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Biomedical subjects

D Douglas

Publications and source records attributed to D Douglas.

At least 19 recordsLinked to original sources
PubMed2003

Long QTc predicts future cardiac death in stroke survivors.

OBJECTIVES: To test the hypothesis that the QTc of any lead of the ECG predicts death after stroke, and to determine which lead of the ECG carries the greatest risk of cardiac death when its QTc is measured. DESIGN: Standard 12 lead ECGs were analysed by one observer who was blind to patient outcome. SETTING: A major teaching hospital in Scotland. PATIENTS: 404 stroke survivors were studied at approximately one year after the cerebrovascular event and followed for up to 6.3 years. OUTCOME MEASURES: Death from any cause and cardiac mortality. RESULTS: The QTc measured from any lead of the ECG (except aVR) was associated with death from any cause. A prolonged QTc in limb lead III and chest lead V6 carried the highest relative risk of cardiac death (a 3.1-fold incease). After adjusting for overt ischaemic heart disease, pulse pressure, glucose, and cholesterol, a prolonged QTc in lead V6 was associated with a relative risk of cardiac death of 2.8 (95% confidence interval (CI) 1.1 to 7.3) (p = 0.028) and of death from all causes of 2.9 (95% CI 1.6 to 5.3) (p < 0.001). If the QTc in V6 exceeded 480 ms, then the specificity of predicting cardiac death within five years after the stroke was 94%. CONCLUSIONS: Although treatment of the conventional modifiable risk factors is important, stroke survivors with a prolonged QTc in lead V6 are still at a high risk of cardiac death and may need more intensive investigations and treatments than are currently routine practice.

Adult↗
PubMed2001

STR primer concordance study.

Over 1500 population database samples comprising African Americans, Caucasians, Hispanics, Native Americans, Chamorros and Filipinos were typed using the PowerPlex 16 and the Profiler Plus/COfiler kits. Except for the D8S1179 locus in Chamorros and Filipinos from Guam, there were eight examples in which a typing difference due to allele dropout was observed. At the D8S1179 locus in the population samples from Guam, there were 13 examples of allele dropout observed when using the Profiler Plus kit. The data support that the primers used in the PowerPlex 16, Profiler Plus, and COfiler kits are reliable for typing reference samples that are for use in CODIS. In addition, allele frequency databases have been established for the STR loci Penta D and Penta E. Both loci are highly polymorphic.

Alleles↗
PubMed2001

Release of biologically active TGF-beta from airway smooth muscle cells induces autocrine synthesis of collagen.

In severe or chronic asthma, there is an increase in airway smooth muscle cell (ASMC) mass as well as an increase in connective tissue proteins in the smooth muscle layer of airways. Transforming growth factor-beta (TGF-beta) exists in three isoforms in mammals and is a potent regulator of connective tissue protein synthesis. Using immunohistochemistry, we had previously demonstrated that ASMCs contain large quantities of TGF-beta1-3. In this study, we demonstrate that bovine ASMC-derived TGF-beta associates with the TGF-beta latency binding protein-1 (LTBP-1) expressed by the same cells. The TGF-beta associated with LTBP-1 localizes TGF-beta extracellularly. Furthermore, plasmin, a serine protease, regulates the secretion of a biologically active form of TGF-beta by ASMCs as well as the release of extracellular TGF-beta. The biologically active TGF-beta released by plasmin induces ASMCs to synthesize collagen I in an autocrine manner. The autocrine induction of collagen expression by ASMCs may contribute to the irreversible fibrosis and remodeling seen in the airways of some asthmatics.

Animals↗
PubMed2000

Sustained kilowatt lasing in a free-electron laser with same-cell energy recovery

Jefferson Laboratory's kW-level infrared free-electron laser utilizes a superconducting accelerator that recovers about 75% of the electron-beam power. In achieving first lasing, the accelerator operated "straight ahead" to deliver 38-MeV, 1.1-mA cw current for lasing near 5 &mgr;m. The waste beam was sent directly to a dump while producing stable operation at up to 311 W. Utilizing the recirculation loop to send the electron beam back to the linac for energy recovery, the machine has now recovered cw average currents up to 5 mA, and has lased cw with up to 1720 W output at 3.1 &mgr;m.

Journal Article↗
PubMed2000

The cost of treatment of distal radial fractures.

In an increasingly cost conscious management of health care, estimating the cost of treatment of distal radial fractures has significant relevance. We studied 100 distal radial fractures, prospectively, from their presentation to eventual discharge. On an average, pound320.50 were spent on each patient during 1997. Ninety percent of the costs were seen to be service costs and only 10% were those of consumables. A proportion of costs incurred due to remanipulations could have been saved by supervised primary treatment. Also, lack of protocols resulted in increased use of clinic time, physiotherapy sessions and radiographs. In-patient treatment was seen to account for the bulk of the expenditure. We have identified certain guidelines to improve the primary treatment of these fractures and the possibility of treating them in designated sessions in the day surgery unit. This is likely to reduce the overall cost of treatment of these very commonly sustained fractures though this will need to be proved in a future validated study.

Accidental Falls↗
PubMed2000

E-cadherin expression is silenced by 5' CpG island methylation in acute leukemia.

E-Cadherin is a transmembrane glycoprotein that mediates Ca2+-dependent intercellular adhesion in normal epithelium. In tumors of epithelial origin, E-cadherin expression frequently is reduced, an event that contributes to tumor invasion and metastasis. The role of E-cadherin in hematopoietic tissues is less clear. In normal bone marrow, E-cadherin is expressed on erythroid progenitors, CD34+ stem cells, and stromal cells, where it likely contributes to intercellular interactions during hematopoiesis. In this study, we used a nested-PCR approach to examine the methylation status of the E-cadherin 5' CpG island in blood and bone marrow samples from normal donors and in bone marrow from patients with acute leukemia. In normal peripheral blood mononuclear cells and bone marrow, E-cadherin was completely unmethylated. In peripheral blood mononuclear cells, expression was evident by reverse transcription-PCR. Immunoblotting confirmed E-cadherin protein expression in two lymphoblastoid cell lines derived from normal donors. In contrast, E-cadherin was aberrantly methylated in 4 of 4 (100%) leukemia cell lines, 14 of 44 (32%) acute myelogenous leukemias, and 18 of 33 (53%) acute lymphoblastic leukemias. Genomic bisulfite sequencing of primary leukemias confirmed dense methylation across the CpG island. Methylation was associated with loss of E-cadherin RNA and protein in leukemia cell lines and primary leukemias. Following treatment with 5-aza-2'-deoxycytidine, a methylated leukemia cell line expressed both E-cadherin transcript and protein. Our results show that methylation of E-cadherin occurs commonly in acute leukemia and suggests a hypothesis for E-cadherin down-regulation in leukemogenesis.

Cadherins↗
PubMed1997

Estrogen receptor variants and mutations.

There is a large and increasing body of experimental and clinical data supporting the existence or variant estrogen receptor (ER) proteins in both normal and neoplastic estrogen target tissues including human breast. Therefore, future examination of ER signal transduction and/or measurement of ER protein must take into account variant ER expression. The functions of variant ER proteins, either physiological or pathological, remain unclear, although a role(s) for some ER variants in breast tumorigenesis and breast cancer progression would be consistent with the accumulated data. Possible tissue specific expression leads to the speculation that ER variants may have a role in tissue specific estrogen action. The following review focuses on the current knowledge available in the scientific literature with respect to the type and characteristics of estrogen receptor variants and mutations that have been identified to occur naturally in tissues and cell lines.

Animals↗
PubMed1997

Oestrogen receptor variants and mutations in human breast cancer.

Several oestrogen receptor variant and mutated mRNA species have been identified in human breast samples and cell lines. Over-expression and altered expression of some of these mRNAs have been correlated with breast tumourigenesis and progression. The following review focuses on the current knowledge available in the scientific literature with respect to the type and characteristics of oestrogen receptor variants and mutations that have been identified as occurring naturally in human breast tissues and cell lines.

Animals↗
PubMed1996

Episodes of care: should we have them?

In this paper the authors discuss the introduction of 'episodes of care', a new system for monitoring hospital-linked patient care services. They consider the proposal in the context of clinical, financial and technical frameworks. The authors conclude that health planners are likely to benefit from the the introduction of this form of monitoring. The proposed change would also allow more accurate analysis of the true cost of interventions. However, it is likely to require significant investment in information technology and there may be loss of patient confidentiality.

Australia↗
PubMed1996

Turning around patient complaints in a regional hospital.

This paper describes the introduction by a regional general hospital of a different system for handling complaints from patients. It outlines the underlying philosophy of the new system and the experiences of the hospital as the new system matured. The paper provides data for the first six quarters of operation of the system.

Attitude of Health Personnel↗
PubMed1996

Biomass accumulation in hydroponically grown sweetpotato in a controlled environment: a preliminary study.

In the development of a plant growth model, the assumptions made and the general equations representing an understanding of plant growth are gradually refined as more information is acquired through experimentation. One such experiment that contributed to sweetpotato model development consisted of measuring biomass accumulation of sweetpotato grown in hydroponic culture in a plant growth chamber. Plants were started from fifteen centimeter long 'TU-82-155' sweetpotato vine cuttings spaced 25 cm apart in each of 18 rectangular growing channels (0.15 by 0.15 by 1.2m) in a system designed to use the nutrient film technique (NFT). Each channel contained four plants. The 3.5m by 5.2m plant growth chamber environmental parameters included an 18h photoperiod, 500 micromoles m-2 s-1 of photosynthetic photon flux (PPF), and a diurnal light/dark temperature of 28 degrees C/22 degrees C. The relative humidity was 80 +/- 5% and the CO2 partial pressure was ambient (350 ppm). The nutrient solution contained in 30L reservoirs was a modified half Hoagland's solution with a 1:2.4 N:K ratio and a pH of 6.2. Solution replenishment occurred when the electrical conductivity (EC) level dropped below 1050. Plants were harvested at 15 days after planting (DAP) and weekly thereafter until day 134. By 57 DAP, stems and fibrous roots had acquired 90% of their total dry biomass, while leaves had reached 84% of their maximum dry biomass. Beginning at 64 DAP dry biomass accumulation in the storage roots dominated the increase in dry biomass for the plants. Dry weight of storage roots at 120 DAP was 165 g/plant or 1.1 kg/m2. Resulting growth curves were consistent with the physiological processes occurring in the plant. Results from this study will be incorporated in a plant growth model for use in conjunction with controlled life support systems for long-term manned space missions.

Biomass↗
PubMed1995

Clinical characteristics related to severity of sexual abuse: a study of seriously mentally ill youth.

OBJECTIVE: In this study we examined demographic, social, and clinical variables related to sexual abuse histories in a sample of severely mentally ill youth. METHOD: Data were collected via a retrospective chart review of all patients treated over a 5-year period (1987-1992) at a tertiary care public sector psychiatric hospital. The sample was divided into four groups: no history of sexual abuse (n = 226); isolated events (n = 62); intermittent abuse (n = 61); and chronic (n = 150). RESULTS: Youth with sexual abuse histories were more often female, had higher rates of social chaos and associated physical abuse and neglect, and had higher rates of post-traumatic stress disorder (PTSD) and substance abuse disorders. Chronically abused subjects came from the most chaotic and abusive backgrounds; were younger when first abused; had the highest number of abusers; were more likely to have been molested; and were more often abused by their father/stepfather and/or their mother/stepmother. Using logistic regression analyses, sexual abuse histories were predicted by sexually inappropriate behaviors, symptoms of PTSD and borderline personality disorders, dissociative symptoms, substance abuse and animal cruelty. CONCLUSION: Sexual abuse histories were quite common in this sample. Sexually abused subjects had increased rates of inappropriate sexual behaviors, substance abuse, and post-traumatic reactions; and were frequently exposed to other confounding environmental risk factors, including physical abuse, family problems and social chaos.

Adolescent↗
PubMed1995

Dehydration and orthostatic vital signs in women with hyperemesis gravidarum.

OBJECTIVES: To assess the hydration status of women presenting to an ED with hyperemesis gravidarum and to determine whether clinically relevant changes in orthostatic vital signs occur. METHODS: A convenience sample of 23 pregnant women who had hyperemesis gravidarum, with each patient serving as her own control. The study took place in the ED observation unit of an urban teaching hospital. Women who had pregnancies of < or = 16 week's gestation who had been vomiting for at least 24 hours were included. Supine and standing pulse rates and blood pressures (BPs) were measured sequentially after 5 minutes in each position. Patient weight and urine specific gravity (SG) also were recorded. After 6 L of lactated Ringer's solution was infused over a 12-hour period, the same measurements were repeated. Pre- and posthydration changes were analyzed using the paired t-test. RESULTS: The mean treatment weight gain as a percentage of the total body weight was 5.6% +/- 2.2% (mean +/- SD). The urine SG decreased from 1.027 +/- 0.004 to 1.008 +/- 0.003 (p < 0.001). The mean change in systolic BP upon assuming the standing position was -8.3 +/- 12.7 mm Hg before hydration vs 2.9 +/- 7.8 mm Hg after hydration (p < 0.001). The corresponding change in mean diastolic BP was 3.7 +/- 10.9 mm Hg before hydration vs 8.6 +/- 10.9 mm Hg after hydration (p = 0.12). The mean change in pulse rate upon standing was 26.8 +/- 14.5 beats/min before hydration vs 14.5 +/- 10.1 beats/min after hydration (p = 0.002). CONCLUSIONS: Women who present to the ED with hyperemesis gravidarum are significantly dehydrated and experience measurable improvement in postural pulse rate and systolic BP changes with rehydration. However, the presenting orthostatic changes lack sufficient sensitivity to be effectively used as quantitative screening tests for dehydration.

Adolescent↗
PubMed1995

A critique of 'at risk' pressure sore assessment tools.

This paper critiques pressure sore risk assessment tools. No attempt is made to describe individual tools in detail as this literature is available elsewhere. The economic case for risk assessment is presented along with the criteria for an effective risk assessment instrument. Reliability and validity studies are reviewed in relation to three risk assessment tools: Norton, Waterlow and Braden. Finally a number of issues related to threshold scores, research design and the need to view pressure sores as a clinical problem rather than a nursing problem are discussed.

Humans↗