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Biomedical subjects

P Olsson

Publications and source records attributed to P Olsson.

At least 73 records · Page 4Linked to original sources
PubMed1992

Intravenous nicotine retards transdermal absorption of nicotine: evidence of blood flow--limited percutaneous absorption.

For most drugs delivered by the transdermal route, percutaneous absorption is limited by the rate of release of the drug from the device or by diffusion across the stratum corneum. However, systemic absorption also requires that the drug be taken up by dermal blood vessels. As part of a bioavailability study of a transdermal delivery system, we observed that a concomitant intravenous infusion of nicotine had a marked effect on the absorption kinetics of transdermal nicotine. Plasma concentrations of nicotine rose less rapidly, reached a lower peak, and peaked at a later time, indicating delayed absorption of transdermal nicotine after intravenous nicotine versus after transdermal nicotine administered alone. Nicotine is known to produce cutaneous vasoconstriction. The likely explanation for our observation is that intravenous nicotine constricts dermal blood vessels, thereby limiting percutaneous absorption. Other vasoconstrictor drugs would be expected to retard the absorption of transdermal nicotine and perhaps other transdermal drugs as well.

Administration, Cutaneous↗
PubMed1992

Injection of xenogeneic endocrine pancreatic tissue into the portal vein--effects on coagulation, liver function, and hepatic hemodynamics. A study in the pig-to-dog model.

The safety of injecting discordant xenogeneic fetal endocrine pancreatic tissue into the portal vein was studied in a pig-to-dog system. It was found that minced fetal porcine pancreas and fetal porcine isletlike cell clusters prepared by collagenase digestion and culture could be injected with only minor or no hepatic hemodynamic disturbances. Coagulation studies revealed a small increase in plasma fibrinopeptide A, but this increase could be prevented by heparinization of the recipient. There was no consumption of fibrinogen or platelets. In contrast, injection of minced adult porcine pancreas caused pronounced hepatic hemodynamic changes and marked coagulation abnormalities, indicating consumption coagulopathy. The present finding that fetal porcine pancreas can be injected intraportally without deleterious effects in dogs provides a foundation for the eventual clinical use of such material as treatment for insulin-dependent diabetes mellitus.

Animals↗
PubMed1992

Efficacy of a topical nasal decongestant in different formulations: the effect of viscosity.

Factors affecting the absorption of drugs through the nasal mucosa are increasingly being studied. Dosage form factors, i.e. the viscosity of the excipients, have been claimed to be of importance for enhanced nasal absorption due to prolongation of contact time between drug and mucosa. In the present study, a comparison was made of the effect of a local nasal sympathomimetic when administered intranasally in formulations with different viscosities. Volunteers received the test drugs as nasal sprays in a randomized cross-over design by a rhinomanometric technique, the effect of the drug being recorded for up to 5 h after administration. No significant differences in effects were observed when the test formulations were compared.

Absorption↗
PubMed1992

Surface-heparinized neonatal ECMO circuit--an experimental animal study.

The present experiment examined the capacity of the Carmeda Bioactive Surface to prevent clot formation in an ECMO circuit designed for neonatal use. The Terumo Capiox oxygenator was used in the seven experiments. Mongrel dogs were perfused with veno-arterial bypass at a low flow rate of 200 ml/min. Without any blood heparinization, the circuit was totally occluded within a few hours. With a very low heparin infusion (10 IUxkg -1xh -1) extracorporeal blood flow could be maintained despite some clots forming in the oxygenator. With a small bolus injection of heparin (20 IU/kg) and a low continuous heparin infusion (20 IUxkg -1xh -1) the ECMO circuit showed negligible clotting. With better haemodynamic design of the device in combination with a thrombo-resistant surface, it may be possible to decrease the need for blood heparinization in the neonatal ECMO circuit.

Animals↗
PubMed1992

Treatment of snoring--with and without carbon dioxide laser.

Thirty patients with bedpartners complaining of their heavy snoring which had resulted in separate bedrooms were treated surgically. Three different methods were used, each group consisted of 10 patients. In group A conventional scalpel excision was used for uvulopalatopharyngoplasty including tonsillectomy. In groups B and C, patients with small tonsils were selected and therefore the tonsils were saved. Group B was operated with carbon dioxide laser under a microscope and using micromanipulator. The same kind of excision was used as in group A but the tonsils were saved. Group C was operated as group B but using conventional scalpel excision technique. With a starting-point of snoring score 3 preoperatively in all groups, the mean postoperative snoring score in Group A was 1.0, in Group B 0.2 and in Group C 1.1. Patients with postoperative snoring scores of 0 and 1 were regarded as successful responders to surgery. No serious side effects were noted due to treatment.

Airway Obstruction↗
PubMed1991

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Community Health Services↗
PubMed1991

Heparin cofactor II significance for the inhibition of thrombin at the injured vessel wall.

The thrombin inhibitory role of antithrombin III (ATIII) and heparin cofactor II (HCII) was studied in vitro using intact and injured rabbit aortae. When intact vessels were loaded with thrombin and then exposed to either heat defibrinogenated human plasma (HDHP) or ATIII the same degree of thrombin inhibition was achieved demonstrating that ATIII was the only plasma component involved in thrombin inhibition on the intact vessel wall. When the media of the vessel wall was loaded with thrombin and then exposed to ATIII or HCII a significantly higher thrombin activity remained on the surface than when it was exposed to defibrinogenated plasma. A mixture of ATIII and HCII resulted in a greater inhibition of thrombin than ATIII or HCII alone. It is concluded that, contrary to what happens on the endothelium, HCII and ATIII inhibit additively thrombin on the injured vessel wall. HCII thus plays an essential role for the inhibition of thrombin at the injured vessel wall. It is also concluded that an additional plasma component participates in thrombin inhibition on the media but its contribution is negligible as compared with ATIII or HCII.

Animals↗
PubMed1991

Thrombin-inhibitory capacity of the injured vessel wall.

The present study examined the appearance of thrombin activity in vitro after single and repeated in vivo balloon injury of the rabbit aorta. The in vitro ability of the injured vessel wall to bind and subsequently inhibit thrombin in the presence of defibrinogenated plasma was also assessed. Thrombin activity was assayed by measuring the levels of fibrinopeptide A generated in the presence of fibrinogen. These findings were correlated with the changes observed in light and electron microscopy. Thrombin activity on the vessel wall was increased five minutes and three hours after the initial and the repeated injury, and returned to control values one week after the initial injury. When the inhibition of thrombin was assayed in the presence of defibrinogenated plasma, a diminished inhibition capacity was observed after the repeated injury, which correlated with deposition of fibrin and an enhanced inflammatory reaction as measured by the density of granulocytes covering the injured neointima. Decreased thrombin inhibitory capacity of the injured neointima appears to be linked with its increased thrombogenicity.

Angioplasty, Balloon↗