Search PubMed⌕ Search

Biomedical subjects

L Börjesson

Publications and source records attributed to L Börjesson.

At least 19 recordsLinked to original sources
PubMed2007

Long-term function and manovolumetric characteristics after ileal pouch-anal anastomosis for ulcerative colitis.

BACKGROUND: Long-term pouch function and physiological characteristics after ileal pouch-anal anastomosis (IPAA) are poorly described. The aim of this study was to undertake a prospective investigation of long-term pouch function and manovolumetric characteristics. METHODS: Forty-two patients with a median follow-up of 16 years after IPAA were included. Function was assessed using a questionnaire and a score was calculated ranging from 0 to 15 (15 being the worst). Manovolumetry was performed and pouchitis recorded. A paired analysis was conducted, as the results were compared with previous data for each patient. RESULTS: The median functional score was 3.5 (range 0-10) at 2 years and 5 (range 1-11) at 16 years (P = 0.013). Resting anal canal pressures were higher (P < 0.001) and squeeze pressures lower (P = 0.008) at long-term follow-up. Ileal pouch volumes at distension pressures of 10, 20 and 40 cm H(2)O were diminished at 16 years (P < 0.001, P = 0.005 and P = 0.058 respectively). The volume and pressure for first sensation and urge to defaecate were reduced. Increased age correlated positively with a poor functional score. A history of pouchitis did not affect functional or physiological characteristics. CONCLUSION: Ileal pouch function declines in the long term. The reasons are unclear, but the ageing process may have an impact.

Adult↗
PubMed2006

The place for colectomy and ileorectal anastomosis: a valid surgical option for ulcerative colitis?

BACKGROUND: Conflicting views regarding the use of ileorectal anastomosis (IRA) in ulcerative colitis (UC) exist and this controversy prompted us to review our experience, especially against the background of the current tendency to choose the ileal pouch-anal procedure (IPAA). METHODS: Thirty-two consecutive patients with IRA were studied. Complications, failure rate, reasons for failure and functional results were assessed. The median follow-up time was 3.5 years. RESULTS: The overall complication rate was 28%. The rectum was excised in 4 patients, indicating a failure rate of 12%. The mean daily evacuation frequency was 5.6. Despite urgency occurring in one-third of the patients, continence function was well preserved. CONCLUSIONS: Employed on a selective basis, IRA is a safe procedure with low mortality and morbidity and good prospects for success in many patients with UC. The patients must be prepared to submit to life-long rectoscopy surveillance.

Adult↗
PubMed2006

Ileal pouch anal anastomosis for ulcerative colitis is feasible for septuagenarians.

OBJECTIVE: Proctocolectomy and ileal pouch anal anastomosis (IPAA) has become the standard surgery for patients with mucosal ulcerative colitis (MUC). Although there is no absolute age limitation, there are concerns as to its use in elderly patients due to the risks of potential complications and poor function. The aim of this study was to assess the complications and outcome of patients over the age of 70 years with MUC who underwent IPAA. Results in these patients were compared to the results in a group of patients aged less than 70 years who had IPAA. METHODS: After Institutional Review Board approval, a retrospective review of the medical records of patients with MUC who underwent IPAA was undertaken. These patients were divided into four age groups: <30 years of age, 30-49 years, 50-69 years, >or=70 years. RESULTS: From 1989 to 2001, 330 patients underwent IPAA for preoperative clinical and histopathological and postoperative histopathologically confirmed MUC; 17 were aged>or=70 years. The mean hospital stay was 5.8 (SEM 0.7) days in the patients aged<70 years and 6.0 (SEM 0.4) days in the patients aged>or=70 years (P=0.911). Postoperative complications occurred in 39% of patients>or=70 years and in 40% in the <70 years group (P=0.08). Pouch failure occurred in two (11.8%) patients>or=70 years and in 6 (1.9%)<70 (P=0.2). CONCLUSION: IPAA is a safe and feasible option in MUC patients over the age of 70 with functional results similar to results seen in younger patients.

Adult↗
PubMed2005

Diffusive solvent dynamics in a polymer gel electrolyte studied by quasielastic neutron scattering.

A quasielastic neutron scattering study has been performed on a polymer gel electrolyte consisting of lithium perchlorate dissolved in ethylene carbonate/propylene carbonate and stabilized with poly(methyl methacrylate). The dynamics of the solvent, which is crucial for the ion conduction in this system, was probed using the hydrogen/deuterium contrast variation method with nondeuterated solvent and a deuterated polymer matrix. Two relaxation processes of the solvent were studied in the 10-400 microeV range at different temperatures. From analysis of the momentum transfer dependence of the processes we conclude that the faster process ( approximately 100 microeV) is related to rotational diffusion of the solvent and the slower process ( approximately 10 microeV) to translational diffusion of the solvent. The translational diffusion is found to be similar to the diffusion in the corresponding liquid electrolyte at short distances, but geometrically constrained by the polymer matrix at distances beyond approximately 5 A. The study indicates that the hindered diffusion of the solvent on a length scale of the polymer network interchain distance ( approximately 5-20 A) is sufficient to explain the reduced macroscopic diffusivity and ion conductivity of the gel electrolyte compared to the liquid electrolyte.

Journal Article↗
PubMed2005

Influence of chain length on the alpha-beta bifurcation in oligomeric glass formers.

A series of oligo(propylene glycol) dimethyl ethers has been investigated using dielectric spectroscopy in order to relate features of the glass transition dynamics to the number of monomer units N in the chain. The results show that (i) when scaled with the glass transition temperature, the beta relaxations systematically become faster for larger N whereas the alpha relaxations display nearly identical temperature evolutions, i.e., the alpha-beta bifurcation shifts towards shorter times for larger N, (ii) the bifurcation scenario displays a crossover in behavior at N approximately 10 monomer units, signaling the transition from oligomeric to polymeric behavior, and (iii) the beta relaxation has a cooperative nature.

Journal Article↗
PubMed2004

Structural investigations of polymer electrolyte poly(propylene oxide)-LiClO4 using diffraction experiments and reverse Monte Carlo simulation.

The structure of an amorphous polymer electrolyte, poly(propylene oxide) (PPO) complexed with LiClO4, has been studied using reverse Monte Carlo (RMC) simulations. The simulations require no force field but are based on experimental data only, in this case from x-ray and neutron diffraction experiments. Excellent agreement between the experimental data and the structures resulting from the RMC simulation is obtained. Samples with ether-oxygen to lithium concentrations (molar ratios) O:Li=16:1 and 5:1 were studied and compared to results of pure PPO from a previous study. We focus on the effects of the solvated salt on the structure of the polymer matrix, the spatial distribution of ions, and the correlations between the anions and the polymer chains. Analyzing the structures produced in the simulations, we find that for a concentration 16:1, the interchain distance is approximately the same as in pure PPO but more well defined. For a concentration 5:1, we find a larger and less well-defined interchain distance compared to the 16:1 concentration. This signifies that at the 16:1 salt concentration, there is enough free volume in the polymer host to accommodate the ions, and that the solvation of salt induces ordering of the polymer matrix. At the higher salt concentration 5:1, the polymer network must expand and become less ordered to host the ions. We also note, in accordance with previous studies, that the solvation of salt changes the conformation of the polymer chain towards more gauche states. The simulations furthermore reveal marked correlations between the polymer chains and the anions, which we suggest arise predominantly from an interaction mediated via cations, which can simultaneously coordinate both ether oxygens in the polymer chains and anions. Interanionic distances at 5 A, which are consistent with two or more anions being coordinated around the same cation, are also observed. On a larger scale, the RMC structure of PPO-LiClO4 16:1 clearly indicates the presence of salt-rich and salt-depleted domains having a length scale of <20 A. In view of such a heterogeneous structure of PPO-LiClO4 16:1, it is plausible that the increased ordering of the polymer matrix is due to rather well-defined structural arrangements within the salt-rich domains, and that the characteristic interchain distance in the salt-rich domains is similar to that of the pure polymer.

Journal Article↗
PubMed2004

Crystal-like nature of acoustic excitations in glassy ethanol.

We report on inelastic x-ray scattering experiments on crystalline and glassy phases of ethanol in order to directly compare the influence of disorder on high frequency acoustic excitations. We find that both the dispersion and the line-width of the longitudinal acoustic excitations in the glass are the same as in the polycrystal in the reciprocal space portion covering the 1st and 2nd Brillouin zones. The structural disorder is found to play little role apart from an intrinsic angular averaging, and the nature of these excitations must essentially be the same in both glass and poly crystal.

Journal Article↗
PubMed2004

The failed pelvic pouch: conversion to a continent ileostomy.

BACKGROUND: Excision of the ileal pouch-anal anastomosis (IPAA) with construction of a conventional ileostomy is in general the ultimate procedure after unsuccessful salvage surgery. Conversion of the IPAA to a continent ileostomy (CI) is an alternative. METHODS: The clinical outcome of 13 patients operated with conversion of IPAA into CI was evaluated. Median follow-up was 6 years. One patient was lost to follow-up. RESULTS: There were two failures with pouch excision. At follow-up, ten patients with intact CI were fully continent and none needed to use a stoma appliance. Revisional surgery had been required in 8 patients. CONCLUSIONS: Conversion of a failed IPAA into CI is a feasible procedure that may be considered an alternative to Brooke's ileostomy in motivated patients. The operation should ideally be done in specialized units.

Adult↗
PubMed2004

The effect of diverticular disease on the colonic J pouch.

OBJECTIVE: The aim of this study was to assess the impact of the diverticular disease (DD) on function and on postoperative complications of the colonic J-pouch (CJP) with pouch-anal anastomosis. METHODS: Patients who underwent a CJP between December 1990 and August 2001, were retrospectively reviewed. The presence of DD in the CJP was assessed on pouchogram prior to ileostomy closure. A questionnaire designed to evaluate the degree of continence (total incontinence score (IS): 0 = worst, 20 = best) and pouch evacuation (total evacuation score (ES): 0 = worst, 28 = best) was used for comparison between patients with DD and those without DD (NDD). RESULTS: Sixty-six patients (47 males; 19 females) with a median age of 68 years (range 28-87 years) were included. The median follow-up period was 22 months (range 2-106 months). Twenty-four patients comprised the DD group and 42 were in the NDD group. The two groups were comparable for age, gender and time from ileostomy closure; all patients with postoperative chemoradiation therapy were in the NDD group. The total ES and IS total did not significantly differ between the two groups with a P-value of 0.11 and 0.09 respectively. Furthermore, there was no significant difference in the total incidence of pouch complications between the two groups (3 strictures, 1 leak, 1 fistula in the NDD group vs. 1 pelvic sepsis in the DD group; P = 0.4). CONCLUSIONS: The presence of DD in a CJP does not seem to impact pouch function or the postoperative complication rate.

Aged↗
PubMed2004

The risk of dysplasia and cancer in the ileal pouch mucosa after restorative proctocolectomy for ulcerative proctocolitis is low: a long-term term follow-up study.

AIM: Some of the rare complications reported in patients with an ileopouch anal anastomosis (IPAA) after coloectomy for chronic ulcerative colitis are dysplasia and carcinoma. The supposed pathway is for the ileal pouch mucosa to go through adaptational changes then is to progress through the phases of chronic pouchitis, dysplasia and subsequently to adenocarcinoma. In many of these studies however, the dysplasia-cancer sequence is inconclusive since the carcinoma might have developed from the ileal mucosa itself or from residual viable rectal mucosa left behind. The purpose of this study was therefore to study the long-term ileal mucosal adaptation patterns and the incidence and grading of dysplasia in the ileal pouch mucosa in patients previously operated on for ulcerative proctocolitis. PATIENTS AND METHODS: Forty-five patients who had been operated on with an IPAA (25 males/20 females), with a median age of 54 years (range 34-76), were invited for clinical examination and pouch endoscopy including mucosal biopsies. The duration of their colitis until surgery was median 6 years (range 1-28) and the time median interval from start of disease until time of follow up 24.8 years (range 17-46). Three independent pathologists from two different centres reviewed sequential mucosal biopsies taken from separate sites of the pouch for dysplasia and mucosal adaptation patterns. RESULTS: The type C pattern with a severe inflammation in lamina propria together with severe atrophy of villi, sometimes with ulceration and granulation tissue, was observed by the two pathologists from one centre in 15 of 45 (33.3%) patients and in 11 (24.4%) of 45 by the third pathologist, respectively. As regards dysplasia one pathologist group evaluated 2/45 (4.4%) cases as low-grade dysplasia while the third pathologist considered one of these cases as indefinite for dysplasia and one as reactive. There was in this respect full agreement between the two centres in 43 (95.6%) of 45 cases. Neither high-grade dysplasia nor invasive carcinoma was diagnosed. CONCLUSION: Dysplastic transformation within the ileal pouch mucosa in patients operated for ulcerative proctocolitis is rare even after a long follow-up. These results are reassuring for both patients and surgeons. There seem to be no solid grounds to support routine surveillance for dysplasia in the ileal pouch mucosa in these patients. The surveillance for neoplastic changes in the remaining muscular/epithelial cuff is a separate issue however.

Adult↗
PubMed2003

Chain-length-dependent relaxation scenarios in an oligomeric glass-forming system: from merged to well-separated alpha and beta loss peaks.

We have studied the relaxation dynamics of a homologous series of propylene glycol based dimethyl ethers in the supercooled regime by means of broadband dielectric spectroscopy. The system is chosen in order to minimize changes of the intermolecular interactions with varying molecular weight, M. A gradual transformation from a scenario of well-separated to one of merged alpha and beta loss peaks was observed with decreasing M. The results give strong evidence for the currently debated excess wing being due to an underlying beta relaxation. The study suggests that the main difference between glass formers with and without excess wings is the relaxation time at the merging temperature.

Journal Article↗
PubMed2002

Using adhesion to probe viscoelasticity of polymer film surfaces: a quartz crystal microbalance study.

We have used a quartz crystal microbalance to monitor the adhesion of small particles to the surface of polystyrene films. This technique is shown to provide a signature of viscoelastic relaxation processes at the polymer surface. For M(n) values less than 10(4) and greater than 10(5), this signature occurs at a temperature approximately 12.5 K above the measured bulk glass transition temperature, T(g). For intermediate values of M(n) however, the relaxation signature occurs at temperatures as low as 7 K above the bulk T(g). This observation suggests a slight decrease in the T(g) value near the polymer surface. A model incorporating the effects of enrichment of polymer chain ends at the free surface was considered and found to provide a quantitative description of the data.

Journal Article↗
PubMed2001

Sound wave scattering in network glasses.

The acoustic branch of two network glasses, (Li2O)xB2O3 ( x = 0.25 and 0.5), is followed over a large momentum transfer range 1-12 nm(-1), using inelastic x-ray scattering. We observe the transition from propagating modes to a region of strong scattering as the Ioffe-Regel limit is reached. A region of Rayleigh scattering of the acoustic modes precedes the strong scattering regime at larger Q, causing a rapid decrease of the mean-free path of the modes.

Journal Article↗
PubMed2001

Functional effects of dextran sulphate sodium (DSS) treatment on the longitudinal muscle of rat distal colon.

1. The current study addressed how acute colitis, induced in male Sprague-Dawley rats by the administration of dextran sulphate sodium (DSS) in their drinking water, may affect some functional properties of the longitudinal muscle layer of the distal colon. 2. Dextran sulphate sodium was provided at a concentration of 3% for 3 or 7 days, or 5% for 7 days, and the rats were thereafter killed. Specimens of the distal colon were taken for histology or for organ bath experiments. 3. The colitis score increased significantly with increasing dose of DSS administered. At 5% concentration, there was sometimes even transmural inflammation. Functionally, there was a progressive increase in optimal preload (P(o)) for the contractile response to carbachol (1 microM), in relation to the severity of the colitis. At 5% DSS, the magnitude of the response to carbachol at P(o) was significantly increased compared with control rats. Such an effect could not be verified when, instead, K+ (60 mM) was used as a spasmogen. 4. It is concluded, that the colitis score increased in severity progressively with increasing amounts of DSS administered. The longitudinal muscle layer was functionally affected by the inflammation. Thus, there was a progressive increase in optimal preload for muscle contraction. Moreover, severe colitis resulted in an increase of the contractile response to carbachol, while a significant increase in the response to depolarization with K+ could not be found.

Animals↗
PubMed2000

Relaxation of rat distal colon by activation of muscarinic, neuronal receptors: possible involvement of P(2y)-purinoceptors.

McN-A-343, which is a ligand at muscarinic receptors on myenteric ganglia, was found to concentration-dependently (1-44 microM) elicit non-adrenergic relaxation of the longitudinal muscle of rat distal colon, having been precontracted with carbachol (1 microM). This effect was partly antagonized by the muscarinic receptor antagonist, pirenzepine (0.3 microM), the nerve blocker, tetrodotoxin (1 microM), or by drugs which interfere with purinergic neurotransmission (apamin [0.5 microM], reactive blue 2 [50 microM]). Blockade of nitric oxide synthase (L-NNA [100 microM]), or of the cAMP (H-89 [1 microM]), or cGMP (ODQ [10 microM]) second messenger pathways did not affect the relaxatory response to McN-A-343 (14 microM). An additional, non-neurogenic component of the relaxation to this compound on carbachol induced tone is suggested to reflect a partial antagonism of the muscarinic receptors on the gut muscle by McN-A-343.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗
PubMed1999

K(+)-induced neurogenic relaxation of rat distal colon.

Relaxations of segments of rat distal colon were elicited by hypertonic solutions of potassium (K(+); final concentration, 20.8 or 50.8 mM). The initial part of the response to K(+) was antagonized by the nerve blocker tetrodotoxin. This effect could, moreover, be significantly antagonized by apamin (a blocker of K(+) channels), reactive blue 2 (a P(2y)-purinoceptor antagonist), N(G)-nitro-L-arginine (an inhibitor of NO synthase), 1H-[1,2,4]- oxadiazolo[4,3-a]quinoxaline-1-one (ODQ; an inhibitor of soluble guanylyl cyclase), or N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89; an inhibitor of cAMP-dependent protein kinase). Sodium nitroprusside (a donor of NO) and vasoactive intestinal peptide (VIP) both relaxed the tissues. The response to sodium nitroprusside was abolished by ODQ and unaffected by H-89, and that to VIP was partially inhibited by VIP(10-28) (a VIP receptor antagonist), ODQ, or H-89. When combining reactive blue 2 and N(G)-nitro-L-arginine, the response to 50.8 mM K(+) was reduced by approximately 70% and was abolished by the concomitant administration of these antagonists and VIP(10-28). ATP, NO, and VIP may, thus, be inhibitory neurotransmitters in rat distal colon.

Animals↗
PubMed1997

DMPP causes relaxation of rat distal colon by a purinergic and a nitrergic mechanism.

The non-adrenergic relaxation of carbachol precontracted longitudinal muscle of the rat distal colon was investigated. Intrinsic nerves were activated by the nicotinic, ganglionic receptor agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP). DMPP at 1 and 4 microM caused a relaxation that was markedly antagonized by the nerve blocker tetrodotoxin (1 microM) or the nicotinic receptor antagonist, hexamethonium (1 mM). The response to DMPP was significantly antagonized by apamin (an inhibitor of ATP-sensitive K+-channels), by reactive blue 2 (a blocker of P2y purinoceptors) and by an inhibitor of nitric oxide (NO)-synthase (N(G)-nitro-L-arginine, L-NNA). The combined treatment with reactive blue 2 and L-NNA reduced the relaxatory response to 1 microM DMPP by 77 +/- 8% and to 4 microM DMPP by 58 +/- 4% of control, but left a residual component. Our results indicate that ATP and NO, together with at least one additional (hitherto unidentified) substance may be inhibitory neurotransmitters in rat distal colon.

Adenosine Triphosphate↗