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Biomedical subjects

H Nielsen

Publications and source records attributed to H Nielsen.

467 records · Page 26Linked to original sources

Short chain fatty acids relax isolated resistance arteries from the human ileum by a mechanism dependent on anion-exchange.

Ileal resistance arteries (internal diameter 184-337 microns) were discussed out under microscope and mounted in a microvascular myograph for isometric tension recording. Experiments were designed to test compounds trophic to the small intestine, namely, epidermal growth factor, glutamine and the three short chain fatty acids, acetic, propionic and butyric acid, for effects on vascular tone. Glutamine in concentrations up to 30 mM and epidermal growth factor in concentrations up to 1 microM had no contractile or relaxant effects on the resistance arteries. The three short chain fatty acids alone and in combination, however, caused a concentration-dependent (range 0.1-30 mM) relaxation of resistance arteries precontracted with 50 mM KCl. This relaxant effect was significantly inhibited by the presence of the anion-exchange inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid whereas it was unaffected by removal of the endothelium, presence of indomethacin, propranolol or phentolamine. These data suggest that the trophic effects of glutamine and epidermal growth factor on the small intestinal mucosa cannot be explained through actions on the resistance vasculature. In contrast, the relaxant effect of short chain fatty acid on resistance arteries in vitro suggests that these compounds may be able to improve the microcirculation in vivo. An improved microcirculation will, all things considered, facilitate the growth of the small intestinal mucosa.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

A neural network method for identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites.

We have developed a new method for the identification of signal peptides and their cleavage sites based on neural networks trained on separate sets of prokaryotic and eukaryotic sequences. The method performs significantly better than previous prediction schemes, and can easily be applied to genome-wide data sets. Discrimination between cleaved signal peptides and uncleaved N-terminal signal-anchor sequences is also possible, though with lower precision. Predictions can be made on a publicly available WWW server: http://www.cbs.dtu.dk/services/SignalP/.

Algorithms↗

The cost of dementia in Denmark: the Odense Study.

In a population-based study of dementia, the cost of care for 245 demented elderly and 490 controls matched by age and gender was estimated. Dementia of Alzheimer's type was diagnosed according to the NINCDS-ADRDA criteria, and vascular dementia and other types of dementia were diagnosed according to the DSM-IIIR criteria. Severity of dementia was determined by the Clinical Dementia Rating scale. The annual cost of medical care, domestic care, home help, nursing home and special equipment for nondemented patients was DKK 22,000 per person while the cost for very mildly, mildly, moderately and severely demented patients was DKK 49,000, DKK 93,000, DKK 138,000 and DKK 206,000, respectively. Except for very mild dementia the cost did not differ between elderly who suffer from Alzheimer's disease and those with other types of dementia. The net cost of dementia is the difference in cost between those with dementia and the matched controls and amounts on average to DKK 77,000 per person per year. However, priority setting cannot be based on the cost of dementia per se, but only on the cost of a specific dementia intervention compared to its health benefit.

Age Distribution↗

Interobserver variation in the radiographic diagnosis of gastric ulcer. Gastroenterologists' guesses as to level of interobserver variation.

A total of 156 double contrast barium examinations were independently interpreted by two observers for the presence of gastric ulcer. The observed agreement between the two readings was 93 per cent, and after adjusting for the expected chance agreement a kappa value of 0.73 was obtained. At the first reading 4 ulcers, and at the second reading 8 ulcers were interpreted as malignant. None of these interpretations agreed. In a questionnaire study it was demonstrated that gastroenterologists had a realistic impression of the level of agreement in the radiographic detection of gastric ulcer.

Adolescent↗

Interobserver variation in the radiographic diagnosis of duodenal ulcer disease.

Interobserver variation was estimated in radiologists' detection of duodenal ulcer and deformity of the duodenal bulb. A consecutive series of 156 patients with upper abdominal pain had a double contrast barium examination. The films were first read by routine by a specialist in radiology. A second reading was performed by another specialist who did not know the result of the first reading. Overall agreement between the two readings in the detection of duodenal ulcer and deformity of the duodenal bulb was 0.91 and 0.94, respectively. The overall agreement was adjusted for the expected chance agreement and kappa values were calculated. Kappa was 0.63 for the detection of duodenal ulcer and 0.85 for the detection of deformity of the duodenal bulb.

Adolescent↗

Modulation of the counts and functions of neutrophils and monocytes under in vivo hyperthermia conditions.

The present work was designed to examine the effect of in vivo hyperthermia on the cell number and functions of polymorphonuclear leucocytes (PMN) and monocytes in human beings. Eight healthy volunteers were immersed into a waterbath (WI) (water temperature 39.5 degrees C) for 2 h, whereby their rectal temperature rose to 39.5 degrees C. On a later day they served as their own controls, being immersed into thermoneutral water (34.5 degrees C) for 2 h. Blood samples were collected before immersion, at body temperatures of 38, 39 and 39.5 degrees C as well as 2 h after water immersion. The neutrophil count was significantly increased at 39.5 degrees C, as well as 2 h after hot WI, compared with control. The monocyte count was significantly augmented at 38 and 39 degrees C and 2 h after hyperthermic load. The FMLP-induced chemiluminescence response, for a given number of PMN, was significantly reduced 2 h after hot WI. The total amount (per litre of blood) of superoxide production by PMN stimulated with opsonized zymosan (OZ) was significantly augmented at 39 and 39.5 degrees C and 2 h after WI. In vivo hyperthermia did not affect the function of monocytes, but when correlated to the changes in the concentrations of monocytes (response per litre blood) a significant increase in the phorbol myristate acetate (PMA)- and OZ-enhanced superoxide production occurred at 38 and 39 degrees C, as well as 2 h after termination of hot WI. Furthermore the OZ-enhanced monocyte chemiluminescence response per litre of blood was significantly enhanced 2 h after hot WI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Vascular (humoral) rejection in human cardiac allograft biopsies: relation to circulating anti-HLA antibodies.

Vascular or humoral rejection (as defined by linear deposits of immunoglobulin and complement in myocardial capillaries) and the presence of circulating lymphocytotoxic anti-HLA antibodies are each associated with reduced long-term graft or patient survival. The relationship between these two factors has not been determined. We used immunofluorescent techniques to study 46 cardiac biopsy specimens in 16 patients from 15 to 412 days after transplantation. Biopsy specimens were selected from the first 2 months, and at approximately 6 and 12 months after transplantation and did not include episodes of acute cellular rejection. Each specimen studied was compared to a serum sample drawn an average of 1.8 days (range, 0 to 9 days) from the time of biopsy to assay for circulating anti-HLA antibodies. Of the specimens obtained at or near a positive anti-HLA antibody test, 90% (27 of 30) were found to have linear deposits of immunoglobulin (not necessarily with complement) versus 75% (12 of 16) of specimens obtained at the time of a negative test. Twenty-one cases of vascular rejection were documented. Both immunoglobulin M and immunoglobulin G were deposited along with complement in 13 instances; immunoglobulin M and complement were deposited in eight cases; no case had only immunoglobulin G and complement. The presence of circulating anti-HLA antibody in the serum was associated with 14 of the 21 cases of vascular rejection. Linear deposits of immunoglobulin in the capillaries of myocardium were frequently observed when anti-HLA antibodies were present in the serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

In vivo measurements of the T1 relaxation processes in the bone marrow in patients with myelodysplastic syndrome. A magnetic resonance imaging study.

Nine patients with myelodysplastic syndrome (MDS) were examined with magnetic resonance imaging and in vivo T1 relaxation time measurements of the vertebral bone marrow in a 1.5 tesla whole body scanner. Two patients underwent transformation to acute myeloid leukemia and were evaluated at follow-up examinations. At the time of diagnosis the T1 relaxation times of the vertebral bone marrow were significantly prolonged compared with normal values. The T1 relaxation times of the vertebral bone marrow in patients with MDS showed significantly lower values compared with patients with acute leukemia and did not differ from patients with polycythemia vera.

Adult↗

Intravenous injection of ioxilan, iohexol and diatrizoate. Effects on urine profiles in the rat.

Effects of intravenous ioxilan, a new third generation non-ionic contrast medium, diatrizoate, iohexol and saline on urine profiles were compared. Albumin, glucose, sodium, phosphate, and the enzymes NAG, LDH and GGT were followed in 24 normal rats over 7 days. Diatrizoate significantly affected all profile components during the first two hours. Albuminuria was significantly greater after diatrizoate than after iohexol or ioxilan, and excretion of glucose, LDH and GGT was significantly higher than after ioxilan. Both iohexol and ioxilan increased the excretion of albumin, LDH and GGT, while iohexol also significantly increased excretion of glucose and sodium. There was a greater excretion of glucose and GGT after iohexol than after ioxilan. Saline did not induce any changes. At day 7, serum sodium, urea, creatinine, and albumin were normal for all test substances, and kidney histology revealed no difference between the groups of animals. It is thus concluded that both high osmolar ionic and low osmolar non-ionic contrast media may cause temporary glomerular and tubular dysfunction in rats. In this model, the kidney is affected most by diatrizoate, less by iohexol, and least by ioxilan.

Animals↗

Effects of intravenous injection of diatrizoate, iohexol or ioxilan on renal size, urine profiles and blood profiles in the rabbit.

Diatrizoate, iohexol or ioxilan were injected intravenously in 18 rabbits. The contrast medium passage through the kidneys was recorded on digital subtraction images for the first 50 s followed by 100 mm exposures up to 15 min after injection. The renal area was measured planimetrically. Urine profiles (glucose, phosphate, LDH, GGT, NAG), blood profiles (potassium, urea) and the relative clearance of albumin and sodium were followed for 5 days and compared with a control group injected with saline. All kidneys were examined by light and immunofluorescence microscopy. All three contrast media produced excellent arteriograms and urograms. The three different contrast media caused a rapid increase of the kidney area within the first minute, reaching an average maximum of 10 to 12 per cent after 5 min, followed by a gradual decline. Contrary to expectations the increase in renal area was similar for all three contrast media, so hyperosmolality is no likely explanation of this phenomenon. None of the contrast agents caused significant changes in any of the profile components with one exception: the GGT excretion was significantly elevated during the first 24 h after diatrizoate administration as compared with the effect of saline. Light and immunofluorescence microscopy revealed no differences.

Animals↗

Reproducibility of the acute rejection diagnosis in human cardiac allografts. The Stanford Classification and the International Grading System.

Transplantation has become an accepted treatment of many cardiac end-stage diseases. Acute cellular rejection accounts for 15% to 20% of all graft failures. The first grading system of acute cellular rejection, the Stanford Classification, was introduced in 1979, and since then many other grading systems have evolved. Most recently, the International Grading System was introduced in The Journal of Heart and Lung Transplantation. In this study the interobserver reproducibility of both the Stanford Classification and the International Grading System is evaluated using Kappa statistics. Three observers evaluated 168 endomyocardial biopsy specimens according to the Stanford Classification and 100 endomyocardial biopsy specimens according to the International Grading System. The evaluation was carried out blindly. Kappa values of 54.1% and 51.5%, respectively, were obtained, both significantly above zero but not optimal. In addition to the interobserver reproducibility analysis of the two grading systems, the International Grading System is discussed. In the original description of the grading system terms such as focal, multifocal, and aggressive infiltrates and myocyte damage and myocyte necrosis are used. These terms create some difficulties in understanding or interpreting the various grades. The main problem is to distinguish between grade 1A and grade 3A. Despite the difficulties, the grading system is easy to use, but a revision is needed.

Biopsy↗