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Biomedical subjects

David Clark

Publications and source records attributed to David Clark.

At least 19 recordsLinked to original sources
PubMed2006

Adverse effects of fluorescein angiography in hypertensive and elderly patients.

PURPOSE: To evaluate adverse effects in patients undergoing fundus fluorescein angiography (FA), and to assess the level of these adverse effects in hypertensive and elderly patients. METHOD: We carried out a retrospective study of 358 patients undergoing FA. They were assessed for adverse effects and their relationship to medical history, pre- and post-FA blood pressure and age. RESULTS: The overall adverse reaction rate (AR) was 11.2%, the majority (80%) of which involved nausea. There were no mortalities and no cases of anaphylaxis or cardiac arrest. Hypertension (systolic or diastolic) did not increase the AR. Interestingly, raised initial systolic blood pressure (BP) > or = 160 showed a statistically significant decreased AR compared with that for BP < 160 (7% versus 15%, respectively; p = 0.04). There was no statistical correlation between AR and age. CONCLUSIONS: FA is a relatively safe procedure, but serious side-effects have been reported in the past and therefore adequate measures need to be in place to cope with such emergencies. In our study, there was no increase in the incidence of adverse effects in patients who were hypertensive or elderly. Therefore, these patients should not be denied an important diagnostic procedure that may improve their quality of life purely because of hypertension or age.

Adult↗
PubMed2006

Measuring inequalities in health: the case for healthy life expectancy.

OBJECTIVE: To evaluate healthy life expectancy (HLE) as a measure of health inequalities by comparing geographical and area-based deprivation-related inequalities in healthy and total life expectancy (TLE). DESIGN: Life table analysis based on ecological cross-sectional data. SETTING AND POPULATION: Council area quarters and postcode sector-based deprivation fifths in Scotland. MAIN OUTCOME MEASURES: Expectation of life in good self-assessed general health, or free from limiting long-term illness, and TLE, for females and males at birth. RESULTS: Women in Scotland have a life expectation of 70.3 years in good health, 61.6 years free from limiting long-term illness, and a TLE of 78.9 years. Comparable figures for men are 66.3, 58.6 and 73.5 years. TLE and HLE decrease with increasing area deprivation. Differences are substantially wider for HLE. A 4.7-year difference is seen in TLE between women living in the most and least deprived fifth of areas. The difference in HLE is 10.7 years in good health and 11.6 years free from limiting long-term illness. The degree of deprivation-related inequality in HLE is 2.5 times wider for women and 1.8 times wider for men than in TLE. CONCLUSIONS: Differences in TLE underestimate health inequalities substantially. By including morbidity and mortality, HLE reflects the excess burden of ill health experienced by disadvantaged populations better. Inequalities in length of life and health status during life should be taken into account while monitoring inequalities in population health.

Adolescent↗
PubMed2006

Trends in exclusive breastfeeding: findings from the 1990s.

This article presents trends and differentials in exclusive breastfeeding patterns that occurred in developing settings during the 1990s and considers these trends in relation to the breastfeeding-support activities in that decade. Between 1990 and 2000, the data suggest that exclusive breast-feeding levels in the developing world increased 15% overall among infants younger than 4 months (from 46% to 53%) and among infants older than 6 months (from 34% to 39%). The increase in urban areas is of special note. Urban areas are presumed to be most susceptible to the ambient health system and social and commercial pressures against breastfeeding; the support activities of the 1990s (eg, the Baby-friendly Hospital Initiative and the International Code of Marketing of Breastmilk Substitutes) were developed to address these pressures. Given this, implementation of the Global Strategy for Infant and Young Child Feeding, which supports these proven interventions, should be effective in further increasing optimal breast-feeding practices.

Adult↗
PubMed2006

Myoid hamartoma of the breast: case report and review of the literature.

Hamartoma is a mass of disorganized but mature specialized cells or tissue indigenous to the particular site. They can occur anywhere in the body, and their common sites of occurrence include lungs, skin, hypothalamus, spleen, and kidneys, of which lungs are the most common. We report a rather unusual, largely unrecognized case of myoid hamartoma of the breast. They constitute approximately 3.9%-4.8% of breast tumors. Myoid hamartomas belong to a spectrum of benign breast lesion of dual origin, containing myoepithelial and myofibroblastic components in varying proportions. They are usually asymptomatic but can present as well-circumscribed masses that do not possess specific diagnostic histologic features, and diagnosis is, therefore, difficult. In contrast to many other benign or malignant breast lesions, the diagnosis of hamartoma can easily be missed. Herein, we discuss the importance of radiologic, immunohistochemical studies and histopathologic findings in the diagnosis of a myoid hamartoma. Extensive review of the literature has been done for this purpose, and we highlight the clinical presentation and therapeutic aspects of this breast lesion.

Breast Diseases↗
PubMed2006

Assessment of malnutrition in hip fracture patients: effects on surgical delay, hospital stay and mortality.

The importance of malnutrition in elderly hip fracture patients has long been recognised. All patients operated upon for a hip fracture over a five-year period were assessed according to two nutritional markers : a) serum albumin levels and b) peripheral blood total lymphocyte count. Patients were subdivided into groups according to the four possible combinations of these results. Outcomes according to four clinical outcome parameters were validated: a) waiting time to operation b) length of hospitalisation, c) in-hospital mortality, and d) one-year postoperative mortality. Significant differences were found between malnourished patients and those with normal laboratory values with regard to surgical delay and one year postoperative mortality. Malnourished patients were also more likely to be hospitalised longer than a month and to die during their hospital stay, but the difference was not significant. The combination of serum albumin level and total lymphocyte count can be used as an independent prognostic factor in hip fracture patients.

Aged, 80 and over↗
PubMed2005

Stories of cancer pain: a historical perspective.

This article considers published accounts by people with personal experience of cancer, and cancer pain, from 1945 to the present. These firsthand stories communicate deeply personal truths and understandings--and this is their value. Narratives of cancer can inform and support others with the disease and contribute meaningful knowledge to health professionals about the subjective experience of living with cancer and cancer pain. They also highlight where improvements can be made in health care and serve as a platform from which patients may criticize, expose, petition, support, share, challenge, and call for autonomy. A cancer diagnosis can rupture the life of the person who receives it, but as this article illustrates, inscribing the words of a narrative and revealing experiences to a public audience can bring meaning to a life event which might otherwise be viewed as meaningless.

Attitude to Health↗
PubMed2005

The syringe driver and the subcutaneous route in palliative care: the inventor, the history and the implications.

Since the early 1980s, the syringe driver has become a commonly used technology in British palliative care, used to administer continuous subcutaneous infusions (CSCI) for symptom management. Although the device itself has not been adopted universally, it has stimulated interest in the use of CSCI in palliative care and played a significant role in the modern history of this approach. This historical case study of the syringe driver examines the life and work of its inventor, explores its development for use in childhood thalassemia, and analyzes the circumstances surrounding its adoption in palliative care. We conclude by considering the reasons for the continued popularity of the syringe driver, despite problems in its use, and reflect on the lessons which can be learned about the use of CSCI in palliative care internationally.

Analgesics↗
PubMed2005

The measurement of pain, 1945-2000.

Three strands of activity can be identified in the history of pain measurement. The first, psychophysics, dates back to the nineteenth century and measures the effect of analgesia by quantifying the noxious stimulation required to elicit pain, as well as the maximum stimulation tolerated. The second uses standardized questionnaires for patients, developed to categorize pain according to its emotional impact, distribution, character, and other dimensions. The third asks patients to report on pain intensity using rating scales, and is used in clinical trials where analgesics are evaluated and results can be combined to influence clinical guidelines and protocols. Although all three strands have found a place in modern clinical practice or drug development, it is the reporting of pain by patients undergoing treatment using simple scales of intensity which has emerged as the crucial method by which analgesic therapies can now be evaluated and compared.

History, 20th Century↗
PubMed2005

Pain and palliative care: the emergence of new specialties.

In the second half of the twentieth century, the clinical management of patients suffering pain from advanced cancer was transformed. This paper describes cancer pain management during this period, identifying three key elements that promoted innovation: First, the development of a patient-centered approach to analgesic evaluation, which resulted from the search for an alternative analgesic to morphine in studies led by Raymond Houde. Second, the re-introduction by John Bonica of the idea that pain is what the individual feels and thinks it is. Third, the work of Cicely Saunders in establishing the foundations of the modern hospice and palliative care movement. The work of these three clinicians must be set in the context of a time when new hopes emerged that cancer could be cured and, at the same time, the cancer patient began to be remolded from a passive participant in treatment and care to an active collaborator.

Analgesia↗
PubMed2005

NS1 protein secretion during the acute phase of West Nile virus infection.

The West Nile virus (WNV) nonstructural protein NS1 is a protein of unknown function that is found within, associated with, and secreted from infected cells. We systematically investigated the kinetics of NS1 secretion in vitro and in vivo to determine the potential use of this protein as a diagnostic marker and to analyze NS1 secretion in relation to the infection cycle. A sensitive antigen capture enzyme-linked immunosorbent assay (ELISA) for detection of WNV NS1 (polyclonal-ACE) was developed, as well as a capture ELISA for the specific detection of NS1 multimers (4G4-ACE). The 4G4-ACE detected native NS1 antigens at high sensitivity, whereas the polyclonal-ACE had a higher specificity for recombinant forms of the protein. Applying these assays we found that only a small fraction of intracellular NS1 is secreted and that secretion of NS1 in tissue culture is delayed compared to the release of virus particles. In experimentally infected hamsters, NS1 was detected in the serum between days 3 and 8 postinfection, peaking on day 5, the day prior to the onset of clinical disease; immunoglobulin M (IgM) antibodies were detected at low levels on day 5 postinfection. Although real-time PCR gave the earliest indication of infection (day 1), the diagnostic performance of the 4G4-ACE was comparable to that of real-time PCR during the time period when NS1 was secreted. Moreover, the 4G4-ACE was found to be superior in performance to both the IgM and plaque assays during this time period, suggesting that NS1 is a viable early diagnostic marker of WNV infection.

Animals↗
PubMed2004

Specificity of choline metabolites for in vivo diagnosis of breast cancer using 1H MRS at 1.5 T.

The purpose was to determine if in vivo proton magnetic resonance spectroscopy ((1)H MRS) at 1.5 T can accurately provide the correct pathology of breast disease. Forty-three asymptomatic volunteers including three lactating mothers were examined and compared with 21 breast cancer patients. Examinations were undertaken at 1.5 T using a purpose-built transmit-receive single breast coil. Single voxel spectroscopy was undertaken using echo times of 135 and 350 ms. The broad composite resonance at 3.2 ppm, which includes contributions from choline, phosphocholine (PC), glycerophosphocholine (GPC), myo-inositol and taurine, was found not to be a unique marker for malignancy providing a diagnostic sensitivity and specificity of 80.0 and 86.0%, respectively. This was due to three of the asymptomatic volunteers and all of the lactating mothers also generating the broad composite resonance at 3.2 ppm. Optimised post-acquisitional processing of the spectra resolved a resonance at 3.22 ppm, consistent with PC, in patients with cancer. In contrast the spectra recorded for three false-positive volunteers, and the three lactating mothers had a resonance centred at 3.28 ppm (possibly taurine, myo-inositol or GPC). This improved the specificity of the test to 100%. Careful referencing of the spectra and post-acquisitional processing intended to optimise spectral resolution of in vivo MR proton spectra from human breast tissue resolves the composite choline resonance. This allows the distinction of patients with malignant disease from volunteers with a sensitivity of 80% and specificity of 100%. Therefore, resolution of the composite choline resonance into its constituent components improves the specificity of the in vivo (1)H MRS method, but does not overcome the problem of 20% false-negatives.

Adult↗
PubMed2004

Entamoeba histolytica alcohol dehydrogenase 2 (EhADH2) as a target for anti-amoebic agents.

OBJECTIVES: The current use of metronidazole as an anti-amoebic agent causes significant side-effects. The purpose of this study was to identify alternative compounds with which to treat amoebiasis. METHODS: We tested the effects of cyclopropyl (CPC) and cyclobutyl (CBC) carbinols on the survival of Entamoeba histolytica trophozoites and on the enzymatic activities of E. histolytica alcohol dehydrogenase 2 (EhADH2), a crucial enzyme in the amoebic fermentation pathway. RESULTS: At 72 h, the estimated 50% inhibitory concentrations of CPC and CBC were 38.9 and 11.2 microM, respectively. The EhADH2 alcohol and aldehyde dehydrogenase activities were inhibited by 1.82 microM CPC and 0.89 microM CBC in vitro. CONCLUSIONS: CPC and CBC are expected to be non-toxic to humans at the concentrations required to eliminate E. histolytica trophozoites. Similarities between EhADH2 and the Giardia lamblia AdhE enzyme indicate that CPC and CBC could be effective drugs for treatment of both amoebiasis and giardiasis.

Alcohol Dehydrogenase↗
PubMed2004

Dendritic cells are dysfunctional in patients with operable breast cancer.

BACKGROUND: Dendritic cells (DCs) play a crucial role in presenting antigens to T lymphocytes and inducing cytotoxic T cells. DCs have been studied in patients with breast cancer to define the factors leading to failure of an effective systemic and locoregional anticancer host response. METHODS: Purified DCs were obtained from peripheral blood (PB) and lymph nodes (LNs) of women with operable breast cancer, using immunomagnetic bead selection. The stimulatory capacity of DCs in the allogeneic mixed leukocyte reaction (MLR) and autologous T cell proliferation test (purified protein derivative (PPD) as stimulator), the expression of surface markers on DCs and the production of cytokines in vitro by DCs from patients with operable breast cancer and from healthy donors (controls) were studied. RESULTS: 70-75% purified DCs were isolated from PB and LNs. PBDCs and LNDCs from patients with operable breast cancer demonstrated a reduced capacity to stimulate in an MLR, compared with PBDCs from normal donors (p<0.01). Autologous T cell proliferation in patients had a decreased ability to respond to PPD, when compared with controls (p<0.01). However, T cells from patients responded as well as control T lymphocytes in the presence of control DCs. PBDCs and LNDCs from patients expressed low levels of HLA-DR and CD86, and induced decreased interleukin-12 (IL-12) secretion in vitro, compared with DCs from normal donors (p<0.01). CONCLUSION: These data suggest a defective DC function in patients with operable breast cancer. Switched-off DCs in patients with early breast cancer and decreased IL-12 production may be important factors for progressive tumour growth.

Adult↗
PubMed2004

Evaluation of a scheme to enhance palliative cancer care in rural Wales.

Since the early 1990s, the United Kingdom has seen several initiatives designed to improve the quality of cancer palliative care in the community. We report on the evaluation of a project that took place in the rural county of Powys in Wales in which a group of general practitioner clinical facilitators (GPCFs) sought to raise the overall standard of palliative care among primary health care teams (PHCTs). The evaluation was conducted over 3 years and made use of several methods: interviews with facilitators and other key stakeholders at regular intervals throughout the project; a survey of PHCT members at two time points; an analysis of patterns of opioid prescribing in the county before and during the project; monitoring of referrals to specialist palliative care services out of county; and an analysis of place of death of those dying from cancer. The evaluation found that local general practitioners (GPs) were willing to work as facilitators and that they made contact with over two thirds of those in the PHCTs. Facilitators undertook a variety of clinical, educational and service development initiatives but did report on problems of role definition and time management. There were no marked changes in patterns of referral to specialist palliative care or in place of death, but there was some evidence to suggest that the facilitators had an influence on their colleagues' opioid prescribing patterns.

Humans↗
PubMed2004

Perioperative complications of intraocular lens exchange in patients with opacified Aqua-Sense lenses.

PURPOSE: To evaluate the perioperative complications of intraocular lens (IOL) exchange in 25 eyes of 22 patients with opacified Aqua-Sense IOLs (Ophthalmic Innovations International). SETTING: Department of Ophthalmology, University Hospital Aintree, Liverpool, United Kingdom. METHODS: The study comprised 22 patients (25 eyes) who had previous phacoemulsification and implantation of Aqua-Sense single-piece hydrophilic acrylic IOLs in the capsular bag and developed severe late opacification of the IOL. All patients reported glare and deterioration in vision. The IOLs were explanted and replaced with new lenses. The perioperative complications were evaluated. The best corrected visual acuity (BCVA) before and after surgery was compared. RESULTS: In 24 eyes, the opacification was complete, involving the optic, haptics, and substance of the IOLs. Uneventful IOL exchange and placement of a new IOL in the bag was achieved in 13 eyes (52%). Complications occurred in the remaining 12 eyes (48%). Ten eyes (40%) developed zonular dehiscence, 4 (16%) of which were managed with anterior chamber IOL implantation. One eye (4%) developed posterior capsule rupture and 1 eye (4%), posterior capsule rupture and zonular dehiscence. The cornea decompensated in 2 eyes (8%). One eye (4%) developed Pseudomonas keratitis. The mean BCVA (decimal scale) before and after IOL exchange was 0.57 +/- 0.24 and 0.60 +/- 0.28, respectively. There was no significant difference in visual acuity between before and after IOL exchange (P=.782, paired t test). CONCLUSIONS: Explantation of Aqua-Sense IOLs was challenging because of the tight adherence of the optic and haptics to the capsule. Long-term follow-up of patients with Aqua-Sense IOLs should be maintained.

Aged↗
PubMed2004

Planning for the end of life: the views of older people about advance care statements.

Advance statements about medical care have been heralded by some as a solution to the problem of end of life decision making for people not able to participate in discussions about their care. Since death is now most likely to occur at the end of a long life, it is important to understand the views and values which older people express in relation to these. This paper reports on a study which used focus groups to explore older people's views about advance statements and the role these might play in end of life care decisions. Participants were 32 older people or their representatives who belonged to six diverse community groups in Sheffield, UK. Advance statements were understood primarily in terms of their potential to aid personal integrity and to help the families of older people by reducing the perceived 'burden' of their decision making. However, concerns were expressed about the perceived link between advance care statements and euthanasia, their future applicability, and the possibility that preferences for care may change. Participants also reported worries and difficulties related to thinking about and discussing death and dying. Trust between doctor and patient, built up over time, was perceived to be important in creating an environment in which the communication necessary to underpin advance care planning could take place. Lastly, participants did not perceive that during dying they would be ready necessarily to adhere to an advance statement and 'disengage' from their lives. We conclude that, rather than emphasising the completion of advance statements, it may be preferable to conceptualise advance care planning as a process of discussion and review between clinicians, patients and families.

Advance Directives↗