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Biomedical subjects

D Clarke

Publications and source records attributed to D Clarke.

At least 55 records · Page 3Linked to original sources
PubMed2001

Automated multiplex assay system for simultaneous detection of hepatitis B virus DNA, hepatitis C virus RNA, and human immunodeficiency virus type 1 RNA.

We have developed an automated multiplex system for simultaneously screening hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus type 1 (HIV-1) in blood donations. The assay, designated AMPLINAT MPX HBV/HCV/HIV-1 Test (AMPLINAT MPX), consists of virus extraction and target sequence-specific probe capture on specimen preparation workstation GT-X (Roche Diagnostics K.K., Tokyo, Japan) and amplification and detection by TaqMan PCR on the ABI PRISM 7700 Analyzer (Perkin-Elmer Applied Biosystems, Foster City, Calif.). An internal control (IC) is incorporated in the assay to monitor the extraction, target amplification, and detection processes. The assay yields qualitative results without discrimination of the three targets. Detection limits (95% confidence interval) are 22 to 60 copies/ml for HBV, 61 to 112 IU/ml for HCV, and 33 to 66 copies/ml for HIV-1, using a specimen input volume of 0.2 ml. The AMPLINAT MPX assay detects a broad range of genotypes or subtypes for all three viruses and has a specificity of 99.6% for all three viruses with seronegative specimens. In an evaluation of seroconversion panels, the AMPLINAT MPX assay detects HBV infection an average of 24 days before the detection of HBsAg by enzyme immunoassay. HCV RNA was detected an average of 31 days before HCV antibody. HIV-1 RNA was detected an average of 14 days before HIV-1 antibody and an average of 9 days before p24 antigen. The Japanese Red Cross has been evaluating the AMPLINAT MPX system since October 1999. The clinical performance indicates that the AMPLINAT MPX system is robust, sensitive, and reproducible, with a high percentage of valid assay runs (96.8%), a low false-positive rate (0.34%), and a low IC failure rate (0.24%).

Blood Donors↗
PubMed2001

Replace fine needle aspiration cytology with automated core biopsy in the triple assessment of breast cancer.

All patients presenting with a symptomatic breast lump are assessed by means of triple assessment (clinical examination, radiology in the form of mammography and cytology by means of a fine needle aspiration) performed by the clinician in the rapid access breast clinic at the Royal Gwent Hospital, Newport, UK. In our initial experience, it was found that a significant number of patients were returning to clinic for the results of the triple assessment to find that the cytology was not conclusive and hence needed a core biopsy, thus delaying diagnosis and definitive treatment. Therefore, a prospective study was carried out over a 6-month period, where all patients presenting with a symptomatic lump with a clinical or radiological suspicion of breast cancer had, in addition to the standard triple assessment, an automated core biopsy, thus giving rise to the quadruple assessment of the breast lump. A total of 52 patients with a clinical or radiological suspicion of breast cancer were included over this 6-month period. Of these 52 patients, 31 had a definitive diagnosis of breast cancer on fine needle aspiration (sensitivity 60%) compared with 50 of the 52 patients on core biopsy (sensitivity 96%). When radiology was diagnostic of breast cancer (R 5), the sensitivity of cytology was 61% compared with 97% with core biopsy. However, when radiology was not diagnostic of cancer (R 1-4), the sensitivity of cytology fell to 53% while the sensitivity of core biopsy remained high at 95%. The overall cellularity rate for cytology was 96%, which exceeds the BASO requirement for fine needle aspiration cytology. From these results, we conclude that automated core biopsy has a superior diagnostic power when compared with fine needle aspiration cytology and hence should replace fine needle aspiration cytology in the assessment of symptomatic breast lumps.

Biopsy↗
PubMed2000

In vitro differentiation of c-myb(-/-) ES cells reveals that the colony forming capacity of unilineage macrophage precursors and myeloid progenitor commitment are c-Myb independent.

Mice homozygous for an inactivated c-myb allele exhibit embryonic (primitive) blood formation but die at about day 15 of gestation because of a failure to generate adult (definitive) haemopoiesis. Recently, it has been shown that commitment to definitive haemopoiesis does occur in vivo, but that some point in the subsequent development towards the differentiated lineages is compromised. Here we have asked whether it is possible to demonstrate this same distinction between the development of primitive and definitive haemopoiesis during the in vitro differentiation of c-myb null ES cells, and whether this can be used to define more precisely at which developmental stage the absence of c-Myb blocks the adult haemopoietic lineages. We investigated the kinetics of progenitor formation and commitment to differentiation using a combination of colony forming assays and analysis of RNA and surface antigen expression. Primitive unilineage macrophage and erythroid precursor commitment could develop in the absence of c-Myb. No precursors characteristic of definitive haemopoiesis were detected; nevertheless, we could show the expression of a programme of transcription and surface antigens which is consistent with the appearance of definitive progenitors blocked at an early multipotential stage.

Animals↗
PubMed2000

Are there gender differences in patients presenting with unstable angina?

BACKGROUND: There are limited studies on gender differences in patients with unstable angina. We investigated the influence of gender in these patients in a tertiary referral centre. METHODS AND RESULTS: Three hundred and thirteen consecutive patients (210 men and 103 women) with unstable angina were studied over a 42-month period. Patient characteristics, cardiovascular risk factors and subsequent management including coronary artery bypass graft (CABG) operation and percutaneous transluminal coronary angioplasty (PTCA) were investigated. There was no difference in age [61.6 (11.0) (S.D.) years for men vs. 63.5 (10.5) years for women]. Diabetes mellitus and hypertension were more common in women (diabetes, 11% vs. 23%, P = 0.007; hypertension, 32% vs. 52%; P = 0.001). The number of smokers was greater in men (73% vs. 46%, P = 0.00001). There was no difference in the prevalence of hypercholesterolaemia or in the incidence of previous myocardial infarction, previous history of angina and family history of ischaemic heart disease. The duration of unstable angina before presentation to the referring hospital was similar in both sexes. The use of aspirin, intravenous heparin and antianginal drugs was also comparable in the two genders. The number of coronary arteries involved in men and women appeared similar (one vessel, 22% vs. 27%; two vessels, 26% vs. 21%; three vessels, 52% vs. 52% in men and women, respectively). The proportion of men and women who underwent subsequent revascularisation was also similar (CABG, 31% vs. 33%; PTCA, 42% vs. 40%). The overall in-hospital mortality was higher in women (6.8% vs. 2.8%), but was not statistically significant (P = 0.18). CONCLUSIONS: Gender differences in unstable angina manifest in the preponderance of selected risk factors including diabetes mellitus and hypertension in women and smoking in men. There is no difference in age, the degree of coronary artery involvement and the subsequent management in a tertiary referral centre.

Angina, Unstable↗
PubMed2000

Depression in holocaust survivors: profile and treatment outcome in a geriatric day hospital program.

The profile of depressive symptoms and the outcome of treatment in Holocaust Survivors (HS) versus non-Holocaust Survivors (NS), attending a Psychiatric Day Hospital Program for depression, were evaluated retrospectively using a clinical database. Approximately 24% of the study population were Holocaust Survivors (HS). The HS group was more likely to receive a diagnosis of major depressive disorder or episode as one of their diagnoses. The HS group, in particular those survivors who had been in ghettos or in concentration camps, were more likely to be given a diagnosis of post-traumatic stress disorder. Both groups showed improvement from baseline in their ratings of depression on the Hamilton Depression Rating Scale (HDRS) and Geriatric Depression Scale at the time of discharge (p<0.001). However, there were no significant differences between the groups in terms of their ratings of depression either at admission, at discharge or in their degree of improvement. Likewise, there was no significant difference between the groups in the profile of their depression, as per the sub-scales of the HDRS, with the exception that the HS group displayed more 'insight' than the NS group (p=0.002). The NS group scored higher on the Mattis Dementia Rating Scale compared to the HS group (119.1 versus 125.4, p<0.001), even when level of education was covaried; however, language may be an important confound. In conclusion, there was no significant difference in the profile or outcome of depression between groups. However, the HS group was more likely to receive a diagnosis of post-traumatic stress disorder, displayed more 'insight', and appear to differ in their cognitive profile.

Aged↗
PubMed2000

Positive and negative selection to reduce tumour contamination in peripheral blood stem cell harvests.

Peripheral blood progenitor cells used during high dose treatments for malignancy may be contaminated with tumour cells that could later contribute to recurrence. CD34+ selected harvests still contain tumour cells and an additional negative selection may be capable of reducing this contamination. We have assessed a two-stage technique in which a CD34+ selection is followed by a tumour specific depletion stage using a B cell or breast cancer specific antibody panel. Initial small-scale selections on 11 patients with NHL and breast cancer showed that cell loss was greatest following the CD34+ selection with a median yield of 38.8 per cent (range 17. 2-56.4 per cent). The addition of the depletion stage resulted in a minimal loss of CD34+ cells with a yield for this step of 94.2 per cent (range 77.5-99.3 per cent). Clinical scale selections were performed on seven patients with CLL and a median of 2.8x10(6)/kg CD34+ cells (range 1.5-6.1x10(6)/kg) were collected. Cell recovery was 53.3 per cent following CD34+ selection and 76.9 per cent following the tumour specific depletion stage, resulting in a final product containing a median of 1.0x10(6)/kg CD34+ cells (range 0. 55-2.0x10(6)/kg). All unmanipulated harvests were heavily contaminated with tumour cells (median contamination 10.2 per cent, range 2.0-83.1 per cent) as measured by flow cytometry and a median 4.7 log (range 3-5 log) tumour cell purge was produced following two-stage selection. Six of the patients have received cells manipulated in this way with median engraftment times of neutrophils>0.5x10(9)/l=16 days (range 13-20 days) and platelets>20x10(9)/l=16.5 days (range 11-42 days). At a median follow-up of 25 months, these transplanted patients remain well and in molecular complete remission.

Adult↗
PubMed2000

Subcutaneous administration of recombinant glycosylated interleukin 6 in patients with cancer: pharmacokinetics, pharmacodynamics and immunomodulatory effects.

This is the first report of the serum profile of a glycosylated recombinant form of human IL-6 (rhIL-6) administered subcutaneously (1-10 microg/kg/day) in a phase I/II trial as a thrombopoietic agent in patients with advanced cancer. The pharmacodynamic effects of IL-6 were also examined. Detailed pharmacokinetic measurements were made in four patients. Peak concentrations at 5-8 h and a median t0.5 of ca. 5 h were similar to those previously reported for non-glycosylated IL-6. However, higher peak concentrations and apparent differences in effective dose levels to those previously reported with the non-glycosylated form were seen. Indications of an apparent attenuation in circulating IL-6 concentrations with continuing injections were seen in eight of 10 patients examined but anti-IL-6 antibody generation was seen in only two patients. Soluble interleukin 6 receptor concentrations generally decreased. No major changes in T cell subsets were seen but expression of CD25 and CD54 by T lymphocytes significantly increased, accompanied by marked increases in soluble CD25 (sIL-2R) and CD54 (sICAM-1). No consistent change in B cells, monocytes or NK cells were seen. No evidence for induction of TNF-alpha was found. This study demonstrates similar biological effects of glycosylated rhIL-6 to those reported for the non-glycosylated form but illustrates several apparent differences which are discussed further.

Adjuvants, Immunologic↗
PubMed2000

"Whole body" mobility after one year of intraoral appliance therapy in children with cerebral palsy and moderate eating impairment.

The reciprocal influence of body postures on the oral structures, but also of the oral structures on body postures, has been proposed by clinicians and is taken into consideration when treating children with poor postural control and moderate to severe eating impairments. However, this relationship has not been rigorously investigated. The purpose of this study was to document the possible relationships among oral-motor, postural, and ambulatory control. Ambulatory skills [exclusive use of wheelchair (w/c) vs w/c and ambulation], postural control when sitting, "pathologic" reflexes, and lip and tongue posture were recorded before and after one year of therapy with an intraoral appliance (ISMAR) in 20 children with cerebral palsy and moderate eating impairment. Significant improvement occurred in sitting (head-trunk-foot control) following one year of ISMAR therapy. Ambulatory status also significantly improved above the level of maturation. Half of the children showed marked improvement in oral posture, i.e., their resting mouth posture was closed rather than open. These results support an hypothesis of interaction between oral structures and postural control of the "whole body." Further studies are needed to determine the controls of such a relationship.

Adolescent↗
PubMed2000

Characterization of the effects of cannabinoids on guinea-pig tracheal smooth muscle tone: role in the modulation of acetylcholine release from parasympathetic nerves.

We investigated the ability of the cannabinoid agonists CP55,940 (CB(1)/CB(2)) and anandamide (endogenous cannabinoid) to modulate electrical field stimulation (EFS)-induced acetylcholine (ACh) release from parasympathetic nerve terminals innervating guinea-pig trachea. We assessed whether modulation of transmitter release translated to an impact on functional responses by investigating the effect of these agents on contractile responses evoked by EFS and ACh. Furthermore, we evaluated the ability of these compounds to elicit bronchodilation in pre-contracted guinea-pig tracheal strips. CP55,940 and anandamide significantly inhibited EFS-evoked ACh release (maximal inhibition of 35.1+/-2.9% and 33.4+/-6.4% at 1 microM, P<0.05, respectively). The CB(1) receptor antagonist SR 141716A (1 microM), had no effect on ACh release and failed to reverse the inhibitory effect of CP55,940 (1 microM). Paradoxically, CP55,940 had no significant effect on EFS-evoked cholinergic contractile responses. Furthermore, CP55,940 did not relax pre-contracted tracheal strips or affect contractile responses to exogenous ACh. This lack of activity on smooth muscle tone is consistent with the fact that no detectable specific binding of [(3)H] CP55,940 was found in tracheal homogenates. These data suggest that cannabinoid agonists inhibit ACh release from cholinergic nerve terminals via activation of CB(2) receptors but that this inhibitory action does not impact on functional responses such as cholinergic contraction.

Acetylcholine↗
PubMed2000

Herpesvirus saimiri-based gene delivery vectors maintain heterologous expression throughout mouse embryonic stem cell differentiation in vitro.

In order to achieve a high efficiency of gene delivery into rare cell types like stem cells the use of viral vectors is presently without alternative. An ideal stem cell gene therapy vector would be able to infect primitive progenitor cells and sustain or activate gene expression in differentiated progeny. However, many viral vectors are inactivated when introduced in developing systems where cell differentiation occurs. To this end, we have developed a mouse in vitro model for testing herpesvirus saimiri (HVS)-based gene therapy vectors. We demonstrate here for the first time that HVS is able to infect totipotent mouse embryonic stem (ES) cells with high efficiency. We have transduced ES cells with a recombinant virus carrying the enhanced green fluorescent protein (EGFP) gene and the neomycin resistance gene (NeoR) driven by a CMV promoter and the SV40 promoter, respectively. ES cells maintain the viral episomal genome and can be terminally differentiated into mature haematopoietic cells. Moreover, heterologous gene expression is maintained throughout in vitro differentiation. Besides its obvious use in gene therapy, this unique expression system has wide ranging applications in studies aimed at understanding gene function and expression in cell differentiation and development.

Animals↗
PubMed2000

beta-Adrenergic regulation of proinflammatory cytokines in humans.

OBJECTIVES: To investigate the effects of beta-adrenergic stimulation on IL-6 secretion in humans, and to determine the potential contribution to this response of adipocytes and peripheral blood cells (PBC). DESIGN: Experimental study in 8 human volunteers, and in vitro studies on murine adipocyte cell-line, 3T3.L1 and 3T3.F442A, and human PBC. MEASUREMENTS: Plasma IL-6 and TNFalpha responses to isoprenaline infusion. Cytokine secretion from differentiated adipocyte cell-lines and PBC in response to isoprenaline. RESULTS: Plasma IL-6 levels increased ninefold (median) by 180 min (baseline median 0.51 [interquartile range 0.47-1.4] vs 180 mins 4.53 [2.58-5.69] pg ml(-1), P=0.01). One hour after infusion, IL-6 levels (2.9 [1.27-3.98]) were lower than at 180 min (P=0.05), but higher than baseline (P=0.01). TNFalpha levels were unchanged. Differentiated adipocytes incubated in isoprenaline (0-0.1 microM) released significantly increased amounts of IL-6 whereas no response was elicited from PBC. CONCLUSIONS: The induction of IL-6 observed in vivo may be attributed to the beta-adrenergic stimulation of IL-6 release specifically from adipocytes, as opposed to circulating blood cells.

3T3 Cells↗
PubMed2000

Work-based learning as a means of developing and assessing nursing competence.

Work-Based Learning is the bringing together of self-knowledge, expertise at work and formal knowledge. It takes a structured and learner-managed approach to maximizing opportunities for learning and professional development in the workplace. The development and assessment of nursing competence can be facilitated through Work-Based Learning, although this may require pedagogic and structural changes within nurse education. There are a number of conditions which must accompany effective participative learning, and these are discussed in the paper in relation to examples of nursing programmes. This method of learning and assessment has potential to bridge the gap between theory and practice, and as such it can only be achieved through commitment and partnership between the individual practitioner, clinical services and universities.

Clinical Competence↗
PubMed2000

The globalization of nursing knowledge.

External influences placed upon nurses working in universities and in clinical practice require them to attract research funding, carry out research, generate new knowledge and publish in national and international journals. While there does not appear to be an agreed, unified body of nursing knowledge, critical and scholarly debate is essential to generate knowledge, but this is not an activity in which the majority of nurses can effectively participate. Nevertheless, nurses in the Western world are free to communicate their research, theories or ideas, essentially uncensored, to a vast invisible audience, and there is global dissemination through a vast array of literature and educational materials. This paper challenges nurses to examine the implications of globalization and suggests that the continuing debate on the nature of nursing knowledge should be updated to include consideration of both a change in philosophical stance and the far reaching effects of global dissemination of information.

Attitude of Health Personnel↗
PubMed2000

History, present status and future of sentinel node biopsy in breast cancer. The Mary Béves Lecture.

The word Sentinel' is defined in The Oxford English Dictionary as 'a guard, one who keeps watch or a sentry'. When translated to the concept of a tumour and its lymph node drainage, the sentinel node could be interpreted to mean the lymph node that guards or keeps watch over a tumour. The sentinel lymph node can thus be defined as the first lymph node that drains a primary tumour within the regional lymphatic basin of that tumour. We know that tumour progression in breast cancer often occurs in an orderly, progressive fashion. So in theory, if the sentinel node is tumour free then the rest of the nodes in the lymphatic basin should also be uninvolved by the tumour.

Biopsy↗
PubMed2000

FreeStyle: a small-volume electrochemical glucose sensor for home blood glucose testing.

FreeStyle accurately measures the concentration of glucose in a 300-nL volume of capillary blood obtained with significantly reduced pain from the forearm where the density of capillaries is much lower than in the fingertips. The readings are independent of temperature, of altitude (O2 pressure) and of hematocrit in the 0%-60% range. At their physiological levels, none of the often interfering constituents of blood affect the readings.

Blood Glucose↗
PubMed2000

Comparative genome sequence analysis of the Bpa/Str region in mouse and Man.

The progress of human and mouse genome sequencing programs presages the possibility of systematic cross-species comparison of the two genomes as a powerful tool for gene and regulatory element identification. As the opportunities to perform comparative sequence analysis emerge, it is important to develop parameters for such analyses and to examine the outcomes of cross-species comparison. Our analysis used gene prediction and a database search of 430 kb of genomic sequence covering the Bpa/Str region of the mouse X chromosome, and 745 kb of genomic sequence from the homologous human X chromosome region. We identified 11 genes in mouse and 13 genes and two pseudogenes in human. In addition, we compared the mouse and human sequences using pairwise alignment and searches for evolutionary conserved regions (ECRs) exceeding a defined threshold of sequence identity. This approach aided the identification of at least four further putative conserved genes in the region. Comparative sequencing revealed that this region is a mosaic in evolutionary terms, with considerably more rearrangement between the two species than realized previously from comparative mapping studies. Surprisingly, this region showed an extremely high LINE and low SINE content, low G+C content, and yet a relatively high gene density, in contrast to the low gene density usually associated with such regions.

3-Hydroxysteroid Dehydrogenases↗