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Biomedical subjects

R Short

Publications and source records attributed to R Short.

At least 19 recordsLinked to original sources
PubMed2006

Nanointerrogation of ultrasonic contrast agent microbubbles using atomic force microscopy.

Predicting the acoustic response of an encapsulated microbubble to ultrasound requires an accurate assessment of the mechanical properties of the microbubble shell. Atomic force microscopy (AFM) provides an unprecedented spatial and force resolution of the order of Angstroms and subnanonewtons, respectively. It is introduced here as a means to interrogate microbubbles manufactured for ultrasonic imaging. The advantage of AFM over scanning electron microscopy (SEM) is that the microbubbles need not be subjected to a low temperature or low-pressure environment. The microbubbles were interrogated in a liquid environment, which could potentially be a simulated physiological environment. AFM was used in tapping mode imaging to reveal topographical detail of biSphere microbubbles. Because microbubbles are large objects compared with the overall size of usual AFM tips, a convolution between the AFM tip and the microbubble was typical of the acquired topographies. However, a part of the top half of the bubble was imaged with nanometer resolution, and roughness measurements are reported. Force-distance curves were captured using contact mode AFM. The range of stiffness or effective spring constant of biSphere was found to be between 1 and 6 N m(-1). In conclusion, the AFM is proposed here for the first time as a tool to image the surface of bubbles at the nanometer range in liquid and to perform reproducible measurements on the mechanical properties of individual microbubbles.

Biomechanical Phenomena↗
PubMed2004

A new autologous keratinocyte dressing treatment for non-healing diabetic neuropathic foot ulcers.

AIMS: To evaluate the use of a new cell-tailored carrier surface (TranCell) for delivery of autologous keratinocytes to promote wound healing in patients with chronic neuropathic foot ulcers. METHODS: TranCell is a sterile medical grade polymer coated with a plasma-polymerized functional surface containing 20% carboxylic acid which enables keratinocytes to attach and proliferate. Six diabetic patients with neuropathic ulcers resistant to conventional therapy were treated with weekly applications of autologous keratinocytes delivered on TranCell. A split-thickness skin biopsy was taken from each patient followed by isolation, expansion and freezing down of keratinocytes. Keratinocytes were thawed and seeded on TranCell 48 h prior to application. This procedure was repeated weekly in addition to conventional therapy until wound healing was achieved. RESULTS: Complete healing was achieved in six out of nine ulcers in six patients, a reduction in ulcer size was achieved in one ulcer and no response was seen in one ulcer. Treatment was discontinued in one patient due to development of Methicillin-Resistant Staphylococcus aureus (MRSA) after only three applications of TranCell. Wound healing took 6-17 applications over 6-20 weeks. There were no recurrences in the healed ulcers after a follow-up of 6 months. CONCLUSIONS: TranCell delivery of autologous cells is a promising treatment for chronic diabetic foot ulcers with no side-effects and no recurrence in the healed ulcers.

Adult↗
PubMed2003

Development of a stable chemically defined surface for the culture of human keratinocytes under serum-free conditions for clinical use.

Within the field of tissue engineering there is a need to develop new approaches to achieve effective wound closure in patients with extensive skin loss or chronic ulcers. This article exploits the well-known interdependency of epithelial keratinocytes and stromal fibroblasts in conjunction with plasma surface technology. The aim was to produce a chemically defined surface, which with the aid of a feeder layer of lethally irradiated dermal fibroblasts would improve the attachment and proliferation of the keratinocyte cell from which subconfluent cells can be transferred to wound bed models. Plasma copolymers of acrylic acid/octa-1,7-diene have been prepared and characterized by X-ray photoelectron spectroscopy. The fibroblasts and keratinocytes were cultured on plasma polymer-coated 24-well plates. Cell attachment and proliferation were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-eluted stain assay (MTT-ESTA) and DNA assay. Attachment and proliferation of both cell types on plasma polymer surfaces were compared with tissue culture plastic and collagen I, plus a negative control of a pure hydrocarbon layer. A pure acrylic acid surface, fabricated at a power of 10 W and containing 9.2% carboxylate groups, was found to promote both fibroblast and keratinocyte attachment and proliferation and permit the serum-free coculture of keratinocytes and irradiated fibroblasts.

Acrylates↗
PubMed2001

Pathways to quality improvement for boarding homes: a Washington State model.

A quality improvement service delivery model was developed, implemented, and evaluated during a boarding home consultation program in Washington State. Standardized quality improvement (QI) pathways were utilized to define resident issues related to quality of life, quality of care, and safety. The pathways assisted boarding homes (n = 126) volunteering for on-site visits with QI consultants to identify and address resident needs and meet statutory requirements. After 6 months in the program, 78 percent of participating residents demonstrated objective clinical improvement. Assisting providers in meeting resident needs by using QI pathways will improve residents' quality of life, quality of care and safety.

Critical Pathways↗
PubMed2001

Satisfaction with on-site boarding home consultation: a Washington State program.

A Quality Improvement Consultation (QIC) program was implemented in Washington State to assist boarding home providers (N = 500) to comply with statutory requirements. Boarding homes (n = 126, 25%) volunteering for the on-site visits with state quality improvement (QI) consultants developed and implemented QI plans to address provider-identified issues. Satisfaction with the program was measured with a 15-item questionnaire given to boarding home administrators, managers, and facility staff. Most agreed that the consultation was helpful and provided them with helpful information to ensure their success.

Aged↗
PubMed2001

Effects of an HMO hospitalist program on inpatient utilization.

OBJECTIVE: To assess the impact of a health maintenance organization (HMO) hospitalist program on inpatient utilization. PATIENTS: The study sample consisted of patients admitted to the hospital for a routine, uncomplicated acute surgical or medical diagnosis included under Milliman and Robertson's Optimal Recovery Guidelines (ORGs). Evaluation involved comparison of 2 physician management groups: inpatients managed by staff primary care physicians (PCPs) (study group) and inpatients managed by network PCPs (comparison group). STUDY DESIGN: Data before and after introduction of the hospitalist program were available. From the same period, data were available from patients of network PCPs who managed their own inpatient stays (nonhospitalist comparison sample). Three outcomes were used to represent inpatient utilization: (1) number of inpatient stays meeting ORG goals; (2) number of inpatient stays not meeting ORG goals that had > or =1 medically necessary days; and (3) number of inpatient stays not meeting ORG goals that had > or =1 medically unnecessary days. RESULTS: Multiple logistic regression results indicated that inpatient stays were more likely to be within ORG utilization goals when managed by hospitalists vs nonhospitalists (P < .05). Introduction of the hospitalist program reduced the number of stays with unnecessary days among staff inpatients. There was an increase in stays with unnecessary days in the comparison group, ie, inpatients managed by network physicians. CONCLUSIONS: Full-time hospitalists are efficient managers of HMO inpatients. The ORGs for acute, uncomplicated diagnoses provided useful hospital utilization measures that captured inpatient management by hospitalists and PCPs.

Adolescent↗
PubMed2000

Role of the zebrafish trilobite locus in gastrulation movements of convergence and extension.

Convergence and extension are gastrulation movements that participate in the establishment of the vertebrate body plan. Using new methods for quantifying convergence and extension movements of cell groups, we demonstrate that in wild-type embryos, dorsal convergence of lateral cells is initially slow, but speeds up between the end of the gastrula period and early segmentation. Convergence and extension movements of lateral cells in trilobite mutants are normal during the gastrula period but reduced by early segmentation. Morphometric studies revealed that during epiboly wild-type gastrulae become ovoid, whereas trilobite embryos remain rounder. By segmentation, trilobite embryos exhibit shorter, broader embryonic axes. The timing of these morphological defects correlates well with impaired cell movements, suggesting reduced convergence and extension are the main defects underlying the trilobite phenotype. Our gene expression, genetic, and fate mapping analyses show the trilobite mutation affects movements without altering dorsoventral patterning or cell fates. We propose that trilobite function is required for cell properties that promote increased speed of converging cells and extension movements in the dorsal regions of the zebrafish gastrula.

Animals↗
PubMed1999

Urinary albumin and insulin as predictors of coronary artery disease: An angiographic study.

Microalbuminuria has been associated with cardiovascular risk factors, events, and mortality. It also clusters with hyperinsulinemia and the metabolic syndrome. How urinary albumin excretion and the fasting serum insulin level relate to coronary artery disease (CAD) has not been previously determined. In 308 patients undergoing elective coronary angiography, the albumin to creatinine ratio was measured in urine from an early morning void. The fasting serum insulin level was also determined. CAD was assessed by angiography. Urinary albumin excretion was 28 +/- 5 mg/g (mean +/- SE) in patients with CAD and 10 +/- 1 mg/g in those without CAD (P < 0.001). Fasting serum insulin levels were also greater in patients with CAD compared with those without CAD; 20 +/- 3 and 13 +/- 1 microU/mL, respectively (P = 0.016). Urinary albumin excretion and fasting serum insulin levels increased progressively with severity of CAD. In patients without diabetes (n = 255), significant relationships of urinary albumin excretion and the fasting serum insulin levels to CAD were observed, but they were more pronounced when patients with diabetes (n = 53) were included. In multiple regression analysis, the odds ratios for severe CAD were 2.2 (95% confidence interval, 1.1 to 4.5) for microalbuminuria and 2. 2 (95% confidence interval, 1.3 to 3.8) for hyperinsulinemia. In summary, urinary albumin excretion and the fasting serum insulin levels were directly related to angiographic evidence of CAD. Microalbuminuria and hyperinsulinemia predict a significantly elevated risk for coronary atherosclerosis.

Aged↗
PubMed1998

Teaching safe sex in school.

OBJECTIVE: To teach safe sex practices to adolescents in school, before they start to become sexually active, using peer group education. METHOD: To send young medical students back to their old schools to do the teaching, and to get them to make videos suitable for showing to teenage audiences that can be widely circulated to all schools. RESULTS: The program has been running in Australia since 1992, and has proved highly popular with school teachers, school children, and particularly with medical students. We are now working with medical schools in Beijing and Shanghai, at the invitation of the Chinese Ministry of Health, to see if we can adapt our program to a very different cultural setting. CONCLUSION: Educating children about Safe Sex is one of the most effective ways of postponing their onset of sexual activity. It is also the best investment that we can make to ensure people's future reproductive health; if they start right, there is every hope that they will stay right.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Using the outcome-based quality improvement model and OASIS to improve HMO patients' outcomes. Outcome Assessment and Information Set.

The study purpose was to determine if use of the Outcome-Based Quality Improvement (OBQI) model, including a subset of the outcome Assessment and Information Set (OASIS), enhanced outcomes for health maintenance organization (HMO) patients referred for care to six contracted home health agencies (HHAs). After four quarters of data-driven quality improvement activities, the improvement scores of the patients were not changed significantly from the baseline period. Stabilization scores increased significantly for two of the five outcome measures. Use of OASIS and the OBQI model for HMO patients referred to multiple HHAs requires that contracted HHAs share outcome results and quality improvement conclusions.

Aged↗
PubMed1997

Circulating antioxidants as determinants of the rate of biological aging in pigtailed macaques (Macaca nemestrina).

The effect of antioxidant activity on the rate of biological aging was studied in 39 pigtailed macaques (Macaca nemestrina) 7-30 years of age. Scores of seven antioxidant compounds (vitamins C and E, carotenoids, urate, bilirubin, ceruloplasmin, and albumin) were combined to produce an antioxidant variable (AOx) that was tested for correlation with a second composite variable, rate of biological aging (RBA). RBA was formed from seven physiological variables that met a stringent set of criteria as biomarkers of aging. Potential effects of disease on RBA and AOx were excluded by experimental design and by statistical control using a composite index of disease (Dis) that was based on four measures of clinical history and pathology. The study produced three salient findings: (1) there was a significant inverse relation between AOx and RBA (i.e., animals that had high AOx scores had low RBA scores and vice versa); (2) the relation was independent of Dis effects, and (3) there was no significant relation between AOx and Dis independent of RBA (i.e., the correlation between AOx and Dis was dependent on the correlation of AOx with RBA). These results further validated the RBA variable as a measure of the rate of biological aging and supported the concept that antioxidant activity influences both the rate of biological aging and vulnerability to disease.

Aging↗
PubMed1995

Diabetes update.

Explore the source record for details and available documents.

Diabetes Mellitus↗
PubMed1994

Immunologic markers in a longitudinal study of aging in pigtailed macaques (Macaca nemestrina).

Blood lymphocyte subsets, serum immunoglobulins (Ig), response of lymphocytes to mitogens, and natural killer (NK) cell activity were evaluated as potential biomarkers for primate aging. All were evaluated in a cross-sectional study of 60 pigtailed macaques (Macaca nemestrina) ranging from 2 to 32 years of age. Lymphocyte responses to mitogens were lower in older animals than in most younger ones. NK cell activity showed no clear relation to age cohort. In a longitudinal study of lymphocyte subsets and immunoglobulins, class I restricted T cells (CD8+bri) of the memory (CD18+bri) subtype increased with age, whereas those of the naive (CD18+dull) subtype decreased with age in females. A class II restricted T-cell subset (CD4+CD45RA-), which includes memory T cells, increased with age in females. Serum IgA increased. These results support the utility of memory and naive subsets of CD8+ T cells, CD4+ T cells, and serum IgA as biomarkers for longitudinal studies. Total lymphocytes, total T cells, CD4+ T cells, and CD8+ T cells may also be useful in this species.

Aging↗
PubMed1992

Seroprevalence of HIV infection in rural South Africa.

OBJECTIVES: To establish the prevalence of HIV infection in rural South Africa and to investigate demographic factors that influence this prevalence. DESIGN: An anonymous HIV seroprevalence survey was performed in conjunction with a population-based malaria surveillance programme. SETTING: The rural area of northern Natal/KwaZulu, South Africa. PARTICIPANTS: A total of 5023 black African participants were recruited by malaria surveillance agents during house-to-house visits; each house in an endemic malaria area is visited approximately once every 6 weeks. Participants included 4044 healthy and 979 febrile individuals (i.e., suspected of having malaria). MAIN OUTCOME MEASURES: HIV-1 and HIV-2 serological status, degree of mobility, age and sex. RESULTS: Sixty of the 5023 blood specimens were confirmed to be HIV-1-antibody-positive by Western blot, an overall prevalence of 1.2% (95% confidence interval, 0.9-1.5). None of the specimens was positive for HIV-2 antibodies. After adjusting for age, presence of fever and migrancy, women had a 3.2-fold higher prevalence of HIV-1 infection than men. HIV-1 infection was approximately three times more common among subjects who had changed their place of residence recently (2.9 versus 1.0%, P < 0.01). CONCLUSIONS: The prevalence of HIV-1 infection is higher among women than men resident in rural Natal/KwaZulu, South Africa. This is at least in part the result of oscillatory migration, particularly of men who work in urban areas but have families and homes in rural areas. Migration is associated with a higher prevalence of HIV-1 infection, suggesting that improving social conditions so that families are not separated and become settled in their communities is one way to help reduce the spread of HIV-1.

Adolescent↗