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Biomedical subjects

C Clarke

Publications and source records attributed to C Clarke.

At least 19 recordsLinked to original sources
PubMed2006

Modulation of TNFalpha, a determinant of acute toxicity associated with systemic delivery of first-generation and helper-dependent adenoviral vectors.

Understanding the determinants of the host innate immune response to systemic administration of adenoviral (Ad) vectors is critical for clinical gene therapy. Acute toxicity occurs within minutes to hours after vector administration and is characterized by activation of innate immune responses. Our data indicate that in mice, indicators of vector toxicity include elevations of cytokine levels, liver transaminase levels and thrombocytopenia. To discern potential targets for blunting this host response, we evaluated genetic factors in the host response to systemically administered first-generation Ad vectors (FGV) and helper-dependent Ad vectors (HDV) containing beta-galactosidase expression cassettes. A preliminary screen for modulation of vector-induced thrombocytopenia revealed no role for interferon-gamma, mast cells or perforin. However, vector-induced thrombocytopenia and interleukin 6 (IL-6) expression are less evident in tumor necrosis factor alpha (TNFalpha)-deficient mice. Moreover, we also demonstrated that TNFalpha blockade via antibody or huTNFR:Fc pretreatment attenuates both thrombocytopenia (>40% increase in platelet count) and IL-6 expression (>80% reduction) without affecting interleukin 12 , liver enzymes, hematological indices or vector transduction in a murine model. Our data indicate that the use of HDV, in combination with clinically approved TNFalpha immunomodulation, may represent an approach for improving the therapeutic index of Ad gene therapy for human clinical trials.

Adenoviridae↗
PubMed2006

Relating with professionals.

This paper addresses my difficulties as a carer in engaging with many professionals in mental health, both locally associated with my son's acute inpatient care, and nationally where policies are being developed and their implementation is pursued. All of us are affected by The Department of Health (DoH) Mental Health policies and their implementation by professionals has formed the way in which professionals relate with my son and myself. The way in which my son is impacted inextricably affects the way I relate to professionals. I think my difficulty in engaging lies in the relationships we all have with each another. In focusing on the process within our relationships, I attempt to raise professionals' awareness of what constitutes a relationship when we dialogue. As it takes two to engage in a dialogue, I perceive my difficulty is also the difficulty of the professionals. Carers are becoming increasingly involved in the training of mental health professionals and our combined difficulty needs to be resolved, so that we all benefit. In order to achieve positive progression, there needs to be a radical change within our relationship to provide ease of engagement from all parties. In this paper I tentatively suggest how this process can be achieved.

Akathisia, Drug-Induced↗
PubMed2006

Acute mountain sickness: medical problems associated with acute and subacute exposure to hypobaric hypoxia.

This article summarises the medical problems of travel to altitudes above 3000 m. These are caused by chronic hypoxia. Acute mountain sickness (AMS), a self limiting common illness is almost part of normal acclimatisation--a transient condition lasting for several days. However, in <2% of people staying above 4000 m, serious illnesses related to hypoxia develop--high altitude pulmonary oedema and cerebral oedema. These are potentially fatal but can be largely avoided by gradual ascent. Short vacations, pressure from travel companies and peer groups often encourage ascent to 4000 m more rapidly than is prudent. Sensible guidelines for ascent are outlined, clinical features, management and treatment of these conditions.

Acute Disease↗
PubMed2005

Development of a zona-free method of nuclear transfer in the mouse.

In the present study, a zona-free nuclear transfer (NT) technique, which had been originally developed in cattle, was modified for the mouse. Steps involved in this approach include removing the zona pellucida and enucleating without a holding pipette; sticking donor cells to the cytoplast before electric pulses are applied to fuse them and culturing reconstructed embryos individually in single droplets, to prevent aggregation. Control zona-free and zona-intact embryos from mated donors showed no significant difference in development to blastocyst, but did show reduced development to term. Removal of the zona pellucida affected the response to activation by strontium in the absence of calcium as a significant proportion of zona-free control oocytes and embryos reconstructed by NT lysed during this treatment. A comparison between cumulus and ES cells as donor cells revealed significant differences in fusion efficiency (58.1 +/- 4.0%, n = 573 vs. 42.9 +/- 2.2%, n = 2064, respectively, p < 0.001), cleavage (77.2 +/- 3.4%, n = 334 vs. 40.8 +/- 2.7%, n = 903, respectively, p < 0.001) but not for development to morula/blastocyst (8.7 +/- 2.1%, n = 334 vs. 13.9 +/- 1.8%, n = 903, respectively, p < 0.1). The stage at which embryo development arrested was also affected by donor cell type. A majority of embryos reconstructed from cumulus cells arrested at two-cell stage, usually with two nuclei, whereas those reconstructed from ES cells arrested at one-cell stage, usually with two pseudo-pronuclei. After transfer of ES cell-derived NT embryos, a viable cloned mouse was produced (3.0% of transferred embryos developed to term). These observations establish that a zona-free cloning approach is possible in the mouse, although further research is required to increase the efficiency.

Animals↗
PubMed2005

Views of bereaved relatives about quality of survival after radiotherapy for malignant cerebral glioma.

OBJECTIVE: To explore the views of bereaved relatives about quality of survival after radiotherapy for malignant cerebral glioma. DESIGN: Semistructured interviews with the bereaved relatives of 56 previously studied patients with glioma. SETTING: Patients treated at six London hospitals from 1990 to 1992 surviving between one and 46 months (median, eight). SUBJECTS: Fifty six relatives (44 spouses, 12 others) seen four to six months after bereavement and 20 again at 13 months. MAIN OUTCOME MEASURES: Views about quality of life and satisfaction with radiotherapy. RESULTS: Relatives described quality of life as "good or acceptable" when patients carried on some normal activities or enjoyed social relationships. They described restricted and dependent states, constant deterioration, or loss of social interaction as giving "poor or unacceptable" quality of life. Length of time lived in such states also appeared important. Relatives' views of good or acceptable quality of life were independently related to low initial cognitive or personality change or low distress in the patient after diagnosis, and to their subsequent survival free from physical disability for at least one month. Satisfaction with radiotherapy was related to low initial distress, some degree of surgical resection, and overall length of survival longer than six months. CONCLUSIONS: Carefully exploring the views of bereaved relatives can bring a useful perspective to difficult treatment decisions. Their values support including disability and distress in quality of life measures, but cast doubt on the QALY-type approach of using full years of survival or time free from disability to judge whether treatments are worthwhile.

Adult↗
PubMed2003

Two year survival after malignant cerebral glioma: patient and relative reports of handicap, psychiatric symptoms and rehabilitation.

PURPOSE: To describe patient outcomes and contact with rehabilitation services two years after the diagnosis of malignant cerebral glioma. METHODS: A cross-sectional interview study of patients treated two years previously between 1990-1992 at six London hospitals. Twenty-two of 181 treated patients were found alive (12%). Fifteen were well enough to approach and 12 male patients (aged 28-60 years) and ten relatives (9 female, 1 male) could be seen by 1994. Semi-structured home interviews carried out separately with patients and relatives assessed return to previous work or activity, patient and relative reports of handicap, psychiatric symptoms, estimated percentage drop in verbal and non-verbal performance and contact with rehabilitation services. RESULTS: Using accounts of return to work or normal activity two years after treatment, five patients were classed as broadly 'active' and seven as 'inactive'. The 'active' group appeared to have few physical or cognitive problems or were able to adapt their work around these. Disagreement between patients and relatives about handicap, patient and relative psychiatric symptoms and severe neuropsychological deficit appeared to cluster in the 'inactive group'. No patient had been formally referred for rehabilitation. CONCLUSIONS: Patient outcome, in terms of managing work and everyday activities, can be very good for some two-year survivors. For others, patient and relative accounts and neuropsychological testing may disclose a range of problems. Such inquiry might suggest referral for rehabilitation or other support.

Activities of Daily Living↗
PubMed2003

A placebo-controlled pharmacodynamic and pharmacokinetic interaction study between tamsulosin and acenocoumarol.

AIM: To evaluate pharmacokinetic and pharmacodynamic interactions between tamsulosin and acenocoumarol. METHODS: Twelve healthy volunteers received tamsulosin 0.4 mg or placebo once daily for 9 days in a double-blind, cross-over study. On day 5 of each study period, a single 10-mg oral dose of racemic acenocoumarol was administered. RESULTS: The ratios (point estimates (90% confidence intervals)) of values in the presence and absence of tamsulosin were: AUCPT 1.01 (0.98, 1.03); maximum prothrombin time (Ptmax) 0.99 (0.94, 1.05); AUC (R)-acenocoumarol 1.02 (0.90, 1.16), and AUC (S)-acenocoumarol 1.03 (0.89, 1.20). Both combinations, tamsulosin and placebo with acenocoumarol, were well-tolerated. CONCLUSIONS: Multiple doses of tamsulosin had no effect on the pharmacokinetics or pharmacodynamics of a single high dose of acenocoumarol.

Acenocoumarol↗
PubMed2003

Adrenal suppression from high-dose inhaled fluticasone propionate in children with asthma.

This cross-sectional study was designed to examine the prevalence of adrenocortical suppression in children with asthma treated with high-dose inhaled fluticasone propionate (FP). Children and adolescents (n=50) with asthma, treated with inhaled FP at a dose of > or = 1,000 mg a day for > or = 6 months, were enrolled. Early morning serum cortisol was performed. Subjects with a serum cortisol of < 400 nmol x L(-1) had a tetracosactrin stimulation test. Fifty subjects of mean age 13.1 yrs were treated with a mean dose of 924.7 microg x m(-2) x day(-1) FP for a mean duration of 2 yrs. Of the 50 subjects, 36 (72%) had serum cortisol levels of < 400 nmol x L(-1) and underwent tetracosactrin stimulation test. Of these, 6 (17%) demonstrated a less than two-fold increase in serum cortisol from baseline and peak cortisol level of < or = 550 nmol x L(-1) at 30 or 60 min poststimulation. There was a significant negative correlation between the dose of FP x m(-2) and stimulated peak cortisol level. Biochemical evidence of adrenocortical insufficiency was demonstrated in 12% of the subjects, indicating that high-dose fluticasone propionate use may be associated with dose-dependent adrenocortical suppression.

Administration, Inhalation↗
PubMed2002

Anti-E-selectin is ineffective in the treatment of psoriasis: a randomized trial.

BACKGROUND: Skin-homing, memory T lymphocytes play an important role in the pathogenesis of psoriasis by interacting with the vascular addressin, E-selectin and trafficking into lesional skin. Thus an attractive option for targeted therapy of the disease would be blockade of skin-homing T cells with an antibody directed at E-selectin. OBJECTIVE: We performed a multicentre, randomized, placebo-controlled trial to investigate the clinical efficacy and side-effect profile of a humanized monoclonal antibody to E-selectin, CDP850, in the treatment of moderate to severe chronic plaque psoriasis. METHODS: Patients with moderate/severe chronic plaque psoriasis were selected for study. Nine male subjects (mean age 37 years, range 25-47) were given 20 mg kg-1 CDP850 intravenously as a single dose and four subjects (three males, one female; mean age 40 years, range 23-50) received placebo infusion. Clinical response to treatment was assessed using the psoriasis area and severity index (PASI). Skin biopsies were taken for immunohistochemical analysis at the baseline, pretreatment, visit and also at day 2 and weeks 1 and 4 postinfusion. RESULTS: The treatment was well-tolerated with a minimal side-effect profile. Plasma E-selectin levels were significantly decreased in those subjects who received CDP850 compared with those who had placebo for the entire study period. At the end of study (8 weeks postinfusion), there was no significant reduction in PASI from baseline for either the CDP850 or placebo-treated groups. Immunohistochemical analysis of biopsies taken from lesional psoriatic skin showed that 2 days after dosing with CDP850, staining for E-selectin was decreased, although not absent, on dermal vascular endothelial cells when compared with baseline (P < 0.01). This decrease in E-selectin expression was maintained 4 weeks after infusion (P < 0.05). It was not, however, accompanied by a significant reduction in numbers of neutrophils or lymphocytes in the dermis. There was a statistically significant increase in CD1a-positive epidermal Langerhans cells compared with pre-dose levels at week 1 (P < 0.05). CONCLUSIONS: This clinicopathological study shows that anti-E-selectin (CDP850), although a well-tolerated, logical and safe therapy, does not appear to possess a therapeutic role in the treatment of chronic plaque psoriasis.

Adult↗
PubMed2002

Regional and urban Victorian diabetic youth: clinical and quality-of-life outcomes.

OBJECTIVES: To compare groups of urban and regional Victorian diabetic children and assess their quality of life, diabetes knowledge, access to services and metabolic control. METHODS: Forty-seven children from three regional Victorian communities (Horsham, Warrnambool and Sale; n = 16, 18 and 13, respectively) were compared with 120 age-, sex- and duration of diabetes-matched children attending the Royal Children's Hospital (RCH) diabetes clinic in Melbourne. Quality of life, diabetes knowledge, use of services, and metabolic control were assessed using the child health questionnaire (CHQ PF-50/CF-80); a diabetes-knowledge questionnaire; access to a diabetes nurse educator (DNE), dietitian and complication screening; and indices of mean HbA1C (values are taken every 3 months in the 'yearly HbA1C'), respectively. RESULTS: Comparisons of CHQ data showed that regional diabetic youth scored significantly lower on most subscales. The greatest deficits were seen in areas of mental health, self-esteem, parent impact (emotional) and family cohesion. Diabetes knowledge and median yearly HbA1C for patients were not significantly different between the regional and urban centres (8.1%, 8.9%, 8.4% and 8.6% at RCH, Horsham, Warrnambool and Sale, respectively). Patients in regional centres had reportedly less access to team-based diabetes care. CONCLUSIONS: Regional youth in Victoria, with similar levels of metabolic control and diabetes knowledge as their urban counterparts, have a markedly lower quality of life, implying a negative synergy between diabetes and the demands of regional lifestyles.

Adolescent↗
PubMed2001

Involvement of water in carbohydrate-protein binding.

The interactions of trimannosides 1 and 2 with Con A were studied to reveal the effects of displacement of well-ordered water molecules on the thermodynamic parameters of protein-ligand complexation. Trisaccharide 2 is a derivative of 1, in which the hydroxyl at C-2 of the central mannose unit is replaced by a hydroxyethyl moiety. Upon binding, this moiety displaces a conserved water molecule present in the Con A binding site. Structural studies by NMR spectroscopy and MD simulations showed that the two compounds have very similar solution conformational properties. MD simulations of the complexes of Con A with 1 and 2 demonstrated that the hydroxyethyl side chain of 2 can establish the same hydrogen bonds in a low energy conformation with the protein binding site as those mediated by the water molecule in the complex of 1 with Con A. Isothermal titration microcalorimetry (ITC) measurements showed that 2 has a more favorable entropy of binding compared to 1. This term, which was expected, arises from the return of the highly ordered water molecule to bulk solution. The favorable entropy term was, however, offset by a relatively large unfavorable enthalpy term. This observation was rationalized by comparing the extent of hydrogen bond and solvation changes during binding. It is proposed that an indirect interaction through a water molecule will provide a larger number of hydrogen bonds in the complex that have higher occupancies than in bulk solution, thereby stabilizing the complex.

Carbohydrate Conformation↗
PubMed2001

Conditional immortalization of freshly isolated human mammary fibroblasts and endothelial cells.

Reports differ as to whether reconstitution of telomerase activity alone is sufficient for immortalization of different types of human somatic cells or whether additional activities encoded by other "immortalizing" genes are also required. Here we show that ectopic expression of either the catalytic subunit of human telomerase (hTERT) or a temperature-sensitive mutant (U19tsA58) of simian virus 40 large-tumor antigen alone was not sufficient for immortalization of freshly isolated normal adult human mammary fibroblasts and endothelial cells. However, a combination of both genes resulted in the efficient generation of immortal cell lines irrespective of the order in which they were introduced or whether they were introduced early or late in the normal proliferative lifespan of the cultures. The order and timing of transduction, however, did influence genomic stability. Karyotype analysis indicated that introduction of both transgenes at early passage, with hTERT first, yielded diploid cell lines. Temperature-shift experiments revealed that maintenance of the immortalized state depended on continued expression of functional U19tsA58 large-tumor antigen, with hTERT alone unable to maintain growth at nonpermissive temperatures for U19tsA58 large-tumor antigen. Such conditional diploid lines may provide a useful resource for both cell engineering and for studies on immortalization and in vitro transformation.

Adult↗
PubMed2001

The needs of children visiting on adult intensive care units: a review of the literature and recommendations for practice.

AIM: The purpose of this paper is to review the current literature and research available and to identify specific, nursing interventions to meet the needs of child visiting within the ICU setting. BACKGROUND: According to recent surveys children are still restricted from visiting their critically ill family and friends on many adult intensive care units (ICUs) within the United Kingdom (UK). Imposing restrictive visiting policies does not respect the rights of patients and their families to be together and to support each other during a period of stress and crisis. METHOD: The motivation to undertake the study was derived from a critical incident involving a small boy who was not allowed to visit his critically ill mother. She subsequently died. Reflection on the available literature identified the value and role of intuition in expert clinical judgement, but the need to support this with evidence based knowledge. CONCLUSION: The implications for practice are discussed and recommendations for further research are made.

Adolescent↗