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Biomedical subjects

A Larsen

Publications and source records attributed to A Larsen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Predictors of IDDM recurrence risk in offspring of Danish IDDM patients. Danish IDDM Epidemiology and Genetics Group.

It has previously been observed that offspring of mothers with insulin-dependent diabetes mellitus (IDDM) have a lower risk of IDDM than offspring of IDDM affected fathers. To assess the offspring IDDM recurrence risk in a Danish population-based study and to investigate parental and offspring-related biological variables that might influence this risk, we identified 2726 IDDM probands and their 2826 offspring from a background population of 1.725 million people (33% of the Danish population). Current age of probands was 20-65 years and their age at IDDM onset was 30 years or less. Sixty-nine offspring (2.4%) were affected with IDDM. The sex difference in the parental-offspring IDDM transmission rate was confirmed. The cumulative IDDM risk up to age 30 years was found to be significantly decreased in maternal offspring compared to paternal offspring (2.3 +/- 0.6 and 5.7 +/- 0.9 %, RR = 2.40, 95% CI 1.30-4.47; p = 0.004) only if parents were diagnosed with IDDM before birth of the offspring. However, due to the low number of diabetic offspring of probands diagnosed with IDDM after offspring birth, this observation needs to be confirmed in a larger population. In a subpopulation of the 2380 offspring, whose parents were all diagnosed with IDDM before offspring birth, the recurrence risk was significantly increased in offspring of male probands diagnosed up to age 17 years compared to offspring of fathers diagnosed at older ages (8.5 +/- 1.8 and 3.6 +/- 1.0%; RR = 2.27, 95% CI 1.21-4.25; p = 0.006). No such relation was found in maternal offspring. Using the Cox proportional hazards model on this offspring subpopulation we found that paternal age at IDDM onset was the only statistically significant predictor of IDDM recurrence risk. Our findings may be important for counselling families in which one parent has IDDM.

Adult↗
PubMed1998

Effects of spatial separation in visual pattern matching: evidence on the role of mental translation.

Effects of the spatial separation between 2 simultaneously presented random patterns on the ability to determine whether the patterns are identical up to a translational displacement across the retina were investigated by using signal-detection methods. The patterns to be compared were presented on the periphery of an imaginary circle centered on fixation. Exposures were brief and postmasked. In Experiments 1 and 2, sensitivity (d') varied with exposure duration but not with the spatial separation between the patterns. In Experiment 3, the task was changed so that members of a "same" pair could differ by both a translation and a rotation. When the rotational component was O, d' was a monotonic decreasing function of the spatial separation between the stimuli. Apparently, in the special case, performance was based on mental alignment by a process of gradual mental translation of one of the members of a stimulus pair to the location of the other one.

Adolescent↗
PubMed1997

[Foreign physicians in Norwegian hospitals].

Because of the increasing number of foreign doctors seeking employment in Norwegian hospitals, a survey was undertaken to estimate their numbers, and to study how they and their chief physicians assess their working situation, and whether it could possibly be improved. 15% of the hospital physicians were foreign, about half of these had other language backgrounds than Swedish or Danish. 55% of the departments employed foreign doctors. The median time in Norway for these doctors was 33 months. Doctors from outside Scandinavia were less satisfied with their working situation than were doctors with a Swedish or Danish background, and this was also reflected in the views of the chief physicians. The language difficulties experienced by the foreign doctors were considered to be greater by their chief physicians than by the foreign doctors themselves. Emphasis should be placed on language and cultural training, building supporting networks, and improving the qualifications of Norwegian physicians to enable them to work in cross-cultural environments.

Communication Barriers↗
PubMed1997

[Follow-up of a procedure of antibiotic prophylaxis in cesarean section].

In order to assess the quality of the treatment given in our department, we studied the use of antibiotic prophylaxis in cases of cesarean section in relation to the implementation of a standard protocol. The records of 606 patients who underwent a cesarean section in 1989 and 1992 were studied retrospectively with regard to risk factors for postoperative infection, antibiotic prophylaxis and infections during hospitalisation. While the use of the antibiotic prophylaxis increased from 1989 to 1992, the number of postoperative infections remained relatively stable, 17% in 1989 and 14% in 1992. 55% of patients who were regarded as candidates for prophylaxis in this study were given antibiotic prophylaxis in 1992 (93 of 169 patients). 49 (53%) of these patients received an antibiotic prophylaxis in accordance with the protocol, whereas 44 (47%) were given other antibiotic regimens. The effect of treatment, as assessed by the number of postoperative infections, remained unchanged, while the use of antibiotic prophylaxis increased in the period after the protocol was implemented. The protocol was not followed as intended.

Adult↗
PubMed1997

Physicochemical characterisation of mangafodipir trisodium.

PURPOSE: To determine the structure and various physicochemical properties of mangafodipir (MnDPDP) trisodium, the active ingredient of Teslascan, a new-organ-specific contrast medium for MR imaging. MATERIAL AND METHODS: The structure of MnDPDP trisodium crystals was determined by X-ray crystallography. The possible existence of polymorphism in MnDPDP trisodium was evaluated by powder X-ray diffraction, optical microscopy, thermal analysis and IR spectroscopy. In addition, various spectroscopic techniques and physicochemical measurements were used for characterisation of MnDPDP trisodium. RESULTS: The crystallographic data obtained for MnDPDP trisodium show that the general core structure of the MnDPDP anion is similar to that seen in related substances. The metal coordination geometry is a distorted octahedron defined by 2 phenolate oxygens, 2 carboxylate oxygens and 2 amine nitrogens. The unit cell contains 2 MnDPDP anions, 6 sodium ions and 50 water molecules. The various spectroscopic data are consistent with the structure determined by X-ray crystallography. The product (Teslascan) has low viscosity, is isotonic with blood and has a physiological pH. CONCLUSION: MnDPDP trisodium is a crystalline, hygroscopic solid which is readily soluble in water. No evidence of polymorphism was seen in the samples studied.

Chemical Phenomena↗
PubMed1997

Comparison of 3 quantitative measures of hand radiographs in patients with rheumatoid arthritis: Steinbrocker stage, Kaye modified Sharp score, and Larsen score.

OBJECTIVE: To compare 3 quantitative hand radiograph scores, Steinbrocker stage, Larsen score, and Sharp score modified by Kaye, to one another and to other measures of clinical status in a cross sectional analysis of hand radiographs of 173 patients with rheumatoid arthritis (RA). METHODS: Radiographs were scored and compared to other measures of clinical status according to correlation and cross tabulation analyses. RESULTS: In these cross sectional studies, radiographic scores according to all 3 methods were correlated at high levels (r(s) > 0.5) with one another and duration of disease, as well as with scores for physical joint deformity and limited motion; at lower levels (0.3 < r(s) < 0.5) with physical joint swelling scores, functional status, and age; and at low levels of marginal or no clinical importance (r(s) < 0.3) with physical joint tenderness scores, laboratory data, and pain scores. CONCLUSION: The 3 scoring methods give similar quantitative information concerning hand radiographs of patients with RA. The Larsen and modified Sharp scores are preferred measures, as the detailed information facilitates comparison of different patients and monitoring of individual patients over time.

Activities of Daily Living↗
PubMed1996

Diagnosis and treatment of enterovesical fistula.

The records of 24 patients with enterovesical fistula treated at the urology sections of Telemark and Vestfold Central Hospitals are presented. Most fistulas were due to diverticulitis or a malignant tumor. The part of the intestine most frequently affected was the sigmoid colon in 14 patients, the rectum in 3, the cecum in 2 and the small intestine in 2. Of the 21 patients operated on, 12 underwent a one-stage procedure with resection of the fistula and primary anastomosis of the intestine. The postoperative course was uneventful for 16 patients. Recurrence of the fistula occurred in 1 patient. Three patients were conservatively treated. We recommend a one-stage operation for patients in a good general operating condition, with a well-organized fistula and no systemic infection.

Adult↗
PubMed1996

A template-matching pandemonium recognizes unconstrained handwritten characters with high accuracy.

Psychological data suggest that internal representations such as mental images can be used as templates in visual pattern recognition. But computational studies suggest that traditional template matching is insufficient for high-accuracy recognition of real-life patterns such as handwritten characters. Here we explore a model for visual pattern recognition that combines a template-matching and a feature-analysis approach: Character classification is based on weighted evidence from a number of analyzers (demons), each of which computes the degree of match between the input character and a stored template (a copy of a previously presented character). The template-matching pandemonium was trained to recognize totally unconstrained handwritten digits. With a mean of 37 templates per type of digit, the system has attained a recognition rate of 95.3%, which falls short of human performance by only 2%-3%.

Algorithms↗
PubMed1995

Synthesis and characterization of iodixanol.

Iodixanol (Visipaque) is a new nonionic roentgen contrast medium intended for general use. Visipaque is a pharmaceutical formulation of iodixanol which is isotonic and iso-osmotic with blood. Two synthetic routes from 5-nitro-isophthalic acid to iodixanol are described. The chemical structure is confirmed spectroscopical data ((1)H-NMR, (13)C-NMR, FAB-MS, UV, IR and Raman). Chromotographic characteristics are related to the isomerism of iodixanol.

Chromatography, High Pressure Liquid↗
PubMed1995

Influence of excitatory amino acids and ischemia on rat retinal choline acetyltransferase-containing cells.

PURPOSE: To compare the effects of glutamate agonists and different types of ischemic insult on choline acetyltransferase (ChAT) immunoreactivity in the rat retina. METHODS: Rat retinas were exposed to different glutamate agonists in vivo or in vitro for specific periods of time, and the retinas were then fixed and processed for the localization of ChAT immunoreactivity. In other experiments, rats were administered an ischemic insult either by ligaturing the carotids (two-vessel occlusion [2-VO] procedure), cannulating the anterior chamber, and raising the intraocular pressure (high intraocular pressure [HIOP] procedure) or placing a ligature around the optic nerve sufficiently tightly to prevent blood flow through the central retinal artery (vascular ligation [VL] procedure). The electroretinogram was recorded, and, after a specific period of time, reperfusion was allowed to occur. Thirty to 36 hours after reperfusion, the retinas were dissected and processed for the localization of ChAT, as well as for parvalbumin, Thy-1, and alpha PKC immunoreactivities. RESULTS: Of the glutamate agonists tested, only kainate reduced ChAT immunoreactivity significantly in vivo and in vitro. This effect of kainate could be counteracted by the antagonist CNQX (6-cyano-2,3-dihydroxy-7-nitroquinoxaline-2,3-dione). The ChAT immunoreactivity was unaffected in retinas in which ischemia was induced by the 2-VO procedure. In contrast, ChAT immunoreactivity was obliterated in retinas in which the HIOP was used and drastically reduced when the VL procedure was used. Interestingly, neither alpha PKC nor Thy-1 immunoreactivities were affected in retinas subjected to HIOP or VL methods. However, parvalbumin immunoreactivity was reduced in the HIOP model but only slightly altered in the VL model. CONCLUSIONS: The current results suggest that kainate receptors are associated with the cholinergic retinal neurones in the rat retina. Activation of these receptors by kainate causes a reduction in the neurones' ChAT content. This effect can be mimicked by subjecting the retina to a sufficiently harsh ischemic insult, as occurs in the VL and HIOP procedures. When the ischemic insult is mild, as in the 2-VO procedure, no obvious change in ChAT immunoreactivity is apparent. The HIOP procedure for inducing an ischemic insult was found to be the most severe of the three procedures used, because ChAT immunoreactivity was obliterated and clear changes in the parvalbumin immunoreactivity also were recorded. Interestingly, neither the HIOP nor the VL procedures caused a change in the Thy-1 and alpha PKC immunoreactivities.

Animals↗
PubMed1995

Quantitative analysis of hand radiographs in rheumatoid arthritis: time course of radiographic changes, relation to joint examination measures, and comparison of different scoring methods.

Quantitative studies of hand radiographs in patients with rheumatoid arthritis (RA) indicate that radiographic joint space narrowing and erosion are seen in more than 67% of patients within the 1st 2 years of disease, and progresses most rapidly during the 1st 5 years of disease, according to currently used scoring methods. Radiographic malalignment is rarely seen until after 5 years of disease. In cross sectional studies, correlations of radiographic scores with physical examination scores are minimally significant for joint tenderness, modestly significant for joint swelling, and highly significant for joint deformity and limited motion. In cross sectional studies, 3 quantitative methods, the Steinbrocker radiographic stage, modified Sharp method, and Larsen method, are highly significantly correlated and yield similar results in comparisons with other clinical measures.

Arthritis, Rheumatoid↗
PubMed1993

[Testicular trauma].

We report the cases of four patients with testicular injury following blunt scrotal trauma, and present a system of classification for testicular injuries. One patient had a rupture of tunica albuginea and three had intratesticular haematomas. Two patients were operated on with uneventful postoperative courses. Two patients with intratesticular injury were not explored. Both testes atrophied. We fear that many testes atrophy because of damage caused by pressure of intratesticular bleeding. Qualified surgical evaluation shortly after testicular injuries is of utmost importance for the prognosis.

Adult↗
PubMed1993

[Urinary bladder fistulas].

During the period 1978 to 1991, 19 patients were treated for fistula of the urinary bladder, 12 of the fistulas were enterovesical, four vesicovaginal, one vesicouterine and two vesicocutaneous. Most of them occurred after diverticulitis or operation, or when the patient suffered from a malignant disease. Four patients received conservative treatment. One patient decided against an operation, two were inoperable, and one fistula closed with use of an indwelling catheter. 15 were operated on. 12 extirpations of fistula were carried out. Additional resection of intestine was performed in seven patients and hysterectomia in two patients. Other procedures included two enterostomias and one ileum bladder. In ten patients postoperative courses were uneventful. Four patients died during the first month after operation. One suffered a relapse, and another damage to the nerves of the bladder.

Adult↗