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Biomedical subjects

C Phillips

Publications and source records attributed to C Phillips.

At least 217 records · Page 12Linked to original sources
PubMed1990

Pertussis toxin treatment of whole blood. A novel approach to assess G protein function in congestive heart failure.

This study was designed to assess G protein function in mononuclear leukocytes (MNL) of patients with congestive heart failure (CHF). MNL membranes were ADP-ribosylated in vitro in the presence of pertussis or cholera toxin. The amount of pertussis toxin substrates did not differ significantly between CHF patients (6,100 +/- 224 fmol/mg, n = 23) and age-matched healthy control subjects (5,812 +/- 972 fmol/mg protein, n = 19). Among the CHF patients, no differences were observed between those with idiopathic and ischemic CHF. The amount of cholera toxin substrates also did not differ significantly between CHF patients (7,522 +/- 1,405 fmol/mg protein, n = 11) and control subjects (5,654 +/- 707 fmol/mg protein, n = 14). Moreover, basal and isoproterenol- and prostaglandin E1-stimulated cyclic AMP (cAMP) accumulation in MNL was similar in control subjects and patients. To detect more subtle alterations of the cAMP-generating system, we incubated anticoagulated blood with 250-400 ng/ml pertussis toxin for 4 hours at 37 degrees C. This treatment completely ADP-ribosylated the MNL pertussis toxin substrates. Incubation with pertussis toxin did not change basal or prostaglandin E1-stimulated cAMP generation in MNL of control subjects, but it significantly enhanced stimulated generation (443 +/- 44 vs. 643 +/- 93 pmol/10(7) cells, p less than 0.025) in MNL of CHF patients. This enhancement was most pronounced in the most severely ill patients (New York Heart Association class IV) and correlated with plasma norepinephrine levels, another marker of CHF severity (r = 0.798, n = 11, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate Ribose↗
PubMed1990

Who seeks surgical-orthodontic treatment?

Clinical examination records of more than 1000 patients evaluated in the Dentofacial Clinic at the University of North Carolina were reviewed to determine whether patients with certain characteristics were more likely to seek and to receive surgical treatment. Facial asymmetry was found in 25% of the patients. Women were twice as likely as men to seek evaluation and were more likely to receive surgical treatment once evaluated. Individuals with a long face or skeletal Class III problem appeared more likely to seek evaluation than did those with mandibular deficiency and normal or short facial height, but the decision to accept or reject a recommendation for surgery did not seem to be related to morphologic characteristics.

Adolescent↗
PubMed1989

Prostaglandin E2 production is enhanced in mice genetically selected to produce high affinity antibody responses.

Spleen cells from mice selectively bred to produce high affinity antibody responses to protein antigens (HI) had reduced responses to both T and B cell mitogens when compared to those from mice selectively bred to produce low affinity (LO) responses. The reduced response by spleen cells from HI mice was partially reversed by the addition of indomethacin in vitro. Spleen adherent cells from HI mice had increased production of prostaglandin E2 when compared to those from LO mice. In addition, spleen adherent cells from mice which fail to show affinity maturation not only produced lower amounts of PGE2 than those from HI mice but also a decreased proportion of spleen cells adhered to plastic in these mice. To test the possibility that the increased PGE2 production in HI mice was responsible for the production of high affinity antibodies, indomethacin was administered in vivo and resulted in a significant reduction in antibody affinity. The possibility that PGE2 production may control the balance between the TH1 and TH2 cells of Mosmann and Coffman is discussed.

Animals↗
PubMed1989

Quantitative and subjective analysis of temporomandibular joint radiographs.

The lateral oblique transcranial radiograph of the temporomandibular joint is commonly used in dentistry. Changes in horizontal angulation of the x-ray beam can produce changes in radiographic condylar position. This study used quantitative and subjective methods to assess and rank changes in radiographic condylar position as a function of known horizontal x-ray beam changes. Six dry skulls were positioned in a craniostat device where known angulations could be measured. Nine sequential transcranial temporomandibular joint radiographs were made of each joint and five of these 12 sets were randomly selected for analyses. The quantitative method involved film digitization, computer calculations, and expressed condylar position as a ratio between posterior and anterior joint space distributions. Eight observers viewed the same films and ranked radiographic condylar position from anterior to posterior. The two methods agreed with known rankings 81.8% of the time. Subjective rankings were more variable than quantitative rankings. Intraobserver differences were insignificant and the observers were consistent among themselves as a group.

Cephalometry↗
PubMed1989

The effect of lesion size, restorative material, and film speed on the detection of recurrent caries.

The purpose of this investigation was to study the effect of the size of carious lesions, radiographic density of composite and amalgam restorative materials, and film speed on the radiographic detection of simulated recurrent caries. Radiographs were made of extracted premolars with either large or small recurrent carious lesions simulated adjacent to Class II amalgam or composite restorations with both E-speed and D-speed intraoral film. For each restorative material, teeth that had no simulated caries were compared with teeth that had small and large simulated caries. Recurrent caries is detected best when the lesion is adjacent to radiopaque composite restorations, and detection is poorest when the lesion is next to radiolucent composite restorations. Large carious lesions are identified correctly more often than small lesions, although many lesions are not detected at all, especially those adjacent to radiolucent composite materials. There is no difference between E-speed and D-speed film for the detection of recurrent carious lesions.

Composite Resins↗
PubMed1989

A method for three-dimensional image reformation for quantitative cephalometric analysis.

Recognition and treatment of craniofacial deformities require an understanding of complex skeletal structures in three planes of space. Traditional imaging techniques rely on biplanar radiographs which provide only two-dimensional data. The introduction of three-dimensional image display (3DIR) has provided a method of object analysis in three planes of space, obviating the need for mental reconstruction, and yielding more spatial information than was previously available. This study was undertaken to investigate the quantitative value of three-dimensional images compared with cephalometric techniques in assessing a craniofacial deformity. Metallic marker references were placed on a deformed skull. Measurements taken from cephalograms and three-dimensional images were compared with corresponding digitized and manual measurements taken from the skull. Three-dimensional image reformation provided a more accurate representation of the deformity than the cephalometric methods. Because all structural relationships are preserved in the CT data matrix, measurements are inherently accurate and reproducible. 3DIR offers dynamic advantages over cephalometric methods because data can be manipulated interactively. Further investigation is needed to study the importance of head position and to develop patient selection criteria, scan protocols, and surgical treatment planning algorithms.

Cephalometry↗
PubMed1989

The effect of orthognathic surgery on occlusal force.

To investigate the effect of orthognathic surgery on occlusal force, such force was measured during maximum effort, chewing, and swallowing in 70 patients who had superior repositioning of the maxilla and/or mandibular advancement or setback. Larger changes in occlusal force than could be accounted for by the altered geometry were observed in all groups. Of 15 patients who had only superior repositioning of the maxilla, ten had greater than 20% increase in occlusal force, three had little change, and two showed a greater than 20% decrease. When the mandible was advanced, 11 of 34 patients had greater than 20% increase in maximum biting force, 11 had little or no change, and 12 had greater than 20% decrease. When the mandible was set back, six of the 21 patients had greater than 20% increase, nine had little or no change, and six had greater than 20% decrease. It appears that considerable change in bit force, which is not primarily related to jaw geometry, occurs after orthognathic surgery.

Bite Force↗
PubMed1989

Surgical orthodontic correction of mandibular deficiency by sagittal osteotomy: clinical and cephalometric analysis of 1-year data.

A homogeneous sample of 76 mandibular retrognathic patients (mean age, 28 years) were examined for postoperative alterations after surgical treatment by bilateral sagittal split osteotomy and mandibular advancement with wire fixation. Skeletal and dental measures were obtained from preoperative, immediate postoperative, fixation-release, and 1-year cephalograms. Spearman correlation was used as a preliminary analysis to assess the relationship between postsurgical change and age, genioplasty, amount of mandibular advancement, and preoperative mandibular plane angle. Genioplasty and amount of mandibular advancement were included as independent factors in the subsequent repeated-measures analysis of variance, since these were the only two factors that showed a consistent trend of correlations with postoperative change. Genioplasty was a significant factor in the X and Y coordinate changes in pogonion, while the amount of mandibular advancement was a significant factor in the X coordinate movements of all mandibular landmarks except gonion and condylion. The mean amount of horizontal advancement was 5.2 mm, and anterior face height increased 5.1 mm. During fixation, B point moved posteriorly (x = -1.6 mm, p less than 0.01) and inferiorly (y = 1.0 mm, p less than 0.01). After fixation release, these trends were reversed, resulting in a nonsignificant net horizontal change (x = -0.5 mm, p = 0.10) and a significant net superior movement (y = -1.3 mm, p = 0.01) by 1 year. Pogonion, menton, and mandibular incisor tip showed similar patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Regulation of cardiac beta-adrenergic receptors by captopril. Implications for congestive heart failure.

The interaction of the renin-angiotensin system and the sympathetic nervous system in patients with congestive heart failure is not well understood. We tested the hypothesis that angiotensin-converting enzyme inhibitors can resensitize the beta-adrenergic receptor system. Guinea pigs were given captopril, isoproterenol, or both for 2 weeks. At death, cardiac sarcolemmal and light vesicle fractions and intact mononuclear leukocytes were prepared. Captopril treatment led to an up-regulation of cardiac beta 1- but not mononuclear leukocyte beta 2-adrenergic receptors and an increase in isoproterenol-stimulated adenylate cyclase activity in the heart. Animals treated with isoproterenol developed cardiac hypertrophy, had increased plasma norepinephrine levels, and had a decreased number and responsiveness of both cardiac and mononuclear leukocyte beta-adrenergic receptors. Concomitant treatment with captopril attenuated alterations of heart weight, plasma norepinephrine levels, and cardiac beta-receptor density and function. In contrast to its cardiac effects, captopril treatment did not diminish the down-regulation of mononuclear leukocyte beta 2-adrenergic receptors by isoproterenol. Our data suggest that captopril may resensitize the cardiac but not the mononuclear leukocyte beta-adrenergic receptor-adenylate cyclase system after long-term catecholamine exposure.

Adenylyl Cyclases↗
PubMed1988

L-428 Reed-Sternberg cells and mononuclear Hodgkin's cells arise from a single cloned mononuclear cell.

The L-428 cell line derived from nodular sclerosing Hodgkin's disease was verified to be a human female cell line with surface marker and morphologic characteristics similar to native Hodgkin's cells. Single cells were cloned and subcloned twice to determine the characteristics of the clonogenic L-428 Hodgkin's cell (resulting in a 10% cloning efficiency). Both mononuclear L-428 cells and classical Reed-Sternberg cells arose from solitary cells. The clonogenic cell was the mononuclear Hodgkin's cell, although small abortive colonies sometimes arose from classical binucleate Reed-Sternberg cells. Cytogenetic and phenotypic analysis supported the clonality of three subclones and indicated, among many findings, consistent abnormalities of the long arm of chromosome 7 (beta-chain of the T cell receptor) and 14q32 (Ig heavy chain). Distinctive abnormalities of cytogenetics, phenotyping and transforming growth factor-beta production were exhibited for each clone as well. These observations demonstrate the relationship of the continuum of malignant mononuclear and multinuclear Reed-Sternberg cells in this cell culture from nodular sclerosing Hodgkin's disease and suggest that a similar relationship exists in native Hodgkin's disease tissue. These observations also support the theory of clonality in Hodgkin's disease and suggest that in vivo contiguous metastasis in the L-428 Hodgkin's disease patient was most likely accomplished by a Ki-1 positive small mononuclear cell.

Cell Line↗
PubMed1988

Expression of Epi 1, an epidermis-specific marker in Xenopus laevis embryos, is specified prior to gastrulation.

The induction of morphologically observable neural structures occurs as the result of tissue interactions between chordamesoderm and overlying ectoderm beginning at gastrulation. Since the future dorsal, and hence neural, side of the embryo is determined around the time of fertilization, we questioned whether the presumptive neural epithelium might have received some developmental instructions prior to contact with the migrating chordamesoderm. Epi 1, a cell surface antigen present only on epidermal epithelium was used as a marker to determine when epithelial cells have been programmed to express (or not express) this epidermal-specific molecule. We find that ligated animal halves of precleavage embryos already contain all the information necessary for expression of Epi 1 at the appropriate developmental time (early neurula). By at least the eight-celled stage, the epithelial cells derived from ventral animal blastomeres are much better at expressing the Epi 1 antigen than their dorsal counterparts. We suggest that the mechanisms responsible for expression of the Epi 1 antigen are localized within the animal hemisphere prior to the onset of cleavage. By the third cleavage division, dorsal animal cells appear to have received information which inhibits the subsequent expression of this epidermal antigen.

Animals↗
PubMed1988

Simultaneous superior repositioning of the maxilla and mandibular advancement. A report on stability.

Fifty-three patients who underwent simultaneous surgical superior repositioning of the maxilla and mandibular advancement were studied cephalometrically and clinically for at least 1 year after surgery (mean 2.4 years). The pattern of change for the maxilla and the percentage of patients who had 2 mm or more movement of landmarks were consistent with that observed following isolated superior repositioning of the maxilla. Although changes similar to those observed with isolated mandibular movement occurred, because the changes in the maxilla also affected the mandible, a greater percentage of patients experienced postsurgical movement of the mandible in this group than in those undergoing mandibular advancement alone. Clinically, satisfactory or better results were observed in 42 (79%) patients at their longest follow-up examination. The only significant variable associated with clinical outcome was the presence (presurgically) of an open bite (p less than 0.04) in 10 of 11 patients with poor clinical results. There was no statistically significant relationship between cephalometric stability and clinical outcome in this series of patients.

Adolescent↗
PubMed1988

Adaptations in lip posture and pressure following orthognathic surgery.

Lip pressures before and after orthognathic surgery were studied to evaluate the relationship between posttreatment soft-tissue adaptation and incisor stability. After all surgical procedures, physiologic adaptation resulted in the maintenance of pressures during speech and swallowing. When the maxilla was advanced by LeFort I osteotomy, a significant decrease in resting pressure of the upper lip was observed instead of the expected increase and incisor stability did not seem related to soft-tissue influences. When the mandible was advanced by sagittal split osteotomy, resting pressure did not increase as expected, but there was a tendency for incisors to become more upright after fixation release, perhaps as a rebound from labial tipping in fixation. When soft tissues were relaxed as the mandible rotated forward following superior repositioning of the maxilla, resting pressures decreased and lower incisors tended to be positioned forward as predicted by equilibrium theory.

Adaptation, Physiological↗
PubMed1988

Quantifying discontent in the nursing profession: a study of staff mobility in Victorian nursing homes.

Two problems facing the Australian health system are discontent within the nursing profession and matching limited resources to a growing aged population. It is argued in this paper that the solutions to these two problems can only be evaluated by quantifying the scale of the problem. Three measures are used to demonstrate how to measure the size of the problem: participation rates, staff turnover rates and proportion of permanent/casual staff. These three measures are useful to monitor both at a systems level and at the level of individual health services. The discussion refers in particular to staffing in Victorian geriatric nursing homes.

Geriatric Nursing↗
PubMed1988

Leukemia of non-T lineage natural killer cells.

An unusual case of an aggressive leukemia of natural killer (NK) cells occurred in a 65-year-old male. Clinical characteristics of this case included hepatosplenomegaly, ascites, marrow infiltrate with leukemic cells, and a WBC up to 82.8 X 10(9) before therapy. One year before his presentation he had been noted to have a WBC of 12.1 X 10(9) with 78% lymphocytes, and 6 months before had noted intermittent fever and weight loss. He and his brother had well documented hereditary cold urticaria. The patient was treated with a modification of ProMACE CYTABOM regimen and had prompt regression of the leukemia with associated acute tumor lysis. Renal, hepatic, and marrow failure predominated during a terminal course that ended 22 days after therapy was commenced, and at autopsy there was no evidence for leukemic cell infiltrate in the liver, spleen or marrow. The leukemic cells were large granular lymphocytes by light and electron microscopic criteria, and had the following immunophenotype: CD2+, DR+, Leu7+, NKH1+, CD11+, CD3-, CD5-, CD4-, CD8-, CD16-. The cells displayed high antibody-dependent cell-mediated cytotoxicity (ADCC) and NK activity, and had a high rate of spontaneous proliferation in vitro that was not augmented by phytohemagglutinin (PHA), concanavalin A (Con A), or pokeweed mitogen (PWM). Southern analysis of DNA from leukemic cells revealed normal germline arrangements for the beta and gamma chains of the T cell antigen receptor and immunoglobulin heavy chain genes. The majority of metaphases were clonally abnormal revealing consistent rearrangements involving extra material attached to the long arms of chromosomes 5 and 11.

Aged↗