Sodium hyaluronate (HA) is known to modulate wound healing and interact with inflammatory reactions. High concentrations of extracellular HA are for example correlated to scarless wound healing. Topical treatment with HA has, however, limited effect due to the rapid clearance of HA in the tissue. In an effort to prolong the dissolution rate and enhance the effect of topically administered HA, HA was incorporated in a cross linked fibrin clot and placed in NaCl. The concentration of HA in the NaCl solution was analysed after 30', 60', 4h, 8h, and 24h. It was found that the dissolution rate of HA incorporated in cross linked fibrin was dramatically decreased in vitro, especially when the HA-fibrin mixture was put at rest and not exposed to a mechanical stress. The findings indicate a new possibility for slow release of HA after topical administration.

Animals↗

PubMed1993

Fibrin glue (Tisseel) added with sodium hyaluronate in microvascular anastomosing.

To test the effect on the handling properties of a two component fibrin glue, the viscosity was increased with sodium hyaluronate and the glue was applied to a microvascular anastomosis in rats. The femoral artery of each rat was anastomosed with three conventional sutures and then sealed with fibrin glue. Three glues with different viscosities were tested: original Tisseel fibrin glue (Immuno AG, Vienna); Tisseel with 0.9% sodium chloride added to the fibrinogen component; and Tisseel with a high molecular weight sodium hyaluronate (10 mg/ml, Healon, Pharmacia, Sweden) added to the fibrinogen component. The increased viscosity of the fibrin glue to which hyaluronate had been added resulted in a significantly higher patency rate 20 minutes after completion of the anastomosis (p < 0.01), and reduced the amount of fibrin that entered the vessels.

Anastomosis, Surgical↗

PubMed1992

Dependence of traumatic vasospasm on blood flow in the central artery of the ear in rabbits.

The effect of total obstruction of blood flow on traumatically induced vasospasm was studied in the central arteries of rabbits' ears. All side branches were ligated along a 7 cm segment of the artery. Obstruction of blood flow was achieved by ligation of the central artery distal to this segment. The inner diameter of the artery was measured microscopically after transillumination. A standardised injury was induced with a clip applying forceps. The duration, intensity (reduction of diameter) and severity (integrated change in diameter over time) of the resulting spasm were assessed. Spasm induced after cessation of blood flow lasted significantly less time (mean (SEM), 6.0 (2.0) minutes compared with 18.1 (2.5) min) and was less severe than spasm induced when the blood flow was intact (1.6 (0.6) mm/min compared with 6.2 (0.6) mm/min). The results may be explained by local accumulation of vasodilating substances in the injured segment of the vessel in the absence of blood flow.

Animals↗

PubMed1992

Evolution of pancreatic transplantation in Sweden.

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Humans↗

PubMed1991

Nervous influence on traumatic vasospasm in the rabbit ear artery.

The effects of partial denervation, partial denervation with additional nervous blockade with bupivacaine, and total denervation achieved by amputation and replantation of the ear on traumatic vasospasm were studied in the rabbit. The central ear artery was exposed and compressed in a standardized fashion. The inner diameter was determined by in vivo microscopy using transillumination with cold light. The resulting spasm was assessed in terms of its duration, intensity (reduction of initial diameter), and severity (integrated change in diameter over time). None of the types of denervation had any influence on the vasospasm. The results suggest that the vasospasm is a local phenomenon of the vascular smooth muscle and is not modified by the nervous system.

Alfaxalone Alfadolone Mixture↗

PubMed1991

Modulatory effects of topically administered lidocaine and pentobarbital on traumatic vasospasm in the rabbit ear artery.

The effect of topical administration of 2 or 20% lidocaine and of 3% pentobarbital on traumatic vasospasm was studied in the central ear artery of the rabbit. The inner diameter of the artery was measured by in vivo microscopy. Vasospasm was induced by a standardised pinch of a 3.2 mm long arterial segment and lasted for 10-20 min. The drugs were given locally at maximal spasm, 1 min after spasm induction. All treatments caused prompt resolution of the vasospasm. This was followed by a plateau phase when the vessel diameter was reduced to about 60% of the initial pre-spasm value as a result of drug-induced vasoconstriction. The vasoconstriction lasted between 40 min and 24 h, depending on the treatment. Twenty per cent lidocaine was most effective, but caused thrombosis in microvessels surrounding the central ear artery. It is concluded that topical lidocaine and pentobarbital are both effective in resolving traumatic vasospasm but should only be used after careful consideration, since they also cause a general decrease in vascular diameter.

Animals↗

PubMed1990

An in vivo method for studies of traumatic vasospasm.

A study was undertaken to develop a model for investigations of traumatically induced vasospasm. The left ear of the rabbit was denervated under short anesthesia. With the animal under light sedation, spasm of the central ear artery was repeatedly induced with a clip applying forceps. To evaluate the vasospasm, the vessel was transilluminated with cold light, and the internal diameter was continuously measured. The spasm was assessed in terms of its duration, intensity (reduction of initial diameter) and severity (integrated change in diameter over time). Repetitive application of the forceps on the same vessel segment shortened the spasm duration. With prolonged pinch duration, the spasm duration was lengthened. The preparation was stable for at least 3 hours. This model was effective for manipulating small vessels and producing spasm and is of potential value for studying the treatment of vasospasm by topical local intra-arterial and systemic methods.

Animals↗