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Biomedical subjects

R Miller

Publications and source records attributed to R Miller.

At least 127 records · Page 7Linked to original sources
PubMed2001

Interfacial behaviour and mechanical properties of spread lung surfactant protein/lipid layers.

The surface behaviour of spread dipalmitoyl phosphatidyl choline (DPPC), lung surfactant protein C (SP-C), and their mixtures were characterised using a captive bubble surfactometer. The surface tension was determined by using axisymmetric bubble shape analysis. Surface dilatational rheological behaviour was characterised by sinusoidal oscillation of the bubble volume and at frequencies 0.006-0.025 Hz. The pi/A isotherms of DPPC, SP-C, and their mixtures were described with a generalised equation of state. Monolayer cycling of mixed DPPC/SP-C layers yields isotherms with a plateau in the range of 50-53 mN/m. When the surface pressure becomes higher SP-C is squeezed out of the film, but it re-enters the film upon expansion. Surface dilatational elasticities of DPPC films had a maximum at about 30 mN/m. At higher surface pressures, the films became brittle and the elasticity decreased. A slightly pronounced maximum was found at a surface pressure exceeding 55 mN/m. The dilatational viscosity had two distinct maxima, corresponding with those in the elasticity curves, i.e. one before the minimum area demand, and one in the range of over-compression. This was explained by the formation of a second ordered complex structure in the range of film over-compression. SP-C films show continuously increasing dilatational elasticities and viscosities with a maximum at f approximately 0.02 Hz. Mixed monolayers, DPPC+2 mol% SP-C, had dilatational elasticities increasing with surface pressure. In contrast to DPPC alone, an elasticity maximum appeared in the range of the squeeze out plateau. The dilatational viscosity had two distinct maxima as observed for DPPC, whereas the maximum before the squeeze out plateau is very broad like that of SP-C. The viscosity decreased for frequencies higher 0.02 Hz favouring elastic properties of the film. Our data provide experimental evidence that SP-C mixed with DPPC yield higher elasticities and viscosities as compared with films formed by the single components. This behaviour is likely to support breathing cycles, especially for the turn from inspiration to expiration and vice versa.

Journal Article↗
PubMed2001

The responsibility of separating truth from myth to patient and family.

The choice of treatment for patients with haemophilia is influenced by the availability of replacement products, evidence-based knowledge and the beliefs of patients and their medical practitioners. Decisions are often restrained by wider political and domestic administrative directives to keep within budgetary limits. Issues about the optimal and most cost-effective care still pose a challenge. When choosing treatments there are as yet no certain answers in many areas and myths can develop around a variety of issues. This article addresses the question of whose responsibility it is to separate truth from myth to patient and family, and suggests some basic counselling principles on which to base practice.

Hemophilia A↗
PubMed2001

General practitioner-hospital communications: a review of discharge summaries.

The objective of this study was to examine the reliability, effectiveness, accuracy and timeliness of hospital to general practitioner (GP) information transfer by discharge summaries produced in a general public hospital in New South Wales, Australia. A retrospective audit of 569 patient discharge summaries and related medical records with a targeted GP interview was performed to determine receipt and clinical value of the recorded information. The main outcome measure was the number and quality of discharge summaries received by patient-nominated GPs. Summaries written for patients discharged from hospital were estimated to be received by the patient-nominated GP in 27.1% of cases. Discharge summaries audited were rated as being 63.6% accurate, with errors occurring in all facets of production. The current method of discharge summary production and distribution is unacceptable. The high number of errors (36.4%) and the low rate of receipt (27.1%), indicates that resources invested in the production of the discharge summary could be better utilized to improve information transfer.

Communication↗
PubMed2001

Validation of an instrument designed to assess medical student attitudes toward home care.

OBJECTIVES: To develop and validate an instrument to assess medical students' attitudes toward home care. DESIGN: Survey administration before and following participation in a home care training program. SETTING: Five medical schools in the United States. PARTICIPANTS: 326 third and fourth year medical students. MEASUREMENTS: Factor analysis was performed on all posttests. Domains were tested for internal reliability (Chronbach's alpha). Interdomain correlation was tested. One-way analysis of variance (ANOVA) was used to determine whether the results for each domain differed among the five programs. RESULTS: Using exploratory factor analysis, the original 20-item survey was revised to yield a 14-item survey consisting of four domains (general attitudes, home-based therapies, home care training, and time and reimbursement). Domain intra-item reliability ranged from 0.60 to 0.82. Interdomain correlations were found to be significant with the exception of one comparison (time and reimbursement and home care training). One-way ANOVA showed significant differences between the training programs for two of the four domains (home-based therapies and home care training). For a third domain, time and reimbursement, there was a trend toward differences across the schools (P = 0.06). CONCLUSION: The instrument described in this paper is a reliable and valid instrument for assessing the impact of home care training on medical student attitudes across a series of important domains.

Attitude of Health Personnel↗
PubMed2001

Promoting collaborations that improve health.

There is growing interest and investment in health-related collaboration in the United States. In an environment characterized by increasingly complex health problems, substantial resource constraints, and a fragmented health system, public and private organizations as well as communities are recognizing that most objectives related to health and health care cannot be achieved by any single person or organization working alone. Partnerships that bring together diverse people and organizations have the potential for developing new and creative ways of dealing with today's turbulent environment. Despite its potential advantages, collaboration also presents daunting challenges. Further, documenting the effectiveness of partnerships in improving health and well-being has been difficult. Given the significant difficulties of collaboration and the lack of evidence of its effectiveness, questioning whether the investment in health partnerships is justified seems reasonable. In this paper we address this question by illustrating the connective power of collaboration. We describe how collaboration, by connecting individual-level services, broadening community involvement in population-based health strategies, and linking individual-level services and population-based strategies, can improve the health of communities. We then discuss activities that could assist partnerships in reaching their collaborative potential and conclude by presenting the most compelling reasons for pursuing collaboration.

Journal Article↗
PubMed2001

Characterization of a basic helix-loop-helix protein, ABF-1: nuclear localization, transcriptional properties, and interaction with Id-2.

The activated B-cell factor (ABF)-1 cDNA was initially isolated from Epstein-Barr virus (EBV)-infected B cells and codes for a DNA-binding protein belonging to the basic helix-loop-helix (bHLH) family of transcription factors. In this study, we characterized the nuclear localization signal of ABF-1, mapped two distinct transcriptional repression domains, and identified one ABF-1-interacting protein, Id-2. By examining the subcellular location of deletion mutants of ABF-1 fused to green fluorescent protein (GFP), critical regions involved in nuclear localization were determined. Analysis of GFP-tagged ABF-1 deletion mutants revealed two separate regions capable of directing nuclear localization. One region mapped to the N-terminal amino acids 71 to 103, whereas the second region localized to the C-terminal bHLH domain. Transient transfection of ABF-1 deletion mutants demonstrated that the N-terminal amino acids 1 to 40 and the bHLH domain function together to achieve maximum repression of E2A activity. Taken together, these results indicate that ABF-1 is a nuclear transcriptional repressor with two distinct regions that function in a synergistic fashion to attenuate E2A-mediated gene activation.

Basic Helix-Loop-Helix Proteins↗
PubMed2001

Development of a universal connectivity and data management system.

Point-of-care testing (POCT) is an increasingly popular method of delivering laboratory testing. Management of POCT is challenging given the variety of devices, locations, and staff that need to be coordinated to ensure quality results and meet regulatory guidelines. Electronic capture and transfer of data are preferred for managing POCT, but there is currently no standard method of connecting different devices. Johns Hopkins Medical Institutions (JHMI) developed a common data management system with interfaces to all of its POCT devices. All POCT data are collected in one database and analyzed in a similar fashion. Where data were once collected by carrying laptops to each nursing unit, the POCT devices can now connect directly to the database over the Internet. Algorithms have been created to automate the data analysis and review process. Over the several years that this software has been used, JHMI has experienced improved quality, accuracy, and management of its POCT program. The labor saved by increased automation of data review is refocused on enhancing the performance and scope of the program. Current connectivity and analysis algorithms have future application to remote consultation, management of home self-monitoring patients, and examination of real-time data.

Academic Medical Centers↗
PubMed2001

Oral contraceptives increase the plasma concentrations of chlorpromazine.

A 21-year-old female inpatient who was enrolled in a population pharmacokinetic study of chlorpromazine was given an oral chlorpromazine dose of 100 mg three times daily, and plasma concentrations of chlorpromazine were measured weekly. This dose was well tolerated during the first week of therapy. In the second week the patient took a combined oral contraceptive; this was followed by severe dyskinesias and tremor. Plasma chlorpromazine levels were found to be about sixfold higher than those in the first week, although the dose of chlorpromazine had not changed. This observation suggests that the oral contraceptive increased the plasma concentration of chlorpromazine.

Adult↗
PubMed2001

Partnership synergy: a practical framework for studying and strengthening the collaborative advantage.

The substantial interest and investment in health partnerships in the United States is based on the assumption that collaboration is more effective in achieving health and health system goals than efforts carried out by single agents. A clear conceptualization of the mechanism that accounts for the collaborative advantage, and a way to measure it are needed to test this assumption and to strengthen the capacity of partnerships to realize the full potential of collaboration. The mechanism that gives collaboration its unique advantage is synergy. A framework for operationalizing and assessing partnership synergy, and for identifying its likely determinants, can be used to address critical policy, evaluation, and management issues related to collaboration.

Cooperative Behavior↗
PubMed2001

Neuronal COX-2 expression in human myenteric plexus in active inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease (IBD) is associated with changes in colonic motility which may contribute to the pain and diarrhoea associated with exacerbations of this disease. These changes may be mediated by prostaglandins which are increased in this condition. Increased expression of the inducible isoform of cyclo-oxygenase (COX-2) has been found in active IBD although its cellular distribution remains uncertain. AIMS: To evaluate the cellular distribution of COX-2 in active IBD. PATIENTS AND METHODS: Using reverse transcription-polymerase chain reaction, in situ hybridisation, and immunohistochemistry, COX-2 expression was evaluated in 12 colectomy specimens from patients with active ulcerative colitis (UC), and six specimens from patients with Crohn's colitis that had failed medical therapy. Histologically normal colon was obtained from 12 patients having resection for colorectal neoplasia and evaluated as above, acting as control specimens. RESULTS: All specimens expressed COX-2 mRNA, with some 6-8-fold increase in inflamed tissues on densitometric analysis (both UC and Crohn's) compared with controls. In situ hybridisation localised this mRNA to myenteric neural cells, surrounding smooth muscle cells, and inflammatory cells of the lamina propria in the IBD specimens, with some weaker labelling seen in the epithelium. No COX-2 labelling was seen in normal tissues. Immunohistochemistry confirmed these sites of COX-2 expression in all inflamed specimens, with absence of immunoreactivity in control tissues. CONCLUSIONS: These findings provide the first evidence of COX-2 expression in neural cells of the myenteric plexus in active IBD which, via increased prostaglandin synthesis at this site, may contribute to the dysmotilty seen in this condition.

Adult↗
PubMed2001

The physiological expression of inducible nitric oxide synthase (iNOS) in the human colon.

BACKGROUND: Inducible nitric oxide synthase (iNOS) is expressed in the colonic epithelium in both inflammatory bowel disease and colorectal cancer. Nitric oxide (NO), the product of this enzyme, has been implicated in the pathogenesis of both conditions. However, there are conflicting data on whether iNOS is expressed in the normal, uninflamed human colon. AIMS: To evaluate the expression of iNOS in histologically normal, non-inflamed human colonic mucosa. PATIENTS/METHODS: Reverse transcription polymerase chain reaction (RT-PCR), immunoblotting, and immunohistochemistry were used to investigate the expression of iNOS in 17 histologically normal specimens obtained at colectomy performed for colorectal neoplasia. In addition, 16 endoscopic mucosal biopsies, taken from normal individuals, were also evaluated. Eleven surgical specimens and 16 endoscopic biopsies from patients with refractory ulcerative colitis were used as inflammatory controls. RESULTS: All types of specimens expressed iNOS mRNA. Immunoblotting revealed a protein of approximately 130 kDa consistent with iNOS in mucosal extracts of 77% of normal individuals, and 85% of diseased controls. Immunolabelling localised this protein to the surface epithelium in most of the normal specimens and also to the crypt epithelium and inflammatory cells in the diseased controls. CONCLUSIONS: These findings provide evidence that iNOS is often expressed in the surface epithelium of non-inflamed human colon, suggesting that it is induced by local luminal factors, such as bacterial lipopolysaccharide (endotoxin). The resultant NO produced at this site might act as an oxidative barrier, reducing bacterial translocation and providing a means of defence against pathogenic microorganisms.

Adult↗
PubMed2001

Photofragment translational spectroscopy of weakly bound complexes: probing the interfragment correlated final state distributions.

The vibrational predissociation dynamics of weakly bound complexes is well known to be highly nonstatistical. In particular, the associated photofragment final state distributions are often far from statistical, consequently reflecting the nature of the dissociation process. For binary complexes consisting of two molecules, a complete description of the final state of the system must include the associated interfragment correlations, specifically between their internal states. Information of this type is imprinted in the translational energies of the fragments, which can be measured using a number of recently developed translational spectroscopy methods. These data can provide detailed insights into the nature of the bond rupture process, as well as accurate values for the dissociation energy of the complexes. The focus of the present review is on experiments that provide correlated final state distributions for weakly bound binary complexes. Where possible, comparisons with theoretical calculations are made.

Journal Article↗
PubMed2001

Colon carcinoma: MR imaging with CO2 enema--pilot study.

Prior to surgery, seven patients with known colonic tumors underwent breath-hold single-shot fast spin-echo magnetic resonance imaging during a CO2 enema. The images were evaluated for depiction of tumor, adjacent structures, and the remaining colon, and findings were compared with findings at surgery. In all seven patients, the tumor was demonstrated, and in four (57%), breach of the muscularis propria was correctly predicted.

Adult↗