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Biomedical subjects

R Nielsen

Publications and source records attributed to R Nielsen.

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

[Recurrence of inguinal hernia: ambulatory surgery under local anesthesia].

In order to assess the feasibility of repair of a recurrent inguinal hernia in unmonitored local anaesthesia in an ambulatory set-up pain scores and data on patient satisfaction were obtained from 76 unselected patients after 79 consecutive operations. Median age was 63 years, and 25%- and 75% quartiles were 49 and 72 years respectively. All operations were conducted in local anesthesia. Three patients stayed in hospital overnight after the operation. Pain: After one, six and 28 days 27, 14 og 7% respectively had severe pain during function (cough and/or rising). Satisfaction: 82% were satisfied with ambulatory surgery in local anaesthesia, 82% were satisfied with the analgesic therapy (tenoxicam and methadone), but one third needed supplementary analgesics during the first week (acetaminophen was recommended). It is concluded, that ambulatory repair of a recurrent inguinal hernia in unmonitored local anaesthesia is a safe and cost effective alternative to operation in general or spinal anaesthesia.

Aged↗
PubMed1996

Comparison of virulence of different Actinobacillus pleuropneumoniae serotypes and biotypes using an aerosol infection model.

An aerosol infection model for inoculation of pigs with Actinobacillus pleuropneumoniae is described. With this model the virulence of three A. pleuropneumoniae biotype 1 strains representing serotypes 2, 5b and 6, and one Danish biotype 2 were compared using 13-week-old pigs for inoculation. The pigs were sacrificed 24 h after aerosol exposure and lung lesions were evaluated. In pigs exposed to aerosols of suspensions containing 10(4) CFU/ml of serotypes 2, 5b and 6, a number of 5-10 lesions of haemorrhagic necrotizing pneumonia were induced. For the biotype 2 strain the dose creating similar lesions was 10(9) CFU/ml. Repeated experiments confirmed these results showing similar virulence of serotypes 2, 5b and 6 whereas the biotype 2 strain proved less virulent. The aerosol infection model allowed a comparison of the number of A. pleuropneumoniae CFU/liter air which were necessary to induce lung lesions in susceptible pigs. This indicates that the model will be well suited for virulence studies of A. pleuropneumoniae serotypes in pigs.

Actinobacillus Infections↗
PubMed1996

Prostaglandin E2 inhibits antidiuretic hormone induced transepithelial sodium transport and cAMP production in frog skin epithelium (Rana esculenta).

The stimulation of transepithelial sodium transport by arginine vasotocin (AVT) and the ability of prostaglandin E2 (PGE2) to inhibit the AVT dependent sodium transport was examined on pieces of frog skin taken from different regions of the frog. The basal sodium transport was of the same magnitude in the abdominal, thoracal and upper and lower dorsal region. In all regions the sodium transport could be stimulated by AVT, though the stimulation was highest in the abdomen. Subsequent addition of PGE2 caused a significant inhibition of the AVT dependent sodium transport in the abdomen but had only minor effects on the other parts of the skin. Therefore, pieces of skin from the abdomen were selected for the remaining experiments. Addition of PGE2 to skin pieces in the presence of AVT resulted in a hyperpolarization of the cellular potential and a decrease in the transepithelial sodium transport, indicating a decreased apical sodium permeability. This was correlated with a decrease in cellular cAMP contents. We conclude that frog skin exhibits large regional differences in sensitivity to AVT and that PGE2 only modulates the natriferic effect of AVT in the abdomen.

Animals↗
PubMed1996

Toombak-associated oral mucosal lesions in Sudanese show a low prevalence of epithelial dysplasia.

Clinical (n = 281) and histopathological (n = 141) characteristics of toombak-associated oral mucosal lesions detected in an epidemiological study in northern Sudan in 1992/93 are described. The lesional site in the majority of toombak users was the anterior lower labial groove and the lower labial mucosa. 4 degrees (1-4) of clinical severity of lesions, similar to those used to characterise Swedish snuff-dipper's lesion, were applied. An association between the severity of mucosal lesions and a longer lifetime duration (> 10 years) of toombak use was found, but the severity was not related to the daily frequency of the habit. Parakeratosis, pale surface staining of the epithelium and basal cell hyperplasia were commonly observed, but epithelial dysplasia was infrequent (10/141). The most significant observation was a PAS-positive amorphous deposit between the lamina propria and the submucosa, found in 25/141 biopsies. The clinical and histopathological features of toombak lesions are closely similar to Swedish moist snuff-dipper's lesions and this may reflect the high alkalinity of these products, resulting in an alkaline burn on the oral mucosa following chronic exposure. The low prevalence of epithelial dysplasia implies a low risk of malignant transformation. Nevertheless, the high concentrations of tobacco-specific nitrosamines present in toombak, and the high prevalence of oral cancer in Sudan, mandate biopsy and careful histopathological analysis of any such lesions detected in habitues.

Adolescent↗
PubMed1996

The symptomatic outcome of transurethral prostatectomy evaluated with the DAN-PSS-1 score system.

We assessed the symptomatic outcome of transurethral prostatectomy with the newly developed self-administered questionnaire, Danish Prostate Symptom Score (DAN-PSS-1), in men suffering from uncomplicated benign prostatic hyperplasia (BPH). The questionnaire was filled in adequately by 53 men, median age 69 (range 52-82), preoperatively and 2, 4 and 6 months after transurethral prostatectomy (TUR-P). The DAN-PSS-1 symptom score showed a high degree of sensitivity as the preoperative total score was median 20 (quartiles 14-36) and decreased to 4, 0 and 1 (quartiles from 0-4) at the 2, 4, and 6-month control respectively. The symptoms related to voiding were relieved totally after 2 months while symptoms related to storage were first relieved completely at 4-month control. Bother from symptoms was relieved after 2 months, although some symptoms still remained. The questionnaire was internally consistent with a reliability coefficient, Cronbach's alpha (alphaCr), of 0.73. We conclude that the DAN-PSS-1 questionnaire is an efficient tool among others in the indication and evaluation of treatment of uncomplicated BPH.

Aged↗
PubMed1996

Serological characterization of Actinobacillus pleuropneumoniae biotype 1 strains antigenically related to both serotypes 2 and 7.

Nine Danish Actinobacillus pleuropneumoniae biotype 1 isolates were shown by latex agglutination and indirect haemagglutination to possess capsular polysaccharide epitopes identical to those of serotype 2 strain 1536 (reference strain of serotype 2) and strain 4226 (Danish serotype 2 strain). Immunodiffusion confirmed the antigenic relationship with serotype 2 and further demonstrated an antigenic relationship with strain WF83 (reference strain of serotype 7). SDS-PAGE with LPS from strains 1536, 4226, WF83 and strain 7317 (representative of the 9 isolates examined) showed that strains WF83 and 7317 had an identical smooth ladder pattern whereas LPS from strains 1536 and 4226 showed a distinctly different pattern. The antigenic similarities of the LPS of strains WF83 and 7317 were confirmed by immunoblots using rabbit or pig antisera prepared against the 3 strains. No antigenic similarities in the LPS of strains 1536 and 7317 were revealed. Since an antigenic determinant specific for the 9 isolates could not be demonstrated with the methods used, the strains are proposed to be designated K2:O7.

Actinobacillus Infections↗
PubMed1995

Detection of antibodies against Actinobacillus pleuropneumoniae, serotype 2 in porcine colostrum using a blocking enzyme-linked immunosorbent assay specific for serotype 2.

A blocking enzyme-linked immunosorbent assay (ELISA) developed for detection of antibodies to Actinobacillus pleuropneumoniae serotype 2 in sera from pigs (Nielsen et al., 1991) was evaluated for its suitability to detect antibodies in colostrum to this serotype. Using colostrum from sows experimentally infected with serotype 2 and from herds known to be infected with this serotype, the sensitivity of the test was 100%. Antibodies to A. pleuropneumoniae serotype 2 could be detected in colostrum of experimentally infected sows until at least 5 days after farrowing. Positive results were not observed with colostrum samples from herds known to be free from A. pleuropneumoniae. The high diagnostic sensitivity and specificity of the assay indicated that screening of herds for A. pleuropneumoniae serotype 2 infection by testing colostrum would be a reliable and simple method for herd monitoring.

Actinobacillus pleuropneumoniae↗
PubMed1995

The impact of activity level on sweat accumulation and thermal comfort using different underwear.

The purpose of this study was to investigate the significance of work level and sweat production for the total amount accumulated and the location of the sweat in a three-layer ensemble as a function of material and textile construction. Furthermore, it was also an aim to investigate how this influenced thermoregulatory responses and thermal comfort during work and during a rest period. Long-legged/long-sleeved underwear manufactured from two different 100% fibre-type materials, polypropylene and wool, was tested as part of a three-layer clothing system. The underwear manufactured from 100% polypropylene was tested in two different knit constructions, a 1-by-1 rib knit and a fishnet structure, and the woollen underwear in a 1-by-1 rib knit construction. The test was performed on eight male subjects (Ta = 10 degrees C, RH = 85%, Va < 0.1 m/s), and comprised a twice-repeated bout of 40-min cycle exercise followed by 20 min rest. Each subject conducted two tests with the work level approximating 30% VO2 max and 40% VO2 max, respectively. Skin temperatures, rectal temperature, weight loss and humidity near the skin were recorded during the test. Total changes in body and clothing weight were measured separately. Furthermore, subjective ratings on thermal comfort and on sensation of temperature and humidity were collected. The results demonstrated that high heat and sweat production during work periods, leading to increased sweat accumulation, will give higher thermal discomfort ratings for rest periods as well as for work periods compared to intermittent work with lower work intensities. Distribution of accumulated sweat in the clothing ensemble after heavy sweating is dependent on the fibre type in the underwear. Further, it can be concluded that underwear construction clearly has an influence on the evaporation rate in a three-layer ensemble during work at a high activity level.

Adult↗
PubMed1995

Prostaglandin E2 release from dermis regulates sodium permeability of frog skin epithelium.

In the present study we have compared the effects of increased intracellular Ca2+ in whole frog skin and isolated epithelium (Rana temporaria). Cellular Ca2+ was increased by the use of the endoplasmic reticulum Ca2+ ATPase inhibitor, thapsigargin. Serosal addition of thapsigargin to the whole frog skin increased the Na+ transport by increasing the apical Na+ permeability. This could be blocked by the addition of indomethacin or by removal of Ca2+ from the serosal solution. The increase in Na+ transport was accompanied by an increased prostaglandin E2 release. This indicated that the response in Na+ transport was due to a Ca2+ dependent activation of the prostaglandin E2 synthesis. Addition of thapsigargin to isolated epithelia inhibited the Na+ transport and had no effect on the prostaglandin E2 release, though the prostaglandin E2 release from the isolated epithelia could be increased by the addition of arachidonic acid. Addition of prostaglandin E2 increased the cAMP contents of the isolated epithelia significantly, whereas thapsigargin had no significant effect on the cAMP level. Our results demonstrate that serosal addition of thapsigargin causes a release of prostaglandin E2 from the dermis below the transporting epithelium. The prostaglandin E2 diffuses to the epithelium where it activates the Na+ transport by increasing cellular cAMP. The epithelium itself does not contribute significantly to the prostaglandin E2 synthesis. Furthermore an increase in intracellular Ca2+ in the epithelial cells without a concomitant increase in prostaglandin E2 release leads to an inhibition of the active Na(+)-transport.

Amiloride↗
PubMed1995

Correlation between chloride flux via the mitochondria-rich cells and transepithelial water movement in isolated frog skin (Rana esculenta).

The coupling between net transepithelial Cl- influx and net water flow was investigated. Experiments were performed on isolated frog skin bathed in isotonic Cl- Ringer's solution in the presence of the Na+ channel blocking agent amiloride in the mucosal solution. The skins were voltage-clamped at -80 or -100 mV (with the serosal solution as reference). Under these conditions the current across the skin is carried by an influx of Cl-. In the absence of antidiuretic hormone the correlation between current and net water flow was low, but in the presence of the antidiuretic hormone, arginine vasotocin, there was a highly significant correlation between current and net water flow. The data presented here indicate that under steady state conditions about 70 molecules of water follow each Cl- ion across the skin. If the water influx is driven by electroosmosis one would expect that a change in current should result in an immediate change in the water flow. There was, however, a considerable time delay between the change in current and water flow. This indicates that the observed coupling between Cl- flux and water flow is caused by current-induced local osmosis and not electroosmosis.

Amiloride↗
PubMed1994

Intracellular calcium modulates basolateral K(+)-permeability in frog skin epithelium.

Cytosolic calcium ([Ca2+]i) has been suggested as a key modulator in the regulation of active sodium transport across electrically "tight" (high resistance) epithelia. In this study we investigated the effects of calcium on cellular electrophysiological parameters in a classical model tissue, the frog skin. [Ca2+]i was measured with fura-2 in an epifluorescence microscope setup. An inhibition of basolateral potassium permeability was observed when cytosolic calcium was increased. This inhibition was reversible upon removal of calcium from the serosal solution.

Animals↗
PubMed1994

Impact of wet underwear on thermoregulatory responses and thermal comfort in the cold.

The purpose of this study was to investigate the significance of wet underwear and to compare any influence of fibre-type material and textile construction of underwear on thermoregulatory responses and thermal comfort of humans during rest in the cold. Long-legged/long-sleeved underwear manufactured from 100% polypropylene in a 1-by-1 rib knit structure was tested dry and wet as part of a two-layer clothing system. In addition cotton (1-by-1 rib knit), wool (1-by-1 rib knit), polypropylene (fishnet), and a double-layer material manufactured from 47% wool and 53% polypropylene (interlock knit) was tested wet in the clothing system. In the wet condition 175 g of water was distributed in the underwear prior to the experiment. The test was done on eight men (T(a) = 10 degrees C, RH = 85%, V(a) < 0.1 m/s), and comprised a 60 min resting period. Skin temperature, rectal temperature, and weight loss were recorded during the test. Total changes in body and clothing weight were measured separately. Furthermore, subjective ratings on thermal comfort and sensation were collected. The tests demonstrated the significant cooling effect of wet underwear on thermoregulatory responses and thermal comfort. Further, the tests showed that textile construction of underwear in a two-layer clothing ensemble has an effect on the evaporation rate from clothing during rest in the cold resulting in a significant difference in mean skin temperature. The thickness of the underwear has more of an influence on the thermoregulatory responses and thermal comfort, than the types of fibres tested.

Adult↗
PubMed1994

RTX toxin genotypes and phenotypes in Actinobacillus pleuropneumoniae field strains.

Actinobacillus pleuropneumoniae serotype reference strains and 204 A. pleuropneumoniae field strains representing all 12 serotypes and both biovars 1 and 2, obtained from laboratories from various countries worldwide, were analyzed for the presence of the toxin genes apxIC, apxIA, apxIB, apxID, apxIIC, apxIIA, apxIIIC, apxIIIA, apxIIIB, and apxIIID by DNA-DNA hybridization with specific gene probes. Expression of the toxins ApxI, ApxII, and ApxIII was assessed by immunoblot analysis with monoclonal antibodies. The results show that the patterns of apx genes and those of the expressed Apx toxins in biovar 1 field strains are the same as those of the genes and toxins of corresponding serotype reference strain. We found only three strains which had certain apx genes missing compared with the genes in their serotype reference strains. Analysis of the expression of the three toxins showed that nearly all strains expressed their apx genes and produced the same Apx toxins as their serotype reference strain. We found only one strain that did not produce ApxI, although it contained the apxICABD genes, and one strain which did not express ApxII but which contained apxIICA. Several field strains which initially showed that their serotype did not correspond to the apx gene profile of the reference strain and which had an unexpected virulence for the given serotype revealed that their initial serotyping was erroneous. We show that the apx gene profiles are inherent to a given serotype. The method cannot differentiate between all 12 serotypes. However, it allowed us to distinguish five groups of toxin gene patterns which showed pathological, toxicological, and epidemiological significance. None of the biovar 2 strains contained apxIII genes. The apxI and apxII genes in the biovar 2 strains, however, were the same as those found in the serotype reference strains of biovar 1.

Actinobacillus pleuropneumoniae↗
PubMed1994

EMLA-induced analgesia inferior to lignocaine infiltration in curettage of common warts--a randomized study.

The analgesic effect of topical application of EMLA cream for the curettage verrucae vulgaris was compared to local infiltration with lignocaine in 89 patients. The main purpose of this randomized study was to evaluate the patients' overall impression of the treatment. All patients anaesthetized by lignocaine infiltration reported it as 'an acceptable procedure' compared to only 71% of the patients treated with EMLA. It cannot be recommended to use EMLA cream as local anaesthetic for curettage of verrucae vulgaris, presumably because the highly keratotic nature of the common warts does not allow sufficient penetration of epicutaneously applied EMLA.

Adolescent↗
PubMed1994

"Which sweater to choose in the cold: knitted or fleece".

The aim of the present study was to investigate the influence of two common wool sweaters in a clothing ensemble on sweat production, sweat accumulation and sweat distribution in the clothing ensemble, as well as on other thermoregulatory responses together with comfort of man. A further aim was to investigate the influence of the two different sweaters on the temperature and the humidity gradient through the clothing ensemble in order to describe the different avenues and forms of heat exchange. Thick woolen middle layer sweaters manufactured in two different constructions, fleece and knitted, were tested as part of a 3-layer clothing system. The test was performed on eight male subjects (Ta = 10 degrees C, RH = 85%, Va < 0.1 m/s), and comprised a twice repeated bout of 40-min cycle exercise followed by 20 min rest. Skin temperatures, rectal temperature, weight loss and humidity near the skin and in the clothing layers were recorded during the test. Total changes in body and clothing weight were measured separately. Furthermore, subjective ratings on thermal comfort and on sensation of temperature and humidity were collected. The results demonstrated that there were no significant physiological and subjective differences when the two sweaters were worn, apart from higher sweat production and accumulation when the knitted sweater was used. It is assumed that this is a result of a larger thickness rather than different construction. Choosing the knitted sweater or the fleece wool sweater for work in an ambient temperature of 10 degrees C will be of minimal significance in practice. However, a sweater with more sweat accumulated will be heavier and this reduces the air layer between the garments, decreasing the clothing ensemble's insulation value.

Adult↗
PubMed1993

Small transepithelial osmotic gradients affect apical sodium permeability in frog skin.

The aim of the present study was to investigate the effects of small, unilateral changes in solution osmolarity on active sodium transport and cellular electrophysiological parameters in frog skin. The active sodium transport across the skin was measured as the amiloride-sensitive short-circuit current (Isc) and cellular potential was monitored with microelectrodes, while small (+/- 20 mOsm) osmotic gradients were imposed on the skin. Increasing the osmolarity of the apical bathing solution (or decreasing the osmolarity of the basolateral solution) increased ISC, lowered tissue resistance (R), depolarized the cellular potential and decreased the fractional resistance of the apical membrane, which indicates an increased apical sodium permeability. Conversely, a similar increase in basolateral osmolarity (or a decrease in apical osmolarity) lowered the Isc, increased R, hyperpolarized the cells and increased the fractional resistance of the apical membrane, indicating a decrease in apical sodium permeability. The results indicate that the osmotic gradient across the skin, rather than solution osmolarity as such, is responsible for the observed changes in Isc and apical sodium permeability after small osmotic perturbations.

Amiloride↗