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Biomedical subjects

D Pope

Publications and source records attributed to D Pope.

At least 19 recordsLinked to original sources
PubMed2001

Study of crystallization of endogenous surfactant in Eudragit NE30D-free films and its influence on drug-release properties of controlled-release diphenhydramine HCl pellets coated with Eudragit NE30D.

This study investigates the crystallization of the endogenous surfactant nonoxynol 100 in Eudragit NE30D-free films during storage and the influences of nonoxynol 100 on the dissolution of diphenhydramine hydrochloric acid (HCl) pellets coated with Eudragit NE30D before and after aging at ambient conditions. Polarizing light microscopy showed that when Eudragit NE30D-free films were stored at ambient conditions, off-white, flower-shaped crystals formed and increased in the polymer film as storage time increased. Also, x-ray diffraction showed polymer crystals in the aged free film. Thermogravimetric analysis showed no evidence of combined volatile molecules with the polymer molecules, and Fourier transformed infrared spectroscopy (FTIR) data suggested the same chemical composition of the polymer before and after phase separation. Further, from normal light microscopy, the appearance of the melting droplets in the polymer film indicated that the polymer molecules did not form the crystals. After the extraction of nonoxynol 100 by water, the free film formed by the water-extracted Eudragit NE30D was found free of the crystals after aging at the same conditions. The combination of the thermogravimetric analysis, FTIR, and microscopy showed that the origin of the crystals in dry Eudragit NE30D-free films came from nonoxynol 100, and not from the polymer molecules themselves. Monitoring by differential scanning calorimeter, it was found that the rates of crystallization of nonoxynol 100 were faster when the films were stored at 30 degrees C and 40 degrees C than when stored at ambient conditions and 45 degrees C. When stored at -5 degrees C, the crystallization rate was nearly zero. As the temperature got closer to melting temperature, the crystallization rate was very low because the system was in a thermodynamically disfavored state. The rate gradually increased and finally passed through a maximum as the crystallization temperature decreased. As the temperature kept decreasing, the crystallization rate became small again and eventually stopped because the system turned into a kinetically disfavored state. Because the phase transition of nonoxynol 100 in Eudragit NE30D occurred at ambient conditions, its influence on the dissolution of diphenhydramine HCl pellets coated with Eudragit NE30D was studied. Three different levels of nonoxynol 100 were used in Eudragit NE30D dispersions to make 3 different batches of Eudragit NE30D film-coated, controlled-release diphenhydramine HCl pellets. The results showed the dissolution rate increased as the level of nonoxynol 100 increased in the coating formula. Compared to the commonly used water-soluble additive human peripheral mononuclear cell, nonoxynol 100 was more effective in enhancing the dissolution of diphenhydramine HCl from pellets coated with Eudragit NE30D. Further study showed that the phase separation of the surfactant during aging tends to stabilize or slightly increase dissolution rates at higher surfactant levels.

Acrylates↗
PubMed2000

Frequent users of the emergency department: a program to improve care and reduce visits.

The authors describe a case-management program for frequent users of the emergency department. The study had a single-subject design, with evaluation for each patient of the number of visits to the emergency department for a 12-month period before referral to the program and a similar period after implementation of an individualized care plan. Referrals were made on the basis of 2 or more of the following criteria: chronic medical condition, complex medical condition, drug-seeking behaviour, violent behaviour and abusive behaviour. A multidisciplinary team developed the individualized care plans. Twenty-four patients agreed to participate. For the 12-month period before their referral, these patients accounted for a total of 616 (median 26.5) visits to the emergency department; for a similar period after implementation of the care plans, they accounted for 175 (median 6.5) visits. The difficult-case management program appeared to be effective in reducing the total number of visits to the emergency department during the study period and in improving the care for these patients.

Adult↗
PubMed2000

Choice of antibiotic and risk of colonization with vancomycin-resistant Enterococcus among patients admitted for treatment of community-acquired pneumonia.

A time-series prospective study of patients admitted to the hospital for treatment of community-acquired pneumonia was undertaken to determine vancomycin-resistant enterococcal perianal colonization rates among patients who received ceftriaxone with or without erythromycin versus those who received levofloxacin. A colonization rate of 16% (8/51) was found in the ceftriaxone-erythromycin group versus 0% (0/52) in the levofloxacin group .

Adolescent↗
PubMed1999

Saccades reduce latency and increase velocity of ocular accommodation.

Horizontal vergence can be stimulated binocularly with disparity (disparity vergence) or monocularly with accommodation (accommodative vergence). The latter results from a neural cross-coupling that causes both horizontal vergence and accommodation to respond when either one is stimulated [Alpern, M., & Ellen, P. (1956). American Journal of Ophthalmology, 42, 289-303]. The velocity of disparity and accommodative vergence is enhanced when accompanied by saccades [Enright, J. T. (1984). Journal of Physiology (London) 350, 9-31; Enright, J. T. (1986). Journal of Physiology (London) 371, 69-89]. Based upon the coupling between accommodation and vergence, we predicted that accommodation should also be facilitated by saccades. An SRI Dual Purkinje Eyetracker was used to measure left and right eye position, and the accommodation of the left eye, in response to stimulation. Horizontal saccades were stimulated by targets separated by 2-6 degrees and accommodation was stimulated monocularly over a range of +/- 2 diopters (D). When saccades occurred within 0-400 ms following a monocular step stimulus to accommodation, latency of accommodation decreased and the associated accommodative-vergence response was synchronized with the saccade. Saccades also enhanced the velocity of accommodation and accommodative-vergence, and this facilitation increased with saccade amplitude. Transient vergence responses that are normally associated with saccades [Erkelens, C. J., Steinman, R. M., & Collewijn, H. (1989). Proceedings of the Royal Society of London B. Biological Sciences, 236, 441-465; Maxwell, J. S., & King, W. M. (1992). Journal of Neurophysiology, 68 (4), 1248-1260] did not affect accommodation when it was not stimulated by defocus. Because saccades and accommodation utilize separate plants and final common pathways, the synchronization of saccades and accommodation and the enhanced velocity of accommodation and accommodative-vergence must occur at more central sites. Possibilities include the superior colliculus, which represents both accommodation and saccades [Nagasaka, Y., & Ohtsuka, K., (1998). Investigative Ophthalmology AVRO supplement], vestibular nuclei which project to regions near the oculomotor nuclei [Lang, W., Buttner-Ennever, J. A., & Buttner, U. (1979). Brain Research, 177, 3-17], and interactions between omni pause neurons and near response cells of the mesencephalic reticular formation (MRF) [Mays, L. E., & Gamlin, P. D. R. (1995a). Current Opinions in Neurobiology, 5, 763-768; Mays, L. E., & Gamlin, P. D. R. (1995b). Eye movement research: Mechanisms, processes and applications. New York: Elsevier] which represent both accommodation and vergence [Judge, S. J., & Cumming, B. G. (1986). Journal of Neurophysiology, 55, 915-930; Zhang, Y., Mays, L. E., & Gamli, P. D. R. (1992). Journal of Neurophysiology, 67, 944-960].

Accommodation, Ocular↗
PubMed1999

Neuropsychological sequelae and impaired health status in survivors of severe acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is a disease of acute respiratory failure manifested by severe hypoxemia with a high mortality rate. Previous outcome studies of ARDS have assessed survival and/or pulmonary function as the primary outcome variables. Cognitive or psychological outcomes following ARDS have not been described, despite the possibility that ARDS patients are at risk for brain injury through hypoxemia or other mechanisms. In the current study 55 consecutive ARDS survivors completed a battery of neuropsychological tests and questionnaires regarding health status, cognitive and psychological outcomes at the time of hospital discharge and 1 yr after onset of ARDS. At hospital discharge, 100% (55 of 55) of survivors exhibited cognitive and affective impairments, as well as problems with health status which affected their quality of life. At 1 yr after ARDS, 17 of 55 (30%) patients still exhibited generalized cognitive decline. Forty-three of 55 (78%) patients had all or at least one of the following: impaired memory, attention, concentration and/or decreased mental processing speed. One year after ARDS a substantial portion of ARDS survivors exhibit impaired health status and cognitive sequelae which may be due to hypoxemia, emboli, inflammation, drug toxicity, and/or other etiologies.

Adolescent↗
PubMed1996

Surveys using general practice registers: who are the non-responders?

BACKGROUND: General practice population registers are important sampling frames for surveys of disease prevalence, lifestyles and health needs. In any survey there is a problem of non-response in the target population which can reduce precision and may bias any estimates derived from the study. Bias related to those who choose not to respond has been studied, but the problems posed by those who no longer live at the address on the register have received less attention. The specific objectives of this study were to estimate the number of non-responders in a registered general practice population who had not received a questionnaire ('ghosts') as distinct from those who chose not to respond to it ('refusers') and to determine whether ghosts and refusers were different from non-responders in ways which might affect the purpose of the survey. METHODS: A total of 500 people aged 18-75 years were selected from a general practice register in Stockport for a postal survey of shoulder pain in the adult population. Forty-one were identified as "ghosts' during the survey. After three mailings of a baseline screening questionnaire for shoulder pain and a further mailing of a final reminder, there were 120 further non-responders. They were classified as ghosts or refusers on the basis of a comparison of their current address on the practice register with that on the electoral roll. A matched sample of 120 survey responders was identified and was used to check the accuracy of the electoral roll in classifying non-responders. Ghosts and refusers were compared with the sample of responders using consultation information obtained from medical records at the practice, if the latter were available. RESULTS: In total, 108 of the 500 people in the sample (22 per cent) were classified as "ghosts'-41 on the basis of information obtained during the survey and 67 on the basis of a comparison with electoral roll details. In addition, 48 were classified as refusers on the basis of the electoral roll comparison. This compared with 8 (7 per cent) of the matched sample of responders who would have been classified as "ghosts' using the electoral roll. People who had addresses outside the electoral district were excluded from classification. Medical records were available for 105 (90 per cent) of the responders, 31 (46 per cent) of the ghosts and 40 (83 per cent) of the refusers. Of those who had consulted at least once for any reason in the previous two years, a similar proportion of responders and refusers (48 per cent and 46 per cent) had attended because of musculoskeletal problems, but responders were more likely to have consulted specifically about shoulder pain (10 per cent compared with 3 per cent, but based on small numbers). Ghosts by contrast had a lower proportion of consultations for both all musculoskeletal (33 per cent) and shoulder-specific problems (none), but were more likely to have consulted with a psychological problem than responders. CONCLUSIONS: We have estimated the number of non-responders to a survey of shoulder pain who were likely not to have received the baseline questionnaire (ghosts) to have been 22 per cent of a sample drawn from a practice-based Family Health Services Authority register. The error of using the electoral roll to make such a classification was found to be small, with only 8 (7 per cent) of the samples of responders being misclassified as ghosts. Those ghosts who still had records at the practice appeared to differ from refusers with respect to musculoskeletal and psychological morbidity. It may be inappropriate to exclude ghosts from the denominator in population surveys.

Adolescent↗
PubMed1995

Rheumatology education and management skills in general practice: a national study of trainees.

OBJECTIVE: To evaluate current rheumatology education and skills during vocational training in general practice. METHODS: A postal questionnaire survey was sent to all general practice trainees who were in United Kingdom training practices in June 1992. A second survey was made of general practice trainers in the UK. RESULTS: Questionnaires were returned by 1624 trainees, representing 70% of all trainees known to be in a training practice on 1 April 1992. Of the 1075 responders who were at the end of their trainee year, 35% had not received any tutorials on rheumatological topics with their trainer, and only 43% had experienced specific rheumatology teaching on local day release courses. Although 84% of these trainees had injected or aspirated the knee, fewer than 40% had acquired shoulder injection skills. Lack of experience was matched by low reported confidence. Trainees rated the amount of their rheumatology education as inadequate. Nine hundred trainers returned questionnaires--a response rate of 33%. Their estimate of the amount of local training provided was similar to that among the trainees, but this sample of trainers reported a higher level of practical teaching than the trainees indicated they had received. CONCLUSIONS: Rheumatology education during vocational training needs to be improved, particularly the component provided by trainers and local day release courses. This process might be facilitated by the development of a standard rheumatology curriculum which could be incorporated into all training schemes.

Clinical Competence↗
PubMed1994

Observer variability in measuring elevation and external rotation of the shoulder. Primary Care Rheumatology Society Shoulder Study Group.

The aim of the study was to assess the observer variation between trained primary care physicians in their assessment of two key shoulder movements: elevation and external rotation. Six observers each examined and recorded their visual estimate of the range of movements in six patients assessed in random order. There was good agreement on the range of passive elevation assessed to the start of pain (if present): intraclass correlation coefficient (ICC) = 0.84, and to the point of maximum elevation: ICC = 0.95. There was no evidence of an important systematic bias between observers. By contrast, external rotation was poorly reproducible: ICC = 0.43, with important systematic differences between observers. In the second experiment, six observers simultaneously witnessed a range of movements in a single volunteer subject, and the agreement on their visual estimation of the angles achieved was assessed. There was a marked reduction in the systematic bias in external rotation, but agreement was still poor. Agreement for elevation remained high with a reduction in the small amount of bias observed in the first experiment when variability in both examination and visual assessment had been investigated. We conclude that shoulder elevation is a reliable measurement for use in multicentre studies by trained primary care physicians. By contrast, external rotation is poorly reproducible because of systematic variation in examination technique and random variation in visual assessment.

Female↗
PubMed1994

Measurement of shoulder related disability: results of a validation study.

OBJECTIVE: To develop and validate a questionnaire to quantify disability associated with shoulder symptoms. METHODS: A set of questions relevant to shoulder symptoms from a general disability interview was developed and the questionnaire applied to a cross-sectional population survey and a prospective study of general practice attenders. Subjects included adults who reported current shoulder pain in a population survey and patients from three general practices who attended with shoulder symptoms during a six month period. The main outcome measures were: frequency of problems with daily living related to shoulder symptoms, total score on 22-item disability questionnaire, and measures of shoulder movement. RESULTS: A higher proportion (80%) of patients attending their general practitioner with shoulder symptoms had five or more disabilities compared with subjects reporting shoulder pain in a community survey (34%). The ranked frequency with which each disability was reported was similar in the two groups, although sleep disturbance was the most common problem in consulters. Self-reported disability is correlated with measures of restricted shoulder movement. CONCLUSION: This disability questionnaire was simple to complete and should prove useful for both general practice and population-based studies of shoulder pain.

Activities of Daily Living↗
PubMed1993

Mortality and cancer morbidity of production workers in the United Kingdom flexible polyurethane foam industry.

OBJECTIVE: To describe cause specific mortality and site specific cancer morbidity among workers employed in factories that produce polyurethane foams, and to determine if any part of the experience may be due to occupation, and in particular to exposure to diisocyanates. DESIGN: Historical prospective cohort study. SETTING: 11 factories in England and Wales. SUBJECTS: 8288 male and female production employees with some employment in the period 1958-79, and with a minimum period of employment of six months. MAIN OUTCOME MEASURES: Observed and expected numbers of deaths for the period 1958-88, and corresponding figures for cancer registrations for the period 1971-86. RESULTS: Compared with the general population of England and Wales, standardised mortality ratios (SMRs) for all causes and all neoplasms were 97 (observed deaths (Obs) 816) and 88 (Obs 221) respectively. Statistically significant excesses were found among women for cancer of the pancreas (expected deaths (Exp) 2.2, Obs 6, SMR 271, 95% CI 100-595) and cancer of the lung (Exp 9.1, Obs 16, SMR 176, 95% CI 100-285). Similar excesses were not found among male employees, and the SMRs for cancers of the lung and pancreas among the total study population were 100 (Obs 81) and 136 (Obs 14) respectively. Overall incidence of cancer was also below expectation (SRR 94, Obs 277), although statistically significant excesses among women were found for cancers of the larynx and kidney, based on three and four cases respectively. Incident cancers of the lung and pancreas among women were also in excess, although these findings were not independent of the findings for mortality. Poison regression did not indicate that ever having been employed in jobs attracting either higher or lower exposure to isocyanates was a risk factor for the mentioned cancers. A nested case-control design was used to investigate any associations with nine other occupational exposures. No statistically significant association was found. CONCLUSIONS: In general, cancer rates in this population were lower than those for the general population. All increased cancer rates among women occurred at sites of cancer known to be related to cigarette smoking, and these excesses are probably due to a combination of cigarette smoking, chance, and factors unrelated to the industry under study.

Adolescent↗
PubMed1993

Clinical performance of a rule-based decision support system for mechanical ventilation of ARDS patients.

We developed a clinical decision support system--ventilation protocols--that managed tidal volume and ventilator rate settings during mechanical ventilation of patients with the Adult Respiratory Distress Syndrome (ARDS). We applied these protocols for a total of 10,903 hours in 40 ARDS patients. The clinical staff suspended the protocols for only 5% of the total application time due to medical procedures, surgeries, transient clinical problems not addressed by the protocols, or because of attending physician request. Of 3,148 instructions generated by the ventilation protocols, the clinical staff followed 2,932 (93%). The staff did not follow some instructions because of patient data errors, computer software and protocol logic errors, inability of the clinical staff to implement protocol instructions because of more pressing duties, and clinical staff objections to specific instructions. Sixty percent of the patients treated by the ventilation protocols survived. Our results demonstrate that the ventilation protocols provided a practical and safe decision support system for the mechanical ventilation of ARDS patients.

Clinical Protocols↗
PubMed1991

Exogenous nerve growth factor reverses age-related structural changes in neocortical neurons in the aging rat. A quantitative Golgi study.

The role of chronic exogenous intracerebroventricular administration of nerve growth factor (NGF) on the morphology of layer V pyramidal cell dendrites in aging rats was quantified using Golgi impregnations. Both dendritic branching and dendritic spines from the basilar tree of randomly selected pyramidal neurons of the frontal cortex were evaluated in young control (4-month-old) Fischer 344 rats, in old controls (24-month-old), and in 24-month-old rats administered NGF for 4 weeks. Sholl analysis of basilar dendritic trees showed that neuronal branching in older rats was significantly greater than that in young rats (probably due to compensatory dendritic hypertrophy). The extent of dendritic material in aged rats receiving NGF, however, was identical to that in young rats, that is, the dendritic tree had regressed in size. Dendritic spine response to NGF treatment depended on the region of the dendritic tree sampled. Normal aging resulted in spine loss. However, NGF treatment restored dendritic spine densities to those seen in young controls on terminal tip segments ("plastic" regions). Internal branch segments ("nonplastic" regions) showed no response to NGF. As dendritic spines are thought to represent the neuroanatomic basis of learning and memory, results suggest that NGF can influence the morphology of cortical neurons (probably indirectly via the basal forebrain projections) and therefore may play an efficacious role in the treatment of geriatric cognitive dysfunction and even perhaps in Alzheimer's disease.

Aging↗
PubMed1990

Benign pigmented nevi in children from Kidderminster, England: prevalence and associated factors.

The prevalence of benign pigmented nevi in a group of 187 children, aged 8 or 9 years, was determined for each of 31 anatomic sites. Information on possible associated factors was obtained from the children's parents with a standard interview questionnaire. Pale skin color was found to be associated with a higher prevalence of nevi. A comparison of these data with recent data from Australia supports the hypotheses that (1) the number of nevi is a risk factor for melanoma and (2) groups at high risk of melanoma may be formed in childhood.

Age Factors↗
PubMed1989

Malignancy in coeliac disease--effect of a gluten free diet.

Two hundred and ten patients with coeliac disease previously reported from this unit were reviewed at the end of 1985 after a further 11 years of follow up. The initial review at the end of 1974 could not demonstrate that a gluten free diet (GFD) prevented these complications, probably because the time on diet was relatively short. The same series has therefore been kept under surveillance with the particular aim of assessing the effects of diet on malignancy after a further prolonged follow up period. Twelve new cancers have occurred: of which one was a carcinoma of the oesophagus and two lymphomas. Thirty nine cancers developed in 38 patients and of 69 deaths, 33 were the result of malignancy. A two-fold relative risk (RR) of cancer was found and was because of an increased risk of cancer of the mouth and pharynx (RR = 9.7, p less than 0.01, 95% confidence interval (CI) = 2.0-28.3), oesophagus (RR = 12.3, p less than 0.01, CI = 2.5-36.5), and of non-Hodgkin's lymphoma (RR = 42.7, p less than 0.001, CI = 19.6-81.4). The results indicate that for coeliac patients who have taken a GFD for five years or more the risk of developing cancer over all sites is not increased when compared with the general population. The risk is increased, however, in those taking a reduced gluten, or a normal diet, with an excess of cancers of the mouth, pharynx and oesophagus (RR = 22.7, p < 0.001), and also of lymphoma (RR = 77.8, p < 0.001). A significant decreasing trend in the excess morbidity rate over increasing use of a GFD was found. The results are suggestive of a protective role for a GFD against malignancy in coeliac disease and give further support for advising all patients to adhere to a strict GFD for life.

Celiac Disease↗