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Biomedical subjects

T D Marshall

Publications and source records attributed to T D Marshall.

At least 19 recordsLinked to original sources
PubMed1998

Identification of a novel cortactin SH3 domain-binding protein and its localization to growth cones of cultured neurons.

Cortactin is an actin-binding protein that contains several potential signaling motifs including a Src homology 3 (SH3) domain at the distal C terminus. Translocation of cortactin to specific cortical actin structures and hyperphosphorylation of cortactin on tyrosine have been associated with the cortical cytoskeleton reorganization induced by a variety of cellular stimuli. The function of cortactin in these processes is largely unknown in part due to the lack of information about cellular binding partners for cortactin. Here we report the identification of a novel cortactin-binding protein of approximately 180 kDa by yeast two-hybrid interaction screening. The interaction of cortactin with this 180-kDa protein was confirmed by both in vitro and in vivo methods, and the SH3 domain of cortactin was found to direct this interaction. Since this protein represents the first reported natural ligand for the cortactin SH3 domain, we designated it CortBP1 for cortactin-binding protein 1. CortBP1 contains two recognizable sequence motifs within its C-terminal region, including a consensus sequence for cortactin SH3 domain-binding peptides and a sterile alpha motif. Northern and Western blot analysis indicated that CortBP1 is expressed predominately in brain tissue. Immunofluorescence studies revealed colocalization of CortBP1 with cortactin and cortical actin filaments in lamellipodia and membrane ruffles in fibroblasts expressing CortBP1. Colocalization of endogenous CortBP1 and cortactin was also observed in growth cones of developing hippocampal neurons, implicating CortBP1 and cortactin in cytoskeleton reorganization during neurite outgrowth.

3T3 Cells↗
PubMed1998

Obsessive-compulsive disorder in post-streptococcal infection.

OBJECTIVE: We describe the sudden onset of obsessive-compulsive symptoms following a peritoneal infection with alpha-haemolytic streptococci. CLINICAL PICTURE: A 35-year-old woman with no past history or family history of obsessions or compulsions developed these symptoms 2 weeks after a peritoneal infection. TREATMENT: The patient received 80 mg fluoxetine daily. OUTCOME: She responded to treatment with a progressive reduction in symptoms. CONCLUSIONS: It is suggested that these obsessions and compulsions may be related to an autoimmune response to the streptococcal infection.

Adult↗
PubMed1991

Retention of pins in amalgam.

The Max 021 titanium alloy self-threading retentive pin was evaluated for retention in amalgam and compared to the Link Plus titanium alloy self-threading pin. Fifteen specimens in which amalgam was condensed around the retentive pins were prepared. The specimens were mounted in a specially constructed test apparatus in an Instron Testing Machine and placed under a continuous tensile force (1 mm/min) until failure occurred. The mean force required to induce failure in the Max pin specimens was 87.6 (+/- 37.4) Newtons while the mean for the Link Plus pins was 180.4 (+/- 39.8) Newtons. The failure of the specimens using the Max pins was primarily a result of fracture of the amalgam with removal of the pin intact. The failure site of the Link Plus pin was primarily fracture of the pin itself. Statistically, a significantly greater force was required to induce failure in the Link Plus pins.

Dental Amalgam↗
PubMed1990

Fluoride release from amalgam restorations lined with a silver-reinforced glass ionomer.

This study evaluated the amount of fluoride released from amalgam restorations lined with a silver-reinforced glass ionomer. Thirty human extracted molars were divided into three groups of 10 teeth each. Group 1: Class V cavities were made on the facial surfaces and restored with Dispersalloy amalgam. Group 2: Same as Group 1 except 1 mm of GC Lining glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 3: Same as Group 2 except 1 mm of Miracle Mix silver-reinforced glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Before any treatment, all samples were placed in polyethylene vials with 4 ml of deionized water and thermocycled (100x) for baseline fluoride release levels. After restoration, each tooth was replaced in a vial with 4 ml of deionized water. At weekly intervals, each tooth was removed from its aqueous medium and transferred to another vial containing 4 ml of deionized water. Fluoride release was measured four times at weekly intervals with an Orion #9609 fluoride-ion electrode. At 1 and 4 weeks, Miracle Mix released significantly more fluoride than GC Lining (P less than 0.0001).

Dental Amalgam↗
PubMed1990

Effect of sterilization on the strength and cutting efficiency of twist drills.

Retentive-pin twist drills were subjected to four methods of sterilization and then examined to determine possible effects on resistance to fracture, cutting efficiency, and surface condition. Sterilization methods included steam autoclave, chemical vapor autoclave, dry heat, and immersion in glutaraldehyde. Although the steam and chemical vapor groups had lower mean fracture strengths after sterilization, there was no statistically significant difference among the groups. Only the steam autoclave group showed a statistically significant loss of cutting efficiency. Scanning electron microscopic evaluation revealed that only drills sterilized by steam autoclave showed changes in the surface condition or cutting edges.

Dental Cavity Preparation↗
PubMed1989

Fluoride release from glass ionomer-lined amalgam restorations.

This study evaluated the amount of fluoride released from glass ionomer-lined amalgam restorations. 50 human extracted molars were divided into five groups of 10 teeth each. Group 1: No restorations. Group 2: Class V cavities (2 x 2 x 7 mm) were made on the facial and lingual surfaces and restored with Dispersalloy amalgam. Group 3: Same as Group 2 except 1 mm of Ketac-Bond glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 4: Same as Group 2 except 1 mm of Chelon-Silver glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 5: Same as Group 2 except 1 mm of Ketac-Silver GIC was used before amalgam insertion. Before any treatment, all samples were placed in polyethylene vials with 4 ml of deionized water and thermocycled (100x) for baseline fluoride release levels. After restoration, each tooth was placed in a vial with 4 ml of fresh deionized water. At weekly intervals, each tooth was removed from its aqueous medium and transferred to another vial containing 4 ml of deionized water. Fluoride release was measured four times at weekly intervals with an Orion #9609 fluoride-ion electrode. At one week, Ketac-Bond released significantly more fluoride than Ketac-Silver (P less than 0.01) which released significantly more fluoride than Chelon-Silver (P less than 0.01). At four weeks, there was no significant difference in fluoride release between Chelon-Silver and Ketac-Silver, but Ketac-Bond released significantly more fluoride than either of the other materials (P less than 0.01).

Cermet Cements↗
PubMed1989

Evaluation of the Max titanium alloy retentive pins.

This study evaluated the Max 017 retentive pin (.019 in./.48 mm) and its twist drill (.017 in./.43 mm) along with the Max 021 pin (.024 in., .61 mm) and its twist drill (.021 in./.53 mm), in relation to shoulder stop position, space between the end of the pin and the end of the channel and the development of cracks in dentin adjacent to pin channels. A total of 20 non-carious human molar teeth were used, 10 for each size pin. Four pins were placed in each tooth for a total of 40 of each size pin. An air turbine contra-angle was used at 1,200 rpm to prepare all channels and seat all pins. Results showed that with the 017 pins, only 14 pins out of 40 (35%) were completely seated with the shoulder stop against dentin, while the 021 pins had 36 out of 38 (95%) of the shoulder stops completely seated. There was a significant difference in the two groups. Cracks were seen adjacent to only one pin. Space between the end of the pin and the end of the channel for the 017 pins whose shoulder stops were seated was an average of .55 mm, while the 021 pins had an average of .14 mm.

Dental Alloys↗
PubMed1986

Rubber dam isolation in a difficult situation.

Rubber dam retainers can be modified easily in the dental office to enable the dentist to isolate teeth with difficult restorative problems with the rubber dam. Isolation with the rubber dam enhances visibility and access and gives the dentist the opportunity to render safe, restorative care of high quality to the patient.

Dental Caries↗