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Biomedical subjects

D C Smith

Publications and source records attributed to D C Smith.

At least 307 records · Page 17Linked to original sources
PubMed1984

Control of postbiopsy renal hemorrhage with renal artery vasopressin infusion.

Persistent, severe renal hemorrhage resulted from a diagnostic renal biopsy in a 19-year-old woman with chronic renal insufficiency. Infusion of vasopressin into the renal artery through an angiographic catheter produced prompt resolution of bleeding. This method has distinct advantages over surgical intervention or transcatheter embolization in the control of traumatic renal hemorrhage.

Adult↗
PubMed1983

Improvements in bracket base design.

Acid etch bonding of orthodontic attachments to the labial and lingual surfaces of teeth is generally adequate for clinical service. Failures do occur, and these are related to technique problems in acid etching or resin manipulation or to bracket base design. The widely used foil mesh base can present problems in retention because of design defects or corrosion. Improvement in mechanical retention of resin to the attachment base would result in significant improvements in bonding and fewer clinical failures. One of our approaches to improved retention is to fuse metallic or ceramic particles onto the bracket base so as to achieve a particulate or porous layer into which resin can penetrate. The results of bond-strength tests showed that a 100 percent increase in bond strength could be obtained with sintered porous metal-coated brackets. Further development is proceeding.

Animals↗
PubMed1983

A scanning electron microscopic study of the odontoblast process in human coronal dentine.

It is generally accepted that the odontoblast process occupies the dentinal tubules only in the inner part of the dentine, extending approx 0.7 mm from the pulp in both animals and man. Twenty-three premolars, molars and third molars from subjects aged 11-24 yr, all caries-free or only slightly decayed, were processed immediately after extraction by one of four methods. (I) Teeth were split in liquid nitrogen and then fixed, dehydrated in ascending ethanol, and dried by critical point drying (CPD). (II) Teeth were fractured by use of a mallet and a chisel and then prepared as in Method I. (III) The root was cut off using a diamond disk or a mallet and a chisel and the crown was then fixed, fractured in liquid nitrogen, dehydrated and CPD. (IV) As Method III but following fixation the teeth were freeze-dried. All specimens were examined in the scanning electron microscope (SEM). In specimens prepared by Methods II, III or IV the odontoblast process was limited to the inner third of crown dentine. However in all the specimens prepared by Method I the odontoblast process extended to the dentine-enamel junction.

Adolescent↗
PubMed1983

Metronidazole prophylaxis in colorectal surgery: the need for additional aminoglycoside?

A randomized double-blind trial was conducted in two phases to compare the efficacy of prophylactic oral and intravenous administration of kanamycin and metronidazole in preventing wound infection and other complications in patients undergoing colorectal surgery, and also to assess the need for inclusion of an aminoglycoside in the prophylactic regimen. Adequate prophylaxis did not depend on the route of antimicrobial administration, but wound infection rates were increased following exclusion of kanamycin.

Aged↗
PubMed1983

Interpersonal tactics and communicative strategies of Anglo-American and Mexican-American mildly mentally retarded and nonretarded students.

In this investigation, we compared the preferred interpersonal tactics of mildly mentally retarded Mexican-American and Anglo-American children in an experimental social problem-solving situation. Sixty subjects were divided into four equal groups based upon ethnicity (Mexican-American or Anglo-American) and educational status (mildly mentally retarded or nonretarded). Results indicated that although there were no ethnic group differences, differences in preferred problem solving strategies were demonstrated by mentally retarded and nonretarded children. Overall, nonretarded children tended to utilize strategies such as cooperation and temporary withdrawal more often than mentally retarded children.

Child↗
PubMed1982

Corrosion of orthodontic bracket bases.

Attention has recently been focused on the development of black and green stains in association with directly bonded stainless steel brackets. Twelve clinical cases of staining were studied in this investigation. After intraoral photography of the stains, the brackets were removed for examination with the scanning electron microscope. Multiple voids were observed at the resin-bracket interface, especially at the periphery. Considerable deterioration of the alloy base and mesh structure was observed in the void areas. Preliminary analysis of the stains showed that chromium compounds were present. The findings suggested that the presence of voids, together with poor oral hygiene, led to crevice corrosion of the Type 304 stainless steel and formation of colored corrosion products which can result in enamel stains. The use of stainless steels of improved corrosion resistance is recommended to overcome this problem.

Chemical Phenomena↗
PubMed1982

The visual field in monocularly deprived cats and its permanence.

The present study had two primary aims. The first was to determine the extent of the visual field of the deprived eye of a monocularly deprived cat using visual perimetry techniques, since recent reports have been contrary to previous research. The second aim was to determine whether enucleation of the experienced eye of a monocularly deprived cat was associated with any increase in the extent of the visual field of the deprived eye compared to forced usage (reverse-suture). The results indicate that the extent of the visual field using the deprived eye is limited to the ipsilateral monocular visual field. Further, enucleation of the experienced eye leads to a rapid expansion of the visual field of the deprived eye to include the entire ipsilateral hemifield which does not occur following reverse-suture. Possible reasons for the conflicting reports in the literature are discussed.

Animals↗