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Biomedical subjects

J Allen

Publications and source records attributed to J Allen.

At least 91 records · Page 5Linked to original sources
PubMed2000

A randomized controlled evaluation of specialist nurse education following accident and emergency department attendance for acute asthma.

We investigated whether hospital-based specialist asthma nurses improved recognition and self-treatment of asthma episodes by patients followed up after attending accident and emergency departments (A&E) for asthma exacerbations. We carried out a randomized prospective controlled trial of adult asthma self-management, following a hospital outpatient nurse consultation in two outer-London District General Hospitals (secondary care centres). The study included 211 adults, over 18 years old (mean age 40 years) who attended for asthma in two accident and emergency departments over 13 months. One hundred and eight evaluable patients were randomized into the control group who continued with their usual medical treatment and were not offered any intervention during the study period. One hundred and three evaluable patients were randomized into the intervention group. They were offered three 6-weekly outpatient appointments with one of two specialist asthma nurses for a structured asthma consultation, after attendance at the accident and emergency department. Following assessment of their asthma treatment and control, the nurses advised patients, through the use of self-management-plans, how to recognize and manage uncontrolled asthma and when to seek medical assistance. Medication and inhaler device type were altered if necessary The primary outcome was patient reported self-management of asthma exacerbations for 6 months. Secondary outcomes were assessed at baseline, 3 months and 6 months. These included home peak flow and symptom diaries, structured telephone questionnaires and audit of general practitioner records to determine utilization of services (6 months before and after A&E). Data were analysed on an intention to treat basis by multiple and logistic regression. The intervention group increased their use of inhaled topical steroids in 31/61 (51%) vs. 15/70 (21%) attacks in controls (OR 3.91 CI 1.8-8.4, P<0.001) and their use of rescue medication in 54/61 (89%) severe attacks vs. 53/70 (76%) controls (OR 2.88 CI 1.1-7.9, P<0.05). Intervention patients had significantly higher (mean 20.1 l min(-1); CI 0.4-39.7; P<0.05) and less variable PEF and significantly lower and less variable symptom scores 6 months after entry. Thirty-four percent of intervention patients vs. 42% controls had severe attacks (61 and 70 respectively, OR 0.96 CI 0.7-1.4) during the 6 months. Intervention patients had fewer days off work than controls in the first 3 months (NS) but similar days off during the 6-month period. Intervention patients had fewer episodes away from work in the first (0.34 vs. 0.54, P = 0.08) and the second 3 months (0.25 vs. 0.30, NS) than the controls. Over 80% of the patients records were audited by their general practitioners; the active group had less routine consultations with the doctor (P = 0.03) and practice nurse (P = 0.03), less consultations for uncontrolled episodes (P = 0.06) and less hospital visits (NS) than the controls. Hospital-based specialist nurses reduced asthma morbidity by improving patient self-management behaviour in acute attacks leading to reduced symptoms, improved lung function, less time off work and fewer consultations with health professionals.

Acute Disease↗
PubMed2000

Scale-up of an oil/water cream containing 40% diethylene glycol monoethyl ether.

The purpose of this study was to scale up an oil/water (o/w) cream formulation containing 40% diethylene glycol monoethyl ether (DGME), developed via 300-g laboratory batches in a 2(5-2) fractional factorial design, to 7-kg batch sizes in a Brogli-10 homogenizer. The o/w cream was manufactured via a standard phase-inversion process in the Brogli-10 homogenizer. Partitioning studies of DGME were conducted in test tubes at ambient temperature and after 24 hr at 70 degrees C in a convection oven. Phase height was measured by vernier calipers. Microscopy studies of excipients with and without treatment with water or a DGME/water mixture were conducted with a Nikon microscope after equilibration at 35 degrees C for 24 hr. During creation of the 7-kg pilot-scale batches, congealed material was observed between the sweep agitation blade and the discharge port, where the Brogli-10 homogenizer is not temperature jacketed. Factors that increased the amount of congealed material were higher temperatures during primary emulsification and longer cooling times. Partitioning studies revealed that DGME resides in the aqueous external phase of this formulation. Microscopy studies revealed that DGME in the external phase of this cream has a profound impact on the solubility of certain solid, waxy excipients (e.g., cetyl alcohol and polyoxyethylene-2-stearyl ether) at 35 degrees C. From this study, it appears that DGME resides in the external phase of the o/w cream. During manufacturing, it is hypothesized that the presence of DGME in the external phase alters the solubility of certain solid, waxy excipients in the formula such that they no longer primarily reside in the internal oil phase. On cooling, these materials precipitate or congeal in the external phase. The fractional factorial experimental design at the 300-g laboratory scale did not predict the issues encountered during scale-up. Differences between laboratory scale and pilot plant scale that explain why this phenomenon was not seen during laboratory scale are differences in cooling times, nonjacketed or "cold spots" in the Brogli-10 homogenizer, and a low proportion of congealed material in relation to the total batch size (< 1.5%).

Chemical Phenomena↗
PubMed2000

Similarity in bilateral photoplethysmographic peripheral pulse wave characteristics at the ears, thumbs and toes.

The characteristics of the photoplethysmography (PPG) pulse signal are body site specific, with pulses from the various peripheral sites showing differences in pulse transit time, strength and shape, and variation of each over time. The aim of this study was to determine the similarity in the right-left pulse characteristics for a group of normal subjects with pulses obtained simultaneously from six peripheral sites (cars, thumbs and big toes). A multi-site photoplethysmography pulse measurement and analysis system is described and comprised six sets of pulse probes and amplifiers, arranged and electronically matched in pairs for the right and left side comparisons. Two sets of data were collected: firstly a set of validation data to test the electronic matching of right left channels, and secondly a set of physiological data for pulses from 40 normal subjects. The right-to-left side similarity in pulse waveform shape at the three segmental levels (ears, thumbs and toes) was assessed using two types of analysis: root mean square error (RMSE) providing a measure of differences, and cross correlation analysis providing a measure of the degree of similarity. Very low levels of RMSE and correlation coefficients close to unity were obtained for the system validation data, demonstrating good right-left channel matching. The RMSE was an order of magnitude lower than that calculated for the normative physiological data, where median RMSE levels were between 0.053 and 0.060 relative to a peak-to-peak pulse amplitude of unity. The median correlation coefficients were greater than 0.98 for all three segmental levels studied, with the maximum values approaching those of the validation data. We have shown that pulses from the right and left sides of normal subjects are highly correlated at each segmental level. We have obtained a normative range of pulse data, with which specific (vascular) patient groups can be compared.

Adolescent↗
PubMed2000

The incidence of major morbidity in critically ill patients managed with pulmonary artery catheters: a meta-analysis.

INTRODUCTION: The impact of pulmonary artery (PA) catheters on patient outcome has been questioned and their usage has become controversial. Meta-analysis on mortality has shown a trend for improved survival with PA catheter-guided therapy. We now perform a meta-analysis on morbidity from PA catheters in the published literature. METHODS: We did a search of the medical database (Medline) from 1970 through 1996, using the headings "pulmonary artery catheterization," "Swan-Ganz catheterization" and "right heart catheterization," and restricting the results to "effectiveness" and "usefulness." We also consulted with other experts regarding published randomized controlled trials (RCTs). This yielded 16 RCTs addressing the question of effectiveness of PA catheter-guided treatment. Of these, 12 were found to include data on morbidity. Major morbidity, defined as organ failures as per the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference criteria, from these trials was entered into a formal meta-analysis. RESULTS: A total of 1,610 patients from the 12 trials were analyzed. Morbidity events were observed in 62.77% of the PA catheter treatment group, and in 74.34% of the control group. A relative risk ratio of 0.78074 was obtained, with a 95% confidence interval of 0.6459-0.94374 and a corresponding p of .0168, a lower morbidity in the PA catheter treatment group. Those with PA catheter-guided treatment had a mean protective effect of 21.9% for risk of morbidity. Other important covariates such as acuity of illness, quality score of trials, year of publication, type of PA catheter-guided treatment used (PA catheter vs. no PA catheter, or PA catheter vs. PA catheter for supranormal hemodynamic values), and surgical or mixed patient population, all increased variability and were not statistically significant predictors for risk ratio of morbidity. CONCLUSIONS: Meta-analysis of RCTs included in this study shows that there is a statistically significant reduction in morbidity using PA catheter-guided strategies.

Catheterization, Swan-Ganz↗
PubMed2000

Left sided valvar regurgitation in normal children and adolescents.

OBJECTIVE: To determine the prevalence and characteristics of left sided valvar regurgitation in normal children and adolescents. DESIGN: Prospective observational study. SETTING: Tertiary paediatric referral centre. PATIENTS: 329 volunteers (194 male, 135 female, age range 3-18 years). MAIN OUTCOME MEASURES: Detection of regurgitation with colour flow mapping after valve closure. Measurement of jet area, maximal velocity, and duration. RESULTS: Mitral regurgitation was present in six subjects (1.82%, 95% confidence interval (CI) 0.38% to 3.3%) and was not seen before 7 years of age. The jets ranged from 1.1 to 1.9 cm(2) (mean 1.4 cm(2)) in area and were confined to the proximal half of the left atrium. All of the detectable jets were pansystolic and five of six arose from the posteriomedial aspect of the mitral valve. Aortic regurgitation was seen in one girl aged 11 years (0.3%, 95% CI 0% to 0.9%). The signal was pandiastolic and 0.44 cm(2) in area. CONCLUSIONS: True mitral regurgitation occurring after rather than during mitral valve closure was detected in < 2% of subjects. These data support previous work in adult patients suggesting that trivial degrees of mitral regurgitation may be related to the process of aging. Aortic regurgitation is very rare in normal children and adolescents and should not be considered as a normal finding.

Adolescent↗
PubMed2000

The relative influence of lesion length and other stenosis morphologies on procedural success of coronary intervention.

As coronary interventional technology improves, the influence of lesion length (LL) on procedural success and device selection may vary. Thus, the authors prospectively analyzed 957 consecutive coronary interventions (CI) in 1,404 stenoses to ascertain the influence of lesion length on CI outcome. Stenosis morphology was prospectively classified by the AHA/ACC criteria. LL was analyzed both as dichotomous (S: < 10 mm, L: > 10 mm) variables and by the three-tiered AHA/ACC criteria (I: < 10 mm, II: 10-20 mm, III: > 20 mm). There was a significant univariate relationship between CI success and S stenosis (S: 95.8% vs L: 91.8%, p = 0.002 and I: 96.0%, II: 91.7%, III: 89.3%). Numerous interrelationships involving the morphologic characteristics were noted: lesion morphologies associated with S lesions were concentric (p = 0.0001) and had smooth contour (p = 0.0001), ostial location (p = 0.05) and little calcification (p = 0.0007), while irregular contour (p=0.0001), calcification (p=0.0076), eccentric (p=0.0001), thrombus (p = 0.0001), recent (p = 0.0001) or chronic (p = 0.001) total occlusion were associated with L lesions. When these relationships were taken into account by multiple logistic regression analysis, lesion length was not predictive of procedural outcome (p = 0.099). One morphologic type was associated with increased CI success: irregular contour (p = 0.022); recent (p < 0.0001) or chronic (< 0.0001) occlusions were associated with decreased CI success. Another factor considered was device selection: S lesions were associated with greater balloon angioplasty usage (p = 0.002), whereas more coronary stents (p = 0.024) and rotoblator (p = 0.018) devices were used in L lesions. More balloon angioplasty was performed in concentric (p < 0.0001) lesions; interventional devices were employed more often in eccentric (p < 0.0001) and irregular lesions (p < 0.0001). More complications were noted in lesions with thrombus (p = 0.0002), but lesion length was not predictive (p = NS). Lesion length is not a significant predictor of procedural success when adjusted for other lesion morphologies in the modern interventional era. The availability of new devices has improved the results in longer lesions since the AHA/ACC criteria were originally proposed.

Aged↗
PubMed2000

Human papillomavirus and risk of laryngeal cancer.

We determined the relationship between human papillomavirus (HPV) infection and the HPV types detected in 44 patients with squamous cell carcinoma, 10 laryngeal leukoplakia patients, and 12 patients evaluated for benign laryngeal conditions (controls). The sources of HPV DNA were from brushings from the upper respiratory tract and lesion (benign or malignant), oral rinses, and biopsies of patient lesions. Polymerase chain reaction (PCR) and DNA sequencing were used to identify and type HPV. We detected HPV in 25.0% (11/44) of patients with laryngeal cancer, in 30.0% (3/10) of patients with laryngeal leukoplakia, and in 16.7% (2/12) of noncancer controls. Patients with cancer were not more likely to be identified with oncogenic HPV types ( 18.2%) than either the leukoplakia group (20%) or the control group (16.7%). An increased risk of disease was associated with current tobacco use and former alcohol drinking in cancer patients versus controls and in leukoplakia patients versus controls (all p < .05). After we controlled for tobacco and alcohol effects on the risk of disease, exposure to oncogenic HPV types was associated with an increased risk of laryngeal cancer (odds ratio = 3.0) and of laryngeal leukoplakia (odds ratio = 6.0) compared to controls, although the results were not statistically significant. This study suggests that although HPV infection and HPV oncogenic types are not found at a higher frequency in laryngeal cancer or laryngeal leukoplakia as compared to controls, infection is associated with an increased risk of disease after controlling for the effects of alcohol and tobacco use.

Adult↗
PubMed2000

Transfusion-associated graft-vs-host disease. A fatal case caused by blood from an unrelated HLA homozygous donor.

Transfusion-associated graft-vs-host disease (TA-GVHD) is a rare complication of transfusion. We report fatal TA-GVHD in a 63-year-old coronary artery bypass patient of European descent after an RBC transfusion from an unrelated donor. The patient had mild lymphocytopenia and received 2 80-mg doses of methylprednisolone and 7 units of RBCs. On day 14 after the transfusion, he had fever, elevated liver enzyme levels, and a macular rash. Pancytopenia and bone marrow aplasia developed. On day 26, he had a massive gastrointestinal hemorrhage and died. At autopsy, histopathologic findings of the skin, liver, bone marrow, and gastrointestinal tract were consistent with TA-GVHD. One donor of the transfused RBCs (3 days old at transfusion) had a 1-way HLA match with the patient. A method using multiplex polymerase chain reaction is presented. This patient with TA-GVHD and mild immune suppression suggests that blood component irradiation guidelines may need to be reevaluated.

Bone Marrow↗
PubMed2000

Sex differences in pain indices, exercise, and use of analgesics.

To understand better reported sex differences in sensitivity to pain, this study examined daily pain frequency and intensity, use of analgesics, physical activity, and both subjective and physiological response to acute pain in 18 men and 24 women, healthy people who provided information about their daily pain symptoms and physical activity before completing a cold pressor task. Compared to men, women reported more frequent and intense pain symptoms, as well as more frequent use of analgesics and lower physical activity. Women evinced higher physiological arousal during the cold pressor task but similar subjective pain. The findings highlight the different ways men and women cope with pain and the effect on their responses to acute pain.

Adaptation, Psychological↗
PubMed2000

Neural representation of consciously imperceptible speech sound differences.

The concept of subliminal perception has been a subject of interest and controversy for decades. Of interest in the present investigation was whether a neurophysiologic index of stimulus change could be elicited to speech sound contrasts that were consciously indiscriminable. The stimuli were chosen on the basis of each individual subject's discrimination threshold. The speech stimuli (which varied along an F3 onset frequency continuum from /da/ to /ga/) were synthesized so that the acoustical properties of the stimuli could be tightly controlled. Subthreshold and suprathreshold stimuli were chosen on the basis of behavioral ability demonstrated during psychophysical testing. A significant neural representation of stimulus change, reflected by the mismatch negativity response, was obtained in all but 1 subject in response to subthreshold stimuli. Grand average responses differed significantly from responses obtained in a control condition consisting of physiologic responses elicited by physically identical stimuli. Furthermore, responses to suprathreshold stimuli (close to threshold) did not differ significantly from subthreshold responses with respect to latency, amplitude, or area. These results suggest that neural representation of consciously imperceptible stimulus differences occurs and that this representation occurs at a preattentive level.

Adult↗
PubMed2000

A phase II study of biochemotherapy for the treatment of metastatic malignant melanoma.

The use of interleukin-2 (IL-2) and interferon-alpha (IFNalpha) in combination with chemotherapy for the treatment of advanced malignant melanoma has generated considerable interest. In particular, the relatively high number of durable complete responses has suggested this may be a significant advance in the treatment of malignant melanoma. We report our experience at the University of Colorado in 43 patients, including many with poor prognostic factors. Patients received cisplatin 20 mg/m2 on days 1-4, vinblastine 1.6 mg/m2 on days 1-4, dacarbazine 800 mg/m2 on day 1, IL-2 9 x 10(6) IU/m2 per day intravenously over 24h on days 1-4 and IFNalpha 5 x 10(6) IU/m2 per day subcutaneously on days 1-5 every 3 weeks. The median follow-up for all patients was 34 months. Responses were seen in 20 patients (47%, 95% confidence interval 31-62%) and comprised five complete responses (CRs) (12%) and 15 partial responses (PRs) (35%). Two patients achieving a CR remain disease free at 45 and 47 months follow-up. In addition three patients who obtained a surgical CR and another with only minor residual changes on computed tomography scan have not progressed at 27, 30, 40 and 27 months, respectively. Toxicity was manageable, but all patients had at least one grade 3 or 4 toxicity, predominantly hypotension and neutropenia. There were no treatment-related deaths. In conclusion, the response rate and duration is within the range previously reported for biochemotherapy. The results of ongoing randomized studies are awaited to better define the value of biochemotherapy in the treatment of advanced melanoma.

Abdominal Neoplasms↗
PubMed2000

Tailoring the message.

Health care practitioners can learn how to recognize and respond to patient differences. Applying the techniques outlined in this article can improve the kind and depth of information a patient shares, patient satisfaction, patient follow-through, and actual health outcomes.

Communication↗
PubMed2000

Foramen of Morgagni hernia: surgical consideration.

We have recently encountered two patients with foramen of Morgagni hernias both of whom were symptomatic and required repair. Both patients did well following repair. Symptomatic Morgagni hernias should be repaired to reduce complications in later life.

Adolescent↗
PubMed2000

Do the attitudes and beliefs of young teenagers towards general practice influence actual consultation behaviour?

BACKGROUND: Teenagers are believed to have health concerns that are not adequately addressed in primary care because of perceived barriers that inhibit them from consulting a general practitioner (GP). We report the results of a study examining links between potential attitudinal barriers and actual help-seeking behaviour. AIM: To determine whether the attitudes of teenagers towards general practice are associated with differences in consultation patterns. METHOD: Results of a postal questionnaire survey of attitudes to general practice, performed among teenage patients aged 13 to 15 years registered with five general practices in the East Midlands, were analysed in relation to consultation data from retrospective casenote analysis for the preceding 12 months. RESULTS: Matched questionnaire and consultation data were available for 678 teenagers. We found few significant differences in overall consultation rates between teenagers expressing differing attitudes about aspects of general practice. Differences did exist in relation to perceived difficulty in getting an appointment, feeling able to confide in a GP, and perception of adequate time being given in the consultation. Fear of embarrassment was associated with lower consultation rates for gynaecological problems and contraception. CONCLUSIONS: Negative perceptions of general practice by teenagers may have less of an influence on actual consultation behaviour than previously believed. However, there are some aspects of care that merit further attention if teenagers are to feel able to consult their GP more easily.

Adolescent↗
PubMed2000

Artificial biospheres as a model for global ecology on planet Earth.

Artificial biospheres of the scale and complexity of Biosphere 2 can only work with coordinated rigorous design at each level of ecology: biospheres, biomes, bioregions, ecosystems, communities, patches, phases, physical-chemical functions, guilds, populations, organisms, and cells (both eucaryotic and procaryotic). This article reviews these theoretical concepts and provides examples of how this structure was applied to the design and development of Biosphere 2. In addition to this ecological engineering design, the addition of humans as inhabitants in the closed system required design of ethnological patterns and of technical and cybernetic systems for meeting specifically human requirements of labor efficiency, climate, nutrition, wastewater recycle, and pure air and water. Ecological levels of biospheric complexity can be directly applied to studies of the Earth's biosphere and, in fact, must be used to understand complex biospheric processes.

Animals↗