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Biomedical subjects

L Højgaard

Publications and source records attributed to L Højgaard.

At least 73 records · Page 4Linked to original sources
PubMed1996

Human gallbladder pressure and volume: validation of a new direct method for measurements of gallbladder pressure in patients with acute cholecystitis.

Increased gallbladder (GB) pressure is probably a part of the pathogenesis of acute cholecystitis, and measurements of GB pressure might therefore be of interest. The aim of this study was to validate a microtip pressure transducer for intraluminal GB pressure measurements. In vitro precision and accuracy was within 0.2 mmHg, (SD) and 0.6 +/- 0.1 mmHg (mean +/- SD), respectively. Pressure rise rate was 24.8 +/- 5.5 mmHg s-1. Zero drift was in the range 0.3 +/- 0.4 to 0.8 +/- 0.9 mmHg (mean +/- SD). GB pressure was investigated in 16 patients with acute cholecystitis treated with percutaneous ultrasonically guided cholecystostomy. Basal intraluminal GB pressure was 8.9 mmHg (2.1-12.2 mmHg; n = 9, open cystic duct) and 1.8 and 5.8 mmHg (n = 2, closed cystic duct). There was no significant difference between two different measurements in the same patients (n = 5). The pressure was significantly influenced by respiration (n = 8) and the pressure seems to be higher in the sitting position than in the supine position (n = 5). Cystic duct opening pressure was 10.4, 11.2 and 16.8 mmHg (n = 3). Pressure-volume responses showed that the GB up to a certain volume could accommodate increases in intraluminal volume with only slight changes in intraluminal pressure (n = 4). Except for the zero drift, this piece of equipment seemed to fulfil the requirements of being able to measure pressure in the GB. In vivo measurements showed a good clinical reproducibility of the method, and also that respiration and patient posture influenced the pressure measurements. Further, a GB pressure-volume relationship was demonstrated, and the possibility of a cystic duct opening pressure was described.

Acute Disease↗
PubMed1996

Change in fat-free mass assessed by bioelectrical impedance, total body potassium and dual energy X-ray absorptiometry during prolonged weight loss.

A total of 16 obese women (body mass index (BMI) 30-43 kg m(-2)) participated in a weight reduction study. Before and after a weight loss of 11.7 +/- 7.4 kg (mean +/- SD), body composition was assessed by dual energy X-ray absorptiometry (DXA), and total body potassium counting (TBK). These measurements were compared with bioimpedance analysis (BIA) by applying 11 predictive BIA equations published in the literature. Predictive equations for the present study population were developed, with the use of fat-free mass (FFM) as assessed by TBK and DXA as references in multiple regression analysis. The results of the BIA equations varied widely; FFM was generally overestimated by BIA as compared with DXA and TBK before and after weight loss. During weight loss, the FFM did not change, as estimated by DXA (1.3 +/- 2.3 kg, p > 0.05) and TBK (0.9 +/- 2.9 kg, p > 0.05). The recorded change in impedance (R) was also insignificant. Three BIA equations from the literature, which were not specific for the degree of obesity in the present study group, predicted changes in FFM (from 0.5 + 3.6 to 2.4 +/- 4.4kg, p > 0.05) that were comparable with those estimated by the reference methods. Eight equations from the literature, which included equations specific for the degree of obesity in the study group, and the group specific equations developed for the present population predicted significant changes in FFM during weight loss (from 2.3 +/- 3.0 to 5.0 +/- 3.0 kg, p < 0.05). We conclude that in obesity most predictive equations are unable to predict static body composition and are not reproducible for individuals over time. However, a significant or insignificant change in R (without accompanying predictive equations) may be used to indicate whether FFM is lost or preserved in groups of obese subjects.

Absorptiometry, Photon↗
PubMed1996

Peptic ulcer pathophysiology: acid, bicarbonate, and mucosal function.

The previously accepted role of gastric acid hypersecretion in peptic ulcer disease has been modified by studies showing no correlation between acid output and clinical outcome of ulcer disease, or between ulcer recurrence rate after vagotomy and preoperative acid secretion. At the same time, studies have been unable to demonstrate increased acidity in the duodenal bulb in patients with duodenal ulcer, and consequently more emphasis has been given to the mucosal protecting mechanisms. The existence of an active gastric and duodenal mucosal bicarbonate secretion creates a pH gradient from the luminal acid to near neutrality at the surface of the epithelial cells, thereby acting as an important mucosal defence mechanism. The regulation of bicarbonate secretion is a complex process related to motility and neural activity. Stimulation is by acid, PGE2, NO, VIP, cAMP, and mucosal protective agents. Bicarbonate secretion is inhibited by atropine, muscarinic antagonists, alpha-adrenoceptor agonists, indomethacin, bile acids, tobacco smoking, and probably also by infection by Helicobacter pylori. Apart from mucus and bicarbonate, the mucosal defence is supported by a hydrophobic epithelial lining, rapid cell removal and repair regulated by epidermal growth factor. Sufficient mucosal blood flow, including a normal acid/base balance, is important for subepithelial protection. In today's model of ulcer pathogenesis, gastric acid and H. pylori work in concert as aggressive factors, with the open question being: why does only a fraction of the infected population develop an ulcer?

Animals↗
PubMed1996

Dynamic cholescintigraphy: induction and description of gallbladder emptying.

UNLABELLED: The main purposes of this study were to investigate the best parameter for describing gallbladder emptying and whether gallbladder bile emptying should be induced with a bolus injection or continuous infusion of cholecystokinin-octapeptide (CCK-8). METHODS: Gallbladder emptying was measured by dynamic cholescintigraphy. Twelve healthy subjects and six patients with gallstones were examined twice with CCK-8 infusion cholescintigraphy, 0.3 ng CCK-8 kg per min for 60 min under identical circumstances. Another six healthy subjects randomly received bolus injection (0.04 microgram/kg) and infusion of CCK-8 (0.3 ng/kg per min for 60 min), respectively, during cholescintigraphy on two separate occasions. The choice of bolus dose was based on recommendations from the CCK-8 manufacturer. The infusion dose was chosen to produce plasma CCK concentrations similar to postprandial plasma CCK levels. RESULTS: A parameter of gallbladder emptying, mean ejection fraction (EF), was defined as 100% minus the area under the time-activity curve normalized to 100% and divided by the time interval from maximum to minimum counts per minute. This parameter proved superior to the well known parameters, EFmax. and EF30, in regard to reproducibility in healthy subjects. The slope of the regression line for the mean EF was 0.998 and the intercept value approximately 0% (p = 0.0001). The mean coefficient of variation was 4%. Apart from a higher mean coefficient of variation, similar reproducibility results were seen in the six patients. The measurements of EF30 in healthy subjects scattered more widely around the mean compared to the mean EF and EFmax, which indicates poorer ability to separate normal from abnormal gallbladder emptying. Intravenous bolus injection of CCK-8 resulted in incomplete gallbladder emptying with a mean EF value of 16% (s.d. 9%; range 7%-32%) compared to 49% (s.d. 7%; range 37%-57%) following CCK-8 infusion (p = 0.004). Abdominal discomfort was observed in all subjects after administration of the bolus injection, whereas no complaints were reported during infusion. CONCLUSION: Mean EF is the best parameter for describing gallbladder emptying. Moreover, slow infusion of a physiological dose of CCK-8 is preferable to induce gallbladder emptying because it results in more complete emptying and has no side effects.

Adult↗
PubMed1996

Body composition during weight loss in obese patients estimated by dual energy X-ray absorptiometry and by total body potassium.

OBJECTIVE: To validate the ability of DXA to measure total body composition before and after weight loss and the composition of the lost body mass. DESIGN: Cross sectional and follow-up study of body composition before and after a weight loss of 10.6 +/- 6.8 kg. SUBJECTS: 31 obese subjects with a mean body weight of 105.2 +/- 15.2 kg at baseline, and a mean body weight of 94.6 +/- 16.5 kg at follow-up. MEASUREMENTS: Body composition was measured by dual X-ray absorptiometry, total body potassium counting, and high precision scales before and after a weight loss. RESULTS: DXA and the scales showed a strong linear relation (r = 1). At baseline, however, DXA underestimated the body weight by a maximum of 3.2 kg because the subjects were too large for the scan table. After weight loss body weight measurements were accurate. Before and after weight loss the linear relations between DXA and TBK for FFM were strong (r = 0.92 and 0.93). Bland and Altman plots showed limits of agreement of +/-9 kg before and after weight loss; DXA underestimated FFM in women and overestimated FFM in men. DXA accounted for 80% of the lost body weight. The composition of the lost body mass did not differ from that estimated by TBK (7.6% FFM and 92.4% FM by TBK; 11% FFM and 89% FM by DXA). CONCLUSION: DXA estimates accurately the body composition and the composition of weight loss in groups of obese subjects. However, the scan table may be too small for patients weighing more than 95 kg.

Absorptiometry, Photon↗
PubMed1995

Cholescintigraphy in patients with acute cholecystitis before and after percutaneous gallbladder drainage.

OBJECTIVE: To investigate gallbladder function by use of cholescintigraphy in patients with acute cholecystitis before and after percutaneous gallbladder drainage. DESIGN: A cholescintigraphy was performed in 40 patients with acute cholecystitis before and after the performance of percutaneous gallbladder drainage. During the post-drainage cholescintigraphies, a cholecystokinin stimulation was performed to investigate gallbladder emptying in 12 selected patients. Gallbladder pressure and volume were measured before drainage in another group of 12 patients with acute cholecystitis. RESULTS: As expected, no gallbladder activity was observed in the cholescintigraphies before drainage, except in a patient with an occluding stone in the common bile duct. Cystic duct patency and gallbladder activity were seen in 80% of patients in cholescintigraphies performed after drainage but before any other treatment. Post-drainage cholescintigraphy revealed a mean gallbladder ejection fraction of 24%, which is significantly lower than the corresponding value in normal individuals and gallstone patients without cholecystitis (n = 12). Gallbladder pressure and volume were markedly increased compared with normal values. CONCLUSION: The relief of increased gallbladder pressure and volume appears to be important for the re-establishment of gallbladder function.

Acute Disease↗
PubMed1994

[Positron emission tomography. A new measurement method for imaging of regional and biochemical parameters].

Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon (11C), oxygen (15O), and nitrogen (13N) elements. With the tomographic principle of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment.

Brain↗
PubMed1994

[Postoperative morbidity among alcohol abusers].

Retrospective studies suggest increased postoperative morbidity among alcohol misusers. We have prospectively studied the risk associated with alcohol intake among patients undergoing surgery. We investigated 15 persons who required colorectal surgery and who were drinking at least five Danish drinks per day. These patients were matched for sex, nutrition, age, weight, cardio-pulmonary disease, diagnosis anesthesia, and surgery to 15 control persons who were consuming no more than two drinks daily. None of the patients showed signs of liver disease. The alcohol group developed more postoperative complications than controls (67 vs 20%, p < 0.05) and hospital stay was prolonged (20 vs 12 days, p < 0.05). Preoperatively, alcohol misusers had reduced left ventricular ejection fraction (54 vs 68%, p < 0.01). Delayed-type hypersensitivity responses were reduced in the alcohol group before (53 mm2 vs 78, p < 0.05) and after (18 mm2 vs 55, p < 0.01) surgery. Alcohol misusers had significantly longer bleeding times. Surgical stress responses, as assessed by changes in plasma cortisol and catecholamines, were higher among alcohol misusers (p < 0.05). Postoperative morbidity was increased in alcohol misusers without signs of liver damage. The mechanisms may include subclinical cardiac insufficiency, immunosuppression, and decreased haemostatic function. Preoperative alcohol consumption may be a more important risk factor for postoperative morbidity than previously thought.

Adult↗
PubMed1994

Plasma cholecystokinin in obese patients before and after jejunoileal bypass with 3:1 or 1:3 jejunoileal ratio--no role in the increased risk of gallstone formation.

BACKGROUND AND AIM: Jejunoileal bypass surgery for obesity increases the risk of gallstone formation, and, contrary to expectations, the incidence is greater in patients with a long as compared to a short ileum left in continuity. Impaired gallbladder motility due to reduced cholecystokinin (CCK) stimulation could be an explanation. The aim of this study was to investigate the CCK levels in such patients. SETTING: The randomized trial of bypass surgery named The Danish Obesity Project. DESIGN AND METHODS: We compared plasma levels of CCK in obese patients at three, nine or 15 months after jejunoileal bypass surgery with either a 1:3 jejunoileal ratio (n = 14) or a 3:1 ratio (n = 15), and in unoperated obese patients (n = 7). Plasma CCK levels were determined during fasting and during 150 min following ingestion of a liquid test meal. RESULTS: There were no significant changes over time following surgery. Basal CCK levels were significantly increased after surgery, and significantly higher in those with a 3:1 than in those with a 1:3 jejunoileal ratio. The postprandial AUC (mean +/- SEM) was 935 +/- 71 pM x min in the 3:1 ratio group and 891 +/- 100 pM x min in the 1:3 ratio group. This difference was not significant, but both bypass groups were significantly higher than the unoperated group (515 +/- 79 pM x min). The integrated increase in plasma CCK above basal level showed a similar pattern, but the difference between the unoperated and the bypass groups was insignificant. CONCLUSION: Postoperative changes in plasma CCK levels neither explain the increased risk of gallstone formation after bypass surgery nor the higher incidence with a long compared to a short ileum left in continuity in the bypass.

Cholecystokinin↗
PubMed1994

Oral cholecystography compared to cholescintigraphy for evaluation of cystic duct patency prior to ESWL treatment.

In a prospective, blinded study of 109 patients with cholecystolithiasis, oral cholecystography and 99Tcm-EHIDA cholescintigraphy were compared in terms of reliability for demonstrating cystic duct patency: one of the prerequisites for extracorporeal shock wave lithotripsy (ESWL) treatment of cholecystolithiasis. Patients with a positive result on one or both tests were regarded as having cystic duct patency. Patients with negative and uncertain result of both tests or one of each were regarded as having no cystic duct patency. Concordance between the two tests was obtained in 93 of 109 patients. The diagnostic reliability of cholescintigraphy and oral cholecystography were 95 and 86%, respectively (P < 0.05), suggesting a more precise determination of gallbladder filling with scintigraphy.

Adolescent↗