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Biomedical subjects

C Hutton

Publications and source records attributed to C Hutton.

At least 19 recordsLinked to original sources
PubMed2003

Older age is an adverse prognostic factor in stage I, favorable histology Wilms' tumor treated with vincristine monochemotherapy: a study by the United Kingdom Children's Cancer Study Group, Wilm's Tumor Working Group.

PURPOSE: To identify clinical prognostic factors in children with stage I, favorable histology (FH) Wilms' tumor treated with vincristine monochemotherapy after immediate nephrectomy to define subgroups for consideration of further reduction in treatment intensity. PATIENTS AND METHODS: During two consecutive trials of the United Kingdom Children's Cancer Study Group (UKW2 and UKW3, 1986 to 2001), 242 children with stage I FH Wilms' tumor were treated with immediate nephrectomy followed by 10 weekly injections of vincristine 1.5 mg/m2. Event-free survival (EFS) and overall survival (OS) were compared by age group. RESULTS: The 4-year EFS rate was 93.2%, 87.2%, and 71.3% for children less than 2 years old, 2 to 4 years old, and 4 years old or older at diagnosis, respectively (log-rank, P =.001); the corresponding 4-year OS rate was 98.1%, 95.0%, and 87.2% (log-rank, P =.01). There were no toxicity- or procedure-related deaths. In multivariate analysis, specimen weight was not of independent prognostic value (P =.66). Among the 186 children younger than 4 years at diagnosis, there were 17 relapses and five deaths, compared with 16 relapses and eight deaths among the 56 children at least 4 years old at diagnosis. OS after relapse was surprisingly poor (61.6% at 4 years). CONCLUSION: Treatment for stage I FH Wilms' tumor is generally successful using vincristine monotherapy after immediate nephrectomy, and therefore, the risks of dactinomycin hepatopathy can be avoided. However, age at least 4 years is a significant adverse prognostic factor. This treatment schedule should be considered in any trial of treatment reduction in very young children with stage I FH Wilms' tumor, regardless of tumor size, and we suggest that the upper age limit for the reduced therapy be set at 4 years.

Adolescent↗
PubMed2003

Optimized EPI for fMRI studies of the orbitofrontal cortex.

A common problem in gradient-echo echo planar imaging (EPI) is the occurrence of image distortions and signal losses caused by susceptibility gradients near air/tissue interfaces. Since EPI is frequently used for functional magnetic resonance imaging experiments based on the blood oxygenation level-dependent effect, functional studies of certain brain regions affected by susceptibility gradients, such as the temporal lobes and the orbitofrontal cortex, may be compromised. In this work a method for signal recovery in certain regions of the orbitofrontal cortex is presented. The influence of in-plane susceptibility gradients is reduced by optimization of the imaging slice orientation. Through-plane susceptibility gradients are partly compensated by means of a moderate preparation gradient pulse similar to z-shimming. In contrast to several other techniques proposed in the literature for reducing susceptibility effects, this method does not compromise the temporal resolution and is therefore applicable to event-related studies.

Algorithms↗
PubMed2002

Compensation of susceptibility-induced BOLD sensitivity losses in echo-planar fMRI imaging.

Gradient-echo echo-planar imaging is a standard technique in functional magnetic resonance imaging (fMRI) experiments based on the blood oxygenation level-dependent (BOLD) effect. A major problem is the occurrence of susceptibility gradients near air/tissue interfaces. As a consequence, the detection of neuronal activation may be greatly compromised in certain brain areas, especially in the temporal lobes and in the orbitofrontal cortex. Common approaches to overcome this problem, such as z-shimming or the use of tailored radio frequency pulses, usually compensate only for susceptibility gradients in the slice selection direction. In the present study, the influence of susceptibility gradients in the phase encoding direction is investigated both theoretically and experimentally. It is shown that these gradients influence the effective echo time TE and may reduce considerably the local BOLD sensitivity, even in the case of acceptable image intensities. A compensation method is proposed and tested in an fMRI experiment based on a hypercapnic challenge. The results suggest that the compensation method allows for the detection of activation in brain areas which are usually unavailable for BOLD studies.

Brain↗
PubMed2001

Modeling geometric deformations in EPI time series.

Even after realignment there is residual movement-related variance present in fMRI time-series, causing loss of sensitivity and, potentially, also specificity. One cause is the differential deformation of the sampling matrix, by field inhomogeneities, at different object positions, i.e., a movement-by-inhomogeneity interaction. This has been addressed previously by using empirical field measurements. In the present paper we suggest a forward model of how data is affected by an inhomogeneous field at different object positions. From this model we derive a method to solve the inverse problem of estimating the field inhomogeneities and their derivatives with respect to object position, directly from the EPI data and estimated realignment parameters. The field is modeled as a linear combination of cosine basis fields, which facilitates a fast way of implementing the necessary matrix operations. Simulations suggest that the solution is tractable and that the fields are estimable given the deformed images and knowledge of the relative positions at which they have been acquired. An experiment on a subject performing voluntary movements in the scanner yielded plausible estimates of the deformation fields and their application to "unwarp" the time series significantly reduced movement-related variance.

Adult↗
PubMed2000

Visual attention to the periphery is enhanced in congenitally deaf individuals.

We compared normally hearing individuals and congenitally deaf individuals as they monitored moving stimuli either in the periphery or in the center of the visual field. When participants monitored the peripheral visual field, greater recruitment (as measured by functional magnetic resonance imaging) of the motion-selective area MT/MST was observed in deaf than in hearing individuals, whereas the two groups were comparable when attending to the central visual field. This finding indicates an enhancement of visual attention to peripheral visual space in deaf individuals. Structural equation modeling was used to further characterize the nature of this plastic change in the deaf. The effective connectivity between MT/MST and the posterior parietal cortex was stronger in deaf than in hearing individuals during peripheral but not central attention. Thus, enhanced peripheral attention to moving stimuli in the deaf may be mediated by alterations of the connectivity between MT/MST and the parietal cortex, one of the primary centers for spatial representation and attention.

Adolescent↗
PubMed2000

Characterization and correction of interpolation effects in the realignment of fMRI time series.

Subject motion in functional magnetic resonance imaging (fMRI) studies can be accurately estimated using realignment algorithms. However, residual changes in signal intensity arising from motion have been identified in the data even after realignment of the image time series. The nature of these artifacts is characterized using simulated displacements of an fMRI image and is attributed to interpolation errors introduced by the resampling inherent within realignment. A correction scheme that uses a periodic function of the estimated displacements to remove interpolation errors from the image time series on a voxel-by-voxel basis is proposed. The artifacts are investigated using a brain phantom to avoid physiological confounds. Small- and large-scale systematic displacements show that the artifacts have the same form as revealed by the simulated displacements. A randomly displaced phantom and a human subject are used to demonstrate that interpolation errors are minimized using the correction.

Algorithms↗
PubMed2000

Randomized controlled trial of nettle sting for treatment of base-of-thumb pain.

There are numerous published references to use of nettle sting for arthritis pain but no randomized controlled trials have been reported. We conducted a randomized controlled double-blind crossover study in 27 patients with osteoarthritic pain at the base of the thumb or index finger. Patients applied stinging nettle leaf (Urtica dioica) daily for one week to the painful area. The effect of this treatment was compared with that of placebo, white deadnettle leaf (Lamium album), for one week after a five-week washout period. Observations of pain and disability were recorded for the twelve weeks of the study. After one week's treatment with nettle sting, score reductions on both visual analogue scale (pain) and health assessment questionnaire (disability) were significantly greater than with placebo (P = 0.026 and P = 0.0027).

Aged↗
PubMed1998

Blood oxygenation level dependent signal time courses during prolonged visual stimulation.

Previous functional magnetic resonance imaging (MRI) studies using extended visual stimulation have reported disparate results. Two studies have shown that blood oxygen level dependent (BOLD) contrast decays over time which is cited as evidence of recoupling between oxygen utilisation and cerebral blood flow during stimulus presentation. These findings have serious implications for the design of functional MRI experiments because they raise the possibility that BOLD contrast may not accurately reflect neuronal activity. Another study reported no decay of BOLD contrast. These studies used different visual stimuli and imaging techniques. We have performed a series of experiments, using different MRI techniques (echo-planar imaging and fast low angle shot) and two different visual stimuli to assess which of these factors may explain the previous results. In all of our experiments the signal time course from areas of significant activation remained largely elevated throughout the duration of stimulation and this is not affected by the imaging method used. Our data, in accordance with that of Bandettini et al., suggest that recoupling between blood flow and oxygen extraction is not a general phenomenon in the human brain when visual stimuli are presented for an extended time.

Adult↗
PubMed1998

Familial dermatomyositis.

A case of familial dermatomyositis (DM) is reported in a 27-yr-old mother and her daughter aged 2 yr and 8 months. Familial DM is a rare occurrence and has never been reported in a child of < 4 yr old, although isolated cases of DM have been found in infants as young as 1 yr. The mother responded readily to corticosteroids; however, the child proved resistant to steroids and was eventually successfully managed on a combination of methotrexate and prednisolone. Another daughter presented with the dermatological stigmata of DM, but with no evidence of muscle involvement.

Adult↗
PubMed1998

Identifying global anatomical differences: deformation-based morphometry.

The aim of this paper is to illustrate a method for identifying macroscopic anatomical differences among the brains of different populations of subjects. The method involves spatially normalizing the structural MR images of a number of subjects so that they all conform to the same stereotactic space. Multivariate statistics are then applied to the parameters describing the estimated nonlinear deformations that ensue. To illustrate the method, we compared the gross morphometry of male and female subjects. We also assessed brain asymmetry, the effect of handedness, and interactions among these effects.

Adult↗
PubMed1986

An intraoral positive-pressure device for treatment of trismus.

Trismus is a challenging clinical problem that may result from several different causes. The dentist may choose from a wide spectrum of treatment modalities, depending on the severity of the individual case and the health and cooperation of the patient. An individual course of treatment must be planned for each patient. It is important to monitor the treatment closely for effectiveness of the therapy and to ensure the patient's compliance. Treatment should be modified as necessary, according to the patient's progress. We have described an intraoral dynamic device that may be used as part of a treatment program and that enhances patient compliance as compared to traditional extraoral devices.

Equipment Design↗
PubMed1986

Defective production of leucocytic endogenous mediator (interleukin 1) by peripheral blood leucocytes of patients with systemic sclerosis, systemic lupus erythematosus, rheumatoid arthritis and mixed connective tissue disease.

Leucocytic endogenous mediator is one of the activities ascribed to the cytokine or family of cytokines known as interleukin 1. In this study we have examined the ability of circulating blood leucocytes from patients with rheumatic diseases to produce this mediator in vitro. Leucocytic endogenous mediator production was found to be significantly decreased below normal values (mean 107 units, s.e.m. +/- 25) in systemic sclerosis (-6 units +/- 18), systemic lupus erythematosus (-25 units +/- 13), rheumatoid arthritis (-3 units +/- 13) and mixed connective tissue disease (-4 units +/- 40). A control group of ill patients with cancer produced 57 units +/- 8.

Adult↗
PubMed1985

A comparison of normal and pathological synovial fluid.

Synovial fluid from 16 normal subjects was compared with that from 149 patients with a variety of rheumatic disorders. Normal fluid had fewer cells and a lower content of beta-glucuronidase than osteoarthritic samples. Particles, including occasional birefringent crystals, were seen in normal fluids as well as pathological samples. Alizarin red staining particles (presumed to contain apatite) were seen in all diagnostic groups; their numbers showed some correlation with radiological calcification in and around the joints and with a hypertrophic subchondral bone response. Lactate levels were highest in septic arthritis. No assay showed disease specificity.

Adult↗