil but only 38 patients given the placebo were alert (p = 0.006). All three response criteria (for sedation, amnesia and subjective assessment of awakening) were fulfilled by 84.4% of the patients given flumazenil and 45.7% of the patients given the placebo (p = 0.0002). Thirty minutes after injection of the test drugs dizziness, nausea, and fatigue were found in 3 patients given flumazenil and in 10 patients given placebo. One day after colonoscopy 9 of 45 patients (20%) given midazolam and flumazenil complained of fatigue and 9 of 46 patients (19.5%) given midazolam and placebo. Eight days (+/- 1 day) later two patients in each group complained of headache, nausea and fatigue. No patient developed phlebitis at the injection site. Flumazenil seems to be a safe and efficient drug for reversing the sedative effect of midazolam, premedication after colonoscopy. However, resedation due to the effects of midazolam may occur. Flumazenil thus permits administration of a higher dose of midazolam without prolongation of the surveillance time. Improved exploitation of time, space and nursing resources is thus possible without jeopardizing patient safety, although caution is necessary since patients may not be fit to resume all normal activities.

Comparison of enteral nutrition and drug treatment in active Crohn's disease. Results of the European Cooperative Crohn's Disease Study. IV

This study compared the effect of enteral nutrition as the sole therapy of active Crohn's disease with drug treatment. Patients with active Crohn's disease (Crohn's Disease Activity Index greater than 200) were randomized to receive either enteral nutrition with a liquid oligopeptide diet (n = 55) or a combination of 6-methylprednisolone, 48 mg daily, subsequently tapered, and sulfasalazine, 3 g daily (n = 52). The two groups were not different with respect to age, sex, body weight, location of disease, or treatment before the study. The severity of disease was similar at the beginning of the study in both groups [Crohn's Disease Activity Index (mean +/- SEM), 323 +/- 12 vs. 316 +/- 11]. Remission was defined as a decrease of the initial Crohn's Disease Activity Index by 40% or at least 100 points. Twenty-nine patients in the diet group and 41 patients in the drug group reached remission within 6 weeks of therapy (chi 2 test, P less than 0.01). The median elapsed time to remission was 30.7 days in the diet group compared with 8.2 days in the drug group (Mantel Cox, P less than 0.01). To determine whether one of these treatments was more beneficial for a subgroup of patients, the effectiveness of both treatments was analyzed separately in patients with very severe disease (initial Crohn's Disease Activity Index greater than 300) and less severe disease (initial Crohn's Disease Activity Index less than 300), and in patients with different disease location. However, no influence of initial disease activity or disease location on the effect of either treatment could be shown. These data show that enteral nutrition is less effective than a combination of 6-methylprednisolone and sulfasalazine in treating active Crohn's disease.

Evaluation of the Crohn's Disease Activity Index (CDAI) and the Dutch Index for severity and activity of Crohn's disease. An analysis of the data from the European Cooperative Crohn's Disease Study

In the European Cooperative Crohn's Disease Study a general documentation of clinical and laboratory data was made at the entry into the study in 452 patients. These patients were in different states of their disease from quiescent to very active. In all patients the Crohn's Disease Activity Index of Best (CDAI) and the Dutch Index of van Hees was calculated. Three gastroenterologists did a global clinical rating and a separate laboratory rating without knowledge of the indices. The ratings were then correlated with the indices in the individual patients. The clinical rating correlated well with the CDAI (r = 0.88) and less with the Dutch Index (r = 0.672). On the other hand the laboratory rating showed a better correlation with the Dutch Index (r = 0.742) than with the CDAI (r = 0.573). This demonstrates that the CDAI preferably is an estimate of the clinical severity of the disease and not of the activity of inflammation. Vice versa the Dutch Index is mainly reflecting the activity of the inflammatory process.

Feasibility and effectiveness of a defined-formula diet regimen in treating active Crohn's disease. European Cooperative Crohn's Disease Study III

In a randomized multicenter trial the efficacy of treatment of active Crohn's disease by means of a liquid defined formula diet (DFD) was tested and compared with a combination of 6-methyl-prednisolone and sulfasalazine. A total of 95 patients participated in the study. By the end of 6 weeks, among 44 patients randomized to drug treatment, 32 showed improvement of the Crohn's disease activity index (CDAI) as compared with 21 of 51 patients receiving oral DFD (p less than 0.05). The proportion of withdrawals in the DFD group (29 of 51) was sevenfold higher than in the drug group (4 of 44). However, most patients (20 of 29) receiving DFD withdrew because of the unpalatability of the liquid diet. Analysis of patients in each group who finished the study showed equal effectiveness of DFD and the drug regimen. In these subsets of patients the CDAI decreased from 280.8 +/- 90.6 to 151.7 +/- 86.5 (DFD) and from 263.7 +/- 86.3 to 129.3 +/- 63.7 (drug), respectively. Improvement of inflammation factors was similar in both groups at the end of the study, although improvement was delayed in the DFD group. In conclusion, our data show a superiority of the drug combination over DFD in the treatment of Crohn's disease under the conditions of this trial. The results do suggest, however, that DFD offers a therapeutic alternative to prednisolone and sulfasalazine in a subgroup of patients, which has to be closer characterized in further studies.