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Biomedical subjects

E Johnsson

Publications and source records attributed to E Johnsson.

At least 19 recordsLinked to original sources
PubMed2006

An antireflux stent versus conventional stents for palliation of distal esophageal or cardia cancer: a randomized clinical study.

BACKGROUND: Self-expandable metal stents placed across the esophagogastric junction for palliative treatment of malignant strictures may lead to gastroesophageal reflux and pulmonary aspiration. This study compared the effects of a Dua antireflux stent with those of a conventional stent. METHODS: Patients with incurable cancer of the distal esophagus or gastric cardia were randomly assigned to receive an antireflux stent (n = 19) or a standard stent (n = 22) at nine Swedish hospitals during the period September 1, 2003 to July 31, 2005. Complications were recorded at clinical follow-up visits. Survival rates were assessed through linkage to the Population Register. Dysphagia, reflux symptoms, esophageal pain, dyspnea, and global quality of life were assessed as changes in mean scores between baseline and 1 month after stent insertion through validated questionnaires. RESULTS: No technical problems occurred during stent placement in the 41 enrolled patients. Fewer patients with complications were observed in the antireflux stent group (n = 3) than in the standard group (n = 8), but no statistically significant difference was shown (p = 0.14). The survival rates were similar in the two groups (p = 0.99; hazard ratio, 1.0; 95% confidence interval, 0.5-2.0). The groups did not differ significantly in terms of studied esophageal or respiratory symptoms or quality of life. Clinically relevant improvement in dysphagia occurred in both groups. Dyspnea decreased after antireflux stent insertion (mean score change, -11), and increased after insertion of standard stent (mean score change, +21). CONCLUSIONS: Antireflux stents may be used without increased risk of complications, mortality, esophageal symptoms, or reduced global quality of life. These results should encourage large-scale randomized trials that can establish potentially beneficial effects of antireflux stents.

Adult↗
PubMed2006

Angiotensin II induced contraction of rat and human small intestinal wall musculature in vitro.

BACKGROUND: Angiotensin II (Ang II) is a well-known activator of smooth muscle in the vasculature but has been little explored with regard to intestinal wall muscular activity. This study investigates pharmacological properties of Ang II and expression of its receptors in small-intestinal smooth muscle from rats and humans. METHODS: Isometric recordings were performed in vitro on small intestinal longitudinal muscle strips. Protein expressions of Ang II typ 1 (AT1R) and typ 2 (AT2R) receptors were assessed by Western blot. RESULTS: Ang II elicited concentration-dependent contractions of rat jejunal and ileal muscle preparations. The concentration-response curve (rat ileum, EC(50): 1.5 +/- 0.9 x 10(-8) M) was shifted to the right by the AT1R receptor antagonist losartan (10(-7) M) but was unaffected by the AT2R antagonist PD123319 (10(-7) M) as well as by the adrenolytic guanethidine (3 x 10(-6) M) and the anticholinergic atropine (10(-6) M). Human duodenal, jejunal and ileal longitudinal muscle preparations all contracted concentration-dependently in response to Ang II. The concentration-response curve (human jejunum, EC(50): 1.5 +/- 0.8 x 10(-8) M) was shifted to the right by losartan (10(-7) M) but was unaffected by PD123319 (10(-7) M). Both AT1R and AT2R were detected in all segments of the rat small intestinal wall musculature, whereas only AT1R was readily detectable in the human samples. CONCLUSION: Ang II elicits contractions of small-intestinal longitudinal muscle preparations from the small intestine of rats and man. The pharmacological pattern and protein expression analyses indicate mediation via the AT1R.

Adrenergic Antagonists↗
PubMed2005

Differential mechanisms for T lymphocyte recruitment in normal and neoplastic human gastric mucosa.

Worldwide, gastric adenocarcinoma (GC) is the second most common cause of death from malignant disease. The reason why immune responses are unable to clear the tumour is not fully understood, although aberrant lymphocyte recruitment to the tumour site might be one factor. Therefore, we investigated the homing phenotype of mucosal T lymphocytes in GC, compared to tumour-free mucosa. We could detect significantly decreased frequencies of mucosal homing alpha4beta7+ T cells in the tumour tissues and increased frequencies of L-selectin+ T cells. This was probably due to the correlated decrease in MAdCAM-1 positive and increase in PNAd positive blood vessels in the tumour mucosa. There were also fewer CXCR3+ T lymphocytes in the tumour tissue. These findings provide evidence that endothelial cells within tumours arising at mucosal sites do not support extravasation of typical mucosa-infiltrating T cells. This may be of major relevance for future immunotherapeutic strategies for treatment of GC.

Adenocarcinoma↗
PubMed2005

Differential expression of chemokine receptors on human IgA+ and IgG+ B cells.

Organ-specific lymphocyte homing is dependent on the expression of tissue-specific homing receptors and selected chemokine receptors. During the effector phase of an immune response, IgA and IgG antibody-secreting cells (ASC) are differently distributed in the body. Still, B cell expression of L-selectin and the mucosal homing receptor integrin alpha4beta7 is not related to the isotype produced, but only to the site of antigen encounter. In this study, we examined if differences in chemokine responsiveness between IgA+ and IgG+ B cells could explain their different tissue localization. Circulating CD19+ B cells were isolated and their expression of IgA, IgG, and selected chemokine receptors was determined by flow cytometry. Few Ig+ cells expressed CCR2, CCR3, or CCR9, and there was no difference in the expression of these receptors between IgA+ and IgG+ cells. In contrast, CCR4, CCR5, and CXCR3 was expressed on significantly more IgG+ than IgA+ cells. The function of chemokine receptors on memory B cells and ASC was then tested in the transwell system. IgG+ memory cells migrated to a higher extent than IgA+ cells towards the CXCR3 ligand CXCL11/I-TAC, while there was only a small migration towards the CCR4 ligand CCL17/TARC and the CCR9 ligand CCL25/TECK. ASC migrated poorly to all chemokines tested. In conclusion, this study shows that IgG+ and IgA+ memory B cells have a differential expression of the Th1 associated chemokine receptor CXCR3, as well as of CCR4 and CCR5. In contrast, none of the studied chemokine receptors was preferentially expressed by IgA+ cells.

Antibody-Producing Cells↗
PubMed2005

Stent insertion or endoluminal brachytherapy as palliation of patients with advanced cancer of the esophagus and gastroesophageal junction. Results of a randomized, controlled clinical trial.

SUMMARY: Esophageal cancer often presents as advanced stage disease with a dismal prognosis, with only 10-15% of patients surviving 5 years. Therefore, in a large proportion of patients, palliative treatment is the only option available. The aim of this study was to prospectively compare the palliative effect of self-expandable stent placement with that of endoluminal brachytherapy regarding the effect on quality of life and on specific symptoms. Sixty-five patients with advanced cancer of the esophagus or gastroesophageal junction were randomized to treatment with either an Ultraflex expandable stent or high-dose-rate endoluminal brachytherapy with 7 Gy x 3 given in 2-4 weeks. Clinical assessment and health-related quality of life (HRQL) were measured at inclusion and 1, 3, 6, 9 and 12 months later. The HRQL was measured with standardized questionnaires (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Oesophageal Module and Hospital Anxiety and Depression Scale). Twenty-eight patients completed the stent treatment and 24 patients the brachytherapy. The group of patients treated with stent reported significantly better HRQL scores for dysphagia (P < 0.05) at the 1-month follow-up, but most other HRQL scores, including functioning and symptom scales, deteriorated. Among brachytherapy-treated patients, improvement was found for the dysphagia-related scores at the 3-months follow-up, whereas other significant changes of scores were few. The median survival time was comparable in the two groups (around 120 days). In conclusion, insertion of self-expandable metal stents offered a more instant relief of dysphagia compared to endoluminal brachytherapy, but HRQL was more stable in the brachytherapy group.

Aged↗
PubMed2005

Sealing of esophageal perforation or ruptures with expandable metallic stents: a prospective controlled study on treatment efficacy and limitations.

Esophageal perforations are surgical emergencies with high mortality rates. A variety of treatment strategies have been advocated. No single strategy has however, been fully applicable to deal with most situations. The aim of this study was to investigate if treatment with covered expandable metallic stents could offer a feasible option for the management of a leaking esophagus regardless of cause. Twenty-two consecutive patients with perforation or leakage from the intrathoracic esophagus were endoscopically treated with placement of a covered expandable metallic stent. Nine patients had esophageal cancer and 13 had benign underlying disease of whom two had a leakage from a surgical anastomosis. The leakage could be sealed in all but one patient. This patient died after an open esophageal diversion procedure. Twelve patients had an uneventful recovery, whereas three patients needed percutaneous drainage of abscesses and one drainage of the pleural cavity through a small thoracotomy. One patient required a conventional thoracotomy to drain the mediastinum. In total five (23%) patients died from the perforation within 30 days. Two of the deaths were unrelated and three (14%) related to the perforation. In patients with benign disease stents were removed or replaced after 3 weeks. In total 17 stents were successfully removed. Leakage from a damage esophagus can be effectively covered by expandable metallic stents seemingly regardless of the underlying cause and is likely to offer a good chance of survival even in severely ill patients.

Adult↗
PubMed2002

Baclofen-mediated gastro-oesophageal acid reflux control in patients with established reflux disease.

AIM: To explore the effect of baclofen on oesophageal acid exposure in patients with gastro-oesophageal reflux disease. METHODS AND MATERIALS: Twenty patients with established reflux disease were included in this double-blind, randomized, crossover study. Baclofen, 40 mg, or placebo was given as a single dose with a washout period of 4 weeks. Symptoms were assessed by a visual analogue scale. Oesophageal pH was registered for 12 h and analysed for the whole period and for the 0-4-h, 4-8-h, 8-12-h and 2-h post-prandial periods. RESULTS: Baclofen significantly reduced the number of reflux episodes during the 0-4-h (7.9 vs. 16.5, P < 0.0001; post-prandially: 6.0 vs. 11.2, P < 0.0001) and 0-12-h (46.5 vs. 73, P=0.0001; post-prandially: 18.8 vs. 29.3, P < 0.0001) periods. The fraction of time with pH < 4 was significantly lowered during the 0-4-h period (9.3 vs. 15.6, P=0.0019; post-prandially: 16.1 vs. 23.5, P=0.0083). Similar results were also obtained in patients with a hiatus hernia (n=13). Belching was significantly reduced (32 vs. 69 episodes, P < 0.01). CONCLUSIONS: A single oral dose of 40 mg baclofen significantly reduced both the number of reflux episodes and the fraction of time with pH < 4, an effect primarily found during the first 4 h after dosing.

Administration, Oral↗
PubMed2002

Randomized clinical study of the prevention of pulmonary complications after thoracoabdominal resection by two different breathing techniques.

BACKGROUND: Pulmonary complications are frequently seen after thoracoabdominal resection of the oesophagus. The aim of this study was to compare the effects of two different breathing exercise regimens applied in the immediate postoperative period on the risk of pulmonary insufficiency after thoracoabdominal resection. METHODS: Seventy patients undergoing thoracoabdominal resection for cancer of the oesophagus and cardia were randomized after operation to breathing exercises by inspiratory resistance-positive expiratory pressure (IR-PEP) (n = 36) or continuous positive airway pressure (CPAP) (n = 34). The study groups were well matched for all relevant clinical and demographic data. RESULTS: Respiratory function deteriorated significantly immediately after operation; the lowest values of forced vital capacity and peak expiratory flow were measured during the first postoperative day and oxygen saturation was lowest on days 4-6. Significantly fewer patients in the CPAP group required reintubation and prolonged artificial ventilation (P < 0.05). There were minor non-significant differences between the study groups with respect to respiratory and other postoperative variables, usually in favour of CPAP. CONCLUSION: Provision of CPAP in the immediate postoperative period decreased the risk of respiratory distress requiring reintubation and the need for artificial ventilation compared with breathing exercises by IR-PEP.

Cardia↗
PubMed2001

Isolated hypervariable regions derived from streptococcal M proteins specifically bind human C4b-binding protein: implications for antigenic variation.

Antigenic variation in microbial surface proteins represents an apparent paradox, because the variable region must retain an important function, while exhibiting extensive immunological variability. We studied this problem for a group of streptococcal M proteins in which the approximately 50-residue hypervariable regions (HVRs) show essentially no residue identity but nevertheless bind the same ligand, the human complement regulator C4b-binding protein (C4BP). Synthetic peptides derived from different HVRs were found to retain the ability to bind C4BP, implying that the HVR corresponds to a distinct ligand-binding domain that can be studied in isolated form. This finding allowed direct characterization of the ligand-binding properties of isolated HVRs and permitted comparisons between different HVRs in the absence of conserved parts of the M proteins. Affinity chromatography of human serum on immobilized peptides showed that they bound C4BP with high specificity and inhibition experiments indicated that different peptides bound to the same site in C4BP. Different C4BP-binding peptides did not exhibit any immunological cross-reactivity, but structural analysis suggested that they have similar folds. These data show that the HVR of streptococcal M protein can exhibit extreme variability in sequence and immunological properties while retaining a highly specific ligand-binding function.

Amino Acid Sequence↗
PubMed2001

IgM and stromal cell-associated heparan sulfate/heparin as complement-independent ligands for CD19.

The more severe phenotype of mice lacking CD19 as compared to CD21 suggests that a complement-independent ligand for the CD19/CD21 complex exists. We sought ligands for CD19 by examining binding reactions with fusion proteins comprised of the extracellular region of CD19 and the Fc region of IgG1. A fusion protein containing the third extracellular domain (D3-Fc) bound to WEHI-231 cells, and this was competed by soluble IgM. This function of IgM was confirmed by the binding of D3-Fc to beads coated with IgM. A second ligand for D3-Fc was found on stromal cells, and was shown to be heparin/heparan sulfate. These two ligands would be considered to reside on follicular dendritic cells, and may account for the observed ability of D3-Fc to bind to sites in germinal centers containing these cells.

Animals↗
PubMed2001

Binding of human C4BP to the hypervariable region of M protein: a molecular mechanism of phagocytosis resistance in Streptococcus pyogenes.

The amino-terminal hypervariable region (HVR) of streptococcal M protein is required for the ability of this virulence factor to confer phagocytosis resistance. The function of the HVR has remained unknown, but the finding that many HVRs with extremely divergent sequences bind the human complement regulator C4b-binding protein (C4BP) has suggested that this ligand may play a role in phagocytosis resistance. We used the M22 system to study the function of bound C4BP and provide several lines of evidence that C4BP indeed contributes to phagocytosis resistance. First, the ability of anti-HVR antibodies to cause opsonization correlated with their ability to inhibit binding of C4BP. Secondly, a short deletion in the HVR eliminated C4BP binding and also reduced the ability of M22 to confer phagocytosis resistance. Thirdly, the addition of an excess of pure C4BP to a phagocytosis system almost completely blocked the effect of opsonizing anti-HVR antibodies. Together, our data indicate that binding of C4BP to the HVR of M22 plays an important role in phagocytosis resistance, but other properties of M22 also contribute. This study provides the first molecular insight into the mechanisms by which the HVR of an M protein confers phagocytosis resistance.

Amino Acid Sequence↗
PubMed2001

Preoperative adjuvant radiochemotherapy may increase the risk in patients undergoing thoracoabdominal esophageal resections.

BACKGROUND/AIM: Fatigue and malaise are common symptoms after radiochemotherapy which could affect patients' working capacity and add to the subsequent postoperative risk. The aim of the study was to investigate whether neoadjuvant radiochemotherapy in patients scheduled for a thoracoabdominal resection impairs their working capacity and adds to the postoperative risk. PATIENTS AND METHODS: 29 patients with resectable tumors (T(3) or N(1)) and a working capacity of > or =80 W on a bicycle test were included into the study. The tumor stage was determined by endoscopic ultrasound and computed tomography scan. The patients were given neoadjuvant radiochemotherapy during 38 days, consisting of two cycles of 5-fluorouracil (1,000 mg/m(2)) daily during 5 days and cisplatinum (100 mg/m(2)) on two occasions. Accelerated radiochemotherapy to a total dose of 40.8 Gy was given. Surgery was planned 4-6 weeks after completion of therapy. The patients had a bicycle test before induction of neoadjuvant treatment and 2-5 days prior to the operation. RESULTS: Three patients died already during the course of neoadjuvant treatment. The 26 remaining patients who had a bicycle test decreased their working capacity by a mean of 30 W (p < 0.0001). Ten patients had a decrease of their working capacity to < or = 90 W, of whom 6 died within 3 months postoperatively, and of the patients who had the working capacity decreased to < or = 80 W, 4 out of 5 died during the corresponding postoperative period. None of the patients, who performed >100 W at the second preoperative bicycle test died. CONCLUSIONS: Preoperative adjuvant radiochemotherapy, according to the present schedule, clearly exerts a detrimental effect on the patients' working capacity. A physical performance, at the time of the operation, < or = 80-90 W strongly predicts the subsequent postoperative risk. Similar adjuvant therapies may, therefore, in fact be harmful to some patients scheduled for a thoracoabdominal resection.

Adenocarcinoma↗
PubMed2000

Human complement regulators: a major target for pathogenic microorganisms.

The C3 convertases of the human complement system are controlled by fluid-phase and membrane proteins in the RCA (regulators of complement activation) family. Accumulated data show that many pathogenic microorganisms interact with these complement regulators. Recent advances in this field include determination of the crystal structure of the binding domains in the measles virus receptor CD46 and identification of a CD46 transgenic mouse line that is sensitive to measles virus. Moreover, recent findings support the hypothesis that pathogenic bacteria binding fluid-phase RCA proteins exploit these proteins to escape complement attack. These studies provide novel insight into the interplay between pathogens and the innate immune system and may have implications for the plans to use animals expressing an RCA protein for xenotransplantation.

Antigens, CD↗
PubMed2000

Unrestricted pore area (A0/Deltax) is a better indicator of peritoneal membrane function than PET.

BACKGROUND: How to measure the peritoneal exchange in uremic patients treated with peritoneal dialysis (PD) is still a matter of controversy. Most clinics use the peritoneal equilibration test (PET), but from a theoretical point of view, it would be more appropriate to determine the "area" parameter, A0/Deltax. The latter reflects the total unrestricted pore area per centimeter diffusion distance and can be obtained by three-pore analysis using, for example, the PD capacity test (PDC). To evaluate the different estimates of peritoneal function, PET data and the A0/Deltax parameters were compared with the independently determined uptake of a small diffusible tracer, iohexol (molecular weight of 821 D), from the abdominal cavity to blood. METHODS: Fourteen patients on routine PD underwent determinations of PET and A0/Deltax using PDC. Within a month, the two-hour uptake of iohexol (6 mg/mL) was also determined from the plasma iohexol concentration following abdominal filling. RESULTS: A strong correlation was found between the rate of iohexol plasma concentration increase (k30-120) and A0/Deltax (A0/Deltax = 76,300. k30-120 - 1.56; r2 = 0.799; N = 14) for the 2 L dwell, while the PET data were far less related to iohexol uptake (D/DPurea, r2 = 0.409; D/Pcreatinine, r2 = 0.436; and D/D0glucose, r2 = 0.015, respectively). CONCLUSION: The "area" parameter, A0/Deltax, is superior to the more widely used routine PET as an indicator of peritoneal membrane function. In addition, the concept of A0/Deltax has the virtue of supplying quantitative information about the peritoneal pathophysiology and physiology.

Adult↗
PubMed1999

An IgA-binding peptide derived from a streptococcal surface protein.

Surface proteins that bind to the Fc part of human IgA are expressed by many strains of Streptococcus pyogenes, a major human pathogen. Studies of these proteins have been complicated by their size and by their ability to bind human plasma proteins other than IgA. Here, we describe a synthetic 50-residue peptide, derived from streptococcal protein Sir22, that binds human IgA but not any of the other plasma proteins known to bind to Sir22. The peptide binds serum IgA and secretory IgA and binds IgA of both subclasses. Evidence is presented that the peptide folds correctly both in solution and when it is immobilized and that it readily renatures after denaturation. Together, these data indicate that the peptide corresponds to a protein domain that binds IgA with high specificity. This is the first report of an IgA-binding domain that retains its properties in isolated form.

Bacterial Outer Membrane Proteins↗
PubMed1999

Improved clearance of iohexol with longer haemodialysis despite similar Kt/V for urea.

BACKGROUND: The efforts to improve the quality of haemodialysis (HD) has renewed the interest in the consequences of blood-flow distribution for removal of solutes. METHODS: To test the effects of HD time per se, 10 patients were studied in a cross-over fashion with HD for 3 h and 1 week later for 6 h, with similar blood urea Kt/Vs, achieved by adjusting the blood flow rate to 290 and 120 ml/min respectively. Injections of iohexol (MW 821 Dalton) were given 2 days prior to the dialysis sessions. Blood samples were taken before, during (6/HD), 1 and 24 h after the HD and analysed for concentrations of urea and iohexol. A urea on-line monitor (Gambro) was used for continuous recordings and sampling of dialysate. RESULTS: According to the study design the blood Kt/V for urea (Daugirdas II) was similar for 3 and 6 h HD, close to 1.0 (n.s), while the removed mass of urea showed that Kt/V was slightly and significantly higher for the 6 h HD. The 'apparent' mass of iohexol, defined as plasma concentration times estimated distribution volume, fell to 29% and 21% of pre-dialysis levels after 3 h and 6 h HD, respectively (P<0.01), but increased after HD, and more so after the short dialysis, reaching 46% of the predialysis mass 24 h after 3 h HD vs. 36% after 6 h HD (P<0.05). The removed mass of iohexol was 920+/-110 mg with 6h HD and 700+/-81 mg with 3h HD, (P<0.01). Thus, the longer dialysis removed 32% more iohexol despite similar blood Kt/V for urea. CONCLUSION: The treatment time per se affects solute removal despite similar blood Kt/V for urea. This is particularly true for an intermediate-size molecule like iohexol.

Aged↗
PubMed1998

Role of the hypervariable region in streptococcal M proteins: binding of a human complement inhibitor.

Antigenic variation allows pathogenic microorganisms to evade the immune system of the infected host. The variable structure must play an important role in pathogenesis, but its function is in most cases unknown. Here, we identify a function for the surface-exposed hypervariable region of streptococcal M5 protein, a virulence factor that inhibits phagocytosis. The hypervariable region of M5 was found to bind the human complement inhibitor FHL-1 (factor H-like protein 1), a 42-kDa plasma protein. Plasma absorption experiments with M5-expressing bacteria showed that the interaction with FHL-1 occurs also under physiologic conditions. Studies of another extensively characterized M protein, M6, indicated that this protein also has a binding site for FHL-1 in the hypervariable region. The complement-inhibitory function of FHL-1 was retained after binding to streptococci, suggesting that bound FHL-1 protects bacteria against complement attack. All available data now indicate that FHL-1, or another human complement inhibitor, binds to the hypervariable region of M proteins. These findings provide insights into the forces that drive antigenic variation and may explain why the hypervariable region of M protein is essential for phagocytosis resistance. Moreover, these data add to a growing body of evidence that human complement inhibitors are major targets for pathogenic microorganisms.

Antigenic Variation↗