Enhanced osteocalcin expression by osteoblast-like cells (MC3T3-E1) exposed to bioactive coating glass (SiO2-CaO-P2O5-MgO-K2O-Na2O system) ions.

This study tested the hypothesis that bioactive coating glass (SiO(2)-CaO-P(2)O(5)-MgO-K(2)O-Na(2)O system), used for implant coatings, enhanced the induction of collagen type 1 synthesis and in turn enhanced the expression of downstream markers alkaline phosphatase, Runx2 and osteocalcin during osteoblast differentiation. The ions from experimental bioactive glass (6P53-b) and commercial Bioglass(TM) (45S5) were added to osteoblast-like MC3T3-E1 subclone 4 cultures as a supplemented ion extract (glass conditioned medium (GCM)). Ion extracts contained significantly higher concentrations of Si and Ca (Si, 47.9+/-10.4 ppm; Ca, 69.8+/-14.0 for 45S5; Si, 33.4+/-3.8 ppm; Ca, 57.1+/-2.8 ppm for 6P53-b) compared with the control extract (Si<0.1 ppm, Ca 49.0 ppm in alpha-MEM) (ANOVA, p<0.05). Cell proliferation rate was enhanced (1.5x control) within the first 3 days after adding 45S5 and 6P53-b GCM. MC3T3-E1 subclone 4 cultures were then studied for their response to the addition of test media (GCM and control medium along with ascorbic acid (AA; 50 ppm)). Each GCM+AA treatment enhanced collagen type 1 synthesis as observed in both gene expression results (day 1, Col1alpha1, 45S5 GCM+AA: 3x control+AA; 6P53-b GCM+AA: 4x control+AA; day 5, Col1alpha2, 45S5 GCM+AA: 3.15x control+AA; 6P53-b GCM+AA: 2.35x control+AA) and in histological studies (Picrosirius stain) throughout the time course of early differentiation. Continued addition of each GCM and AA treatment led to enhanced expression of alkaline phosphatase (1.4x control+AA after 5 days, 2x control+AA after 10 days), Runx2 (2x control+AA after 7 days) and osteocalcin gene (day 3, 45S5 GCM+AA: 14x control+AA; day 5, 6P53-b GCM+AA: 19x control+AA) and protein expression (40x-70x control+AA after 6 days). These results indicated the enhanced effect of bioactive glass ions on key osteogenic markers important for the bone healing process.

Screening of plant extracts for antiprotozoal and cytotoxic activities.

Methanolic and aqueous extracts derived from 43 plant species, selected either from ethnobotanical or chemotaxonomical data, were screened for their antiprotozoal activity against Leishmania donovani and Trypanosoma brucei brucei. The cytotoxic activity against KB cells was also determined. Eight extracts had IC50 values of less than 10 microg/ml against Leishmania donovani. The most active was Triclisia patens with an IC50 value of 1.5 microg/ml against Leishmania donovani. Annona purpurea and Alstonia macrophylla had IC50 values below 10 microg/ml against Trypanosoma brucei brucei. Annona purpurea was the most cytotoxic against KB cells.

Antiplasmodial and antiamoebic activities of medicinal plants from Sierra Leone.

Crude ethanol extracts of 18 medicinal plants from Sierra Leone, West Africa were examined for antiplasmodial activity against Plasmodium falciparum, using an in vitro microtest. Eleven of these extracts were also screened for in vitro antiamoebic activity against Entamoeba histolytica. Only one plant extract, Triclisia patens (Menispermaceae) showed significant antiplasmodial activity (IC(50) = 8 microg/mL). None of the plant extracts was effective against Entamoeba histolytica.

Chiropractic and osteopathic education at Royal Melbourne Institute of Technology. A student perspective.

OBJECTIVE: To assess the attitudes of undergraduate chiropractic and osteopathic students at Royal Melbourne Institute of Technology (RMIT) in 1992 on the education they are receiving and on the effectiveness of chiropractic and osteopathic care. DESIGN: Cross-sectional descriptive survey. PARTICIPANTS: Undergraduate chiropractic and osteopathic students enrolled at RMIT School of Chiropractic and Osteopathy in 1992. RESULTS: This study surveyed 272 students, 196 who were chiropractic students and 76 who were osteopathic students from RMIT School of Chiropractic and Osteopathy in Melbourne, Australia. The students that responded represented 73.4% of chiropractic students and 85.4% of osteopathic students currently enrolled in their respective courses. Chiropractic and osteopathic students entered their respective courses from non-chiropractic/non-osteopathic families. More chiropractic students than osteopathic students (1.3:1.0) had their respective course as their first choice when applying for tertiary education. A majority (95.8 chiropractic students and 94.8% osteopathic students) of both groups surveyed were pleased with their choice of course. Students from both disciplines held considerable respect for each other in the care of certain conditions, but did not see the other profession's care as effective as their own. A greater percentage of osteopathic students believed there was sufficient difference between chiropractic and osteopathy to justify two separate professions (57.6% compared to 97.2%). DISCUSSION: High quality education is a major aim in our schools and colleges. For this standard to be maintained it requires continual re-evaluation and assessment. Surveys such as this should be performed regularly as a method of evaluating student attitude and how these attitudes change during the course. This would also allow administrators to determine whether they are achieving their academic intentions. An immediate follow up survey asking the same questions is suggested to ascertain whether the same attitudes exist today.

In vitro antiplasmodial, antiamoebic, and cytotoxic activities of a series of bisbenzylisoquinoline alkaloids.

Twenty-four bisbenzylisoquinoline alkaloids were screened for antiplasmoidal, antiamoebic, and cytotoxic activities by use of in vitro microtests. Eight of the alkaloids had antiplasmodial activity, with a 50% inhibitory concentration (IC50) of less than 1 microM against a multidrug-resistant strain of Plasmodium falciparum (chloroquine had an IC50 of 0.2 microM). The three alkaloids most active against Entamoeba histolytica, aromoline, isotrilobine, and insularine, had IC50s of 5 to 11.1 microM (metronidazole had an IC50 of 1.87 microM). None of the 24 bisbenzylisoquinoline alkaloids exhibited significant cytotoxicity against the KB cell line, the most toxic being berbamine, with an IC50 of 17.8 microM (the IC50 of podophyllotoxin was 0.008 microM). Bisbenzylisoquinoline alkaloids merit further investigation as potential novel antimalarial agents.

Scanning electron microscopic examination of intracanal wall dentin: hand versus laser treatment.

Conventional cleaning and shaping of root canal spaces involves the use of hand and rotary instruments with irrigation. The procedure results in the formation of a smear layer consisting of dentin shavings, organic tissue remnants and microorganisms. The laser has been suggested as an aid in root canal preparation. In this study, pulsed and continuous wave 1.06 microns wavelength Nd:YAG lasers were used to compare their abilities to clean and shape root canal spaces to conventional methods. After preparation, the test teeth were sectioned longitudinally and examined by scanning electron microscopy. The results demonstrated that the laser was capable of removing the smear layer in its entirety and could occasionally alter dentin walls.

X-ray diffraction and SEM/EDS analyses of phases in new dental amalgams.

The superior clinical performance of several dental amalgams which contain high Cu concentrations and little or no gamma 2 has stimulated the introduction of a number of new amalgam alloys. This investigation sought to study the nature of the phases present in eight commercial systems after trituration. Samples were powdered for X-ray diffraction phase analysis or were polished for SEM/EDS analysis. These methods were complementary since they permitted positive identification of the phases and their distribution and composition, respectively. The matrix phase of all systems was gamma 1 (Ag-Hg). Cu6Sn5 was found as the major Sn-rich amalgamation product. The Cu6Sn5 phase forms reaction zones around th Cu-rich particles with morphological variations from system to system. All amalgams contained the gamma (Ag3Sn) phase, but it was microstructurally distinct only in two particle systems. Small amounts of the gamma 2 (Sn-Hg) phase were found in three systems. These results suggest that there are important microstructural variations in the new Cu-rich systems which could eventually result in variations in clinical performance.