Search PubMed⌕ Search

Biomedical subjects

R E Coleman

Publications and source records attributed to R E Coleman.

At least 91 records · Page 5Linked to original sources
PubMed2000

Placental site trophoblastic tumour: a rare but potentially curable cancer.

Placental site trophoblastic tumour (PSTT) is a rare form of gestational trophoblastic disease (GTD). We have conducted an analysis of all cases of PSTT managed at the Trophoblastic Disease Screening and Treatment Centre, Sheffield, from 1984 to 1996. During this time we received 4,988 registrations for GTD and managed seven cases of PSTT. A large range of interval between antecedent pregnancy and presentation was observed - the most common presenting symptoms being irregular vaginal bleeding with or without preceding amenorrhoea. Three out of seven patients had disease confined to the uterus at diagnosis and were successfully treated by hysterectomy alone. Two out of seven patients had pulmonary metastases in addition to uterine tumour and were treated with combination chemotherapy--both are alive and well. Of the remaining two patients one had distant and the other loco-regional metastases and both died despite numerous therapeutic interventions.

Adult↗
PubMed2000

Persistent gestational trophoblastic disease: results of MEA (methotrexate, etoposide and dactinomycin) as first-line chemotherapy in high risk disease and EA (etoposide and dactinomycin) as second-line therapy for low risk disease.

Persistent gestational trophoblastic disease is potentially fatal, but the majority of patients are cured with chemotherapy. Any developments in treatment are therefore being directed towards maintaining efficacy and reducing toxicity. We evaluated efficacy and toxicity of methotrexate, etoposide and dactinomycin (MEA) as first-line therapy for high risk disease and etoposide and dactinomycin (EA) as second-line therapy for methotrexate-refractory low risk disease in a retrospective analysis of 73 patients (38 MEA, 35 EA) treated since 1986 at a supra-regional centre. The median follow-up period was 5.5 years and the median number of cycles received was 7. The overall complete response rate was 85% (97% for EA, 75% for MEA). Of eight patients who failed to respond, four have since died and four were cured with platinum-based chemotherapy. Alopecia was universal. Grade II or worse nausea, emesis, or stomatitis was observed in 29%, 30% and 37% respectively. Fifty-one per cent experienced grade II/III anaemia, 8% grade II or higher thrombocytopenia and 64% grade III or IV neutropenia; in six cases this was complicated by sepsis. Fifty-four per cent of patients went on to have a normal pregnancy. No patient has developed a second malignancy. In conclusion, the MEA and EA chemotherapy regimens for persistent trophoblastic disease are very well tolerated, do not appear to affect future fertility and are associated with excellent, sustained complete response rates.

Adult↗
PubMed2000

Radiation-induced pulmonary injury: symptomatic versus subclinical endpoints.

PURPOSE: To assess the relationship between radiation (RT)-induced pulmonary symptoms and subclinical changes in pulmonary functions tests (PFT) and radiographs. MATERIALS AND METHODS: A total of 184 patients irradiated between 1992 and 1998 were prospectively evaluated for RT-induced pulmonary symptoms, changes in computed tomography (CT) density, reductions in single photon emission CT (SPECT) perfusion, and changes in pulmonary functions tests (forced expiratory volume in 1 s [FEV1] and diffusion capacity to carbon monoxide [DLCO]). Comparisons between the evaluable patients with (N=34) and without (N=106) RT-induced pulmonary symptoms were made. RESULTS: Within 6 months of RT, 80% of the RT-induced symptoms were noted. There was no association between the presence or absence of RT-induced pulmonary symptoms and the frequency of RT-induced radiographic changes (p=0.53), or in the dose-response curve for RT-induced reductions in regional perfusion. Overall, RT-induced changes in SPECT images were more commonly seen than increased density changes on CT (p<0.001). Most patients with pulmonary symptoms had relatively low pre-RT PFTs and experienced further declines following RT. CONCLUSIONS: Regional radiographic changes in CT-defined tissue density or SPECT-defined tissue perfusion are similar in patients with and without RT-induced pulmonary symptoms because these endpoints do not consider the volume of lung affected. RT-induced pulmonary symptoms are better related to post-RT PFT because they are an assessment of whole lung function. Additional studies are necessary to better define models that can predict the degree of radiation-induced changes in whole lung function.

Adult↗
PubMed2000

Prediction of myocardial perfusion abnormalities by quantitative regional function using a radionuclide angiography database: a comparison with wall motion analysis.

PURPOSE: Myocardial perfusion and functional information during the same study is now feasible. A new assessment of regional ejection fraction at rest and peak exercise by first-pass radionuclide angiography using a "normal" database file has been developed. OBJECTIVE: This study was performed to assess the relation between this new method of quantitative regional ejection fraction and myocardial perfusion abnormalities and to compare this new technique with visual analysis of regional wall motion. METHODS: Consecutive patients (n = 126) with simultaneous first-pass radionuclide angiography and perfusion SPECT imaging were studied at rest and peak exercise using a same-day protocol. The area under the receiver-operator characteristic curve (C index) was used to assess the concordance probability between perfusion and functional measurements, and logistic regression models were used to examine the ability of functional variables to predict perfusion results. RESULTS: A high concordance was found between the visual analysis of wall motion and perfusion abnormalities (C index = 0.796), and also between regional ejection fraction and perfusion defects (C index = 0.784). The maximal predictive power of functional variables was obtained by combining wall motion analysis and regional ejection fraction (C index = 0.859). Regional ejection fraction contributed, with 20% more information than provided by wall motion analysis alone (chi2 = 9.2, P = 0.0025). CONCLUSIONS: Quantitative regional ejection fraction using a normal database file has a strong relation to perfusion abnormalities and provides incremental information to regional wall motion analysis for predicting perfusion abnormalities. This new technique should be regarded as a potential adjunct to functional studies to evaluate patients with ischemic heart disease.

Cardiac Catheterization↗
PubMed2000

Poststress measurements of left ventricular function with gated perfusion SPECT: comparison with resting measurements by using a same-day perfusion-function protocol.

PURPOSE: To investigate the relationship between the development of ischemia during stress testing and the changes in left ventricular ejection fraction (LVEF) measurements obtained after stress and at rest with a same-day perfusion-function imaging protocol. MATERIALS AND METHODS: One hundred twenty-six patients underwent a same-day rest-stress (61%) or stress-rest (39%) protocol and gated single photon emission computed tomography (SPECT). Perfusion analysis was performed with a 12-segment model. Defects were scored (0 = no defect, 1 = mild defect, 2 = moderate defect, and 3 = severe defect); differences between the summed stress and resting scores of greater than three indicated substantial ischemia. RESULTS: Resting and poststress LVEFs correlated significantly (r = 0.97, P <.001); however, patients with and patients without ischemia had significant differences in poststress versus resting LVEFs (-4.0 vs 1.0, respectively; P <.01). In patients with ischemia versus patients without ischemia, subgroup analysis stress-rest (-2.5 vs 1.0, P =.047) and rest-stress (-4.0 vs 1.0, P =.006) protocols yielded similar results. CONCLUSION: In patients with clinically important stress-induced perfusion abnormalities, the LVEF after stress was significantly lower than the LVEF at rest with same-day rest-stress and stress-rest imaging protocols. In the clinical setting, poststress LVEFs may be lower than true resting measurements, particularly in patients with moderate to severe stress-induced ischemia.

Adenosine↗
PubMed2000

Brain morphological changes and early marijuana use: a magnetic resonance and positron emission tomography study.

BACKGROUND: The focus of this report is on the possible role that the age of first use of marijuana may play on brain morphology and function. METHODS: Magnetic resonance imaging (MRI) and positron emission tomography (PET) were utilized to study 57 subjects. Brain volume measures (whole brain, gray matter, white matter and lateral ventricle volumes), global cerebral blood flow (CBF) and body size were evaluated. RESULTS: There are three primary findings related to age of first use of marijuana. Subjects who started using marijuana before age 17, compared to those who started later, had smaller whole brain and percent cortical gray matter and larger percent white matter volumes. Functionally, males who started using marijuana before 17 had significantly higher CBF than other males. Both males and females who started younger were physically smaller in height and weight, with the effects being greater in males. CONCLUSIONS: These findings suggest that the age at which exposure to marijuana begins is important. Early adolescence may be a critical period for effects that are not present when exposure begins later. These results are discussed in light of reported effects of marijuana on gonadal and pituitary hormones.

Adolescent↗
PubMed2000

Development and evaluation of a dipstick assay for detection of Plasmodium falciparum and P. vivax sporozoites in mosquitoes (Diptera: Culicidae).

We developed a nitrocellulose-based, dipstick circumsporozoite (CS)-enzyme immunoassay [ELISA] for the simultaneous detection of Plasmodium falciparum and P. vivax-210 CS protein. The assay had a detection threshold of < 250 P. falciparum or 400 P. vivax sporozoites per sample, gave results concordant with dissection of salivary glands and CS-ELISA, but was slightly less sensitive than the CS-ELISA in microtiter plates. The assay consistently detected one infected mosquito in a pool of 10 or 20 mosquitoes, and was 100% specific in discriminating between species of Plasmodium when mosquito suspensions were spiked with sporozoites. The assay could be completed in 1 h, required no specialized equipment, and therefore was useful for field applications.

Animals↗
PubMed2000

Vector competence of Peruvian mosquitoes (Diptera: Culicidae) for epizootic and enzootic strains of Venezuelan equine encephalomyelitis virus.

Mosquitoes collected in the Amazon Basin, near Iquitos, Peru, were evaluated for their susceptibility to epizootic (IAB and IC) and enzootic (ID and IE) strains of Venezuelan equine encephalomyelitis (VEE) virus. After feeding on hamsters with a viremia of approximately 10(8) plaque-forming units of virus per milliliter, Culex (Melanoconion) gnomatus Sallum, Huchings, & Ferreira, Culex (Melanoconion) vomerifer Komp, and Aedes fulvus (Wiedemann) were highly susceptible to infection with all four subtypes of VEE virus (infection rates > or = 87%). Likewise, Psorophora albigenu (Peryassu) and a combination of Mansonia indubitans Dyar & Shannon and Mansonia titillans (Walker) were moderately susceptible to all four strains of VEE virus (infection rates > or = 50%). Although Psorophora cingulata (Fabricius) and Coquillettidia venezuelensis (Theobald) were susceptible to infection with each of the VEE strains, these two species were not efficient transmitters of any of the VEE strains, even after intrathoracic inoculation, indicating the presence of a salivary gland barrier in these species. In contrast to the other species tested, both Culex (Melanoconion) pedroi Sirivanakarn & Belkin and Culex (Culex) coronator Dyar & Knab were nearly refractory to each of the strains of VEE virus tested. Although many of the mosquito species found in this region were competent laboratory vectors of VEE virus, additional studies on biting behavior, mosquito population densities, and vertebrate reservoir hosts of VEE virus are needed to incriminate the principal vector species.

Animals↗
PubMed2000

Management of bone metastases.

Metastatic bone disease develops as a result of the many interactions between tumor cells and bone cells. This leads to disruption of normal bone metabolism, with the increased osteoclast activity seen in most, if not all, tumor types providing a rational target for treatment. The clinical course of metastatic bone disease in multiple myeloma, breast and prostate cancers is relatively long, with patients experiencing sequential skeletal complications over a period of several years. These include bone pain, fractures, hypercalcemia, and spinal cord compression, all of which may profoundly impair a patient's quality of life. External beam radiotherapy and systemic endocrine and cytotoxic treatments are the mainstay of treatment in advanced cancers. However, it is now clear that the bisphosphonates provide an additional treatment strategy, which reduces both the symptoms and complications of bone involvement. Additionally, new specific molecules such as osteoprotogerin have been developed that are based on our improved understanding of the cellular signaling mechanisms involved in cancer-induced bone disease. These potent molecules are now entering clinical trials. Ongoing research is aimed at trying to define the optimum route, dose, schedule and type of bisphosphonate in metastatic bone disease and its use in the prevention and treatment of osteoporosis in cancer patients. In vitro suggestions of direct anticancer activity and some promising clinical data in early breast cancer have resulted in considerable interest in the possible adjuvant use of bisphosphonates to inhibit the development of bone metastases.

Bone Neoplasms↗
PubMed2000

FDG PET of pleural effusions in patients with non-small cell lung cancer.

OBJECTIVE: We determined the ability of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to differentiate benign and malignant pleural effusions in patients with non-small cell lung cancer. MATERIALS AND METHODS: Over a 6-year period, we reviewed all patients with primary non-small cell lung cancer and a pleural effusion on staging CT who underwent FDG PET. We examined 25 patients (18 men and seven women; age range, 37-86 years; mean age, 65 years). FDG PET revealed positive findings if pleural activity was greater than background mediastinal activity; FDG PET revealed negative findings if pleural activity was the same as or less than background mediastinal activity. Results of FDG PET were correlated with pathologic diagnosis determined with thoracentesis or pleural biopsy. RESULTS: All patients had effusions on the same side as the primary tumor. Twenty-two patients had a malignant pleural effusion confirmed with thoracentesis (n = 19) or biopsy (n = 3). FDG PET revealed positive findings in 21 patients and negative findings in one. Three patients had no evidence of malignancy in the pleural space determined with cytologic findings (n = 2) or biopsy results (n = 1). FDG PET uptake revealed positive findings in one of these patients and negative findings in two. Therefore, of 22 patients with positive findings on FDG PET, 21 had pleural metastases, and of three patients with negative findings on FDG PET, one had metastases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET for detecting pleural metastases were 95%, 67%, 95%, 67%, and 92%, respectively. CONCLUSION: This study suggests that FDG PET may be useful in improving staging evaluation in patients with non-small cell lung cancer and a pleural effusion. Increased pleural FDG uptake usually indicates pleural metastases; however, because the number of benign effusions studied was small, the relevance of negative findings on FDG PET in this setting is uncertain.

Adult↗
PubMed2000

VEDex (vincristine, epirubicin dexamethasone): an effective and well tolerated palliative chemotherapy regimen for non-Hodgkin's lymphoma.

An evaluation was carried out of the efficacy and toxicity of a novel weekly palliative chemotherapy regimen comprising vincristine, epirubicin and dexamethasone (VEDex) in 57 patients with non-Hodgkin's lymphoma (NHL) treated at this centre. The age range was 34-88 years and the median age was 67 years. Twenty-three patients (40%) had low grade disease and 4 patients (7%) had transformed NHL. Thirty patients (53%) had high grade NHL; 7 had relapsed after conventional chemotherapy and were not fit for high-dose chemotherapy, 7 were heavily pre-treated, 8 had received prior radiotherapy and 8 had not received any prior therapy. Responding patients received a total of 8 weeks of treatment, but treatment could be repeated at a later stage if required. The overall response rate was 66.6%; 11 patients (19.3%) achieved a complete response and 27 (47.3%) achieved a partial response. A further 11 patients (19.3%) had stable disease. Twenty-four patients (42.1%) reported complete resolution of symptoms and 21 (36.8%) had partial resolution of symptoms. The median survival from the onset of treatment was 6 months. Grade III neutropenia was seen in 9 patients (15.8%). Other toxicity included nausea and vomiting grade II (3.5%), grade III (1.8%) and alopecia grade III (1.8%). There were no treatment related deaths. We conclude that VEDex is an effective palliative treatment in patients with indolent or aggressive lymphoma with poor performance status or who have been heavily pre-treated. It is well tolerated in the elderly.

Adult↗
PubMed2000

Transmission scanning system for a gamma camera coincidence scanner.

UNLABELLED: The goal of this research was to develop and evaluate a practical transmission scanning system for attenuation correction on a 2-head gamma camera coincidence scanner. METHODS: The transmission system operates in singles mode and uses point sources of 137Cs that emit 662-keV gamma-radiation. Each point source is inserted between existing septa that are normally used to provide an approximately 2-dimensional emission acquisition geometry. The sources are placed along a line parallel to the axis of rotation near the edge of 1 camera. Data are acquired with the opposing camera. The septa provide axial collimation for the sources so that the transmission system operates in a 2-dimensional offset fanbeam geometry. Camera energy and spatial resolution were measured at 511 and 662 keV. Sensitivity was measured at 662 keV. The effects on axial resolution of adding supplemental collimation to the septa were shown. The system was calibrated and tested using a resolution (rod) phantom and a uniformity phantom. Torso phantom data were acquired. Patient transmission and emission scans were obtained. Postinjection transmission data were used to correct patient emission data. RESULTS: The camera resolution at postinjection counting rates was 11.7% full width at half maximum (FWHM) for 662-keV gamma-rays. Intrinsic spatial resolution was 2.7 mm (FWHM) at 662 keV. The sensitivity of the system was 280 Hz/MBq using five 74-MBq sources of 137Cs in the transmission geometry, with supplemental collimation added to the septa to improve axial resolution. The transaxial resolution of the system was such that the smallest rods (6-mm diameter and 12-mm spacing) were well resolved in a reconstructed resolution-phantom image. The corrected patient emission scans were free of attenuation-induced artifacts. CONCLUSION: An easily implemented transmission system for a 2-head gamma camera coincidence scanner that can be used for postinjection transmission scanning has been developed.

Cesium Radioisotopes↗
PubMed2000

FDG PET imaging in patients with pathologically verified dementia.

UNLABELLED: The purpose of this study was to confirm with pathologic verification 2 beliefs related to Alzheimer's disease (AD): (a) the long-standing impression that bilateral temporo-parietal hypometabolism, as noted on FDG PET imaging, is the metabolic abnormality associated with Alzheimer's disease (AD) and (b) that the sensitivity, specificity, and diagnostic accuracy of the metabolic pattern of bilateral temporo-parietal hypometabolism allows differentiation between other degenerative causes of dementia. METHODS: Twenty two individuals (8 women, 14 men) with difficult-to-characterize memory loss or dementia (using standard clinical criteria), and who eventually received pathologic confirmation of diagnosis, were evaluated. FDG PET brain scans were obtained and visually graded by an experienced nuclear medicine physician as to the presence of classic bilateral temporo-parietal hypometabolism as seen in Alzheimer's type dementia. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the metabolic pattern of bilateral temporo-parietal hypometabolism were determined using pathologic diagnosis as the gold standard. RESULTS: The clinical diagnosis of possible or probable AD was determined as the primary cause of dementia in 12 patients. The sensitivity and specificity of the clinical diagnosis for probable AD were 63% and 100%, respectively. The sensitivity and specificity of the clinical diagnosis for possible and probable AD were 75% and 100%, respectively. The sensitivity, specificity, and diagnostic accuracy of bilateral temporo-parietal hypometabolism being associated with AD were 93%, 63%, and 82%, respectively. CONCLUSION: This study confirms that bilateral temporo-parietal hypometabolism is indeed the classic metabolic abnormality associated with AD. Furthermore, in individuals with dementia whose FDG PET scans indicated a metabolic pattern other than bilateral temporo-parietal hypometabolism, a cause of dementia other than AD should be suspected. These observations may be of clinical importance in differentiating dementia syndromes. The sensitivity, specificity, and diagnostic accuracy of FDG PET are acceptable as tests to be used in the evaluation of dementia and particularly to confirm the clinical suspicion of AD.

Aged↗
PubMed1999

The effect of patient-specific factors on radiation-induced regional lung injury.

PURPOSE: To assess the impact of patient-specific factors on radiation (RT)-induced reductions in regional lung perfusion. METHODS: Fifty patients (32 lung carcinoma, 7 Hodgkin's disease, 9 breast carcinoma and 2 other thoracic tumors) had pre-RT and > or = 24-week post-RT single photon emission computed tomography (SPECT) perfusion images to assess the dose dependence of RT-induced reductions in regional lung perfusion. The SPECT data were analyzed using a normalized and non-normalized approach. Furthermore, two different mathematical methods were used to assess the impact of patient-specific factors on the dose-response curve (DRC). First, DRCs for different patient subgroups were generated and compared. Second, in a more formal statistical approach, individual DRCs for regional lung injury for each patient were fit to a linear-quadratic model (reduction = coefficient 1 x dose + coefficient 2 x dose2). Multiple patient-specific factors including tobacco history, pre-RT diffusion capacity to carbon monoxide (DLCO), transforming growth factor-beta (TGF-beta), chemotherapy exposure, disease type, and mean lung dose were explored in a multivariate analysis to assess their impact on the coefficients. RESULTS: None of the variables tested had a consistent impact on the radiation sensitivity of regional lung (i.e., the slope of the DRC). In the formal statistical analysis, there was a suggestion of a slight increase in radiation sensitivity in the dose range >40 Gy for nonsmokers (vs. smokers) and in those receiving chemotherapy (vs. no chemotherapy). However, this finding was very dependent on the specific statistical and normalization method used. CONCLUSION: Patient-specific factors do not have a dramatic effect on RT-induced reduction in regional lung perfusion. Additional studies are underway to better clarify this issue. We continue to postulate that patient-specific factors will impact on how the summation of regional injury translates into whole organ injury. Refinements in our methods to generate and compare SPECT scans are needed.

Adult↗