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Biomedical subjects

C L Phillips

Publications and source records attributed to C L Phillips.

61 records · Page 4Linked to original sources
PubMed1986

Autoshaping a leverpress in rats with lateral, medial, or complete septal lesions.

Rats with either control operations or lateral, medial, or complete septal lesions received 600 trials of leverpress training using an autoshaping procedure, i.e., food delivery followed a 10 s illuminated lever presentation, or occurred immediately after a leverpress. Rats with complete septal lesions acquired the leverpress faster than controls and had more food-tray entries per minute during the first 100 trials than the other groups. Rats with lateral or medial septal lesions had leverpress and food-tray entries equivalent to controls. The facilitation of autoshaping a leverpress may partially be explained by the general increase in motor reactivity to stimuli found following septal lesions.

Animals↗
PubMed1984

Subanesthetic doses of ketamine, diazepam, and nitrous oxide for adult outpatient sedation.

The use of ketamine in adults has been complicated by untoward hallucinatory emergence reactions. The addition of nitrous oxide and diazepam to subanesthetic doses of ketamine may be effective in decreasing these reactions. Adult patients were sedated for outpatient oral and maxillofacial surgery procedures using nitrous oxide, diazepam, and either fentanyl or ketamine. Postoperative questionnaires were used to evaluate hallucinatory reactions, amnesia, and patient acceptance. Comparison of the results of patients receiving ketamine and those receiving fentanyl revealed no statistical differences in hallucinatory reactions or patient acceptance. Amnesia was more complete in the ketamine than the fentanyl group.

Adolescent↗
PubMed1981

Growth in the basicranial synchondroses of adolescent Macaca mulatta.

Tritiated thymidine was administered to five Macaca mulatta monkeys ranging in skeletal age from 39 to 48 months. The animals were then serially sacrificed according to the following postinjection schedule: 6 hours, 12 hours, 2, 4, and 7 days. Each animal was given oxytetracycline 370, 103, and 7 days prior to sacrifice. The spheno-occipital and midsphenoidal synchondroses were excised and sectioned midsagittally for histologic preparation and undecalcified "ground" sections. Results from this investigation indicate that from 39 to 48 months of age growth occurs primarily in the spheno-occipital synchrondroses. The greatest mitotic activity occurs within the proliferative zones, while the central zone appears to be relatively inactive. The surface remodeling pattern, which tends to flex the basiocciput relative to the basisphenoid, appears to be compensated for by a supero-inferior growth rate differential within the spheno-occipital cartilage.

Animals↗
PubMedDate not supplied

Transfer of proalpha2(I) cDNA into cells of a murine model of human Osteogenesis Imperfecta restores synthesis of type I collagen comprised of alpha1(I) and alpha2(I) heterotrimers in vitro and in vivo.

The oim mouse is a model of human Osteogenesis Imperfecta (OI) that has deficient synthesis of proalpha2(I) chains. Cells isolated from oim mice synthesize alpha1(I) collagen homotrimers that accumulate in tissues. To explore the feasibility of gene therapy for OI, a murine proalpha2(I) cDNA was inserted into an adenovirus vector and transferred into bone marrow stromal cells isolated from oim mice femurs. The murine cDNA under the control of the cytomegalovirus early promoter was expressed by the transduced cells. Analysis of the collagens synthesized by the transduced cells demonstrated that the cells synthesized stable type I collagen comprised of alpha1(I) and alpha2(I) heterotrimers in the correct ratio of 2:1. The collagen was efficiently secreted and also the cells retained the osteogenic potential as indicated by the expression of alkaline phosphatase activity when the transduced cells were treated with recombinant human bone morphogenetic protein 2. Injection of the virus carrying the murine proalpha2(I) cDNA into oim skin demonstrated synthesis of type I collagen comprised of alpha1 and alpha2 chains at the injection site. These preliminary data demonstrate that collagen genes can be transferred into bone marrow stromal cells as well as fibroblasts in vivo and that the genes are efficiently expressed. These data encourage further studies in gene replacement for some forms of OI and use of bone marrow stromal cells as vehicles to deliver therapeutic genes to bone.

Adenoviridae↗
PubMedDate not supplied

Gender trends among specialists in pediatric dentistry.

The number of women entering the dental profession has increased over the past few years and the percentage of females enrolling in pediatric postdoctoral studies surpassed 50 percent in 1990. The impact of the shift in the gender of practicing pediatric dentists was examined in this study. A survey was designed to evaluate the relationship between the age and gender of the pediatric dentist, location of principle practice site, and the number of hours dedicated to direct patient care. Twenty-seven hundred and sixty surveys were mailed to pediatric dentists in the United States and 1246 were returned (46 percent). Significantly more males were in private practice than females, although the difference in percentages was small (85 percent versus 80 percent). Women identified universities, hospitals, and institutions as their principle site of practice significantly more often than males (20 percent versus 15 percent). On average, females in private practice work only slightly fewer hours per week providing patient care than do males (32 versus 35 hours/week). In university, hospital, and institution, settings the reverse is true: women spend more time in direct patient care than men (27 versus 23 hours/week).

Adult↗