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Biomedical subjects

D C Smith

Publications and source records attributed to D C Smith.

At least 271 records · Page 15Linked to original sources
PubMed1986

Interpersonal problem-solving skills of retarded and nonretarded children.

Interpersonal problem-solving skills of 17 mildly mentally retarded and two groups of nonretarded subjects (Ns = 30) matched on mental age (MA) and chronological age (CA) were assessed, utilizing a series of hypothetical problem-solving situations. Results indicated similarities between mentally retarded subjects and MA-matched nonretarded subjects both in types and number of strategies produced. Nonretarded CA-matched subjects, on the other hand, exhibited a wider range of problem-solving strategies and increased use of strategies thought to reflect higher levels of social understanding.

Child↗
PubMed1986

Cardiac dysrhythmias during oral surgery. Comparison of hyoscine and droperidol premedication.

The incidence of cardiac dysrhythmias during inpatient dental anaesthesia under halothane was studied following either hyoscine or droperidol as a supplement to papaveretum for premedication. Forty-three percent of patients given hyoscine exhibited cardiac dysrhythmias compared to 23 percent of the group given droperidol (p = 0.03). The incidence of dysrhythmias bore no relationship to the age, sex or weight of the patient, nor to the end tidal carbon dioxide tension.

Adolescent↗
PubMed1986

Intestinal perforation in Wegener's granulomatosis.

Wegener's granulomatosis is a disease characterised by a necrotising vasculitis and granulomatous inflammation. The localised form involves the upper and/or lower respiratory tracts while in the commoner generalised form there is a widespread necrotising vasculitis and renal involvement. Intestinal involvement, which may be severe, has been detected at necropsy in 24% of cases. Gastrointestinal symptoms are uncommon, however, none being mentioned in a recent series of 87 cases. There has been only one reported case of intestinal perforation secondary to Wegener's granulomatosis. We report a case of small and large bowel perforations in a patient with Wegener's granulomatosis.

Colonic Diseases↗
PubMed1986

A clinical and radiographic assessment of a porous-surfaced, titanium alloy dental implant system in dogs.

A new endosseous dental implant system incorporating a porous-surface geometry with a tapered, truncated-cone shape was placed bilaterally in edentulous areas of dog mandibles in a two-stage procedure. All implants had been stabilized by bone ingrowth by the time of the second procedure (insertion of a transgingival collar and implant-supported bridge). The transgingival collar had a porous-surface geometry on its apical one-third, and was meant to encourage gingival connective tissue ingrowth and attachment, but in fact provided an excellent milieu for bacterial contamination. As a consequence, many of the implants showed clinical and radiographic signs of impending failure by eight months. Only those implants for which the porous coat, including that of the transgingival collar, was completely submerged in bone were observed to be successful. This study reports on the radiographic and clinical assessment of this implant system in dogs during the period of function.

Alloys↗
PubMed1986

Fracture toughness of dental composites determined using the short-rod fracture toughness test.

Plane strain fracture toughness (KIC) has been evaluated for a number of commercially-available dental composites. A modified Short-rod Fracture Toughness (SRFT) specimen design has been used, enabling small specimens to be tested conveniently. The effect on KIC of aging in water at 37 degrees C for seven days, one month, and six months has been determined for conventional, microfilled, and hybrid (coarse and fine filler particle-containing) composites. Our results suggest that aging for one month or more caused a reduction of KIC for the composites so aged. Comparison of the KIC values determined using the modified SRFT specimen with values obtained using more conventional specimen geometries gave good agreement, thereby suggesting the suitability of the small SRFT specimens for valid KIC determinations.

Composite Resins↗
PubMed1986

A randomized comparison of tamoxifen with surgical oophorectomy in premenopausal patients with advanced breast cancer.

We randomized 122 premenopausal women to receive tamoxifen or to undergo a surgical oophorectomy. Of 54 evaluable women treated with tamoxifen, 24% had an objective response, as compared with 21% of 53 women having an oophorectomy. The median duration of response for tamoxifen (20 months) was longer than that for surgical oophorectomy (7 months), but this did not achieve statistical significance (P = .056). Overall median survival was 15 months for 58 patients receiving tamoxifen and 25 months for 53 patients undergoing oophorectomy (P = .18). Toxicity was greater in those undergoing oophorectomy, though both treatments were well tolerated. In those premenopausal women for whom hormonal therapy is indicated, tamoxifen is a suitable alternative to surgical oophorectomy.

Adult↗
PubMed1986

Acidity of glass ionomer cements during setting and its relation to pulp sensitivity.

Recent findings regarding pulp sensitivity to luting glass ionomer cements have aroused controversy as to the cause of the problem. Contributing factors may include chemical irritation from the material and leakage. The pH changes during setting were determined for three glass ionomer cements, a zinc phosphate cement, and a polycarboxylate cement. The data showed that the glass ionomer luting cements may show lower pH values for longer times than the other cements. This initial acidity, involving a prolonged period at pH below 3, coupled with cytotoxicity of other ingredients, may lead to damaging effects on the pulp when manipulation of the material and tooth preparation and cementation procedures are less than ideal.

Dental Cements↗
PubMed1986

Catheterization of synthetic vascular grafts.

One hundred nine percutaneous catheterizations of synthetic vascular grafts in 89 patients who had angiographic procedures were reviewed to determine the risk of major complications. Ninety-six of the catheterizations were inserted into the inguinal portion of aortofemoral grafts. There were no instances of hematoma, graft infection, aneurysm formation, suture line disruption, or embolic events distal to the puncture site. One local thrombus developed within a vascular graft that was corrected by a simple thrombectomy performed with a surgical catheter. One puncture site required 2 hours of compression to maintain hemostasis. Because of the extremely low risk of complications from catheterization of synthetic vascular grafts, it is the preferred route for angiographic procedures when the native femoral arterial route is unavailable.

Adolescent↗
PubMed1986

Oestrogen receptor status of breast cancers from related patients.

Breast tumours from nine pairs of related women have been studied with respect to their oestrogen receptor (ER) concentrations and histological appearance and grade. 72% of these tumours were oestrogen receptor positive in both soluble and nuclear fractions. in eight of the nine pairs, the tumours were of the same ER status. Apart from a suggestion of a similar host response to the tumours in two related pairs, the histological appearance of the tumours showed no striking similarities. This small study suggests that familial breast cancers are more likely to be hormone dependent.

Breast Neoplasms↗
PubMed1985

Binocular competitive interactions and recovery of visual acuity in long-term monocularly deprived cats.

Changes in visual acuity brought about by altering competitive interactions between the eyes of cats monocularly deprived (MD) from natural eye opening to 7-12 months of age were studied. In MD cats given binocular experience, median visual acuity using the deprived eye was 0.75 c/deg. If the deprived eye was given a slight competitive advantage via reverse-suture, median visual acuity reached 1.52 c/deg. Further, giving the deprived eye the greatest competitive advantage was accomplished by complete removal of the experienced eye which yielded a median deprived eye acuity of 2.3 c/deg. Obstacle avoidance and stimulus size data were also obtained. The previously published electrophysiological effects of these manipulations on striate cortical cells were noted to mirror these increases in visual acuity and this correlation was discussed, as were the effects of analogous manipulations in the monkey and man.

Animals↗