Vascular and cellular responses to guanidino propyl piperazine CK0569A, a new anti-plaque agent.

Guanidino propyl piperazine CK0569A (abbreviation piperazine) used as a 0.1% mouthrinse has been shown to be effective against plaque bacteria. In addition to its efficacy as an antibacterial agent, its safety should be taken into consideration. In this study the effect of piperazine on the microcirculation of the hamster cheek pouch was studied. The effect of this drug was also investigated on rat leukocytes in vivo and on macrophages and erythrocytes in vitro. Piperazine caused a distinct retardation in the microcirculation of the hamster cheeck pouch even at a low concentration (0.01%), but the effect was abolished in 5 min. The number of leukocytes decreased markedly in the experimentally induced inflammatory exudate in the presence of 0.05% piperazine as compared to the controls. The macrophages in vitro released their lysosomal and cytoplasmic enzymes and lost their viability. The erythrocytes in vitro were destroyed in the presence of 0.005% piperazine as well. Based on these results it can be suggested that 0.005-0.05% piperazine under experimental conditions causes changes that indicate loss of cell viability.

Antithrombotic effects of lidocaine and related compounds on laser-induced microvascular injury.

The aim was to study whether topically applied local anaesthetics and related compounds exert an antithrombotic effect. The assay was carried out through vital microscopy of the microcirculation in the hamster cheek pouch model as injured by laser microbeam irradiation, essentially in order to record the differences in the incidence of thrombus formation between two main experimental and control series. The application of lidocaine hydrochloride was found to inhibit thrombus formation and also to restore the microcirculation after laser-induced injury. The other investigated compounds, mono-ethyl-glycinexylidide, tocainide and bupivacaine were found to be less active with regard to inhibition of thrombus formation and flow restitution effects. It is concluded that an antithrombotic effect may be attributed to lidocaine in particular.

Effect of chlorhexidine on the hamster cheek pouch. Microcirculation and penetration studies.

The application of chlorhexidine gluconate on the intact cheek pouch of hamsters led to an immediate increase of flow velocity determined in venules beneath the epithelium. The application of [14C]chlorhexidine on the intact cheek pouch led to accumulation of labeled material in the liver and kidneys. Both findings indicate that penetration of the drug occurred through the epithelium of the cheek pouch.

Differences in the osteoinductive potential of transplanted isogeneic dental structures of the rat.

Pulp tissue, enamel and incisal and basal dentine of the mandibular incisor were taken from one litter of rats and transplanted subcutaneously or intracerebrally to sex-matched, 5-day-old animals of the subsequent litter of the same parents. As sham-operations the mere transplantation instrument was inserted into the transplantation sites. With some exceptions, the host animals were killed 4, 32, 128-138 and 210 days after the operation and the transplantation sites were examined either grossly or microscopically or both. The pulp tissue transplantation had resulted in formation of osseous tissue observed 128 days post-operatively. Bone was found in association with many of the basal dentine transplants 128-210 days after their insertion whereas no such tissue was observed with the transplanted enamel of incisal dentine. The sham-operation seemed to have elicited intracerebral bone formation in two animals. The osteoinductive activity of the transplanted tissues seemed reduced by their mineral phase. Further, in contrast to demineralized hard tissues, the non-demineralized inductive agents do not seem to possess bone morphogenetic properties.