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Biomedical subjects

D Pearson

Publications and source records attributed to D Pearson.

At least 19 recordsLinked to original sources

Bone density: is it affected by orchidectomy and radiotherapy given for stage I seminoma of the testis?

A cross-sectional study of bone density involving 30 patients who had undergone orchidectomy and para-aortic radiotherapy for Stage I seminoma of the testis, has been performed. Bone density measurements were made of the whole body, lumbar spine and hips, including all irradiated areas. Comparison was made with previously obtained standard sex and age matched control data. The 30 patients treated for seminoma had a significantly increased mean bone density compared with age matched normal values. No significant differences were demonstrated between the mean bone densities of the irradiated and non-irradiated hips. There was no significant relationship between bone density measurement and time since orchidectomy or radiotherapy. These results suggest that nodal irradiation for seminoma has little long term effect on bone density.

Absorptiometry, Photon

Implementation of the Henry J. Kaiser Family Foundation's Community Health Promotion Grant Program: a process evaluation.

The Community Health Promotion Grants Program, sponsored by the Henry J. Kaiser Family Foundation, represents a major health initiative that established 11 community health promotion projects. Successful implementation was characterized by several critical factors: (1) intervention activities; (2) community activation; (3) success in obtaining external funding; and (4) institutionalization. Analysis of the program was based on data from several sources: program reports, key informant surveys, and a community coalition survey. Results indicate that school-based programs focusing on adolescent health problems were the most successful in reaching the populations they were targeting. The majority of the programs were able to attract external funding, thereby adding to their initial resource base. The programs were less successful in generating health promotion activities and in achieving meaningful institutionalization in their communities.

Adolescent

Maternal care, hippocampal glucocorticoid receptors, and hypothalamic-pituitary-adrenal responses to stress.

Variations in maternal care affect the development of individual differences in neuroendocrine responses to stress in rats. As adults, the offspring of mothers that exhibited more licking and grooming of pups during the first 10 days of life showed reduced plasma adrenocorticotropic hormone and corticosterone responses to acute stress, increased hippocampal glucocorticoid receptor messenger RNA expression, enhanced glucocorticoid feedback sensitivity, and decreased levels of hypothalamic corticotropin-releasing hormone messenger RNA. Each measure was significantly correlated with the frequency of maternal licking and grooming (all r's > -0.6). These findings suggest that maternal behavior serves to "program" hypothalamic-pituitary-adrenal responses to stress in the offspring.

Adrenocorticotropic Hormone

Zidovudine, didanosine, or both as the initial treatment for symptomatic HIV-infected children. AIDS Clinical Trials Group (ACTG) Study 152 Team.

BACKGROUND: Zidovudine has been the drug of choice for the initial treatment of symptomatic children infected with the human immunodeficiency virus (HIV). This trial was designed to assess the efficacy and safety of treatment with zidovudine alone as compared with either didanosine alone or combination therapy with zidovudine plus didanosine. METHODS: In this multicenter, double-blind study, symptomatic HIV-infected children 3 months through 18 years of age were stratified according to age (<30 months or > or =30 months) and randomly assigned to receive zidovudine, didanosine, or zidovudine plus didanosine. The primary end point was length of time to death or to progression of HIV disease. RESULTS: Of the 831 children who could be evaluated, 92 percent had never received antiretroviral therapy and 90 percent had acquired HIV perinatally. An interim analysis (median follow-up, 23 months) showed a significantly higher risk of HIV-disease progression or death in patients receiving zidovudine alone than in those receiving combination therapy (relative risk, 0.61; 95 percent confidence interval, 0.42 to 0.88; P=0.007). The study arm with zidovudine alone was stopped and unblinded; the other two treatment arms were continued. At the end of the study, didanosine alone had an efficacy similar to that of zidovudine plus didanosine (median follow-up, 32 months) (relative risk of disease progression or death, 0.98; 95 percent confidence interval, 0.70 to 1.37; P=0.91). A significantly lower risk of anemia or neutropenia was seen in patients receiving didanosine alone (P=0.036). CONCLUSIONS: In symptomatic HIV-infected children, treatment with either didanosine alone or zidovudine plus didanosine was more effective than treatment with zidovudine alone. The efficacy of didanosine alone was similar to that of the combination therapy and was associated with less hematologic toxicity.

Adolescent

The nucleotide sequence of Saccharomyces cerevisiae chromosome IX.

Large-scale systematic sequencing has generally depended on the availability of an ordered library of large-insert bacterial or viral genomic clones for the organism under study. The generation of these large insert libraries, and the location of each clone on a genome map, is a laborious and time-consuming process. In an effort to overcome these problems, several groups have successfully demonstrated the viability of the whole-genome random 'shotgun' method in large-scale sequencing of both viruses and prokaryotes. Here we report the sequence of Saccharomyces cerevisiae chromosome IX, determined in part by a whole-chromosome 'shotgun', and describe the particular difficulties encountered in the random 'shotgun' sequencing of an entire eukaryotic chromosome. Analysis of this sequence shows that chromosome IX contains 221 open reading frames (ORFs), of which approximately 30% have been sequenced previously. This chromosome shows features typical of a small Saccharomyces cerevisiae chromosome.

Base Composition

The nucleotide sequence of Saccharomyces cerevisiae chromosome XIII.

Systematic sequencing of the genome of Saccharomyces cerevisiae has revealed thousands of new predicted genes and allowed analysis of long-range features of chromosomal organization. Generally, genes and predicted genes seem to be distributed evenly throughout the genome, having no overall preference for DNA strand. Apart from the smaller chromosomes, which can have substantially lower gene density in their telomeric regions, there is a consistent average of one open reading frame (ORF) approximately every two kilobases. However, one of the most surprising findings for a eukaryote with approximately 6,000 genes was the amount of apparent redundancy in its genome. This redundancy occurs both between individual ORFs and over more extensive chromosome regions, which have been duplicated preserving gene order and orientation. Here we report the entire nucleotide sequence of chromosome XIII, the sixth-largest S. cerevisiae chromosome, and demonstrate that its features and organization are consistent with those observed for other S. cerevisiae chromosomes. Analysis revealed 459 ORFs, 284 have not been identified previously. Both intra- and interchromosomal duplications of regions of this chromosome have occurred.

Base Composition

Long-term quality control of DXA: a comparison of Shewhart rules and Cusum charts.

Long-term clinical trials using bone mineral density (BMD) measurements are now commonplace. It is important to maintain a high standard of quality control. In this study two methods of monitoring quality control measurements of dual-energy X-ray absorptiometry (DXA) equipment have been compared using receiver operating curve (ROC) analysis: Shewhart multi-rule charts and Cusum charts. Computer-generated faults within daily spine phantom measurements were used. The Charts were then applied to 3 years of quality control data from one machine and the results related to hardware faults, random events and changes in the underlying BMD measurement. In the ROC analysis the Shewhart multi-rule chart performed as well or better than the cusum chart, but the stringency of the rules must be tightened to obtain optimal performance.

Absorptiometry, Photon

Use of pump-assisted hemofiltration in children with acute renal failure.

In critically ill children, acute renal failure (ARF) is associated with a high mortality. To assess the outcome and complications of pump-assisted hemofiltration (PAHF) using a standard volumetric pump to regulate blood flow, we retrospectively reviewed our experience in 52 patients with ARF treated with PAHF from 1989 to 1995. These patients ranged in age from < 1 month to 19 years and in weight from 2 to 125 kg. The most common underlying diagnoses were congenital heart disease and infection. The duration of PAHF averaged 9 +/- 8 days (range 24 h to 43 days). Hemodiafiltration for solute control was required in 40 patients. Total fluid intake while on PAHF was 136 +/- 95 ml/kg per day, while urine output and ultrafiltration averaged 15 +/- 24 ml/kg per day and 89 +/- 58 ml/kg per day, respectively. Management of laboratory abnormalities was efficient with only 4 patients requiring 1 or 2 additional treatments of hemodialysis for control of uremia. Complications included hyponatremia in 13 patients, hypokalemia in 14 patients, hypovolemia in 8 patients, hyperglycemia in 6 patients, and bleeding in 9 patients. No complications specifically related to use of the volumetric infusion pump for PAHF were noted. PAHF using a volumetric infusion pump for blood flow regulation in critically ill children with ARF is a practical and efficient therapy.

Acute Kidney Injury

Long-term results from the first UKCCSG Ewing's Tumour Study (ET-1). United Kingdom Children's Cancer Study Group (UKCCSG) and the Medical Research Council Bone Sarcoma Working Party.

The aim of this study was to evaluate multimodal chemotherapy and radiotherapy in patients with Ewing's sarcoma. 142 (74 male, 68 female) patients were entered into the ET-1 study between 1978 and 1986. They were treated with vincristine, doxorubicin, actinomycin D, and cyclophosphamide with radiotherapy plus or minus surgery to the primary tumour. Of the 120 who had no metastases at diagnosis, 45 remain alive with a median follow-up of 11.2 years. Only 2 of those with metastases at diagnosis remain alive. The major prognostic factor was site of disease, but age and serum lactic dehydrogenase at diagnosis also had an influence on outcome. 45 of the 61 patients who survived 4 years or more had late effects documented. The type and extent were dependent on tumour site, type of local therapy, volume and dose of radiotherapy. 4 patients had second malignancies. Prospects for long-term survival have improved in patients treated for Ewing's sarcoma. However, late sequelae are present in the majority of patients.

Adolescent

Changes in bone mineral density in patients with Paget's disease treated with risedronate.

OBJECTIVES: To study changes in bone mineral density (BMD) in patients with Paget's disease of bone treated with risedronate. METHODS: Whole body dual energy x ray absorptiometry (DXA) scans were carried out on 20 patients with Paget's disease treated with oral risedronate. DXA scanning was carried out at baseline and 11 months. Whole body bone mineral content (BMC) was measured. In addition, regions of interest were drawn around the skull, individual lumbar vertebrae, hemipelvis, femora, and tibiae to obtain BMD for these sites. An uncoupling index was also calculated as the area under the curve for serum alkaline phosphatase (ALP) divided by the area under the curve for hydroxyproline excretion (HYPRO) for the period of treatment. RESULTS: Median whole body BMC increased from 3057 g to 3156 g (p < 0.001) resulting from an increase in pagetic and non-pagetic BMD. From the analysis of regions of interest it was found that pagetic trabecular bone showed the largest increase in BMD. The pretreatment HYPRO and the uncoupling index were significantly related to the change in BMD for all pagetic sites for a patient (r = 0.65, p < 0.01 and r = 0.57, p < 0.05 respectively). CONCLUSION: Bisphosphonate treatment of Paget's disease results in an increase in BMD of pagetic bone without redistribution of mineral from non-pagetic bone. The remodelling space and extent of uncoupling are significantly related to increases in BMD at pagetic sites.

Absorptiometry, Photon

Synthesis, structure, and structure-activity relationships of divalent thrombin inhibitors containing an alpha-keto-amide transition-state mimetic.

A new class of divalent thrombin inhibitors is described that contains an alpha-keto-amide transition-state mimetic linking an active site binding group and a group that binds to the fibrinogen-binding exosite. The X-ray crystallographic structure of the most potent member of this new class, CVS995, shows many features in common with other divalent thrombin inhibitors and clearly defines the transition-state-like binding of the alpha-keto-amide group. The structure of the active site part of the inhibitor shows a network of water molecules connecting both the side-chain and backbone atoms of thrombin and the inhibitor. Direct peptide analogues of the new transition-state-containing divalent thrombin inhibitors were compared using in vitro assays of thrombin inhibition. There was no direct correlation between the binding constants of the peptides and their alpha-keto-amide counterparts. The most potent alpha-keto-amide inhibitor, CVS995, with a Ki = 1 pM, did not correspond to the most potent divalent peptide and contained a single amino acid deletion in the exosite binding region with respect to the equivalent region of the natural thrombin inhibitor hirudin. The interaction energies of the active site, transition state, and exosite binding regions of these new divalent thrombin inhibitors are not additive.

Amides

Thoracoscopic splanchnicectomy for chronic pancreatitis pain.

BACKGROUND: The study was undertaken to quantitate the effects of thoracoscopic splanchnic nerve resection (SPL) on pain from chronic pancreatitis. METHODS: Patients with chronic pancreatitis pain completed an analog pain scale before operation and at postoperative visits. Midepigastric and left-sided pain was treated with left SPL; right-sided pain was treated with right-sided SPL. If pain recurred on the contralateral side, the patient underwent contralateral SPL. RESULTS: Fifteen patients underwent SPL. Eleven patients required daily narcotics for relief of pain before operation. Eight patients had unilateral SPL, whereas seven ultimately had a bilateral operation (median follow-up, 18 months). Fourteen patients had constant pain before operation, which decreased to a mean of 2.8 attacks per month (p < 0.0001). Before operation, the "worst pain within last two months" was 9.1 on pain scale (range, 0 for no pain, to 11 for constant pain). After operation this decreased to 5.1 (p < 0.002). "Current severity" of pain decreased from 6.5 before operation to 2.0 after operation (p < 0.0005). The "amount pain is interfering with daily activities" decreased from 7.3 before operation to 2.3 after operation (p < 0.0001). Seven patients (46%) no longer require narcotics and are classified as having had good results. Five patients (33%) are classified as improved and have had a major reduction in narcotic needs. Three have had no significant pain relief and are classified as having had poor results. CONCLUSIONS: Thoracoscopic SPL offers substantial promise in the therapy of pain from chronic pancreatitis.

Adolescent

External radiation protection audit in National Health Service hospitals. Radiation protecgtion advisors (RPA) of the Nottingham City Hospital NHS Trust and the Oxford Radcliffe Hospital NHS Trust.

Radiation protection advisers are accustomed to carrying out internal audit in organizations for which they provide services but, traditionally, external audit has not been a part of the radiation protection adviser function. To provide an external audit function, two teams of radiation protection advisers undertook external radiation protection audits of their respective organizations, including the radiation protection adviser function itself. These audits were more representative of audits or inspections carried out by government agencies, for example the Health and Safety Executive and the former Inspectorate of Pollution, now the Environment Agency. Subsequently, reports, including recommendations for remedial action, were prepared for each management by the external auditors. The process of setting up and carrying out the external audits is described. Guidelines are suggested for those seeking to carry out an external audit.

England

Kaposi's sarcoma-associated herpesvirus in Kaposi's sarcoma occurring in immunosuppressed renal transplant recipients.

Kaposi's sarcoma-associated herpesvirus (KSHV) has been implicated in the genesis of Kaposi's sarcoma and other tumors occurring in immunosuppressed individuals. Using amplification by the polymerase chain reaction and nucleotide sequencing of extracted DNA, we have detected the KS330(233) sequence of KSHV DNA in Kaposi's sarcoma tissue from 4 immunosuppressed renal transplant recipients. The sequences shared a greater than 98% homology with those described in KSHV DNA from Kaposi's sarcoma in patients with acquired immunodeficiency syndrome. In another 2 renal transplant recipients KSHV DNA could not be detected in scar tissue at the site of previous Kaposi's sarcoma that had resolved after immunosuppression was discontinued and haemodialysis recommenced. These findings support the hypothesis that KSHV may be the infectious agent concerned in the genesis of Kaposi's sarcoma.

Acquired Immunodeficiency Syndrome

Quantitative bone scintigraphy in the management of monostotic Paget's disease of bone.

OBJECTIVE: To assess the use of quantitative bone scanning (QBS) in the monitoring of patients with intravenous pamidronate-treated symptomatic monostotic Paget's disease of bone in whom biochemical markers of bone turnover are relatively normal. METHODS: QBS was performed in 9 patients and the results were expressed as a ratio, obtained by comparing isotope uptake at an affected and a control (unaffected) site. RESULTS: Serum alkaline phosphatase levels were normal in 7 of the 9 patients and changed minimally with treatment. The median QBS ratio was 2.72 (range 1.69-24.6) at baseline and 1.49 (range 0.63-4.18) posttreatment (P = 0.008). The median symptom score decreased with treatment, but QBS ratios provided the only objective measure of disease activity by which response to pamidronate therapy could be judged. CONCLUSION: QBS may be a useful technique for evaluating the effects of treatment in patients with Paget's disease of bone.

Adult

Effect of corticosteroid on lymphocyte adhesion.

Pulse steroid therapy is utilised in the treatment of vasculitis and active rheumatoid arthritis. Decreased entry of lymphocytes to sites of cell-mediated immune reactions is well recognised, though the mechanism is not fully understood. It may involve adhesion to endothelium. We have therefore measured the effect of methylprednisolone on lymphocyte adhesion to porcine lamina propria endothelium. A marked decrease in adhesion was found after incubating cells at 4 degrees C or at room temperature, with a clear dose response effect, from 0.46mM to 6.3mM. We have previously demonstrated binding of rheumatoid synovial fluid mononuclear cells to lamina propria endothelium. It is suggested that the ameliorating effect of steroid pulsing may be mediated by down-regulating adhesin expression of a gut-seeking population of cells.

Animals

A new immunohistochemical antibody for the assessment of estrogen receptor status on routine formalin-fixed tissue samples.

We describe a method for the immunocytochemical assessment of estrogen receptor (ER) status on routinely processed, formalin-fixed tissue using a recently developed commercially available monoclonal antibody (Dako 1D5) with a microwave antigen retrieval technique. A series of 90 cases of human breast carcinoma was analyzed and the staining was assessed using a semiquantitative microscopic scoring method and by assessment of the percentage of nuclei showing positive staining. The results were compared with assessment using another commercially available antibody (Abbott H222) and with clinical response to tamoxifen therapy. Direct comparison of the paired sets of H scores and the percentage of positively stained nuclei using the two different techniques showed a significant correlation. By assigning an arbitrary cut-off for positivity of H score = 50, assessment of ER status using DAKO 1D5 antibody was found to correlate with response to tamoxifen therapy with a sensitivity of 90% and a specificity of 51%, similar to values in previous studies using other methods. We conclude that assessment of ER status using this new antibody and technique gives accurate results on routinely processed, formalin-fixed tissue and may be used as an alternative to other methods.

Adult

Pre-treatment serum levels of tumour markers in metastatic breast cancer: a prospective assessment of their role in predicting response to therapy and survival.

The value of pre-treatment serum tumour marker levels in 85 consecutive patients of newly diagnosed metastatic breast cancer was prospectively assessed for predicting response to therapy and survival. The markers studied were carcinoembryonic antigen (CEA), orosomucoid (ORO), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), ferritin (FERR), human milk fat globule membrane 1 and 2 (HMFG1 and 2), CA 15-3 and NCRC-11. There was no correlation between serum marker levels and response to therapy. Only serum concentrations of CRP (P = 0.02), FERR (P = 0.001), HMFG1 (P = 0.004) and HMFG2 (P = 0.04) were predictive for survival. The prognostic significance of HMFG1 was restricted to a minority of patients (7%) with extreme values of these serum markers.

Aged