Ursolic Acid Loaded PLGA Nanoparticles: <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis> Evaluation to Explore Tumor Targeting Ability on B16F10 Melanoma Cell Lines

Purpose

Ursolic acid (UA), a pentacyclic triterpenoid extracted from plants, shows promising inhibitory effect in different tumor bearing cell lines. In the present study we fabricated UA loaded PLGA nanoparticles (UA-NPs) as the drug carrier and thoroughly evaluated in vitro and in vivo the differential tumor targeting effects of UA and UA-NPs in B16F10 melanoma cells.

Methods

Ursolic acid loaded PLGA nanoparticles were prepared by emulsion solvent evaporation technique and evaluated for particle size, polydispersity, zeta potential and drug release potency. MTT assay as well as flow cytometric and confocal microscopic analyses were done in B16F10 mouse melanoma cell lines. Formulations were labeled with technetium-99m to evaluate the biodistribution and perform scintigraphic imaging studies following intravenous administration in tumor bearing mice model.

Results

Single emulsification technique produced smooth spherical nanoparticles of small size with relatively narrow size distribution (154?±?4.56 nm). On B16F10 cell line, the formulation showed higher cytotoxicity compared to the free drug due to increased in vitro cellular uptake. The formulation was successfully radiolabeled and remained substantially (>90%) stable when incubated (37°C, 6 h) separately in normal saline or freshly collected rat serum or histidine solution. The radiolabeled UA-NPs exhibited slower blood clearance and comparatively high uptake in tumor region as evidenced by biodistribution and scintigraphic studies.

Conclusions

The in vitro and in vivo studies have proved the tumor targeting potential of UA-NPs in B16F10 melanoma cell lines.

     

Mandibular changes in persons with untreated and treated Class II Division 1 malocclusion

The growth potential of individuals with Class II malocclusions is of interest to the practicing orthodontist because such malocclusions constitute a significant percentage of cases. The purpose of this study was to evaluate on cross-sectional and longitudinal bases the changes in mandibular length and relationship and maxillary-mandibular relationships in untreated Class II subjects from deciduous to permanent dentition and also to evaluate the effects of orthodontic treatment, with and without the extraction of first premolars, on these relationships. Class II samples were compared with matched normal, untreated individuals. The Class II Division 1 (Class II/1) untreated sample comprised 30 subjects, 15 males and 15 females. Each subject had a complete set of data at three stages of dental development—namely, Stage I, after the completion of eruption of the deciduous dentition; Stage II, at the time when the permanent first molars and most of the incisors have erupted (i.e., in mixed dentition); and Stage III, at the completion of eruption of the permanent dentition, excluding third molars. The Class II treated sample comprised 44 subjects (21 males, 23 females) treated with four first-premolar extractions and 47 subjects (20 males, 27 females) treated without extraction. Treatment was accomplished with the use of an edgewise appliance, appropriate extraoral traction, and Class II elastics. The extraction decision was based mainly on the presence of crowding and profile consideration. Records on 35 normal subjects (20 males, 15 females) were available from the Iowa Longitudinal Facial Growth Study. Cephalograms for the normal individuals were matched to the corresponding ages of the Class II cases. With regard to these findings, few consistent differences were noted between the untreated Class II/1 and normal subjects on cross-sectional comparisons. The differences in mandibular length and position were more evident in the early stages of development than at later stages. Longitudinal comparisons of growth profiles indicated that the growth trends were essentially similar between the untreated Class II/1 and normal subjects in the various parameters compared. The comparisons of growth magnitude indicated the presence of greater skeletal facial convexity in the untreated Class II/1 subjects, accompanied by a tendency for a more retruded mandible. Initial comparisons between the Class II/1 treated groups and normal subjects indicated that the Class II/1 malocclusions were associated with a larger overjet, deeper overbite, and greater ANB angle. After a 5-year treatment and observation period, an overall “normalization” in the mandibular and maxillary-mandibular skeletal relationships was noted in the treated Class II/1 subjects in both the extraction and the nonextraction groups compared with normal subjects. The changes were more pronounced in the extraction group.(Am J Orthod Dentofacial Orthop 1998;113:661-73)     

The effect of disinfectants on the properties of dental gypsum, part 2: Surface properties

PURPOSE: This study is part of an ongoing investigation to evaluate the surface properties of dental stones mixed with disinfection solutions, and to determine the effect of adding gum arabic and calcium hydroxide on the same properties. MATERIALS AND METHODS: Aqueous solutions of 2 chemical disinfectants were used in mixing 2 types of dental stones (type III and type V). These dental stones were modified further by adding 1% gum arabic and 0.132% calcium hydroxide to their hemihydrate powders before mixing. Five specimens prepared from each type of dental stone were classified into 7 groups according to the hemihydrate powder modification and mixing liquid/powder ratio. Surface roughness was tested by 2-dimensional profilometery and scanning electron microscopy (SEM). Knoop hardness testing was carried out, and detail reproduction was assessed using ADA specification 25 in addition to SEM and 3-dimensional profilometer studies. RESULTS: Dental stones mixed with chemical disinfectants showed higher average roughness (R(a)) values than those of the controls. However, adding gum arabic and calcium hydroxide to the hemihydrate powders before mixing restored values to the level of the control. The additives seemed to have a role in the improvement of surface hardness. There was no significant difference between the experimental and the control group in the terms of detail reproduction. CONCLUSIONS: Using SEM, 3-dimensional profilometry, and ADA testing methods, we found that the surface roughness of stone casts was adversely affected by using the disinfectant solutions as mixing water substitutes. Gum arabic and calcium hydroxide additives can yield a harder stone surface without compromising other surface properties.     

Treatment of traumatic injuries to an anterior tooth. Case report

A procedure is described in which a multi-disciplinary approach to restoration of a subgingivally-fractured anterior tooth is performed.     

Computer use in private dental practice in Australia, 1991

There was a 70 per cent response to a mail questionnaire to a 1:3 sample of Australian Dental Association members in private practices (n = 1931). Computers were used by 37 per cent of practices. Main computer applications used were for: accounting (84%); patient billing (80%); word processing (79%); and patient recall (61 %). External bureau services were used by 4 per cent of practices with most computers being in-house (single terminal 66%; multiple terminal 33%). The more dentists in a practice, the more likely was a computer to be used. Principal users were secretary/receptionists. Service and software were the most important factors in choice of computer system. Many practice computer users (67%) also had a Personal Computer at home compared with only 36 per cent of the non-users. Many respondents indicated the need for continuing education in computers (67% users; 61% non-users). More than half of the non-users indicated future use of computers for accounting, billing and recall. There has been a considerable increase in the use of computers in private practice (37%) since the Australian Dental Association Dental Practice Survey in 1983/84 (9%).     

Appropriate dental care for employees at the workplace

The data from a dental health survey of an Australian employee group in Brisbane were used to test the value of dental health programmes at the workplace as a means of improving general dental health.
The amount and complexity of treatment needs were investigated. Although both dental caries and periodontal disease were widespread, few of the employees had major treatment needs, most requiring minimal, simple dental care. Because of the minor treatment needs of a relatively static group of employees, the viability of a dental practice at work with emphasis on restorative dental care was questioned. Given the disease levels, the treatment needs indicated that a system based on prevention and maintenance care would be more appropriate.     

Hereditary gingival fibromatosis with a recessive mode of inheritance. Case reports

Hereditary gingival fibromatosis is characterized by varying degrees of attached gingival hyperplasia and may in rare cases present as a feature of a generalized syndrome. It is usually inherited as an autosomal dominant condition though recessive forms are described. The dental and genetic features of an affected brother and sister with a probably unique autosomal recessive hereditary fibromatosis syndrome are presented.     

Abnormal reaction to subgingivally placed dental amalgam studied by transmission electron microscopy and microprobe analysis. Case report

An abnormal clinical response to dental amalgam is reported. The patient presented with a generalized burning sensation having a focus of pain in a region approximating a subgingivally placed dental amalgam restoration. Replacement of the amalgam restoration with glass ionomer cement relieved the pain and burning. Gingival tissue associated with the amalgam, excised to render the new restoration supragingivally, displayed ultrastructural changes in both the epithelium and connective tissue, with mercury demonstrated in the connective tissue and the epithelium by electron microprobe analysis. The significance of the presence of mercury and absence of the other constituents of dental amalgam are discussed.     

The effect of enamel bonding agents on in vitro composite bond strengths

The role of the enamel bonding agents in improving composite retention to etched enamel was investigated by comparing the bond strengths of the composites alone, the composites with the bonding agents and the bonding agents alone. The bonding agents were not found to increase composite retention to etched enamel, but thermal cycling results suggested that a more durable bond may form when these agents are employed.

For all the materials tested the same mechanism of adhesion and mode of failure operated. This involved the formation of an unfilled resin layer which penetrated the enamel irregularities and remained on the enamel surface after failure.     

Hemostatic effect of n-butyl-2-cyanoacrylate (histoacryl) glue in warfarin-treated patients undergoing oral surgery

PURPOSE: Our goal was to evaluate the local hemostatic effect of n-butyl-2-cyanoacrylate (Histoacryl; B. Braun, Melsungen, Germany) glue in warfarin-treated patients who undergo outpatient oral surgery without a change in their level of anticoagulation. MATERIALS AND METHODS: Thirty consecutive warfarin-treated patients randomly assigned to study and control groups and 10 patients who had never been on anticoagulant therapy serving as the negative control group were included in this trial. Before multiple teeth extractions, all patients had a prothrombin time and the international normalized ratio (INR) determined. To gain hemostasis and primary closure, gelatin sponge and multiple interrupted resorbable sutures were used in the control and negative control groups, and Histoacryl glue and the minimal number of interrupted resorbable sutures were used in the study group. Postoperatively, patients were to contact the oral surgeon if abnormal bleeding occurred. Patients who did not have postoperative bleeding were seen on the 10th postoperative day. Data were collected, and statistical differences in age and gender distributions, number of teeth extracted, INR levels, and bleeding that required treatment were analyzed with the Mantel-Haenzel test. Statistical significance was defined as a value of P <.05. RESULTS: Local hemostasis was obtained immediately in study patients and only after 10 to 20 minutes in the control and negative control patients. In relation to bleeding complications, there were no cases of postoperative bleeding requiring treatment in both the negative control patients and study patients. In the control patients, 5 cases had postoperative spontaneous bleeding that required treatment. This difference was statistically significant. No patient had wound infection and the healing process appeared to be normal. CONCLUSION: Multiple extractions can be performed in patients taking oral anticoagulant therapy without a change in their level of anticoagulation provided an efficient local hemostatic measure is instituted. And, in this regard, Histoacryl glue, used as a topical adhesive over approximated wound edges, is an effective and easily applicable local hemostatic for oral surgery in such patients.