PubMed Health⌕ Search

Biomedical subjects

C Phillips

Publications and source records attributed to C Phillips.

At least 199 records · Page 11Linked to original sources
PubMed1992

Surgical-orthodontic correction of mandibular deficiency: five-year follow-up.

Changes in dental and skeletal relationships at 5 years postsurgery were evaluated in a group of 35 patients whose mandibular deficiency had been corrected by the same surgeon, using sagittal split osteotomy of the mandibular ramus. From 1 to 5 years postsurgery, there was a small (0.9-mm) but statistically significant mean decrease in mandibular length (condylion to point B). In six patients, the decrease in mandibular length was 2 to 4 mm, and in two it was more than 4 mm, but only one of these individuals had more than a 2-mm increase in overjet. There was no mean change in overjet, but three patients had a 2 to 4-mm increase. Of these, one had 3.2 mm shortening of the mandible, one had 1.4 mm shortening of the mandible, and one had no change in mandibular length but repositioning of the incisors. Most patients had a deep overbite initially, and there was a tendency for the bite to deepen between the first and fifth years postoperatively, more as a result of extrusion of incisors than of mandibular rotation. Remodeling of the gonial angle area, with vertical and/or horizontal repositioning of gonion, was noted in more than half the subjects. It appears that morphologic changes related to continued skeletal remodeling, often compensated for by small changes in mandibular posture or tooth positions, continue after 1 year postsurgery for many patients.

Adolescent↗
PubMed1991

The structure of 6-phosphogluconate dehydrogenase refined at 2.5 A resolution.

The three-dimensional structure of ovine 6-phosphogluconate dehydrogenase, refined at 2.5 A resolution with a residual for all data of 18.5%, is reported. This model, based on improved diffraction data and a corrected sequence, supersedes that reported earlier. Each subunit of the dimer has three domains: a beta-alpha-beta domain binds NADP; an all alpha domain provides much of the dimer interface; the C-terminal tail burrows into the second subunit.

Molecular Structure↗
PubMed1991

The t(1;22) (p13;q13) is nonrandom and restricted to infants with acute megakaryoblastic leukemia: a Pediatric Oncology Group Study.

We report the nonrandom occurrence and frequency of the t(1;22)(p13;q13) in acute myeloid leukemia (AML) and its close association with the French-American-British M7 subtype of AML in infants (less than 1 year). This chromosomal abnormality occurred in 6 of 252 (2.4%) children and adolescents with AML (6 of 28 infants, 22%; 6 of 18 M7 AML cases overall, 33%; and 6 of 6 M7 cases in infants). Infants with AML of M7 subtype and the t(1;22) often presented with prominent abdominal masses. Two of these infants were not treated and died early. Three of four treated infants entered complete remission with therapy for AML; the remaining infant died of hemorrhage on day 8. Of the three infants who entered remission, only one remains alive and disease free at 5+ months. The other two infants relapsed in the bone marrow at 5 and 2 months from the start of therapy, respectively. We conclude that M7 AML with the t(1;22) usually presents in infants with extensive infiltration of abdominal organs by leukemic cells and may confer a poor prognosis despite intensive AML-directed treatment. Identification of this nonrandom translocation exclusively in infants with acute megakaryoblastic leukemia (AMkL) implies that it may serve as an additional diagnostic marker for this disease and links it to the pathogenesis of AMkL in infants.

Antigens, CD↗
PubMed1991

Incidence of an estrogen receptor polymorphism in breast cancer patients.

We previously identified a polymorphism in the human estrogen receptor (ER) gene, within the coding region for the protein's amino terminal B-domain. In estrogen receptor-positive (ER+) breast tumors, the variant allele was preferentially associated with lower levels of ER, and was clinically correlated with frequent spontaneous abortions. DNA sequencing revealed a point mutation that changes codon 86 from Ala to Val and a silent mutation in codon 87. Because we initially detected the variant allele by analyzing RNA, only those tissues in which the ER gene is actively expressed were suitable for genotype analysis. We now describe an assay that uses genomic DNA as the substrate for determining the ER B genotype, DNA containing the polymorphic region of the ER gene is amplified by the polymerase chain reaction, then the amplified DNA is hybridized with radiolabeled oligonucleotide probes complementary to the wild type and variant ER alleles. This method allowed us to determine the ER B genotype of women with ER+ and ER- tumors, starting with minute amounts of DNA from frozen or paraffin embedded tissues. ER B genotyping was also performed on women without breast cancer using DNA extracted from blood cells. The combined results from analyses of RNA and DNA from 300 breast cancer patients showed that 12% were heterozygotes. In the ER+ group (n = 183), 11.5% carried the variant gene compared to 12.8% in the ER-negative group (n = 117) (chi 2 = 0.11; df = 1; p greater than 0.25).(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1991

Induction of leukotriene production before antigen challenge enhances antibody affinity in genetically selected mice.

Mice genetically selected for their incapacity to produce high-affinity antibody to protein antigens in adjuvant (nonmaturing (NM) mice) were treated with indomethacin, an inhibitor of the cyclooxygenase pathway of arachidonic acid metabolism. Pretreatment with indomethacin significantly enhanced the affinity of antibodies produced 21 days after immunization with human serum albumin (HSA). Blockage of the cyclooxygenase pathway in this way was shown to induce the production of leukotrienes via the lipoxygenase pathway. The production of leukotrienes may well be responsible for the enhanced antibody affinity, since blockage of the lipoxygenase pathway in addition to the cyclooxygenase pathway reversed the effect. In an attempt to elucidate the mechanisms involved, IL-1 production and Ia expression by macrophages were examined. Ia expression by peritoneal cells from untreated NM mice was significantly lower than that by their high-affinity-producing counterparts 3 days after immunization. Indomethacin pretreatment raised inducible Ia antigen levels on macrophages of NM mice to those seen on cells from untreated high-affinity mice. Indomethacin treatment alone induced the production of IL-1 by macrophages in NM mice. However, 3 days after immunization and the withdrawal of indomethacin in NM mice, IL-1 production was significantly lower than the response of NM mice given antigen alone, suggestive of the induction of a feedback mechanism. Thus indomethacin pretreatment results in a cascade of events in macrophages which produce a decrease in IL-1 production and an increase in inducible Ia expression 3 days after antigen challenge.

Animals↗
PubMed1991

Validity of digital subtraction of transcranial plain films in quantification of positional changes of the mandibular condyle.

Condylar positioning problems have been associated with temporomandibular joint signs and symptoms. The position of the mandibular condyle is difficult to predict and quantify with existing routinely used radiographic techniques. An investigation was implemented to test the validity and reliability of digital subtraction to enhance transcranial plain films and to quantify positional changes of the condyle in a laboratory model. The model consisted of a mounted dried human skull and a mandibular condyle attached to a micromanipulator. Controlled changes in condylar position were made, and the condyle and fossa were imaged. The data were analyzed with descriptive statistics, analyses of variance to evaluate the sources of variability, and linear contrasts to evaluate the differences between observed and expected values. The results indicated that digital subtraction detected posterior positional change within 10% of the expected value. However, inferior positional changes were poorly detected and lateral positional changes could not be evaluated by this technique. We conclude that digitally subtracted transcranial radiographs may be useful for detection of posterior condylar movements, assuming that appropriate head-holding devices are used to fix x-ray source and head geometry.

Analysis of Variance↗
PubMed1991

Molecular characterisation of a protective, 11-kDa excretory-secretory protein from the parasitic stages of Trichostrongylus colubriformis.

An 11-kDa protein occurring as a major component of the non-glycosylated fraction of 4th larval stage (L4) and adult Trichostrongylus colubriformis excretory-secretory (ES) fluid has been found to be highly protective in guinea pigs, an alternate host for T. colubriformis. The protein has been purified, characterised and partly sequenced. With a reverse-complement oligonucleotide based on the carboxy-terminal sequence of the protein, recombinant lambda gt11 clones were detected in an L4 cDNA library. The DNA sequence from one clone has a single extended open reading frame coding for a highly charged 11-kDa protein which lacks a leader sequence and contains a potential N-glycosylation site. Expression of the cloned DNA in Escherichia coli was detected with an antibody, raised in rabbits against gel-purified 11-kDa protein.

Amino Acid Sequence↗
PubMed1991

Diagnosis related groups: choice, economy and nurse education.

The recently created internal market for the NHS has resulted in an increasing interest in the ways that funding is allocated for patient care. Ways in which funding is allocated will affect all nurses at some point. Associated with the issue of funding of patient care have been attempts to identify case-mix. A variety of classification systems are available but the most widely utilised is that of Diagnosis Related Groups (DRGs). This paper outlines the nature of this system and identifies some of the issues surrounding the DRG system and nurse education.

Diagnosis-Related Groups↗
PubMed1991

Factors related to root resorption in edgewise practice.

In a series of 200 consecutively debanded patients receiving comprehensive orthodontic treatment with the edgewise appliance, six (3%) showed severe resorption (greater than one-quarter of the root length) of both maxillary central incisors. For other teeth, resorption of this extent occurred in less than 1% of the patients. Using a case-control design, the characteristics of 21 patients with severe resorption were compared to randomly selected controls from the case series. There were significantly more Class III patients among the severe resorption cases than would have been expected. Risk indicators for resorption that were related to treatment procedures included approximation of the maxillary incisor roots against the lingual cortical plate (odds ratio 20), maxillary surgery (odds ratio 8), and root torque (odds ratio 4.5).

Adolescent↗
PubMed1991

The effect of orthognathic surgery on head posture.

Changes in resting head and neck posture were studied in 201 patients following five different orthognathic surgery procedures: (1) LeFort I osteotomy for superior repositioning (intrusion) of the maxilla (n = 45); (2) bilateral sagittal split ramus osteotomy for mandibular advancement (n = 78); (3) mandibular setback (n = 19); (4) combined maxillary intrusion and mandibular advancement (n = 46); (5) combined maxillary intrusion and mandibular setback (n = 13). Head and neck posture were measured on standardized serial cephalograms taken in natural head position prior to, immediately after, and 1 year after surgery for each subject. Immediately after surgery, there was flexion of the head as measured by the craniovertical and craniocervical angles in all of the groups except the mandibular setback group, which showed little change. By 1 year post-surgery, the mean craniovertical and craniocervical angles were approximately the same as before surgery in the groups with one-jaw surgery. Statistically significant head flexion at 1 year (P less than 0.05) was observed in the combined maxillary intrusion and mandibular advancement group, and with maxillary intrusion plus mandibular setback, there was a trend toward persistent flexion. Neck posture showed no significant short- or long-term changes in any of the surgical groups.

Adult↗
PubMed1991

Characterization of skin-infiltrating lymphocytes in patients with psoriasis.

In this study, skin-infiltrating cells in psoriasis patients were characterized in biopsies from both involved and uninvolved skin. Histologic examination of biopsies showed the presence of both CD4+ and CD8+ T cells and the lack of B lymphocytes. Skin biopsies were also placed in tissue culture medium supplemented with human serum, interleukin-2 (IL-2), and irradiated autologous blood lymphocytes. T lymphocytes grew from both plaques and univolved skin biopsies and consisted of a heterogeneous population of T-cell subsets. The immunophenotypic analysis of cultured cells was comparable to the histologic examination on frozen section, i.e., there was a greater number of CD4/CDw29+ cells than CD8+/CD45+ cells. Cultures were tested in the primed lymphocyte test (PLT) and cell-mediated lympholysis (CML) assays. All cultures tested demonstrated secondary proliferative but not cytolytic reactivity. The PLT results indicate that the cell cultures generated are autoreactive. This autoreactivity was found to be directed against non-human leukocyte antigens (HLA), i.e., minor HLA with some restriction to major HLA antigens.

Antigens, CD↗
PubMed1991

Stability after surgical-orthodontic correction of skeletal Class III malocclusion. 2. Maxillary advancement.

Nearly half the patients with skeletal Class III malocclusion have maxillary deficiency as the major component of their problem, and modern surgical techniques allow maxillary osteotomy to correct the deformity. Changes at surgery and postsurgically were studied in 49 patients who underwent isolated surgical maxillary advancement. Thirty-one had wire osteosynthesis and maxillomandibular fixation, and 18 had rigid fixation with bone plates. In nearly half the patients, the maxilla was moved down as well as forward, indicating that the patient had both vertical and anteroposterior deficiency. In the anteroposterior plane, 80% of the patients had excellent stability at 1 year, while 20% had 2 to 4 mm of posterior movement of anterior maxillary landmarks. There was no difference in anteroposterior stability between wire/maxillomandibular fixation and rigid internal fixation groups. When the maxilla was moved down as well as forward, there was a strong tendency for relapse upward in both fixation groups. As a result, the chin frequently became more prominent from immediate postsurgery to 1-year followup, as upward movement of the maxilla allowed the mandible to rotate upward and forward.

Adult↗
PubMed1991

Stability after surgical-orthodontic corrective of skeletal Class III malocclusion. 3. Combined maxillary and mandibular procedures.

Stability after combined Le Fort I and bilateral sagittal split osteotomies was reviewed in 51 patients with skeletal Class III malocclusion. Because vertical changes in the position of the maxilla affect both the vertical and anteroposterior positions of the mandible, the sample was subdivided by the direction of vertical movement of the maxilla at surgery. Excellent postsurgical stability was observed in the long-face Class III patients in whom upward and forward movement of the maxilla was combined with ramus osteotomy to prevent excessive forward rotation of the mandible. When the maxilla was moved forward and the mandible set back with minimal vertical change, moderate relapse tendencies were observed in both jaws, but most of the correction was maintained at 1 year. When the maxilla was moved down and forward while the mandible was set back, moderate vertical relapse of the maxilla and anteroposterior relapse of the mandible followed. Stability of the downward movement of the maxilla was, on average, better than that resulting from maxillary surgery alone.

Adult↗
PubMed1991

Trisomy 21: association between reduced recombination and nondisjunction.

To assess the association between recombination and nondisjunction of chromosome 21, we analyzed cytogenetic and DNA markers in 104 trisomy 21 individuals and their parents. Our DNA marker studies of parental origin were informative in 100 cases, with the overwhelming majority (94) being maternal in origin. This value is significantly higher than the 75%-80% maternal nondisjunction rate typically observed in cytogenetic studies of trisomy 21 and illustrates the increased accuracy of the molecular approach. Using the maternally derived cases and probing at 19 polymorphic sites on chromosome 21, we created a genetic map that spans most of the long arm of chromosome 21. The map was significantly shorter than the normal female linkage map, indicating that absence of pairing and/or recombination contributes to nondisjunction in a substantial proportion of cases of trisomy 21.

Adult↗
PubMed1991

Stability after surgical-orthodontic correction of skeletal Class III malocclusion. I. Mandibular setback.

Postsurgical stability of mandibular setback to correct mandibular prognathism was compared for three approaches: transoral vertical ramus osteotomy, bilateral sagittal split osteotomy with wire osteosynthesis and maxillomandibular fixation, and bilateral sagittal split osteotomy with rigid internal fixation via bone screws. In the transoral vertical ramus osteotomy group, the mean postsurgical change in chin position was almost zero, but nearly 50% of the patients did have clinically significant changes in chin position; two thirds of these movements were posterior and one third anterior. In the bilateral sagittal split osteotomy groups, the chin either stayed in its immediately postsurgical position or moved anteriorly. In one fourth of the patients who received maxillomandibular fixation and in nearly half of the patients who received rigid internal fixation, the chin moved forward more than 4 mm.

Adult↗
PubMed1991

Effects of indomethacin and PEEP on oleic acid induced pulmonary oedema in rabbits.

This study was designed to determine whether indomethacin, a suggested treatment for adult respiratory distress syndrome (ARDS), would inhibit the efficacy of positive end-expiratory pressure (PEEP) in an animal model of ARDS. Functional residual capacity (FRC), alveolar-to-arterial oxygen difference (A-aPo2) and total lung water were measured in rabbits: 30 controls and 30 with oleic acid induced pulmonary oedema. Within each group, four treatments were administered: diluent (n = 12), PEEP (n = 6), indomethacin (n = 6), or PEEP + indomethacin (n = 6). Lung injury was induced at 30 mins and treatment commenced at 45 min. Oleic acid caused a significant increase at 3 h in % increase in A-aPo2 from baseline (105 +/- 12%) attenuated by PEEP (59 +/- 17%) and indomethacin (57 +/- 7%), with the combination of PEEP + indomethacin preventing a significant increase (26 +/- 9%). PEEP increase FRC in both saline and oleic acid animals; this was not reversed by indomethacin. Oleic acid caused an increase in total lung water (5.16 to 6.58 +/- 0.16 g), not influenced by any treatment. These findings suggest that indomethacin did not inhibit the efficacy of PEEP in this model of ARDS.

Animals↗