MAGNOLOL DECREASES BODY TEMPERATURE BY REDUCING 5 HYDROXYTRYPTAMINE RELEASE IN THE RAT HYPOTHALAMUS

1. The effects of magnolol, isolated and purified from the cortex of Magnolia officinalis Rehd. et Wils, on thermoregulation and hypothalamic release of 5-hydroxytryptamine (5-HT) by in vivo microdialysis were assessed in normothermic rats and in febrile rats treated with interleukin-1β. 2. Intraperitoneal administration of magnolol (25–100 mg/kg) produced a decrease in colon temperature, an increase in foot skin temperature, a decrease in metabolic rate and a decrease in the endogenous release of 5-HT in the rat hypothalamus. 3. Depletion of rat brain 5-HT, produced by intracerebro-ventricular pretreatment with 5,7-dihydroxytryptamine, attenuated the magnolol-induced hypothermia, cutaneous vasodilation and decreased metabolism. 4. Intracerebroventricular administration of (±)-2,5-dimethoxy-4-iodoamphetamine (a 5-HT₂ receptor agonist; 5–10 μg/5 μL) increased basal colon temperature and reversed the magnolol-induced hypothermia. 5. The increases in both colon temperature and hypothalamic 5-HT release produced by interleukin-1β injection were attenuated by treatment with magnolol. 6. The data suggest that magnolol decreases body temperature (due to increased heat loss and decreased heat production) by reducing 5-HT release in rat hypothalamus.     

Cytosol intermediates in the transport of iron

Three 59Fe-labeled nonheme components of the cytosol were identified when rabbit reticuloyctes were incubated with 59Fe-labeled plasma under conditions in which the iron supply was not limiting. Two of these components were identified as ferritin and transferrin. The latter was characterized by gel filtration as having apparent molecular weight higher than transferrin, indicating that the transferrin may be complexed to another moiety. The third component, referred to as iron- binding protein-I (IBP-I), is as yet uncharacterized. When the reticulocytes were incubated with unlabeled plasma after pulse-labeling with 59Fe-labeled plasma, 59Fe radioactivity in these cytosol components decreased; after 15 min of chase, the 59Fe in ferritin, transferrin, and IBP-I fell to 64.6%, 26.5%, and 65.8% of the initial values, respectively. A good correlation existed between the decrease of 59Fe in these three nonheme compartments and the associated increase in 59Fe-heme. The data presented suggest that cytosol ferritin, transferrin, and IBP-I are intermediates in the transport of 59Fe from the plasma membrane to the mitochondria.     

Antimicrobial activity and enterococcus faecalis biofilm formation on chlorhexidine varnishes

Objective: To evaluate, in vitro, the antimicrobial activity and biofilm formation of three chlorhexidine varnishes in four Enterococcus faecalis strains: E. faecalis ATCC 29212, E. faecalis EF-D1 (from failed endodontic treatment), E. faecalis 072 (cheese) and E. faecalis U-1765 (nosocomial infection), and one Enterococcus durans strain (failed endodontic treatment). Study Design: The direct contact test was used to study the antimicrobial activity. Bacterial suspensions were exposed for one hour to EC40, Cervitec (CE) and Cervitec Plus (CEP) varnishes. “Eradication” was defined as 100% bacterial kill. The formation of enterococci biofilms was tested on the surface of the varnishes after 24 hours of incubation and expressed as percentage of biofilm reduction. Results: EC40 eradicated all strains except E. faecalis ATCC 29212, where 98.78% kill was achieved. CE and CEP showed antimicrobial activity against all the strains, but most clearly against E. durans and E. faecalis 072. EC40 completely inhibited the formation of biofilm of E. faecalis ATCC 29212, E. faecalis 072 and E. durans. CE and CEP led to over 92% of biofilm reduction, except in the case of E. faecalis U-1765 on CEP (76.42%). Conclusion: The three varnishes studied were seen to be effective in killing the tested strains of enterococci and in inhibiting the formation of biofilm, the best results being observed with EC40. Key words:Biofilm, chlorhexidine varnish, direct contact test, Enterococcus durans, Enterococcus faecalis, intracanal medication.     

Guidelines for the management of traumatic dental injuries. I. Fractures and luxations of permanent teeth

Crown fractures and luxations occur most frequently of all dental injuries. An appropriate treatment plan after an injury is important for a good prognosis. Guidelines are useful for delivering the best care possible in an efficient manner. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the current best evidence, based on literature research and professional opinion. In this first article of three, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented.