Biomedical subjects
Publications and source records attributed to S Oberg.
"In this article, we discuss the types of scientific knowledge that could be used to estimate migration flows." Theories from the disciplines of economics, geography, geopolitics, sociology, demography, econometrics, and history are reviewed. The authors find that "each field provides a partial explanation of...migration flows." The geographical focus is on Europe.
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In a randomized single-blind cross-over study on 14 volunteers the relation between dose, effect and serum concentration was studied when diazepam in solution was administered in a dose of 0.5 mg/kg bodyweight rectally with the volunteer placed either laterally or prone. When lying prone the delivered diazepam dose was on average 24% higher compared to in the lateral position. The difference in delivered dose affected sedation as well as serum concentration but did not prolong recovery time. At the time of clinical recovery, the serum concentration was still at a very high level. Oxygen (p02) and carbon dioxide (pCO2) tensions were monitored transcutaneously in 9 subjects and were unaffected by the sedative level. The study suggests that when diazepam enemas similar to the ones used here, they should be administered with the patient in a prone position.
Unilateral removal of the pelvic ganglion affected the bladder-half on the denervated side more profoundly than that on the non-denervated side. At an early stage (3-7 days) the former was heavier, had a lower choline acetyltransferase activity, developed less tension to nerve stimulation and, in course of time, became more sensitized to methacholine in vitro than the latter. At a late stage (30-60 days) the nerve-evoked contractile responses on the denervated side had increased, which was almost wholly attributed to the atropine-sensitive part of the contraction, but the recovery was not complete. On the non-denervated side the nerve-evoked responses were not significantly changed. It was calculated that in the normally innervated bladders 25-30% of the cholinergic nerves of each half were of contralateral origin. The figure was lower (18%) for the nerves mediating the atropine-resistant response.
Labial minor gland salivary flow rate and sodium concentration were analyzed in relation to 1) histologic findings in labial biopsy specimens and 2) the occurrence of chronic graft-versus-host disease (GVHD) in patients who received bone marrow transplants. Biopsy specimens and samples were obtained from 61 recipients of marrow transplants (including three twins) 51 to 1,260 days post transplantation. Labial saliva sodium concentrations were elevated in some patients, and these increases were associated with inflammation and destruction of minor salivary gland acini and ducts by chronic GVHD or other factors. The predictive value of the salivary sodium changes in evaluating labial salivary gland pathologic changes was 91 per cent, and the sensitivity was 74 per cent. Thus, if a transplant recipient is found to have an elevated labial saliva sodium level, then the probability that he has pathologic labial gland changes is 91 per cent. When analyses were restricted to include only patients who received no irradiation during transplantation, then elevated labial saliva sodium concentration was significantly associated with the occurrence of chronic GVHD. The sensitivity of this relationship was 42 per cent, but the predictive value was 100 per cent. Thus, if a nonirradiated transplant recipient is found to have an elevated labial saliva sodium concentration, then it is virtually certain that he has chronic GVHD. We found no significant changes in labial saliva flow rates in these bone marrow transplant recipients.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
In the rat model, esophageal adenocarcinoma reproducibly develops following surgically induced duodenal reflux into the esophagus and administration of nitrosamine. In addition, decreasing gastric acid via partial or total gastrectomy increases the prevalence of adenocarcinoma in this model. We questioned whether carcinogen was necessary for cancer development in the gastrectomized model and whether esophageal acidification could reverse the effect of gastrectomy. Three groups of 26 rats each were randomized to a surgical procedure to produce one of the following reflux models: gastroduodenal reflux by esophagojejunostomy, duodenal reflux by total gastrectomy and esophagojejunostomy, or no reflux by Roux-en-Y reconstruction. In a second experiment, 42 rats were operated on to induce duodenal reflux. One week following surgery, they were randomized to receive acidified water (pH 1.8) or tap water. The animals were killed at 24 weeks of age, and the esophagus was evaluated histologically. All animals with reflux had severe esophagitis and 87% developed columnar lining of the distal esophagus. Nearly half (48%) developed adenocarcinoma at the anastomotic site 16 weeks postoperatively and without carcinogen administration. Cancer prevalence did not differ between animals with gastroduodenal or duodenal reflux but tended to be lower in animals receiving acidified water. Duodenoesophageal reflux is carcinogenic in the rat model. Exogenous carcinogen is not necessary for cancer development in gastrectomized rats.
Gastroeosphageal reflux disease has been associated with long segments of Barrett's esophagus </=3 cm), but little is known about its association with shorter segments. The aim of this study was to evaluate anatomic and physiologic alterations of the cardia and esophageal exposure to gastric and duodenal juice in patients with short and long segments of Barrett's esophagus. Furthermore, these patients were compared to each other and to patients with erosive esophagitis and those with no mucosal injury. Two hundred sixty-two consecutive patients with foregut symptoms were divided into the following four groups based on endoscopic and histologic findings: group 1, no mucosal injury; group 2, erosive esophagitis; group 3, short-segment Barrett's esophagus; and group 4, long-segment Barrett's esophagus. Esophageal exposure time to acid and bilirubin, lower esophageal sphincter characteristics, and endoscopic anatomy of the cardia were compared between the groups. Patients with short-segment Barrett's esophagus had elevated esophageal acid and bilirubin exposure, decreased lower esophageal sphincter pressure and length, and a high incidence of hiatal hernia. These abnormalities were similar to those in patients with esophagitis and in general less profound than those found in patients with long-segment Barrett's esophagus. The length of intestinal metaplasia was higher in patients with a defective lower esophageal sphincter. Short-segment Barrett's esophagus is a complication of severe gastroesophageal reflux disease and is associated with the reflux of both gastric and duodenal juice similar to that seen in patients with long-segment Barrett's esophagus.
A structurally intact and competent lower esophageal sphincter in the experimental model shortens and becomes incompetent during gastric distention. The aim of this study was to evaluate postprandial reflux as an indirect measure of this volume-induced sphincter shortening and incompetency. Reflux (pH <4) in the 2-hour period following a meal was retrospectively analyzed from the 24-hour esophageal pH recordings of 94 healthy volunteers and 609 symptomatic patients. Forty-six percent of patients had pathologic postprandial reflux (>95th percentile of normal). The prevalence was lower in patients with a structurally intact compared to a defective lower esophageal sphincter (32% vs. 58%; P <0.001). Pathologic postprandial reflux was greater in patients with abnormal compared to normal findings on 24-hour pH study (76% vs. 21%; P <0.001). Patients with a normal 24-hour pH study and postprandial reflux had shorter sphincter lengths (2.33 vs. 2.82 cm; P <0.001) and lower pressures (10.78 vs. 14.24 mm Hg; P <0.005). A hiatal hernia increased the prevalence of postprandial reflux (P <0.001) in all patients (67% vs. 38%) and in the subgroup with a structurally intact sphincter (75% vs. 27%, P <0.001). Postprandial reflux is a dynamic indicator of sphincter competency, and increases as the structural sphincter characteristics deteriorate and is augmented by a hiatal hernia.
The relative importance of the lower esophageal sphincter (LES) and hiatal hernia in the pathogenesis of gastroesophageal reflux disease is controversial. To identify the role of hiatal hernia and LES in reflux disease, 375 consecutive patients with foregut symptoms and no previous foregut surgery were evaluated. All patients underwent upper endoscopy, stationary manometry, and 24-hour esophageal pH monitoring. Hiatal hernia was diagnosed endoscopically, when the distance between the crural impression and the gastroesophageal junction was >/=2 cm. The LES was considered structurally defective when the resting pressure was </=6 mm Hg, the overall length was less than 2 cm, and/or the abdominal length was less than 1 cm. Factors predicting abnormal esophageal acid exposure (composite score >14.7) were analyzed using multivariate analysis. The presence of a hiatal hernia and a defective LES were identified as independent predictors of abnormal esophageal acid exposure. LES pressure and abdominal length were reduced in patients with hiatal hernia by 4 mm Hg and 0.4 cm, irrespective of the presence of gastroesophageal reflux disease. It is concluded that both a structurally defective LES and hiatal hernia are important factors in the pathogenesis of reflux disease. It is hypothesized that in the presence of a structurally normal LES, the altered geometry of the cardia imposed by a hiatal hernia facilitates the ability of gastric wall tension to pull open the sphincter.
Laparoscopic Nissen fundoplication has been applied with increasing frequency in the treatment of gastroesophageal reflux disease. The aim of this study was to determine the variables that predict outcome of laparoscopic Nissen fundoplication. A multivariate analysis was performed on data from 199 consecutive patients undergoing laparoscopic Nissen fundoplication. Variables included age, sex, body mass index, primary symptoms, clinical response to acid suppression therapy, erosive esophagitis, 24-hour esophageal pH score, and the percentage of time the esophageal pH was less than 4 on 24-hour pH monitoring, lower esophageal sphincter competence, status of the esophageal body motility, hiatal hernia, carditis, intestinal metaplasia of cardiac epithelium limited to the gastroesophageal junction, and Barrett's esophagus of any length. Clinical outcome was obtained from all patients at a median follow-up of 15 months (range 6 to 74 months) after surgery. One hundred seventy-three patients had an excellent or good outcome (87%) and 26 had a fair or poor outcome. Three factors were significantly predictive of a successful outcome: an abnormal 24-hour pH score (odds ratio = 5.4; 95% confidence interval [CI] = 1. 9-15.3), a typical primary symptom (odds ratio = 5.1; 95% CI = 1. 9-13.6), and a clinical response to acid suppression therapy (odds ratio = 3.3; 95% CI = 1.3-8.7). We conclude that 24-hour pH monitoring provides the strongest outcome predictor of laparoscopic Nissen fundoplication and that outcome is based more on the correct identification of the disease than on its severity.
Barrett's esophagus is a premalignant metaplastic change in the lining of the distal esophagus. It represents a peculiar form of healing which occurs in response to chronic gastroesophageal reflux. The etiology of this condition is unknown but clinical and experimental data points to esophageal exposure to duodenal juice as the key factor in its development. Barrett's esophagus should be considered in all patients undergoing endoscopy for symptoms of reflux disease. It is confirmed by the presence of intestinal metaplasia in an area of columnar mucosa, regardless of the macroscopic appearances of the distal esophagus. Endoscopic surveillance with multiple biopsy of the columnar mucosa is indicated for all medically fit patients with Barrett's esophagus. Identification of intestinal metaplasia with high-grade dysplasia heralds the development of invasive cancer and offers the physician an opportunity to intervene. Esophagectomy is the treatment of choice for patients with high-grade dysplasia, since occult early adenocarcinoma is identified in up to 50 percent of the esophageal specimens.