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Biomedical subjects

B Jones

Publications and source records attributed to B Jones.

At least 217 records · Page 12Linked to original sources
PubMed1997

Radical radiotherapy for carcinoma of the uterine cervix using external beam radiotherapy and a single line source brachytherapy technique: the Clatterbridge technique.

At the Clatterbridge Centre for Oncology, a single line source brachytherapy technique using the Selectron (Nucletron) low dose rate remote afterloading equipment has been developed for use in conjunction with homogenous whole pelvis external beam radiotherapy in the radical treatment of carcinoma of the cervix. The technique incorporates several modifications aimed at reducing treatment related morbidity while maintaining satisfactory local tumour control and cure rates. A flexible dose prescription system has been devised to allow individualization of the brachytherapy isodose distribution according to the clinical findings and the estimated normal tissue doses. Modifications of source loading distributions are carried out to limit the point "A" dose rate to a narrow range to take into account the dose rate effect on the risk of complications. Source loading distributions are also modified according to the estimated normal tissue doses in order to respect normal tissue tolerance. This paper describes the technique and its underlying principles.

Brachytherapy↗
PubMed1997

An audit of the treatment of carcinoma of the uterine cervix using external beam radiotherapy and a single line source brachytherapy technique.

A single line source brachytherapy (BT) technique has been developed at Clatterbridge to boost the dose to the primary tumour after whole pelvis external beam radiotherapy (EBRT) for the radical treatment of carcinoma of the cervix. 226 patients with invasive carcinoma of the uterine cervix were treated with radiotherapy alone using this technique (median age 57 years; range 25-87 years). 49 patients had Stage IB disease, 97 had Stage II, 73 had Stage III and seven patients had biopsy confirmed Stage IVA disease. Patients with low bulk disease were given 40-42.5 Gy in 20 fractions while those with bulky disease received 45 Gy in 20 fractions or 50 Gy in 25 fractions. On completion of EBRT, 186 patients (82.3%) proceeded to intracavitary BT using a linear arrangement of sources with the Selectron (Nucletron) remote afterloading unit. Most of the patients (137/226, 60.6%) received a single insertion of 20 Gy to point "A", at a preferred dose rate within the range 0.95-1.05 Gy h-1. In another 30 patients (13.3%), BT was possible at a later date after further tumour regression. Only 10 patients (4.4%) did not receive BT as part of their treatment. The 5 year actuarial cause-specific survival rate was 79% in Stage I disease, 61% in Stage II, 31% in Stage III and 71% in the small number of patients with Stage IVA disease. The 5 year pelvic control rates were 88% for Stage I, 69% for Stage II, 45% for Stage III and 71% for Stage IVA. Significant prognostic variables for survival and local pelvic control on univariate analysis included disease stage, patient age, tumour bulk, nodal status, anaemia, renal failure and overall treatment time. Tumour grade was a significant prognostic variable for survival but not for local tumour control. The extent of parametrial involvement was a significant prognostic variable for survival and local control for Stage IIB but not for Stage IIIB. There was a statistically significant decrease in survival and local tumour control for patients receiving > or = 70 Gy to point "A", or > or = 55 Gy to point "B". On multivariate analysis, the independent prognostic variables for survival and local control were disease stage, overall treatment time and renal failure. Patient age was also an independent prognostic variable for survival while nodal status was an independent prognostic variable for local control. A high proportion of the patients had adverse prognostic features resulting in a very high actuarial risk of distant metastases of 38.1% at 5 years (68.8% for Stage III patients). The overall treatment time was significantly longer in Stage III patients compared with Stage I and Stage II patients. The actuarial rate of Grade 2 late radiation morbidity was 2.7% and 4.3% for the urinary tract and bowel respectively while that of Grade 3 morbidity was only 0.6% and 1.4%, respectively. Good local control can be achieved for patients with nonbulky tumours using relatively low biological doses while minimizing the risk of late treatment related toxicity. Several changes in treatment policy have been made in an attempt to improve local tumour control and possibly survival, particularly for Stage III patients and patients with bulky disease.

Adult↗
PubMed1997

Ankle braces effectively reduce recurrence of ankle sprains in female soccer players.

OBJECTIVE: The purpose of this study was to examine the effectiveness of ankle bracing and taping in preventing recurrencess of ankle sprains, specifically in female athletes. DESIGN AND SETTING: Varsity soccer players' medical records over a five-year period were retrospectively reviewed at a Division III women's college. Data were extracted regarding any history of ankle sprain(s), type of intervention used as prophylaxis after the ankle sprain, number of exposures, and any incidence of recurrence. SUBJECTS: All collegiate varsity soccer players who had suffered a previous sprain to either one or both ankles (38 players) were identified as subjects. MEASUREMENTS: Each previously injured ankle (n = 56) was considered as a case for the analysis. Ankles that had a previous sprain received one of four interventions: 1) a canvas, laced ankle brace (n = 19), 2) taping (n = 12), 3) a combination of taping and ankle bracing (n = 8), or 4) no treatment (n = 17). RESULTS: The four intervention groups had a total of 1717 practice exposures and 650 competitive game exposures; exposures did not differ among the 4 groups. Ankle sprain recurrence frequency was 0%, 25%, 25%, and 35% for the braced, taped, combination, and untreated groups, respectively. The recurrence incidence for the braced group was significantly lower than that of the other three groups. The ankle sprain recurrence frequency did not differ among the taped, combination, and no treatment groups. CONCLUSION: We suggest that prophylactic ankle bracing is effective in reducing the incidence of ankle sprains in female soccer players with a previous history of ankle sprains.

Journal Article↗
PubMed1997

Small bowel cancer. Imaging features and staging.

Small bowel neoplasms are relatively rare. This article presents the imaging features of the most frequently encountered small bowel masses, with emphasis on adenocarcinomas and carcinoid tumors. The CT scan findings and correlative barium and angiographic studies of various small bowel tumors are illustrated. The staging of adenocarcinoma of the small intestine is addressed, with attention to the role of CT scans for radiologic staging.

Humans↗
PubMed1997

Mammographically directed breast biopsies: a College of American Pathologists Q-Probes study of clinical physician expectations and of specimen handling and reporting characteristics in 434 institutions.

OBJECTIVES: To determine (1) the information that clinical physicians want in surgical pathology reports of biopsies performed for mammographic abnormalities, (2) how specimens are received and processed, and (3) what information is actually present in pathology reports. DESIGN: The standard data collection and questionnaire format of the College of American Pathologists' Q-Probes quality improvement program was used. Laboratories (1) surveyed clinical physicians working in selected specialties involved in the care of patients with breast disease concerning what information they wanted in a surgical pathology report, (2) documented laboratory specimen handling for 20 consecutive breast biopsy tissues obtained to investigate mammographic abnormalities, and (3) documented the information content of surgical pathology reports of these cases. PARTICIPANTS: Four hundred thirty-four participating laboratories surveyed 1469 clinical physicians and collected information on 7300 cases regarding specimen processing and report content. RESULTS: Clinical physicians were unanimous in the majority of items they desired for patient care. The information, however, differed depending on the diagnosis. In processing of tissues, 89% of specimens were received without fixative. In 83% of cases, radiographs were performed. Eighty-two percent of specimens were marked in some manner, but in only 45% of cases was a report of the radiographic abnormality given to the Pathology Department. The median number of blocks used to sample the lesion and the whole specimen was three and six blocks, respectively. The latter correlated with specimen size. Fifty-seven (13%) surgical pathology laboratories had radiography equipment. Radiographs of specimens and tissue blocks were made in 5% and 4% of cases, respectively. Correlation of a mammographic abnormality with a microscopic finding was documented in 62% of reports. In 92% of malignant cases the margin status was reported, and 77% of reports contained the lesion size. Eighty-three percent of reports with invasive carcinoma stated the tumor grade, and 76% stated the extent of intraductal carcinoma. The percentage of reports containing information items was significantly higher (P < .05) for institutions using checklists. SUMMARY: This multi-institutional Q-Probes study describes the current clinical expectations and laboratory practices associated with mammographically directed biopsies. Disparities between pathology reporting and clinician desires, as well as radiology and laboratory specimen handling practices, have been identified and may help focus future quality improvement efforts.

Biopsy↗
PubMed1997

Current management of small-bowel obstruction.

In conclusion, most of the recent advances in the management of small bowel obstruction consist of developments in the imaging modalities available to assist in the diagnosis itself, particularly with regard to the distinction between partial and complete obstruction. Unfortunately, little progress has been made to enable physicians to detect early, reversible strangulation, and therefore the surgical management of small-bowel obstruction has changed very little over the past 10 years. Because of the inability to detect reversible ischemia, there is a substantial risk of progression to irreversible ischemia (and an inherent rise in morbidity and mortality) when surgery is delayed for an extended period of time, especially in the setting of suspected complete obstruction. However, almost all patients do benefit from an initial 12 to 24 hours of resuscitation and decompression in cases of complete obstruction; resuscitation and decompression can usually be extended for a longer period of time in those patients with partial obstruction who exhibit no signs of progression (Fig 6). It is encouraging, however, that some advances have been made in understanding the pathophysiology and prevention of adhesion formation. Research efforts in the future should continue to focus on these issues as well as on the development of methods to better recognize early signs of strangulation.

Algorithms↗
PubMed1996

Immunization with soluble BDC 2.5 T cell receptor-immunoglobulin chimeric protein:antibody specificity and protection of nonobese diabetic mice against adoptive transfer of diabetes by maternal immunization.

The BDC 2.5 T cell clone is specific for pancreatic beta-cell antigen presented by I-Ag7, and greatly accelerates diabetes when injected into 10-21-d-old nonobese diabetic (NOD) mice. The BDC 2.5 T cell receptor (TCR) has been solubilized as a TCR-IgG1 chimeric protein. All NOD mice immunized against BDC 2.5 TCR-IgG1 produced antibodies recognizing TCR C alpha/C beta epitopes that were inaccessible on the T cell surface. 56% of the mice produced antibodies against the BDC 2.5 clonotype that specifically blocked antigen activation of BDC 2.5 cells. We have used the adoptive transfer model of diabetes to demonstrate that maternal immunization with soluble TCR protects young mice from diabetes induced by the BDC 2.5 T cell clone.

Adoptive Transfer↗
PubMed1996

Radiobiologically based assessments of the net costs of fractionated radiotherapy.

PURPOSE: To examine how the long-term costs of radiation therapy may be influenced by modifications to fractionation schemes, and how any improvements in tumor control might, in principle, be translated into a potential cost saving for the responsible healthcare organization. METHODS AND MATERIALS: Standard radiobiological modeling based on the linear-quadratic (LQ) model is combined with financial parameters relating to the estimated costs of different aspects of radiotherapy treatment delivery. The cost model includes provision for the long-term costs of treatment failure and enables the extra costs of near optimal radiotherapy to be balanced against suboptimal alternatives, which are more likely to be associated with further radiotherapy, salvage surgery, and continuing care. RESULTS: A number of caveats are essential in presenting a model such as this for the first time, and these are clearly stated. However, a recurring observation is that, in terms of the whole cost of supporting a patient from first radiotherapy treatment onwards, high quality radiotherapy (i.e., based on individual patterns of fractionation that are near optimal for particular subpopulations of tumor) will frequently be associated with the lowest global cost. CONCLUSIONS: This work adds weight to the case for identifying fast and accurate predictive assay techniques, and supports the argument that suboptimal radiotherapy is usually more costly in the long term. Although the article looks only at the cost-benefit consequences of altered patterns of fractionation, the method will, in principle, have application to other changes in the way radiotherapy can be performed, e.g., to examining the cost-benefit aspects of tumor dose escalation as a consequence of using advanced conformal treatment planning (10).

Cost-Benefit Analysis↗
PubMed1996

Modelling and design of cross-over trials.

There are many diseases and conditions that can be studied using a cross-over clinical trial, where the subjects receive sequences of treatments. The treatments are then compared using the repeated measurements taken 'within' subjects. The actual plan or design of the trial is usually obtained by consulting a published table of designs or by applying relatively simple rules such as using all possible permutations of the treatments. However, there is a danger is this approach because the model assumed for the data when the tables or rules were constructed may not be appropriate for the new trial being planned. Also, there may be restrictions in the new trial on the number of treatment sequences that can be used or on the number of periods of treatment particular subjects can be given. Such restrictions may mean that a published design of the ideal size cannot be found unless compromises are made. A better approach is to make the design satisfy the objectives of the trial rather than vice versa. In this paper we describe an approach to constructing such tailor-made designs which we hope will lead to ill-fitting 'off the peg' designs being a thing of the past. We use a computer algorithm to search for optimal designs and illustrate it using a number of examples. The criterion of optimality used in this paper is A-optimality but our approach is not restricted to one particular criterion. The model used in the search for the optimal design is chosen to suit the nature of the trial at hand and as an example a variety of models for three treatments are considered. We also illustrate the construction of designs for the comparison of two active treatments and a placebo where it can be assumed that the carry-over effects of the active treatments are similar. Finally, we illustrate an augmentation of a design that could arise when the objectives of a trial change.

Algorithms↗
PubMed1996

Trials to assess equivalence: the importance of rigorous methods.

The aim of an equivalence trial is to show the therapeutic equivalence of two treatments, usually a new drug under development and an existing drug for the same disease used as a standard active comparator. Unfortunately the principles that govern the design, conduct, and analysis of equivalence trials are not as well understood as they should be. Consequently such trials often include too few patients or have intrinsic design biases which tend towards the conclusion of no difference. In addition the application of hypothesis testing in analysing and interpreting data from such trials sometimes compounds the drawing of inappropriate conclusions, and the inclusion and exclusion of patients from analysis may be poorly managed. The design of equivalence trials should mirror that of earlier successful trials of the active comparator as closely as possible. Patient losses and other deviations from the protocol should be minimised; analysis strategies to deal with unavoidable problems should not centre on an "intention to treat" analysis but should seek to show the similarity of results from a range of approaches. Analysis should be based on confidence intervals, and this also carries implications for the estimation of the required numbers of patients at the design stage.

Clinical Trials as Topic↗
PubMed1996

Analysis of cross-over trials for duration data.

Survival models and cross-over designs both have an established place in biomedical research. Surprisingly, there are a few examples of proper exploitation of two in combination. A number of advantages and disadvantages of such studies are discussed. Two examples are used to illustrate the application of semi-Markov models with time-varying covariates, as standard log-linear models, to such data.

Cross-Over Studies↗
PubMed1996

A model for cross-over trials evaluating therapeutic preferences.

A preference trial is a special form of cross-over trial where clinical conditions determine when patients change treatment, in a prescribed order. This can be modelled using a geometric distribution. The model can be simply fitted using standard logistic regression methodology. The procedure is applied to a trial studying the effects of bronchodilators in the treatment of chronic asthma.

Asthma↗
PubMed1996

Reading and spelling deficits among children attending a psychiatric day treatment program.

To investigate the specific behavioural and cognitive characteristics which may account for academic deficits in children with psychiatric disorders, 50 children admitted to a day treatment and school program were assessed using behaviour questionnaires for parents and teachers, and tests assessing intelligence (WISC-R), language (CELF-R) and academic performance (Kaufman Test of Educational Achievement). The academic measures Reading Decoding, Reading Comprehension and Spelling formed the dependent variables. Behaviour and cognitive measures which distinguished the sample from normative data constituted the independent variables. Hierarchical multiple regression analyses were performed in order to identify behaviour and cognitive measures accounting for the academic deficits. In the analyses, three measures (Digit Span, Sentence Assembly, Recalling Sentences), probably assessing overlapping cognitive/linguistic functions, accounted for a large proportion of variance for Reading Decoding (0.47), Reading Comprehension (0.63) and Spelling (0.29). None of the behaviour measures accounted for any variance of the academic variables. It is argued that linguistic dysfunction is a primary deficit which underlies problems in academic learning.

Adolescent↗
PubMed1996

Simple radiographic evaluation of ileoanal pouch volume.

PURPOSE: Total colectomy and mucosal protectomy with ileal reservoir and anal pull-through is used in the treatment of ulcerative colitis or familial polyposis, with one complication being frequent bowel movements. A simple radiographic test to predict frequency of bowel movements and measure spasticity was evaluated. METHODS: Fourteen patients underwent evaluation after ileal reservoir and anal pull-through J-pouch construction. Barium sulfate suspension was instilled into the pouch via the anus in the standing position until reflux flowed into the small intestine proximal to the pouch and patients felt the urge to defecate. Total volume infused (VOLtot), volume to reflux (VOLrflx), and volume voided (VOLvoid) were measured. RESULTS: VOLvoid and the "voiding efficiency" (VOLvoid/VOLtot) correlated significantly with stool frequency (R=-0.744, P<0.002 and R=-0.754, P<0.002, respectively). Time from operation was correlated with VOLvoid and stool frequency (R=-0.723, P<0.003 and RO.573, P<0.032, respectively). CONCLUSIONS: The addition of quantitative measurements to this radiographic test gives useful information about pouch performance. Furthermore, the data imply that spasticity, as measured by voiding quantum and efficiency, rather than actual pouch volume is a major determinant of bowel movement frequency.

Adult↗
PubMed1996

Establishing a reliable visual function test and applying it to screening optic nerve disease in onchocercal communities.

The computer Controlled Video Perimetry (CCVP) is a computer screening test for detecting visual function loss caused by onchocerciasis, glaucoma, etc. Installed on portable computers, the CCVP has been shown to be high acceptability in field community investigation. However, it is regarded to be difficult in obtaining reliable results from portable computer screening tests because of human behavioural variants and the lack of standard testing environment. In this paper, we propose an architecture for implementing a more reliable CCVP system. In particular, a self-organising neural network is applied to manage measurement noise caused by behavioural factors. A control unit is introduced to manage the overall behaviour of the system. The integrated test system has been used to screen optic nerve disease in onchocercal communities of rural Nigeria and the experimental results obtained from a large number of test records are very encouraging: reliable results from volatile test environments may be obtained using the proposed method.

Artifacts↗
PubMed1996

Helping health professionals involved in cancer care acquire key interviewing skills--the impact of workshops.

To assess the impact of workshops on key interviewing skills, 169 health professionals involved in cancer care interviewed a simulated patient immediately before and after the workshops and 6 months later. Each interview was audiotaped, transcribed and rated by trained raters using a newly developed rating system which permits an utterance by utterance analysis. The workshops led to significant increases in the use of three behaviours which promote patient disclosure of key concerns. Namely, open directive questions, questions with a psychological focus and clarification of psychological aspects. However, there was no increase in the use of educated guesses and empathic statements which promote disclosure of key problems and feelings. There were significant reductions in behaviours which inhibit disclosure including the use of questions with a physical focus, utterances clarifying physical aspects and the giving of advice prematurely. These significant gains were still evident 6 months later, but there had been some decline over time. There were also significant improvements in the ability of health professionals to elicit patients key problems. Before the workshop, 75 (44%) participants were able to identify at least 60% of their patients' main problems (a criterion of clinical competence) compared with 119 (70%) at 6-month follow-up, an increase in numbers of 59%. Before training, health professionals used as many behaviours which inhibit disclosure as those that promote it. This was unaffected by their professional discipline, prior training or age. It highlights the need for health professionals involved in cancer care to have training in these communication skills. We believe that more intensive group work in smaller groups which focuses on the feelings and attitudes of participants as well as their interviewing behaviour would lead to an increase in the use of educated guesses and empathy and better exploration of patients' feelings.

Clinical Competence↗