Biomedical subjects

E Burton

Publications and source records attributed to E Burton.

At least 19 recordsLinked to original sources

PubMed2001

Measuring the built environment: validity of a site survey instrument for use in urban settings.

There are few reliable measures of place with which to study the effects of socio-economic context on health. We report on the development and inter-rater reliability of a 27-item observer-rated built environment site survey checklist (BESSC). Across eleven 'housing areas' (defined as areas of homogeneity in housing form) and two raters, kappa coefficients were > or =0.5 for fifteen categorical items, and intra-class correlation coefficients exceeded 0.6 for a further three continuous measures. Ratings on several BESSC items were associated to a statistically significant degree with the prevalence of depression and residents' dissatisfaction with 'their area as a place to live'. BESSC items may prove to be valuable descriptors of the urban built environment in future studies.

Cohort Studies↗

PubMed2000

Myelopoietin, an engineered chimeric IL-3 and G-CSF receptor agonist, stimulates multilineage hematopoietic recovery in a nonhuman primate model of radiation-induced myelosuppression.

Myelopoietins (MPOs) constitute a family of engineered, chimeric molecules that bind and activate the IL-3 and G-CSF receptors on hematopoietic cells. This study investigated the in vivo hematopoietic response of rhesus monkeys administered MPO after radiation-induced myelosuppression. Animals were total body irradiated (TBI) in 2 series, with biologically equivalent doses consisting of either a 700 cGy dose of Cobalt-60 ((60)Co) gamma-radiation or 600 cGy, 250 kVp x-irradiation. First series: On day 1 after 700 cGy irradiation, cohorts of animals were subcutaneously (SC) administered MPO at 200 microg/kg/d (n = 4), or 50 microg/kg/d (n = 2), twice daily, or human serum albumin (HSA) (n = 10). Second series: The 600 cGy x-irradiated cohorts of animals were administered either MPO at 200 microg/kg/d, in a daily schedule (n = 4) or 0.1% autologous serum (AS), daily, SC (n = 11) for 23 days. MPO regardless of administration schedule (twice a day or every day) significantly reduced the mean durations of neutropenia (absolute neutrophil count [ANC] < 500/microL) and thrombocytopenia (platelet < 20,000/microL) versus respective control-treated cohorts. Mean neutrophil and platelet nadirs were significantly improved and time to recovery for neutrophils (ANC to < 500/microL) and platelets (PLT < 20,000/microL) were significantly enhanced in the MPO-treated cohorts versus controls. Red cell recovery was further improved relative to control-treated cohorts that received whole blood transfusions. Significant increases in bone marrow-derived clonogenic activity was observed by day 14 after TBI in MPO-treated cohorts versus respective time-matched controls. Thus, MPO, administered daily was as effective as a twice daily schedule for multilineage recovery in nonhuman primates after high-dose, radiation-induced myelosuppression.

Animals↗

PubMed2000

Evaluation of polyethylene terephthalate for ABO and Rh typing and alloantibody screening.

BACKGROUND: For many years, hospitals and laboratories have used evacuated glass tubes for blood collection. To improve the safety of blood collection, plastic polyethylene terephthalate (PET) tubes (Vacutainer PLUS, Becton Dickinson) have been developed. The objectives of this study were to compare the accuracy of ABO grouping, Rh typing, and antibody screening of blood samples collected in plastic tubes with that in glass tubes and to determine if refrigerated blood samples collected in plastic tubes remained stable over a 28-day period. STUDY DESIGN AND METHODS: Samples were collected from 121 volunteers, at least 30 from each of the A, B, O, and AB blood groups, in four types of Vacutainer tubes: silica-coated plastic, K(2) EDTA plastic, uncoated glass, and K(2) EDTA glass. Samples from each tube were tested for ABO group and Rh type by use of the microtyping gel identification card system and the tube method. A three-cell antibody screen was performed by the microtyping gel card technique with a monospecific IgG reagent. Initial samples were tested within 3 hours of collection. Refrigerated samples were retested for ABO and Rh type and antibody screening 1, 2, 21, and 28 days later. Agreement between test results was determined by using Cohen's Kappa statistic. RESULTS: Complete agreement was observed between the ABO and Rh typing results in samples drawn into glass and plastic tubes of both the EDTA and nonanticoagulated type (kappa = 1.0). In retesting, there were no examples of a change in ABO or Rh type over the 28-day study period. Only two alloantibodies (1.7%) were identified in the 121 samples, and no difference was observed in alloantibody expression in either plastic or glass Vacutainer tubes over the 28-day study period. CONCLUSION: Samples collected into the PET serum or EDTA tubes provided accurate ABO and Rh typing results that remained consistent over a 28-day period. Samples collected in these tubes also appeared to enable accurate alloantibody identification. However, the number of alloantibodies identified in this study was small, and this result should be confirmed in a larger series.

ABO Blood-Group System↗

PubMed1999

The effects of motion on parametric fMRI analysis techniques.

Subject motion during the time course of functional activation studies has been shown to cause spurious signals which can mimic 'true' activation. Therefore, the importance of motion correction has been widely recognized. Correction with post-processing using image registration software is common practice in functional imaging and analysis. Many image registration algorithms, developed for analysis requirements other than fMRI, assume rigid body motion. Although these techniques are now routinely used by a number of groups, rigid body coregistration has not yet been shown to reduce the effects of motion to an acceptable level in fMRI analysis, i.e. the effects on resulting correlation analysis directly. In this paper we have used volume data to assess rigid body co-registration in terms of motion artefacts for the different correlation approaches used in fMRI. We have developed a new way of visualizing motion effects in correlation analysis based on generating a scatter plot of correlation score against local image gradient. This technique has been tested on fMRI data sets from a functional paradigm suffering from motion correlated artefacts, with and without rigid body motion correction. Although we do not attempt to estimate the actual residual motion, this technique can be used to verify the results of analysis and select regions of relatively unambiguous activation. This paper assesses directly the rigid body assumption and proves the need for, and effectiveness of, co-registration for all correlation based analysis techniques. The specific differences between the popular correlation forms used are investigated and explained. We show that for certain forms of correlation analysis the effects of motion, while not removed altogether, are effectively statistically eliminated.

Adult↗

PubMed1999

New chemotherapy options for the treatment of malignant gliomas.

Chemotherapy remains part of the treatment triad that includes surgery and radiation therapy for the management of malignant gliomas. In recent years there has been an increased understanding of the molecular pathways of malignant transformation. Based on this research, new drugs have been evaluated, with specific cellular targets in mind that can be modified or inhibited. Many of these agents are now being tested in phase I and II clinical trials and have shown some promising results. Clearly, not all patients with malignant gliomas respond equally to chemotherapy. Recent evidence suggests that certain molecular markers may predict chemosensitivity in some tumor types, particularly anaplastic oligodendroglioma. This article reviews recent trends in the use of chemotherapy and clinical trials of new therapies for adults with malignant gliomas.

Adult↗

PubMed1998

Everyday planning difficulties following traumatic brain injury: a role for autobiographical memory.

The present study examines the role of autobiographical memory in describing how to perform both open-ended and closed everyday activities in 12 patients suffering traumatic brain injury and 12 aged-matched controls. The frequency (high versus low) of performing the activities was also manipulated. Patients seemed less well able to benefit from using specific autobiographical memories; they reported using significantly fewer specific autobiographical memories for describing how to perform low-frequency activities and significantly more such memories for high-frequency activities compared with controls. The quality of their descriptions was also significantly poorer for the open-ended activities. Finally, significant correlations were found between the quality of the descriptions and the retrieval of specific autobiographical memories for the controls only. The importance of the retrieval of specific autobiographical memories for everyday problem-solving is discussed.

Activities of Daily Living↗

PubMed1997

Superior vena cava thrombosis and chylothorax: relationship in pediatric nephrotic syndrome.

We report a 40-month-old black male with nephrotic syndrome who developed chylothorax associated with superior vena cava (SVC) thrombosis. To our knowledge, this is the third reported case of spontaneous SVC thrombosis in a nephrotic patient and the first in which chylothorax was also present. Ultrasonography of the pleura and thoracic vasculature was invaluable in making the diagnosis and monitoring the resolution of this condition during treatment. Contrary to previous reports, thoracic chylous effusions complicating uncontrolled nephrotic syndrome do not originate exclusively as a consequence of abdominal pathology, but rather as this case demonstrates, they can occur from lymphatic obstruction caused by thoracic vein thrombosis.

Anticoagulants↗

PubMed1997

Lateral advantages in same-different comparison of two-note, dichotically presented chords to a successively-presented probe.

An experiment is reported which examines same-different comparison of dichotically presented, two-tone chords to a probe. A prediction of a fast 'same' response indicative of holistic processing was tested. Stimuli and probes were systematically related by similarity relationships established in a previous experiment. No evidence was found for fast 'same' responding overall or on either ear, but a right ear advantage for the making of difficult 'different' decisions was found for accuracy. It is argued that the concepts of analytic and holistic processing may require some redefinition and a preliminary account is offered in terms of Krueger's [23] noisy operator model.

Acoustic Stimulation↗

PubMed1997

Intradermal recombinant human nerve growth factor induces pressure allodynia and lowered heat-pain threshold in humans.

Nerve growth factor (NGF) plays a biologic role in the development and maintenance of sympathetic and small sensory neurons. Because it facilitates nerve fiber regeneration, lowers heat-pain threshold (hyperalgesia), and prevents or improves nerve dysfunction in experimental neuropathy, it is being considered as a putative treatment for certain human polyneuropathies. In 16 healthy subjects, we tested whether intradermal injection of minute doses of recombinant human NGF (1 or 3 micrograms) compared with saline induces hyperalgesia or alters cutaneous sensation (at the site of injection) as measured by symptom scores, clinical examination, or quantitative sensory testing with Computer Assisted Sensory Examination (CASE IV). Most subjects had, as their only symptom, localized tenderness of the NGF-injected site and only when the site was bumped or compressed. Slight discomfort developed in volar wrist structures (with flexion of fingers) or tenderness of deep structures to palpation over the bicipital groove or supraclavicular region. The Neuropathy Symptoms and Change questionnaire indicated that pressure allodynia was significantly localized to the NGF-injected side from 3 hours to 21 days after injections. Light stroking of the skin did not induce tactile allodynia. Compression of injected sites induced pressure allodynia that occurred more frequently and significantly on the NGF-injected side after 3 hours and was maintained for several weeks. No abnormality of vibratory or cooling detection threshold developed from NGF injection. By contrast, heat-pain threshold (HP 0.5, p = 0.003) and an intermediate level of heat-pain (HP 5.0, p < 0.001) were significantly lowered 1, 3, and 7 days (and in some cases at 3 hours and 14 and 21 days) after NGF injection. The time course of pressure allodynia and heat-pain hyperalgesia is too rapid to be explained by uptake of NGF by nociception terminals, retrograde transport, and upregulation of pain modulators. Local tissue mechanisms appear to be implicated. It remains to be tested whether recombinant human NGF prevents, stabilizes, or ameliorates small fiber human neuropathies.

Adolescent↗

PubMed1996

Acceleration of hematopoietic reconstitution with a synthetic cytokine (SC-55494) after radiation-induced bone marrow aplasia.

The synthetic cytokine (Synthokine) SC-55494 is a high-affinity interleukin-3 (IL-3) receptor ligand that stimulates greater in vitro multilineage hematopoietic activity than native IL-3, while inducing no significant increase in inflammatory activity relative to native IL-3. The aim of this study was to investigate the in vivo hematopoietic response of rhesus monkeys receiving Synthokine after radiation-induced marrow aplasia. Administration schedule and dose of Synthokine were evaluated. All animals were total-body irradiated (TBI) with 700 cGy 60Co gamma radiation on day 0. Beginning on day 1, cohorts of animals (n = 5) received Synthokine subcutaneously (SC) twice daily with 25 micrograms/kg/d or 100 micrograms/kg/d for 23 days or 100 micrograms/kg/d for 14 days. Control animals (n = 9) received human serum albumin SC once daily at 15 micrograms/kg/d for 23 days. Complete blood counts were monitored for 60 days postirradiation and the durations of neutropenia (NEUT; absolute neutrophil count [ANC] < 500/microL) and thrombocytopenia (THROM; platelet count < 20,000/microL) were assessed. Synthokine significantly (P < .05) reduced the duration of THROM versus the HSA-treated animals regardless of dose or protocol length. The most striking reduction was obtained in the animals receiving 100 micrograms/kg/d for 23 days (THROM = 3.5 v 12.5 days in HSA control animals). Although the duration of NEUT was not significantly altered, the depth of the nadir was significantly lessened in all animal cohorts treated with Synthokine regardless of dose versus schedule length. Bone marrow progenitor cell cultures indicated a beneficial effect of Synthokine on the recovery of granulocyte-macrophage colony-forming units that was significantly higher at day 24 post-TBI in both cohorts treated at 25 and 100 micrograms/kg/d for 23 days relative to the control animals. Plasma pharmacokinetic parameters were evaluated in both normal and irradiated animals. Pharmacokinetic analysis performed in irradiated animals after 1 week of treatment suggests an effect of repetitive Synthokine schedule and/or TBI on distribution and/or elimination of Synthokine. These data show that the Synthokine, SC55 94, administered therapeutically post-TBI, significantly enhanced platelet recovery and modulated neutrophil nadir and may be clinically useful in the treatment of the myeloablated host.

Anemia, Aplastic↗

PubMed1995

Predictors of restenosis after excimer laser coronary angioplasty.

One hundred twenty-five lesions successfully treated with excimer laser coronary angioplasty at 3 centers were analyzed in a central core laboratory using detailed quantitative angiographic analysis. Sixty-seven narrowings had restenosis (> or = 50% diameter stenosis at restudy). Correlates of restenosis were as follows: baseline diameter stenosis was 79% in the restenosis group versus 71% in the group without restenosis (p = 0.0002), baseline minimal diameter stenosis was 0.55 mm in the restenosis group versus 0.72 mm in the group without restenosis (p = 0.006), final diameter stenosis was 40% in the restenosis group versus 32% in the group without restenosis (p = 0.002), lesion length > or = 7 mm was present in 43% of the restenosis group versus 21% in the group without restenosis (p = 0.009), and Thrombolysis in Myocardial Infarction trial flow 0 to 2 was 33% in the restenosis group versus 15% in the group without restenosis (p = 0.025). The strongest multivariate correlate of restenosis was the baseline diameter stenosis (p = 0.003). Whereas most predictors were not controllable, achieving a low residual diameter stenosis that is operator-dependent can favorably influence the restenosis rate.

Aged↗

PubMed1995

Combined superwarfarin and ethylene glycol ingestion. A unique case report with misleading clinical history.

A markedly elevated prothrombin time (PT) and activated partial thromboplastin time (APTT) were observed in a 24-year-old man who was admitted with a history of ethylene glycol ingestion. Further laboratory evaluation suggested that the coagulopathy was related to acquired factor deficiencies. The PT and APTT improved transiently on usual doses of vitamin K, but rapidly became abnormal again. The coagulopathy was controlled only after large doses of vitamin K for at least 37 days. On further questioning, the patient admitted to consuming a large quantity of a rodenticide. The second generation anticoagulant rodenticides (superwarfarins) result in a potent and prolonged anticoagulant effect by reducing the activity of the vitamin K dependent factors (II, XII, IX, and X). To our knowledge, this is the first reported concomitant ingestion of both ethylene glycol and a superwarfarin compound. This case serves to illustrate how a logical laboratory evaluation can lead to the proper diagnosis, despite a misleading clinical history.

4-Hydroxycoumarins↗

PubMed1994

The effects of two matched memory tasks on concurrent finger tapping.

In a dual task experiment, subjects were instructed to perform a single finger tapping task whilst either, concurrently memorizing words appearing randomly on a screen in front of them, or concurrently memorizing the positions of the words. Analysis of percentage change scores revealed a significant tapping hand by task interaction; subjects showed a significantly larger left- than right-hand decrement when the task required memorizing the positions of the words and a non-significantly larger right- than left-hand decrement when the task required memorizing the words. These results suggest that the nature of the task demands determined the pattern of interference observed.

Attention↗

PubMed1992

Promotional activities of the non-genotoxic carcinogen bemitradine (SC-33643).

Bemitradine (SC-33643), a diuretic antihypertensive agent, was studied for its carcinogenicity in a 2-year bioassay in Charles River CD rats via dietary admix at dosages of 50, 150 and 450 mg kg-1 for up to 97 weeks (after which they were followed for eight additional weeks without treatment). Body weights were decreased compared to controls: 5-15% in the female and 10-12% in the male dosage groups by week 105 of the study. Prolactin values were significantly increased in 150 and 450 mg kg-1 females. The compound caused significant increased incidences of liver, thyroid (both sexes) and mammary (females only) neoplasms. The metabolism of bemitradine was studied in both rats and man. Bemitradine and its primary metabolite (SC-36741; desethylbemitradine) were tested and found to be non-genotoxic in Ames, rat primary hepatocyte UDS, CHO/HGPRT, CHO cytogenetics, in vivo mouse micronucleus and mouse lymphoma TK+/- (bemitradine only) assays. Finally, in an altered hepatic foci (Y-glutamyl transpeptidase positive) promotion assay in female Charles River CD rats, bemitradine was found to be a promotor, though not as potent as phenobarbital. We concluded that bemitradine (which has been dropped from development) is a non-genotoxic carcinogen which appears to act by a hormonally modulated promotional activity in inducing tumors in the liver and mammary glands. Tumors seen in the thyroid were probably secondary to the effects of bemitradine on metabolism.

Animals↗

PubMed1991

A method for rapid and frequent blood collection from the rat tail vein.

A technique is described for the collection of blood samples after dilation of rat tail veins using a controlled temperature device. Frequent blood samples of seven or eight per rat were collected during a 6-hr period. Further samples were taken from the same vein after recannulation during the next 5 days. This technique was also used to administer drugs intravenously through one vein and to collect blood samples from the contralateral vein.

Animals↗

PubMed1991

Opportunities for using computers in speech and language therapy: a study of one language unit.

Whilst the use of information technology is increasing in importance as an aid to speech and language therapy, its introduction has so far been unsystematic. Systems analysis methodologies for assessing how information technology can best be employed have been developed for use in the business world. The present study used one such methodology--Checkland's soft systems--to investigate which aspects of the activities of one language unit were most likely to be improved or helped by the introduction of new technology. Such an approach was found to yield useful insights and several opportunities for increased computer use were revealed. However, it was also concluded that, to take maximum advantage of new technology, changes would need to be introduced and resources made available at a higher organisational level than that of the individual unit or department.

Child↗

PubMed1989

Variations in demethylation of N-methylnaltrexone in mice, rats, dogs, and humans.

1. Rats and mice have a greater capacity than dogs or humans to N-demethylate the quaternary ammonium compound, N-methylnaltrexone. 2. In dogs, following the i.v. administration of N-[14C-methyl]methylnaltrexone, 50% of the radioactivity was excreted in the urine and an additional 30% in the faeces within 120 h. 3. In humans following the i.v. administration of 14C-N-methylnaltrexone, 40-60% of the radioactivity was excreted in the urine within the first 24 h. The plasma radioactivity-time curves indicated a biphasic decay and a short distribution phase between 6 and 9 min. with a longer elimination phase between 238 and 1320 min.

Aged↗

PubMed1988

A multidot immunobinding assay for the serodiagnosis of tuberculosis. Comparison with an enzyme-linked immunosorbent assay.

A simple dot immunobinding (dot blot) assay procedure has been developed for the detection of antibodies directed against a soluble mycobacterial antigen preparation. This technique was compared with the widely used ELISA, in a study of samples from tuberculous patients. Dot blots were read on a densitometer. The correlation between both assays was excellent (r = 0.91; P less than 0.001); 90% of sera from tuberculous patients were detected using both techniques and a serial two-fold dilution method. Assessments of the end-points of titration curves by reflectometry and simple visual interpretation gave similar results. The dot blot assay is easier to perform and appears to be a practical alternative to ELISA for the detection of anti-mycobacterial antibodies in tuberculous patients.

Adult↗