Biomedical subjects

C Phillips

Publications and source records attributed to C Phillips.

At least 19 recordsLinked to original sources

PubMed1998

Benefit of early Class II treatment: progress report of a two-phase randomized clinical trial.

Preadolescent children with overjet greater than 7 mm were randomly assigned to observation only, headgear (combination), or functional appliance (modified bionator) and were monitored for 15 months. Of the 166 patients who completed this first phase of the trial, 147 continued to a second phase of treatment. The data from the first 107 patients to complete phase 2 are available and form the basis of this progress report. During phase 1, on average there was no change in the jaw relationship of untreated children, but 5% showed considerable improvement and 15% demonstrated worsening. Both early-treatment groups had a significant average reduction in ANB angle, more by change in maxillary dimensions in the headgear group and mandibular growth in the functional appliance group. There were wide variations in response, however, with only 75% of the treated children showing favorable skeletal response. Failure to respond favorably could not be explained by lack of cooperation alone. The preliminary results from phase 2 show that, on average, time in fixed appliances was shorter for children who underwent early treatment, but the total treatment time was considerably longer if the early phase of treatment was included. Only small differences were noted in anteroposterior jaw position between the groups at the completion of treatment, and the changes in dental occlusion, judged on the basis of Peer Assessment Rating scores, were similar between groups. Neither the severity of the initial problem nor the duration of treatment was correlated with the occlusal result. The number of patients who required extraction of permanent teeth was greater in the early functional appliance group than in the headgear or control group. The option of orthognathic surgery was presented more often in the cases of children who did not undergo early treatment, but surgery was accepted or was still being considered almost as frequently in the previous headgear group as in the controls, less often in the patients previously treated with functional appliances.

Activator Appliances↗

PubMed1998

Functional brain imaging of human sleep.

This paper presents an overview of the contribution of functional brain mapping to the study of human sleep. Early studies were essentially successful in describing the variations of the global level of cerebral metabolism. More recently, regional distribution of cerebral blood flow was reported. The results suggest that the permissive and executive processes of slow wave sleep and REM sleep are similar in humans and in animals. They also show cortical blood flow distributions specific to each sleep stage. The cellular mechanisms underlying the involvement of these cortical areas in sleep are not yet precisely known. They should be looked for by further investigations in animals. Future research in functional neuroimaging will attempt to explore functional and, hopefully, effective connectivity between cerebral areas involved in sleep processes. This final goal will probably require the co-registration of two or more brain imaging techniques to precisely describe the spatio-temporal course of neuronal interactions occurring during sleep.

Brain↗

PubMed1998

MEG covariance difference analysis: a method to extract target source activities by using task and control measurements.

A method is proposed for extracting target dipolesource activities from two sets of evoked magnetoencephalographic (MEG) data, one measured using task stimuli and the other using control stimuli. The difference matrix between the two covariance matrices obtained from these two measurements is calculated, and a procedure similar to the MEG-multiple signal classification (MUSIC) algorithm is applied to this difference matrix to extract the target dipole-source configuration. This configuration corresponds to the source-configuration difference between the two measurements. Computer simulation verified the validity of the proposed method. The method was applied to actual evoked-field data obtained from simulated task-and-control experiments. In these measurements, a combination of auditory and somatosensory stimuli was used as the task stimulus and the somatosensory stimulus alone was used as the control stimulus. The proposed covariance difference analysis successfully extracted the target auditory source and eliminated the disturbance from the somatosensory sources.

Algorithms↗

PubMed1998

Environmental correlates of resident agitation in Alzheimer's disease special care units.

OBJECTIVE: To determine the point prevalence of agitated behaviors in a representative sample of Alzheimer's disease Special Care Units, and to determine the extent to which agitation is associated with aspects of the treatment environment. DESIGN: A cross-sectional study in which nonparticipant observers recorded 3723 observations of resident behaviors in 53 Alzheimer's disease Special Care Units. Observational data were gathered on the physical environment and staff treatment in these settings, and resident characteristics were extracted from a data base developed in the study states by the Health Care Financing Agency. Analyses studied the association between aspects of the staff and physical environment and resident agitation levels, controlling for resident cognitive and functional status. SETTING: Special Care Units in nursing homes in Kansas, Maine, Mississippi, and South Dakota. PARTICIPANTS: All residents and staff of the participating units. MAIN OUTCOME MEASURES: Eight specific agitated behaviors and two indexes of resident agitation were measured by direct observation by research assistants on three to four data collection walk-throughs in each of the study facilities. RESULTS: The most common agitated behaviors noted were repetitive mannerisms (4.5% of resident observations) and non-loud verbal excess (3.8%). Wandering, which frequently reflects agitation, was noted in 6.5% of resident observations. The proportion of residents exhibiting an agitated behavior varied from none in some units to 38% in one unit. Independent correlates of low unit agitation levels included favorable scores on measures of the physical environment and of staff treatment activities, low rates of physical restraint use, a high proportion of residents in bed during the day, small unit size, low levels of resident functional dependency, and fewer numbers of comorbid conditions. CONCLUSIONS: While the prevalence of agitation tends to increase as Alzheimer's disease progresses, modifiable treatment factors appear to have a strong influence on the prevalence of agitation. Both physical design and staff treatment appear to influence agitation rates, as do some measures consistent with a low stimulus approach to Alzheimer's care.

Activities of Daily Living↗

PubMed1998

Teaching the microscopic examination of urine sediment to second year medical students using the Urinalysis-Tutor computer program.

The microscopic examination of urine sediment is a common diagnostic tool taught to medical students, medical technologists, and others. The urine microscopic exam is difficult to teach because supervised instruction and textbook-based teaching suffer from numerous drawbacks. Here, we describe Urinalysis-Tutor, a computer program that uses digitized microscope images and computer-based teaching techniques to systematically teach the urine microscopic exam. In addition, we report the results of a 2-year study that evaluated the effectiveness of the program in 314 second year medical students who were required to use the program. The program contained two, 20-question exams. In the first year of the study (1996), one of the exams was chosen as the pretest and the other as the posttest; the pretest had to be completed before the students viewed the contents of the program, and the posttest was taken after finishing the tutorial. In 1997, the order of the two exams was reversed. In 1996, 159 students completed the study. The mean pretest score was 34% (SD, 14%), the mean posttest score was 71% (SD, 13%), and the improvement was significant (P <0.001, paired t-test). In 1997, 155 students participated. The mean pretest score was 41% (SD, 11%), the mean posttest score was 71% (SD, 13%), and the improvement was significant (P <0.001, paired t-test). The study shows that Urinalysis-Tutor helps medical students learn to interpret the microscopic appearance of urine sediment and that it is feasible to implement this tutorial in a medical school class.

Computer-Assisted Instruction↗

PubMed1998

Ultrastructural, cell culture and karyotype study of bone marrow in a patient with congenital dyserythropoietic anaemia (CDA)-type III presenting with recurrent still-births.

A 28 year old female patients presented with refractory anaemia since childhood and recurrent still-births at 28-30 weeks of gestation. One still-born child was hydropic at birth. Bone marrow showed characteristic morphological changes of congenital dyserythropoietic anaemia (CDA)-Type III. Electron microscopy showed disruption of the nuclear membrane, spongy appearance of nuclei, stacks of microtubules in intermediate normoblasts and myelin figures in erythroid cells. In vitro culture and karyotype data from the bone marrow of the patient is presented. Recurrent still-births in association with congenital dyserythropoietic anaemia has rarely been reported in the literature.

Adult↗

PubMed1997

The murine IgM secretory poly(A) site contains dual upstream and downstream elements which affect polyadenylation.

Regulation of polyadenylation efficiency at the secretory poly(A) site plays an essential role in gene expression at the immunoglobulin (IgM) locus. At this poly(A) site the consensus AAUAAA hexanucleotide sequence is embedded in an extended AU-rich region and there are two downstream GU-rich regions which are suboptimally placed. As these sequences are involved in formation of the polyadenylation pre-initiation complex, we examined their function in vivo and in vitro . We show that the upstream AU-rich region can function in the absence of the consensus hexanucleotide sequence both in vivo and in vitro and that both GU-rich regions are necessary for full polyadenylation activity in vivo and for formation of polyadenylation-specific complexes in vitro . Sequence comparisons reveal that: (i) the dual structure is distinct for the IgM secretory poly(A) site compared with other immunoglobulin isotype secretory poly(A) sites; (ii) the presence of an AU-rich region close to the consensus hexanucleotide is evolutionarily conserved for IgM secretory poly(A) sites. We propose that the dual structure of the IgM secretory poly(A) site provides a flexibility to accommodate changes in polyadenylation complex components during regulation of polyadenylation efficiency.

Alternative Splicing↗

PubMed1997

Report of the European DNA profiling group (EDNAP): an investigation of the complex STR loci D21S11 and HUMFIBRA (FGA).

This paper describes a collaborative exercise which was intended to demonstrate whether uniformity of DNA profiling results could be achieved between European laboratories using two complex short tandem repeat (STR) loci. The loci D21S11 and HUMFIBRA (FGA) were chosen because they are commonly used by different European laboratories. D21S11 has approximately 14 common alleles (f > 0.001), whereas HUMFIBRA has 19 common alleles. Laboratories were asked to test seven blood stains, one of which was a known control, and to report the results to the coordinating laboratory. The exercise demonstrated that complex STRs were amenable to standardisation.

Alleles↗

PubMed1997

Processing of vowels in supratemporal auditory cortex.

The auditory evoked neuromagnetic fields elicited by synthesized vowels of two different fundamental frequencies F0 were recorded in six subjects over the left and right temporal cortices using a 37-channel biomagnetometer. Single equivalent current dipole modeling of the fields elicited by all vowel types localized activity to a well-circumscribed area in supratemporal auditory cortex in both hemispheres. There were hemisphere asymmetries in the amplitude and latency of the M100 response. We also observed changes in M100 latency related to vowel type, but not to F0. There was no clear effect of vowel type or F0 on dipole localization for the M100, but a possible vowel type by latency interaction. These M100 data provide further evidence that vowels are processed independently of their pitch.

Adult↗

PubMed1997

Fibrinolysis, inhibitors of blood coagulation, and monocyte derived coagulant activity in acute malaria.

Different parameters of fibrinolytic systems like t-PA, PAI, D-dimer, and inhibitors of blood coagulation, i.e., protein C (PC), protein S(PS), and antithrombin III (AT-III), have been studied in cases of acute malaria due to Plasmodium falciparum and plasmodium vivax infection, and these patients were followed up. It was observed that the plasma PAI-1 was very high in cases of P. falciparum malaria infection as compared to normal controls and P. vivax infection. The changes in complicated cases of P. falciparum were remarkable as compared to uncomplicated ones. The PC, PS, and AT-III levels were also low in P. falciparum, particularly so in complicated cases, and were normal in P. vivax infection. The factor VIII R:Ag levels were invariably high in acute malaria. On follow-up of some of these cases the values came back to normal after the antiparasite treatment. The monocyte procoagulant activity was found to be significantly higher in P. falciparum infection as compared to that of P. vivax infection. All these findings therefore contribute towards the production of a hypercoagulable state in P. falciparum infection and partly explain the complications of P. falciparum infection like cerebral malaria.

Antithrombin III↗

PubMed1997

A qualitative study of breast cancer self-help groups.

This study reports on the experience of women in four community breast cancer self-help groups in Ontario, Canada. Semi-structured interviews were conducted with 24 women, asking them about benefits and limitations of their group involvement, and about their perspectives on group processes and structures. Overall, participants reported their group involvement to be extremely helpful for navigating the short and long-term impact of breast cancer. Emotional support benefits included connecting with other breast cancer survivors, feeling understood and sharing experiences, providing hope, and sharing healing laughter. Informational and practical support benefits included sharing of important information and learning how to get what you want. Even where there were concerns about limitations or tensions of group experience, these occurred against a backdrop of appreciation and commitment. From the discussion of group processes and structures, a number of issues were identified as problematic. Most notable were how to deal with deaths of group members and how to balance the group's primary purpose of providing mutual support with secondary goals of dealing with group business and engaging in meaningful advocacy.

Adaptation, Psychological↗

PubMed1997

Mechanisms of drug-induced lupus. III. Sex-specific differences in T cell homing may explain increased disease severity in female mice.

OBJECTIVE: To determine if sex-specific differences in lymphocyte trafficking could contribute to increased disease severity in female mice. METHODS: A lupus-like disease was induced by injecting male and female mice with procainamide-treated T cell clones. Trafficking was examined by labeling the injected cells with 51Cr or 5-chloromethylfluorescein diacetate. RESULTS: Females developed more autoimmune liver disease and greater titers of anti-DNA antibodies than did males, and 2-7 times more cells accumulated in the female spleens. Splenectomy prevented the development of autoantibodies and renal and liver disease. Oophorectomy decreased the splenic homing, autoantibody titer, and liver disease severity, to levels found in males. CONCLUSION: T cells traffic differently to the spleen in male and female mice, and the spleen appears to be essential in the disease process. This suggests that differences in T cell homing could contribute to sex-specific disease severity in this murine model, and also possibly in human disease.

Adoptive Transfer↗

PubMed1997

PDZ domains: targeting signalling molecules to sub-membranous sites.

PDZ (also called DHR or GLGF) domains are found in diverse membrane-associated proteins including members of the MAGUK family of guanylate kinase homologues, several protein phosphatases and kinases, neuronal nitric oxide synthase, and several dystrophin-associated proteins, collectively known as syntrophins. Many PDZ domain-containing proteins appear to be localised to highly specialised submembranous sites, suggesting their participation in cellular junction formation, receptor or channel clustering, and intracellular signalling events. PDZ domains of several MAGUKs interact with the C-terminal polypeptides of a subset of NMDA receptor subunits and/or with Shaker-type K+ channels. Other PDZ domains have been shown to bind similar ligands of other transmembrane receptors. Recently, the crystal structures of PDZ domains, with and without ligand, have been determined. These demonstrate the mode of ligand-binding and the structural bases for sequence conservation among diverse PDZ domains.

Amino Acid Sequence↗

PubMed1997

A biomechanical study of the flexor digitorum superficialis: effects of digital pulley excision and loss of the flexor digitorum profundus.

Many reports have been devoted to characterizing the significance of the pulleys for the flexor digitorum profundus (FDP). However, no comparable work has been published on the flexor digitorum superficialis (FDS). This study characterized the FDS in a human cadaver model. Eleven fresh-frozen cadaver hands were used. By using a tensiometer, data were gathered for tendon excursion, tendon load, and work of flexion. Changes in efficiency were caused by excision of annular pulleys A1, A2, A3, and the palmar aponeurotic pulley. We also measured the effect of FDP excision on FDS efficiency. Sectioning of the A2 and A3 pulleys together caused statistically significant losses of efficiency in all three parameters (work, load, and excursion). When the FDP was removed from a finger with an intact pulley system, losses in both work and excursion efficiencies were significant. Removing the FDP while cutting different pulleys caused significant decrease in FDS excursion efficiency. We conclude that A2 and A3 are the most important pulleys for maintaining normal FDS function, and that the presence of the FDP in the digital sheath is essential for optimal FDS excursion efficiency.

Biomechanical Phenomena↗

PubMed1997

Influences on the outcome of early treatment for Class II malocclusion.

In the first phase of a randomized clinical trial of early versus late Class II treatment, statistically significant differences were observed between the treatment and observation groups. However, there were wide variations in response. The change in jaw relationship (categorized as the annualized reduction in ANB angle) was favorable or highly favorable in 76% of the headgear, 83% of the functional appliance, and 31% of control (observation only) groups. The patient's initial skeletal severity, age/maturity at the outset of treatment, growth pattern, and cooperation with treatment were examined as possible influences on early growth modification treatment. Correlations between the annualized change in the ANB angle and any of the possible influences were close to zero and not statistically significant. We conclude that there is little to be gained from precisely timing early treatment to specific age/maturity markers and that a favorable reduction in Class II skeletal problems can occur for patients in a broad range of skeletal severity and growth patterns. Cooperation, measured as the number of hours of reported wear, or the clinical assessment of compliance, explained little of the variation in treatment response. The wide variation in growth seen in the untreated patients highlights the importance of well-controlled studies if clinicians are to improve their ability to select children with the greatest chances of a favorable treatment response.

Activator Appliances↗

PubMed1997

The effect of early intervention on skeletal pattern in Class II malocclusion: a randomized clinical trial.

Early treatment for Class II malocclusion is frequently undertaken with the objective of correcting skeletal disproportion by altering the growth pattern. Because the majority of previous studies of growth modification for Class II malocclusion have been based on retrospective record reviews, the efficacy of such an approach has not been well established. In this controlled clinical trial, patients in the mixed dentition with overjet > or = 7 mm were randomly assigned to either early treatment with headgear, or modified bionator, or to observation. All patients were observed for 15 months with no other appliances used during this phase of the trial. The three groups, who were equivalent initially, experienced statistically significant differences (p < 0.01) in skeletal change. There was considerable variation in the pattern of change within all three groups, with about 80% of the treated children responding favorably. Although patients in both early treatment groups had approximately the same reduction in Class II severity, as reflected by change in the ANB angle, the mechanism of this change was different. The headgear group showed restricted forward movement of the maxilla, and the functional appliance group showed a greater increase in mandibular length. The permanence of these skeletal changes and their impact on the subsequent treatment remains to be evaluated.

Analysis of Variance↗

PubMed1997

Changes in hospitalization associated with introducing the Resident Assessment Instrument.

OBJECTIVE: To compare the rates of hospitalization among cohorts of nursing home residents assembled before and after the implementation of the federally mandated Resident Assessment Instrument (RAI). SAMPLE: Subjects were nursing home residents chosen from 268 facilities in major Metropolitan Statistics Areas in 10 states and representing more than 1500 facilities and 60,000 residents. Two resident cohorts (1990 and 1993) were sampled (8 to 16 residents per facility, depending upon facility size) as part of an evaluation of the impact of implementing the RAI. METHODS: Research nurses reviewed records, interviewed staff, observed patients, and completed an RAI at baseline and 6 months later. All transitions during this interval (hospital admissions, nursing home transfers, returns home, death, etc.) were tracked. Using polytomous logistic regression, we tested the effect of cohort on the probability of being hospitalized in light of the competing risks of dying or remaining in the home, controlling for demographic and casemix variables, and having a DNR order in the chart. RESULTS: A total of 4196 residents were studied, 2118 in 1990 (age 81.3, female 77.7%, LOS 6+ months 49.8%) and 2078 in 1993 (age 81.7, females 75.5%, LOS 6+ months 50.2%). The unadjusted probability of hospitalization dropped from .205 to .151. Multivariate analyses revealed a significant adjusted odds of hospitalization of .74 (95% CI .60-.91) and no cohort effect on home discharge or death. Among severely cognitively impaired residents, the adjusted odds of hospitalization in 1993 compared with the 1990 cohort was 0.74 (.53-1.03). Finally, among survivors in both cohorts who had a follow-up MDS performed, and whose ADL remained stable, 15.9% were hospitalized in 1990, whereas only 10.9% were hospitalized in 1993. On the other hand, ADL decliners were more likely to have been hospitalized in 1993 than in 1990 (40.6% vs 25.2%). CONCLUSIONS: Although other changes in the industry, clinical practice, and health care policy may have influenced hospitalization of nursing home residents, the substantial reductions observed among the cognitively impaired and those with stable ADL suggest superior and uniform assessment information in the form of the RAI contributed significantly to this decline.

Activities of Daily Living↗

PubMed1997

A commitment to change: revision of HCFA's RAI.

OBJECTIVE: To describe the reliability of new assessment items and their clinical utility as judged by experienced nurse assessors, based on the results from the field test of Version 2.0 of the Resident Assessment Instrument (RAI). DESIGN: Independent dual assessment of residents of nursing facilities by staff nurses using a draft of Version 2.0 of the minimum data set (MDS). SETTING AND PARTICIPANTS: A total of 187 randomly selected residents from 21 nursing homes in seven states volunteered to test Version 2.0 of the MDS. MEASUREMENT: The full array of MDS assessment items included measures in the following areas: Background information, cognitive patterns, communication/hearing, vision, mood and behavior, psychosocial well-being, physical functioning and structural problems, continence, disease diagnoses, health condition, oral/nutritional status, dental status, skin condition, activity pursuit patterns, medications, special treatments and procedures, and discharge potential and overall status. RESULTS: Evaluative data address issues of MDS item utility and reliability. For new items, almost all achieved a reasonably high-weighted Kappa interrater reliability; revised items also surpassed earlier items, and with the updated training materials, even the non-changed items had higher average reliability levels. Based on the success of the field test and the positive response of the industry, Version 2.0 of the RAI has been adopted, and HCFA has initiated a more long-range process to update further the RAI when necessary. CONCLUSION: Findings support the reliability and clinical utility of the new and revised assessment items incorporated by HCFA in Version 2.0 of the MDS.

Activities of Daily Living↗