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Biomedical subjects

C Edwards

Publications and source records attributed to C Edwards.

At least 73 records · Page 4Linked to original sources
PubMed2000

Functional brain imaging of movement disorders.

Functional brain imaging techniques such as positron emission tomography (PET) have contributed to our understanding of the pathophysiology of Parkinson's disease (PD) and other movement disorders. PET employs small amounts of positron emitting radioligands to produce quantitative measures of physiological and biochemical processes in the brain and other organs. In a PET experiment, a subject is given a compound of biological interest. The spatial and temporal distribution of the radiotracer is measured quantitatively in the course of the PET study, providing a tomographic representation of regional radioactivity concentration. In this review, we focus on the potential application of PET in the selection of suitable candidates and the assessment of surgical interventions such as pallidotomy, thalamotomy, and deep brain stimulation.

Brain↗
PubMed2000

Rapid detection of Campylobacter jejuni in stool specimens by an enzyme immunoassay and surveillance for Campylobacter upsaliensis in the greater Salt Lake City area.

The Alexon-Trend, Inc. (Ramsey, Minn.), ProSpecT Campylobacter microplate assay was compared with culture on a Campy-CVA plate (Remel, Lenexa, Kans.) and blood-free campylobacter agar with cefoperazone (20 microg/ml), amphotericin B (10 microg/ml), and teicoplanin (4 microg/ml) (CAT medium; Oxoid Limited, Hampshire, England) with 631 patient stool samples. The CAT medium was used to isolate Campylobacter upsaliensis. The enzyme immunoassay (EIA) had a sensitivity and a specificity of 89 and 99%, respectively, and the positive and negative predictive values were 80 and 99%, respectively. Even though we extensively looked for C. upsaliensis in stool samples from patients from the greater Salt Lake City area, we did not isolate this species during the study period. The overall excellent specificity of the EIA allows rapid detection and treatment of positive patients; however, a negative result should be confirmed by culture when clinical suspicion is high.

Campylobacter↗
PubMed2000

Problems posed by natural environments for monitoring microorganisms.

Microorganisms in natural environments have evolved to withstand fluctuations in physical and chemical conditions. This means that they often manifest very different biochemical and morphological features compared with those seen during laboratory culture. A major limitation in natural ecosystems is nutrient limitation under which microorganisms are exposed to starvation conditions and grow slowly or not at all. This review identifies the role of inimical processes on microbial properties such as the responses to starvation that may result in the adoption of viable but nonculturable (VBNC) states, discusses the problems that altered physiological states pose for detection and identification and highlights novel methods that have been developed to circumvent these difficulties. These factors dictate that to survive and respond to environmental stimuli, a cell must have evolved sophisticated programs of gene expression. These include the sigma factor rpoS that directs RNA polymerase to transcribe genes whose expression aids survival during severe nutrient limitation or cell-cell communication systems that promote a concerted population response termed quorum sensing.

Adaptation, Physiological↗
PubMed2000

The influence of (R)- and (S)-warfarin, vitamin K and vitamin K epoxide upon warfarin anticoagulation.

The contribution of (R)- and (S)-warfarin enantiomers, vitamin K and vitamin K epoxide and patient factors to inter-individual variability in daily warfarin requirements were examined in a group of 73 patients. Simple correlation analysis showed a significant positive relationship between INR values and plasma (S)-warfarin concentrations (r = 0.25; p = 0.038). Multivariate analysis for relationships with INR demonstrated a highly significant positive relationship between INR and (S)-warfarin (p = 0.004) and plasma vitamin K epoxide concentrations (p = 0.028), and a significant negative relationship between INR and plasma vitamin K concentrations (p = 0.034). Twenty five percent of variation in INR could be explained by these variables (adjusted R2 = 0.25). Correlation analysis of data showed that warfarin dosage was significantly and negatively correlated with patient age (r = -0.42; p <0.0001). Patient age accounted for 25% of variation in warfarin dosage requirements (R2 = 0.25). The combined effects of age and vitamin K appear to account for much of the inter-individual variability in warfarin dosage requirements.

Adult↗
PubMed2000

Disseminated osteoarticular sporotrichosis: treatment in a patient with acquired immunodeficiency syndrome.

We report a case of multiple skin lesions, lymphadenopathy, and osteoarticular sporotrichosis in a man infected with human immunodeficiency virus (HIV). He subsequently died of tuberculosis after successful treatment for osteoarticular sporotrichosis with amphotericin B. We describe the unusual histopathology in disseminated sporotrichosis with acquired immunodeficiency syndrome (AIDS) and compare it with that seen in patients without AIDS. Although the optimal treatment of osteoarticular sporotrichosis in patients with AIDS is unknown, use of amphotericin B in our patient appeared successful. Culture and histologic stains of all tissues taken at autopsy were negative for sporotrichosis. Recent studies of similar cases have shown initial treatment with amphotericin B followed by long-term maintenance with itraconazole to be beneficial.

AIDS-Related Opportunistic Infections↗
PubMed2000

Photosensitization of pancreatic tumour cells by delta-aminolaevulinic acid esters.

A series of straight chain, branched and cyclo-delta-aminolaevulinic acid (ALA) esters have been synthesized and their photosensitizing properties analysed using an in vitro system of rat pancreatoma cells. Structurally favourable ALA esters not only induced the formation of more of the endogenous photosensitizer, protoporphyrin IX (PpIX), but they did so at a faster rate than ALA itself. This action was reflected in a substantial increase in photocytotoxicity of some 270 times, using the more potent ALA esters. An important structural feature was identified in two of the ALA esters which greatly limited PpIX production, i.e. a branch point located next to the site of ester cleavage. Experiments on the transport of ALA and of ALA esters across the cell membrane showed that ALA, but not ALA esters, gain access to the cell via the di- and tripeptide transporter, PEPTI. Finally, these results show that the esterification of ALA can greatly increase its cellular uptake, so generating more intracellular PpIX, improved tumour cell photosensitization and enhanced photocytotoxicity.

Aminolevulinic Acid↗
PubMed2000

Complications following combined surgery (radical vulvectomy versus wide local excision) and radiotherapy for the treatment of carcinoma of the vulva: report of 73 patients.

Cancer of the vulva is uncommon, accounting for only 5% of all gynecologic malignancies, and usually occurs in women over 60 years of age. The historic treatment of choice for invasive squamous cell carcinoma of the vulva is radical vulvectomy with bilateral inguinal lymphadenectomy, which has produced excellent long-term survival. We retrospectively analyzed the complications of wide local excision plus postoperative radiotherapy compared with those of radical vulvectomy and bilateral lymphadenectomy plus pre-or postoperative radiotherapy in 73 patients with vulvar cancer. There were no significant differences among these treatments in terms of primary tumor control, 5-year disease-free survival, and overall survival. Based on these results, the best treatment alternative for advanced vulvar cancer is wide local excision plus radiotherapy, as this method retains the high survival of traditional therapy but has less morbidity.

Adenocarcinoma↗
PubMed1999

REM sleep in depression is influenced by ethnicity.

The influence of ethnicity on the manifestation of EEG sleep changes in depression was studied in 95 patients (21 African-Americans [AA], 17 Asians [AS], 37 Caucasians [C] and 20 Hispanics [H]) with unipolar major depression. Subjects were studied twice for 2 consecutive nights. On the second night of each 2-night session, placebo or scopolamine (1.5 microg/kg, IM, at 23.00 h) was administered. On the baseline (placebo) night, sleep architecture, sleep continuity and rapid eye movement (REM) sleep variables were generally comparable among the groups. However, REM sleep was less in AA and AS subjects than in C and H subjects. Furthermore, the distribution of REM sleep over the course of the night in AA and AS subjects differed significantly from that in the C and H groups. Although scopolamine significantly affected sleep continuity and REM sleep measures, no significant differential effects of scopolamine were observed. Because many antidepressants suppress REM sleep, the differences in baseline REM sleep observed might be related to the greater sensitivity of some ethnic-minority depressed patients to pharmacotherapy.

Adult↗
PubMed1999

Soluble tumor necrosis factor receptor prevents post-pump syndrome.

Post-pump syndrome is an acute lung injury following cardiopulmonary bypass (CPB) which is indistinguishable from the adult respiratory distress syndrome (ARDS). Tumor necrosis factor (TNF) is central to the inflammatory process and is capable of triggering the entire pathophysiologic response leading to ARDS. We hypothesized that treatment with a soluble TNF receptor-binding protein (TNFbp) would reduce the increase in serum TNF and prevent acute lung injury in our sequential insult model of ARDS following CPB. Anesthetized pigs were randomized to one of three groups: Control (n = 3), surgical preparation only; CPB + LPS (n = 6), femoral-femoral hypothermic bypass for 1 h followed by infusion of low dose Escherichia coli lipopolysaccharide (LPS; 1 microg/kg); and TNFbp + CPB + LPS (n = 4), pretreatment with intravenous TNFbp (2 mg/kg) followed immediately by both insults. CPB + LPS caused severe lung injury demonstrated by a significant fall in PaO2 and an increase in both intrapulmonary shunt and peak airway pressure as compared to all groups (P < 0.05). These changes were associated with a significant increase in plasma TNF level and pulmonary neutrophil sequestration. TNFbp significantly reduced plasma levels of TNF and prevented the lung injury typically observed with this ARDS model, but did not reduce pulmonary neutrophil sequestration. Thus, elevated serum TNF is not responsible for neutrophil sequestration but does play a role in neutrophil activation which causes lung injury. Prophylactic use of TNFbp in CPB patients may prevent neutrophil activation and reduce the incidence of post-pump ARDS.

Animals↗
PubMed1999

Molecular Ecological Analysis of Methanogens and Methanotrophs in Blanket Bog Peat.

Abstract Methane production and methane oxidation potential were measured in a 30 cm peat core from the Moorhouse Nature Reserve, UK. The distribution of known groups of methanogens and methane oxidizing bacteria throughout this peat core was assessed. Using 16S rRNA gene retrieval and functional gene probing with genes encoding key proteins in methane oxidation and methanogenesis, several major groups of microorganisms were detected. Methane production and oxidation was detected in all depths of the peat core. PCR amplification and oligonucleotide probing experiments using DNA isolated from all sections of the peat core detected methanotrophs from the groups Methylosinus and Methylococcus and methanogens from the groups Methanosarcinaceae, Methanococcaceae, and Methanobacteriaceae. 16S rDNA sequences amplified with the Methylosinus-specific primer were shown to have a high degree of identity with 16S rDNA sequences previously detected in acidic environments. However, no methanogen sequences were detected by the probes available in this study in the sections of the peat core (above 7 cm) where the majority of methanogenesis occurred, either because of low methanogen numbers or because of the presence of novel methanogen sequences.http://link.springer-ny.com/link/service/journals/00248/bibs/38n3p225.html</hea

Journal Article↗
PubMed1999

Effects of cultural conditions on denitrification by pseudomonas stutzeri measured by membrane inlet mass spectrometry

Denitrification is a globally important process leading to loss of fertiliser efficiency and the production of the greenhouse gas nitrous oxide and nitric oxide, an ozone depleter. Membrane inlet mass spectrometry (MIMS) was employed to study the effect of different variables on the process of denitrification by Pseudomonas stutzeri in a defined salts medium. MIMS was used for concomitant measurements of nitrous oxide, nitrogen and oxygen and showed that denitrification occurred in the presence of dissolved oxygen. A nitrate concentration of 15 mmol l-1 and a nitrite concentration of 5 mmol l-1 were found to be optimum for complete denitrification of nitrate or nitrite to nitrogen and varying these concentrations had a marked effect on the ratio of gaseous products released. Denitrification products were also dependant on pH with neutral or alkaline conditions being best for production of gaseous end products. Our results suggest that under nutrient rich conditions the most important factor in the regulation of denitrification by Ps. stutzeri is the amount of nitrite generated at the first enzymatic stage of the process. This appears to cause inhibition of the denitrification pathway above 5 mmol l-1 and at high enough concentrations (15 mmol l-1) restricts growth.

Journal Article↗
PubMed1999

'Something always comes up': nurse-patient interaction in an acute psychiatric setting.

In this study, 10 nurses and 10 patients were interviewed to explore factors influencing nurse-patient interactions in an acute psychiatric inpatient facility. The six themes that emerged from the nursing interviews were; environment, something always comes up, nurses' attributes, patient factors, instrumental support and focus of nursing. The four themes from the patient interviews were; nurses' attributes, role perceptions, clinical care, and time. These findings have implications for clinical practice, the nurses' role and nursing education.

Acute Disease↗
PubMed1999

Factors influencing nurse-patient interaction in the acute psychiatric setting: an exploratory investigation.

Nurse-patient interaction in acute psychiatric in-patient facilities has been the subject of much discussion in the literature and remains a contentious issue. How and why nurses interact with patients in the acute care setting requires definition within the current dynamic environment of mental health service provision. Factors which impact on the manner in which nurses care for patients also require investigation. This article presents the findings of a collaborative research study that investigates factors that influence nurse-patient interaction in the acute psychiatric setting. Ten nurses on the study ward were given opportunity, through semi-structured interviews, to outline and describe the factors perceived to influence nurse-patient interaction. Factors identified as influencing interaction included the ward environment, something always comes up, nurses' attributes, patient factors, instrumental support and focus of nursing. Issues which emerged from the study provide managers and clinical nurses with an opportunity for generating new possibilities for nurse-patient interaction. However, these issues must be addressed in a sensitive way that takes into account the complex and dynamic nature of acute care settings.

Acute Disease↗
PubMed1999

Patients with t(8;21)(q22;q22) and acute myeloid leukemia have superior failure-free and overall survival when repetitive cycles of high-dose cytarabine are administered.

PURPOSE: To examine the effect of single compared with repetitive (at least three) cycles of high-dose cytarabine after induction therapy for patients with acute myeloid leukemia (AML) who have the t(8;21)(q22;q22) karyotype. PATIENTS AND METHODS: Patients entered onto the study had AML and t(8;21) and attained a complete remission on four successive Cancer and Leukemia Group B studies. In these studies, either > or = three cycles of high-dose cytarabine or one cycle of high-dose cytarabine was administered, followed by sequential cyclophosphamide/etoposide and mitoxantrone/diaziquone with or without filgrastim support. Outcomes of these two groups of t(8;21) patients were compared. RESULTS: A total of 50 patients with centrally reviewed AML and t(8;21) were assigned to receive one (n = 29) or > or = three cycles (n = 21) of high-dose cytarabine as postinduction therapy. The clinical features of these two groups of patients were similar. Initial remission duration for t(8;21) patients assigned to one cycle of high-dose cytarabine was significantly inferior (P =.03), with 62% of patients experiencing relapse with a median failure-free survival of 10.5 months, compared with the group of patients who received > or = three cycles, in which only 19% experienced relapse and failure-free survival is estimated to be greater than 35 months. Furthermore, overall survival was also significantly compromised (P =.04) in patients assigned to one cycle of high-dose cytarabine, with 59% having died as a consequence of AML, compared with 24% of those who received > or = three cycles of high-dose cytarabine. CONCLUSION: These data demonstrate that failure-free survival and overall survival of patients with t(8;21)(q22;q22) may be compromised by treatment approaches that do not include sequential high-dose cytarabine therapy.

Adolescent↗
PubMed1999

Success habits of long-term gastric bypass patients.

BACKGROUND: By identifying common habits of the most successful long-term gastric bypass patients, one is able to establish more specific guidelines for new patients to follow. The first postoperative year is a critical time that must be dedicated to changing old behavior and forming new, lifelong habits. METHODS: 100 gastric bypass patients from 1979 to 1995 participated in a comprehensive survey. Surveys were completed in person, by phone, or in writing. Participants were asked to answer questions regarding their eating, drinking, sleeping, exercise, and personal habits. RESULTS: The survey revealed that specific habits are common in gastric bypass patients who have maintained their weight loss for many years. CONCLUSION: Identifying and defining the common habits of patients who are successful with long-term weight loss enabled specific guidelines to be established for new patients to implement during the initial weight loss phase, which will contribute to life-long success.

Data Collection↗