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Biomedical subjects

K S Nielsen

Publications and source records attributed to K S Nielsen.

16 recordsLinked to original sources
PubMed2000

[Circulatory support with the mechanical heart, "HeartMate"].

Treatment with the mechanical heart, HeartMate, has been introduced in Denmark. Short-term circulatory support can be obtained by intraaortic balloon counterpulsation, an external centrifugal pump and the total artificial heart. Long-term circulatory support can be established by treatment with the HeartMate. The principle of the mechanical heart is simple--a pump is implanted in parallel to the existing heart and connected to external, portable batteries. The patient quickly improves and is brought in an optimal state for transplantation. A few patients have been able to omit the subsequent heart transplantation. The patient's own heart improved during the treatment and the native heart functioned again after the system was explanted. The main complications during treatment are bleeding, infection, thromboembolic events and systemic failure. Permanent, fully implantable mechanical circulatory pumps are under development--which may herald the beginning of a whole new era for treatment of cardiac failure.

Assisted Circulation↗
PubMed2000

[Economic aspects of implementation of the mechanical heart, "HeartMate"].

This economic evaluation was performed to assess the economic consequences for society and for the Danish health care sector of replacing the traditional treatment with Biomedicus assist device with The Mechanical Heart, HeartMate, as a bridge to transplantation for patients with severe cardiac failure. A cost-effectiveness analysis showed that the use of HeartMate is more cost-effective than the use of Biomedicus assist device. Using HeartMate one life-year gained costs DKK 225,000. Using Biomedicus one life-year gained costs DKK 270,000. The use of HeartMate results in an additional expenditure of DKK 615,000 per patient. By this additional expenditure the patients gain 3.6 extra life-years on average. The marginal expenditure by replacing the Biomedicus treatment with HeartMate is DKK 170,000 per extra life-year gained.

Cost-Benefit Analysis↗
PubMed2000

Treatment of femoral shaft fractures with Grosse-Kempf intramedullary nail.

Ninety consecutive femoral shaft fractures in 87 patients treated by reamed Grosse-Kempf intramedullary nailing were reviewed. The median observation time was 45 months. The functional results were excellent or good in 82% of the fractures, fair in 16%, and poor in 2%. Four non-unions and two superficial infections were observed. Leg shortening of more than 2 cm was recorded in 2 patients. Rotatory malalignment exceeded more than 15 degrees in 2 patients. We conclude that reamed Grosse-Kempf intramedullary nailing is an excellent treatment for femoral shaft fractures. Although this study represents the first period during which we used the nail, the number of complications was acceptable.

Adolescent↗
PubMed1998

Effects of piracetam on the performance of rats in a delayed match-to-position task.

1. The influence of acute and chronic treatment with piracetam on spatial working memory of rats was examined. A new version of an operant chamber "delayed match-to-position task" was used, in which the animals had to visit one randomly baited box out of three boxes ("choice boxes") in a front panel. Hereafter a delay period began, in which the subjects had to visit an alcove in the back panel ("reference box"). At the end of the delay the animals should return to the front panel and choose the same choice box that was baited before the delay, thereby obtaining a reward. 2. Rats were trained to a stable level of performance, measured as per cent correct responses during sessions of 20 trials. Additionally, the time spent between leaving the choice box and entering the reference box was recorded. Results were obtained from a single group of rats tested repeatedly under different experimental conditions. 3. Injections of scopolamine (0.6 mg/kg) significantly reduced the percentage of correct choices and increased the time spent to reach the reference box. The impairment of correct choices was reversed after chronic treatment with piracetam (250 mg/kg). However, the same treatment did not reverse the effect of scopolamine on the time performance. 4. Scopolamine also induced an increase of repetitive errors (a measure of perseverance), and the chronic treatment with piracetam caused full reversal of this increase. These results represent the first observation of a piracetam induced reversal of scopolamine impairments in a working memory test. 5. In normal animals not treated with scopolamine, acute injection of piracetam had no effect compared to saline injected controls, but chronic treatment with the nootropic significantly enhanced working memory performance. The drug did not affect the time used to reach the reference box.

Animals↗
PubMed1997

Class I mGlu receptor antagonist 1-aminoindan-1,5-dicarboxylic acid blocks contextual but not cue conditioning in rats.

It is widely believed that metabotropic glutamate (mGlu) receptors play a potential role in memory formation. However, the particular function of different classes of mGluRs, or even subtypes, remains elusive. We show here that intraperitoneal injection of the class I selective antagonist 1-aminoindan-1,5-dicarboxylic acid (AIDA) in concentrations of 0.18 or 1.8 mg/kg 25 min prior to acquisition training blocks hippocampus-dependent contextual, but not hippocampus-independent cue, conditioning in rats. These data provide the first evidence for a specific role of mGlu receptors, class I in particular, in hippocampus-dependent learning tasks.

Acoustic Stimulation↗
PubMed1995

On-line monitoring of ethanol, acetaldehyde and glycerol during industrial fermentations with Saccharomyces cerevisiae.

Industrial fermentations carried out in a 500-l bioreactor were monitored on-line by a prototype of a split-flow modified thermal biosensor. Acetaldehyde and glycerol in the extracellular broth were monitored over the first 48 h of fed-batch fermentations. The aim was to determine the usefulness of these secondary metabolites for on-line monitoring and control. When fermentation of the 13-16 g/l batch sugar was monitored, using immobilised aldehyde dehydrogenase, the acetaldehyde reached a peak value of 0.3 g/l. With immobilised alcohol oxidase a much larger peak of 3.5 g/l ethanol was seen immediately after the acetaldehyde peak. When glycerokinase was used a delayed peak of 1 g/l glycerol was monitored. Of the three metabolites monitored, the ethanol proved the most valuable indicator of suitable timing for the start of the feeding phase and later for controlling and preventing overfeed using the on-line biosensor system.

Acetaldehyde↗
PubMed1991

Effect of thyroxine therapy on bone metabolism in substituted hypothyroid patients with normal or suppressed levels of TSH.

The statement that pituitary hyperthyroidism reflects peripheral hyperthyroidism is still controversial. To evaluate a possible relationship between the calcium and the thyroid metabolism, 29 women with thyroxine (T4) substituted hypothyroidism were examined. They were separated into two groups, one with normal (0.15 to 6 mU/l) and one with suppressed TSH (less than 0.15 mU/l). All the women were judged euthyroid both by their T4 and T3 and by their clinics. The daily dose of T4 (median 0.15 mg in both groups) had been unchanged and TSH level had been stable during the previous six months. Bone mineral content (BMC) of the lumbar spine, bone mineral density (BMD) of left and right collum femoris, serum alkaline phosphatase activity (AP), serum concentration of osteocalcin (Ost) and urinary excretion of hydroxyproline/creatine (Hpr/crea) were similar in the two groups. Furthermore, sex- hormone-binding-globulin (SHBG) was equal in the two groups, but significantly higher than in normals (p less than 0.01). A significant positive correlation was found between serum Ost and Hpr/crea (p less than 0.05) indicating a balanced state where bone formation equals bone resorption. AP failed to correlate to Ost and Hpr/crea because the AP raises from both bone and liver of bone and liver metabolism whereas the two others predominantly reflect bone metabolism. SHBG, being a marker of liver metabolism, was elevated in both groups, probably because of the oral administration of T4. Our data suggest that euthyroid, T4 substituted patients have a normal calcium metabolism whether TSH levels are suppressed or not.

Aged↗
PubMed1979

The effect of repeated intramuscular gonadotrophin-releasing hormone injections on luteinizing hormone, follicle-stimulating hormone, testosterone, oestrogens, dehydroepiandrosterone and dehydroepiandrosterone sulfate in normal men.

The endocrine response to three daily intramuscular injections of 500 microgram LH-RH was measured in 9 normal men during a period of 3 days. A marked but declining response in LH was seen in addition to a significant increase in the serum concentration of FSH, testosterone, oestradiol and the urinary excretion of oestrogenic substances. No change could be demonstrated in the DHA, DHAS or cortisol secretion which confirms our previous results of a direct effect of clomiphene on adrenal steroidogenesis.

Adrenal Cortex↗