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Biomedical subjects

C S Solomon

Publications and source records attributed to C S Solomon.

13 recordsLinked to original sources
PubMed2003

Dominant negative alpha-subunit of farnesyl- and geranylgeranyl-transferase I inhibits insulin-induced differentiation of 3T3-L1 pre-adipocytes.

OBJECTIVE: To investigate whether the expression of a dominant negative (DN) farnesyl- and geranygeranyl-transferase I (FTase/GGTase I) alpha-subunit in 3T3-L1 pre-adipocytes can inhibit insulin's ability to induce differentiation. DESIGN: 3T3-L1 pre-adipocytes were stably transfected with vector alone or vector expressing a mutated DN FTase/GGTase I alpha-subunit (S60A)(S62A) and incubated in serum-free medium in the absence and presence of insulin. MEASUREMENTS: Various assays were performed to determine the effect of DN FTase/GGTase I alpha-subunit expression in 3T3-L1 pre-adipocyte on insulin-induced DNA synthesis, cell count, phosphorylation of the FTase/GGTase I alpha-subunit, FTase and GGTase I activity, amounts of prenylated p21Ras and RhoA, phosphorylation of MAP kinase and Akt, and differentiation to mature fat cells. RESULTS: Expression of DN FTase/GGTase I alpha-subunit inhibited insulin's ability to increase DNA synthesis, cell count, FTase and GGTase I activity, amounts of prenylated p21Ras and RhoA, and magnitude of phosphorylation of MAP kinase. Expression of DN FTase/GGTase I alpha-subunit in 3T3-L1 pre-adipocytes was without effect on insulin-induced Akt phosphorylation. CONCLUSION: Expression of DN FTase/GGTase I alpha-subunit inhibits insulin-induced differentiation of 3T3-L1 pre-adipocytes to mature adipocytes, and thus could indicate potential therapeutic avenues to assuage the deleterious effects of obesity and type 2 diabetes.

3T3 Cells↗
PubMed2003

Aesthetic restoration of the compromised root: a case report.

The amount of tooth structure that remains after endodontic therapy and post preparation is of prime importance as the strength and resistance to root fracture of an endodontically treated tooth is directly related to the amount of residual dentine. The desired post diameter is determined by tooth morphology and the endodontic procedures (for root canal debridement) with the aim being to avoid removing too much tooth structure. Increasing the diameter of the post does not provide a significant increase in the retention of the post; it only increases the stiffness of the post at the expense of the remaining dentine and the fracture resistance of the root. There is little indication for increasing the post width beyond the endodontic cleaning and shaping procedures for all post systems. The post diameter needs to be controlled to preserve the radicular dentine, reduce the potential for perforations, and permit the tooth to resist fracture. However, endodontic treatment often involves wide flared canals where cast posts are the standard method of treatment. These thin-walled canals are then further compromised by the placement of a tapered cast post--thus increasing its risk for fracturing. The Luminex light, transmitting posts provide an alternative treatment option by strengthening weakened, endodontically treated teeth by the combined bonding action of dentine bonding agents and composite resin restorative material. The paper reports on a case where a wide flared root canal was rehabilitated with composite resin using a light-transmitting post.

Adolescent↗
PubMed2001

Dominant negative farnesyltransferase alpha-subunit inhibits insulin mitogenic effects.

Farnesylation of p21Ras is required for translocation to the plasma membrane and subsequent activation by growth factors. Previously we demonstrated that insulin stimulates the phosphorylation of farnesyltransferase (FTase) and its activity, whereby the amount of farnesylated p21Ras anchored at the plasma membrane is increased. Herein we report that substitution of alanine for two serine residues (S60A)(S62A) of the alpha-subunit of FTase creates a dominant negative (DN) mutant. VSMC expressing the FTase alpha-subunit (S60A)(S62A) clone showed a 30% decreased basal FTase activity concurrent with a 15% decrease in the amount of farnesylated p21Ras compared to controls. Expression of alpha-subunit (S60A,S62A) blunted FTase phosphorylation and activity in the presence of hyperinsulinemia, and inhibited insulin-stimulated increases in farnesylated p21Ras. Insulin-stimulated VSMC expressing the FTase alpha-subunit (S60A,S62A) showed decreased (i) phosphorylation of FTase, (ii) FTase activity, (iii) amounts of farnesylated p21Ras, (iv) DNA synthesis, and (v) migration. Thus, down-regulation of FTase activity appears to mitigate the potentially detrimental mitogenic effects of hyperinsulinemia on VSMC.

Alkyl and Aryl Transferases↗
PubMed1999

Evaluating the efficacy of curing lights.

The use of light curing units has increased tremendously over the past few years with the introduction of photoactivated composite restorative resins. The advantages of light-cured composites are well documented especially the ease of placement of restorations as a result of extended working time and control of setting. Many of the advantages of these composites are dependent on the adequate polymerisation and therefore the source of the visible light, especially the wavelength and the intensity of the light source. The aims of this study were (i) to determine the intensity output of curing lights in state clinics, private dental practices and dental clinics run by trade unions using a radiometer and (ii) to relate their output to various factors that may affect the intensity of the light produced by each unit. The light intensity of each light curing unit was measured using the Efos Cure Rite radiometer (Cure Rite, Efos model #8000; Efos Inc, Mississauga, Canada). Mean readings ranged from a high of 448 to a low of 22 mW/cm2 for curing lights at the time of evaluation. Nineteen (54.3%) of the light curing units were functioning at optimal intensities, followed by 10 (28.6%) functioning at levels between 150 and 300 mW/cm2 and 6 (17.1%) functioning at levels far below that required to achieve adequate photocuring. No statistically significant differences were found when comparing intensity readings with age, last maintenance service and bulb replacement (P > 0.05). All of the clinicians interviewed (100%) expressed subjective satisfaction with the performance of the light curing units, even though 45.7% functioned below optimal intensities (P > 0.05). Not one of the clinicians expressed dissatisfaction with the performance of any of the light curing units. The results of this study showed that the light intensities f light curing units used within private dental practices, state and trade union dental clinics were inadequate for optimum curing.

Composite Resins↗
PubMed1996

Munchausen syndrome.

Explore the source record for details and available documents.

Dental Pulp Diseases↗
PubMed1989

External root resorption--fact or fancy.

A review of external resorption is presented with an emphasis on a wide range of etiological factors. This case report details the possible pitfalls in basing the diagnosis solely on radiographic interpretation.

Female↗
PubMedDate not supplied

An efficacious oral health care protocol for immunocompromised patients.

A twice-weekly oral and perioral examination was provided to 120 patients receiving antineoplastic therapy. Sixty patients were monitored while following the traditional hospital oral care protocol (chlorhexidine, hydrogen peroxide, sodium bicarbonate, thymol glycol, benzocaine mouthrinse, and nystatin). The mouth care protocol was then changed (experimental protocol = chlorhexidine, benzocaine lozenges, amphotericin B lozenges), and patients were monitored until the sample size matched that of the hospital mouth care regime. There was a statistically significant reduction in oral complications upon introduction and maintenance of the experimental protocol.

Adolescent↗