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Biomedical subjects

Peter Andersson

Publications and source records attributed to Peter Andersson.

4 recordsLinked to original sources
PubMed2006

Azathioprine as a postoperative prophylaxis reduces symptoms in aggressive Crohn's disease.

OBJECTIVE: Recurrence of Crohn's disease (CD) after surgery is common. Azathioprine/6-mercaptopurine (Aza/6-MP) is effective in controlling medically induced remission but, so far, has only been sparsely investigated after surgically induced remission. This study comprises a subset of CD patients considered to have an aggressive disease course and chosen for treatment with Aza postoperatively. MATERIAL AND METHODS: In 1989-2000, a total of 100 patients with CD were given Aza/6-MP as a postoperative prophylaxis. Fourteen Aza/6-MP-intolerant patients were compared with 28 Aza-tolerant patients, matched for gender, age, and duration of disease. Patients were prospectively registered for symptoms using a modified Crohn's disease activity index (CDAI) and perceived health was assessed on a visual analogue scale (VAS). The primary outcome variable was the modified CDAI postoperatively integrated over time; other variables were time to first relapse (modified CDAI >or= 150), time to first repeated surgery, number of courses of steroids, and repeated surgery per year of follow-up. Patients were followed for a median of 84.7 months (23.2-140). RESULTS: The modified CDAI integrated over time was 93 for Aza-treated patients compared with 184 for controls (p=0.01) and time to first relapse was 53 and 24 months, respectively (p<0.05). Aza-treated patients needed fewer courses of corticosteroids (p=0.05) compared with controls. Perceived health did not differ between the groups, nor did need of repeated surgery. Time to first repeat operation was 53 and 37 months, respectively. CONCLUSIONS: In CD patients considered to have an aggressive disease course, Aza reduced symptoms after surgery and prolonged the time to symptomatic relapse. The findings support a role for Aza as a postoperative maintenance treatment in CD.

Adolescent↗
PubMed2004

In situ tracer tests to determine retention properties of a block scale fracture network in granitic rock at the Aspö Hard Rock Laboratory, Sweden.

Experiments were conducted at the Aspö Hard Rock Laboratory in order to improve the understanding of radionuclide retention properties of fractured crystalline bedrock in the 10-100 m scale (TRUE Block Scale Project, jointly funded by ANDRA, ENRESA, Nirex, JNC, Posiva and SKB). A series of tracer experiments were performed using sorbing tracers in three different flow paths. The different flow paths had Euclidian lengths of 14, 17 and 33 m, respectively, and one to three water conducting structures. Four tests were performed using different cocktails made up of radioactive sorbing tracers (22,24Na+, 42K+, 47Ca2+, 85Sr2+, 83,86Rb+, 131,133Ba2+ and 134,137Cs+). For each tracer injection, the breakthrough of sorbing tracers was compared to the breakthrough of a conservative tracer, 82Br-, 131I-, HTO and 186ReO4-, respectively. In the two longer flow paths, no breakthrough of 83Rb+ and 137Cs+ was observed after 8 months of pumping. Selected tracer tests were subject to basic modelling in which a one-dimensional (1D) advection-dispersion model, including surface sorption, and an unlimited matrix diffusion were used for the interpretation of the results. The results of the modelling indicated that there is a slightly higher mass transfer into a highly porous material in the block-scale experiment compared with in situ experiments performed over shorter distances and significantly higher than what would have been expected from laboratory data obtained from studies of the interactions in nonaltered intact rock.

Geological Phenomena↗
PubMed2003

Increased anal resting pressure and rectal sensitivity in Crohn's disease.

PURPOSE: Anal pathology occurs in 20 to 80 percent of patients with Crohn's disease in which abscesses, fistulas, and fissures account for considerable morbidity. The etiology is not clearly defined, but altered anorectal pressures may play a role. This study was designed to investigate anorectal physiologic conditions in patients with Crohn's disease compared with healthy controls. METHODS: Twenty patients with Crohn's disease located in the ileum (n = 9) or the colon (n = 11) without macroscopic proctitis or perianal disease were included. All were subjected to rectal examination, anorectal manometry, manovolumetry, and rectoscopy. Comparison was made with a reference group of 173 healthy controls of whom 128 underwent anorectal manometry, 29 manovolumetry, and 16 both examinations. RESULTS: Maximum resting pressure and resting pressure area were higher in patients than in controls (P = 0.017 and P = 0.011, respectively), whereas maximum squeeze pressure and squeeze pressure area were similar. Rectal sensitivity was increased in patients expressed as lower values both for volume and pressure for urge (P = 0.013 and P = 0.014, respectively) as well as maximum tolerable pressure (P = 0.025). CONCLUSIONS: This study demonstrates how patients with Crohn's disease without macroscopic proctitis have increased anal pressures in conjunction with increased rectal sensitivity. This may contribute to later development of anal pathology, because increased intra-anal pressures may compromise anal circulation, causing fissures, and also discharging of fecal matter into the perirectal tracts, which may have a role in infection and fistula development.

Abscess↗