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Biomedical subjects

F Knudsen

Publications and source records attributed to F Knudsen.

At least 19 recordsLinked to original sources
PubMed1997

[Cerebral blood flow and indomethacin. The effect of different doses administered as continuous intravenous infusions or as suppositories in healthy adults].

Administration of indomethacin may aid treatment of intracranial hypertension, and the present study was conducted to determine the optimal dose. In healthy volunteers, cerebral blood flow (CBF) has been shown to decrease considerably after a bolus dose of indomethacin, 0.4 mg/kg, followed by continuous infusion, 0.4 mg/kg/h. This decrease was sustained for 6 h without any evidence of adaptation. In a randomized study in healthy volunteers, indomethacin, 0.1, 0.2 and 0.3 mg/kg, was given as bolus, followed by continuous infusion of 0.1, 0.2 and 0.3 mg/kg/h. CBF decreased from normal levels (52-74 ml/100 mg/min) to 38-51 ml/100 g/min. There were no differences among the three groups in CBF reduction, and the reduction was sustained during the 6-h infusion period. Rectal application of 100 mg indomethacin was found to reduce CBF from normal levels (54-74 ml/100 mg/min) to 33-48 ml/100 mg/min. These low levels were only sustained for 2 h, and values returned to normal over the next 6 h. We observed no rebound phenomenon 2 h after stopping the infusion and no rebound after 100 mg of rectally applied indomethacin. Since a dose as low as 0.1 mg/kg/h is effective, it is possible to treat most patient in a 24-h schedule without going over maximum recommended doses.

Adult↗
PubMed1997

EBV-positive primary central nervous system lymphomas in monozygote twins with common variable immunodeficiency and suspected multiple sclerosis.

Common variable immunodeficiency represents the most frequently occurring primary immunodeficiency disorder and is usually detected sporadically in patients with no family history of immunodeficiency. We present the case stories of two monozygote twins, who following a period of decreasing serum immunoglobulins developed primary central nervous system lymphomas. One twin had clinical and paraclinical features mimicking multiple sclerosis. Immunohistochemical investigations on biopsy tissue showed expression of the bcl-2 and p53 gene products, and Epstein-Barr virus (EBV) encoded small RNA's (EBER) indicating latent infection were detected in lymphoma cells using in situ hybridisation techniques. The pathogenetic role of EBV in oncogenesis is discussed.

Adult↗
PubMed1996

The effect of combined treatment with dextran 40 and acetylsalicylic acid on patency in severely traumatized small veins and arteries: an experimental study in the rabbit.

The effects of pharmacologic intervention on the fates of severely traumatized small veins and arteries have been studied in a rabbit model. Controls were given bolus doses of saline and a group treated with a combination of dextran 40 and acetylsalicylic acid starting prior to traumatization and continuing until postoperative day 5. Relative to controls, bleeding times in the treated group were significantly lengthened in arteries but not in veins, and venous patency significantly improved throughout the interval ending 2 weeks postoperatively. Arterial patency was at first highly improved but by 2 weeks, occlusion was virtually 100 percent. Since some of the occlusions took place more than a week after traumatization, the effects of antithrombotic agents on patency may need to be evaluated over considerably longer time periods than has previously been the rule.

Animals↗
PubMed1996

Effect of graduated intravenous and standard rectal doses of indomethacin on cerebral blood flow in healthy volunteers.

Administration of indomethacin may aid treatment of intracranial hypertension, and the present study was conducted to determine the optimal dose. In healthy volunteers, cerebral blood flow (CBF) has been shown to decrease considerably after a bolus dose of indomethacin, 0.4 mg/kg, followed by continuous infusion, 0.4 mg/kg/h. This decrease was sustained for 6 h without any evidence of adaptation. In a randomized study in healthy volunteers, indomethacin, 0.1, 0.2, and 0.3 mg/kg, was given as bolus, followed by continuous infusion of 0.1, 0.2, and 0.3 mg/kg/h. CBF decreased from normal levels (52-74 ml/100 mg/min) to 38-51 ml/100 g/min. There were no differences among the three groups in CBF reduction, and the reduction was sustained during the 6-h infusion period. Rectal application of 100 mg indomethacin was found to reduce CBF from normal levels (54-74 ml/100 mg/min) to 33-48 ml/100 mg/min. These low levels were only sustained for 2 h, and values returned to normal over the next 6 h. We observed no rebound phenomenon 2 h after stopping the infusion and no rebound after 100 mg of rectally applied indomethacin. Since a dose as low as 0.1 mg/kg/h is effective, it is possible to treat most patients in a 24-h schedule without going over maximum recommended doses.

Administration, Rectal↗
PubMed1995

Effects of the prostacyclin analogue iloprost on patency in small arteries and veins: an experimental study in the rabbit.

Arteriotomy/intimectomy and venotomy/intimectomy were performed in the ears of 43 rabbits. Twenty were treated with iloprost given as intravenous doses of 10 micrograms/kg body weight (bw) administered shortly before reperfusion followed by hourly infusions (3 micrograms/kg b w) until 12 hrs after reperfusion. At reperfusion venous and arterial bleeding times were noted. Patency was determined at 15-min intervals until 2 hrs after reperfusion and at 1 and 2 weeks postoperatively. As controls, 23 rabbits were given a single infusion of saline. Compared to controls, iloprost significantly prolonged arterial and venous bleeding times and significantly improved patency 2 hrs after reperfusion. One and two weeks later, however, virtually all vessels were occluded. Administered in this fashion, iloprost does not improve long-term patency in highly traumatized small veins and arteries.

Animals↗
PubMed1995

Massive vasopressin-resistant polyuria induced by dexamethasone.

A case of severe polyuria elicited by intravenous administration of a normal pharmacological dose of dexamethasone is reported. The polyuria did not respond to treatment with vasopressin. A 15-year-old girl with a brain tumour was referred for surgery. After induction of anaesthesia she received dexamethasone 4 mg i.v., and developed a massive polyuria with hourly diuresis of up to 1250 ml. There was no response to treatment with vasopressin in doses well above those normally used. The patient did not fulfil any known cause of diabetes insipidus, and to our best knowledge, this case is the first with glucocorticoid-induced and vasopressin-resistant polyuria ever reported in man.

Adolescent↗
PubMed1995

The effect of dextran 40 on patency following severe trauma in small arteries and veins.

Arteriotomy/intimectomy and venotomy/intimectomy were performed in the rabbit ear. Low molecular-weight dextran (dextran 40) was infused 2 h before reperfusion and on postoperative days 1, 3 and 5 using a standard clinical protocol. Bleeding-times at reperfusion were recorded and patencies determined at intervals up to 2 weeks. Rabbits given single preoperative bolus doses of saline were used as controls. Dextran significantly prolonged bleeding-times in arteries and significantly improved early patency in both types of vessel, but the enhancements disappear by one week. Dextran 40 infusion thus has little effect on long-term patency.

Animals↗
PubMed1994

[Cerebral arteriovenous malformations. 10 years of therapeutic results].

Results of treatment of 92 supratentorial and 19 infratentorial cerebral arteriovenous malformations from a 10 year period are discussed. The role of interventional embolization is emphasized. The results seems comparable to major international centres. Danish incidence evaluations indicate that it will be possible to gain further experience and thus better results by centralizing the treatment of larger arteriovenous malformations.

Adolescent↗
PubMed1994

Cloning of a new allelic variant of a Saccharomyces diastaticus glucoamylase gene and its introduction into industrial yeasts.

A new allelic variant of the STA2 gene, designated as STA2K, coding for a secreted glucoamylase, was cloned. Differences were revealed both in the structural gene and in the promoter region, as compared to other STA genes. The most peculiar structural features of STA2K are 1. a 1.1-kb natural deletion in its promoter located 189 nucleotides upstream of the translation start codon; and 2. an Asn-->Asp single amino acid change within the putative active site of the encoded glucoamylase. Neither the presence of glucose in the medium nor the host cell's mating type constellation affected the expression level of STA2K in S. cerevisiae. Self-replicating yeast plasmids containing STA2K were constructed and used to transform a laboratory yeast strain and various brewing strains. Pilot brewing tests with glucoamylase-secreting transformants of a brewing strain produced superattenuated beers at accelerated fermentation rates.

Alleles↗
PubMed1993

Hepatitis C in dialysis patients: relationship to blood transfusions, dialysis and liver disease.

Antibodies to hepatitis C virus (anti-HCV) were determined in an unselected group of 340 patients with chronic renal failure treated with maintenance dialysis. A second generation hepatitis C virus (HCV) enzyme-linked immunosorbent assay (ELISA) was used and confirmation made by a second generation recombinant immunoblot assay (RIBA). Sixteen patients (4.7%) were anti-HCV positive and 8 (2.4%) were anti-HCV indeterminate. All anti-HCV positive and anti-HCV indeterminate patients had received blood transfusions. No statistically significant differences were found between anti-HCV positive and indeterminate patients considering blood transfusions, dialysis and liver disease. The combined group of anti-HCV positive and indeterminate patients had had more blood transfusions (P < 0.005) and had been on dialysis for a longer period (P < 0.01) compared with anti-HCV negative patients. Further, significant correlation with elevation of transaminases and anti-HCV was observed (P < 0.001). Thirty patients (8.8%) had elevated transaminase levels and 13 (43%) of these were anti-HCV positive or indeterminate. In conclusion, HCV infection accounts for a substantial proportion of liver disease in dialysis patients, probably most often transmitted by blood transfusions but other routes of transmission could not be excluded.

Adolescent↗