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Biomedical subjects

R Thomas

Publications and source records attributed to R Thomas.

At least 55 records · Page 3Linked to original sources
PubMed2004

Role of postdose cyclosporine monitoring in living renal transplant recipients.

Achieving optimal cyclosporine (Neoral) absorption is critical for successful graft outcome. Recently there have been studies on postdose monitoring of cyclosporine. Two- and 3-hour postdose cyclosporine levels measured by radioimmunoassay were correlated with occurrence of rejection and cyclosporine nephrotoxicity in 30 patients; C(2) and C(3) levels were significantly lower than the desired therapeutic levels in patients with acute rejection. Based on our study and those of others we suggest C(3) levels should be adopted in clinical practice.

Acute Disease↗
PubMed2004

Associations of fitness and fatness with mortality in Russian and American men in the lipids research clinics study.

OBJECTIVE: To examine the relative size of the effects of fitness and fatness on mortality in Russian men, and to make comparison to US men. DESIGN: Prospective closed cohort. SUBJECTS: 1359 Russian men and 1716 US men aged 40-59 y at baseline (1972-1977) who were enrolled in the Lipids Research Clinics Study. MEASUREMENTS: Fitness was assessed using a treadmill test and fatness was assessed as body mass index (BMI) calculated from measured height and weight. Hazard ratios were calculated using proportional hazard models that included covariates for age, education, smoking, alcohol intake and dietary keys score. All-cause and cardiovascular disease (CVD) mortality were assessed through 1995. RESULTS: In Russian men, fitness was associated with all-cause and CVD mortality, but fatness was not. For mortality from all causes, compared to the fit-not fat, the adjusted hazard ratios were 0.87 (95% CI: 0.55, 1.37) among the fit-fat, 1.86 (95% CI: 1.31, 2.62) among the unfit-not fat and 1.68 (95% CI: 1.06, 2.68) among the unfit-fat. Among US men, the same hazard ratios were 1.40 (95% CI: 1.07, 1.83), 1.41 (95% CI: 1.12, 1.77) and 1.54 (95% CI: 1.24, 2.06), respectively. There were no statistically significant interactions between fitness and fatness in either group of men for all-cause or CVD mortality. CONCLUSION: The effects of fitness on mortality may be more robust across populations than are the effects of fatness.

Adult↗
PubMed2004

A logical (discrete) formulation for the storage and recall of environmental signals in plants.

When subjected to an appropriate asymmetric stimulus, seedlings of Bidens pilosa L. "store" a symmetry-breaking instruction that will finally take effect (in the form of a differential growth of the cotyledonary buds) only if the plants are in a state in which they can "recall" this information. The ability of the plants to recall the stored symmetry-breaking instruction may be switched "on" or "off" by the application of a variety of stimuli. Although its detailed phenomenology is rather complicated, the overall behaviour of the plant storage/recall system can be modelled by use of an asynchronous, logical (discrete) description involving positive and negative feedback circuits, which are required for the existence of multi-stationarity and stability, respectively. The state tables, as used in this formalism, give a concise and easy-to-handle description of the evolution of the system and make it particularly easy to determine its stable states. This modelling approach may be extended to the formulation of many other experimental systems.

Biological Clocks↗
PubMed2004

Multiphasic helical CT diagnosis of early medullary and papillary necrosis.

PURPOSE: The feasibility of identifying early manifestations of renal papillary necrosis (RPN) and medullary necrosis (RMN) on multiphasic helical CT, leading to prompt treatment for the causative conditions, and its impact on reducing the incidence of late-stage RML and RPN, was investigated. PATIENTS AND METHODS: Sixty-eight patients (35 male, 33 female) aged 19 to 88 years were examined by multiphasic helical CT for complaints of microscopic hematuria (N=49), macroscopic hematuria (N=2), bacteriuria (N=45), pyuria (N=10), fever (N=15), and flank pain (N=27). Preenhancement, arterial corticomedullary, parenchymal, and excretory phase scans generated 1.25 to 7-mm-thick slices. Follow-up CTs were performed at 1 month (N=62) and 3 months (N=58). RESULTS: While the attenuation coefficients of areas suspect for RMN and RPN were similar on preenhancement CT, they differed substantially on the arterial corticomedullary phase (lesions 55 HU mean; normal medulla 120 HU mean) and parenchymal phase (lesions 58 HU mean, normal medulla 210 HU mean). Investigation for predisposing conditions identified diabetes in 18 patients, upper urinary-tract infections in 48, sickle-cell disease or trait in 17, urinary obstruction in 7, and cirrhosis of the liver in 1. On follow-up examinations, enhancement had normalized in 26 compromised areas of 14 patients at 1 month, and 47 areas (23 patients) at 3 months, remained stationary in 28 patients at 1 month and 9 at 3 months, and progressed in 20 at 1 and 26 at 3 months (P<0.001; Fisher's exact test). Patients (N=35) treated for underlying conditions causing ischemia showed reperfusion in 12 cases at 1 month and 20 at 3 months, while of the untreated patients (N=10), none showed reperfusion, and all lesions increased in size. CONCLUSIONS: Multiphasic helical CT is recommended for identification of RMN and RPN at a stage when effective treatment of underlying causative conditions can arrest or reverse the process of devascularization and prevent loss of medullary tissue.

Adult↗
PubMed2004

Multiphasic helical CT criteria for differentiation of recurrent neoplasm and desmoplastic reaction after laparoscopic resection of renal mass lesions.

BACKGROUND AND PURPOSE: Differentiation of recurrent neoplasm and desmoplastic reaction following laparoscopic resection of renal mass lesions poses a problem. The usefulness of multiphasic helical CT-generated criteria based on enhancement and morphologic characteristics was investigated. PATIENTS AND METHODS: The findings in 5 female and 12 male patients aged 29 to 68 years having renal-cell carcinoma (11-38 mm; N = 15) or solitary angiomyolipomas (N = 2) treated by laparoscopic resection (N = 15) or open segmental surgery (N = 2) were analyzed. Multiphasic helical CT was performed in the preenhancement, arterial corticomedullary, parenchymal, and excretory phases generating 2.5- to 7-mm slices. RESULTS: Both recurrent neoplasms showed median postcontrast enhancement of 119 HU in the arterial corticomedullary phase; the median enhancement of desmoplastic masses was 48 HU. In the parenchymal and excretory phase, recurrent neoplasms showed progressive loss of enhancement, whereas desmoplastic lesions sustained enhancement at about the same level. Recurrent neoplasms presented a defined mass with characteristic spiculation, whereas desmoplastic reaction was characterized by an ill-defined mass with spidery projections extending to abutting fat and residual fascial planes. On 2- to 3-month follow-up scans, recurrent neoplasms showed progressive increases in size and desmoplastic reaction a sharp decrease. CONCLUSION: Enhancement of the mass at the operative site on arterial corticomedullary-phase CT to >90 HU strongly suggests recurrent renal-cell carcinoma, while progressive decrease in size on 1- to 3-month follow-up CT suggests a desmoplastic reaction.

Adult↗
PubMed2004

Policy implications associated with the socioeconomic and health system impact of telehealth: a case study from Canada.

This research was undertaken to inform future telehealth policy directions regarding the socioeconomic impact of telehealth. Fifty-seven sources were identified and analyzed through a comprehensive literature search of electronic databases, the Internet, journals, conference proceedings, as well as personal communication with consultants in the field. The review revealed a focus on certain socioeconomic indicators such as cost, access, and satisfaction. It also identified areas of opportunity for further research and policy analysis and development (e.g., social isolation, life stress, poverty), along with various barriers and challenges to the advancement of telehealth. These included confidentiality, reimbursement, and legal and ethical considerations. To become fully integrated into the health care system, telehealth must be viewed as more than an add-on service. This paper offers 19 general and 20 subject-specific telehealth recommendations, as well as seven policy strategies.

Alberta↗
PubMed2004

Multiphasic helical computerized tomography for the assessment of microscopic hematuria: a prospective study.

PURPOSE: We evaluated multiphasic helical computed tomography for the detection and characterization of lesions responsible for hematuria not diagnosed on prior urological surveillance studies. MATERIALS AND METHODS: A total of 393 men and 207 women with recurrent microscopic hematuria but negative urological surveillance studies were examined at 4 participating institutions by multiphasic helical computerized tomography, consisting of pre-enhancement, arterial corticomedullary, parenchymal and excretory phase sequences generating 2 to 5 mm slices through the kidney and lower pelvis. RESULTS: The cause of microscopic hematuria was established in 256 of 600 patients with prior negative urological surveillance examinations with 0.91 sensitivity and 0.94 specificity. The diagnosis was correct in all subsequently proven cases of calculous and renal vascular disease. A total of 67 of 70 inflammatory kidney lesions, 24 of 25 renal neoplasms, 15 of 16 bladder neoplasms, 27 of 35 inflammatory bladder conditions and 21 of 23 ureteral lesions were also correctly diagnosed. The diagnosis of renal medullary and papillary necrosis, and neoplastic lesions of the kidney and bladder allowed the early institution of medical therapy or appropriate surgery. CONCLUSIONS: Multiphasic helical computerized tomography diagnosed lesions responsible for microhematuria in 42.6% of 600 patients with negative urological surveillance examinations. This relatively low cost and low co-morbidity examination is advocated for patients with negative urological surveillance examinations or even as a first examination.

Adult↗
PubMed2004

Measuring information strategies in oncology - developing an information satisfaction questionnaire.

The benefits of providing accurate and culturally sensitive information for patients are now undisputable and information strategies are generally being adopted nationally. Measuring their benefits and adapting strategies to local needs is now a new challenge. Although questionnaires to measure global satisfaction are available, no concise tool has previously existed to specifically measure the information aspects of care. The aims of this study are: to establish which aspects of information were most important to the patients during their cancer pathway; to develop a robust single-page questionnaire that is sensitive to patient priorities to measure and compare satisfaction between patient groups; and to audit information provision within routine clinical practice. Seventy-seven consecutive patients were asked to complete a priority list of which aspects of information were most important to them during their recent cancer care. A total of 303 answers were categorized into five final categories of equal weighting. The data were combined with demographic issues to produce a robust one-page questionnaire which has been adopted formally by the West Anglia Cancer Network. One hundred consecutive patients were then audited to highlight the information shortcomings of a busy community oncology department and the findings are reforming information services. We recommend the use of this practical audit tool in routine clinical practice, which can be downloaded free from cancernet.co.uk in seven languages.

Adult↗
PubMed2004

Dose and outcome of care in haemophilia--how do we define cost-effectiveness?

Severe haemophilia (factor [F]VIII/FIX activity < 0.01 IU mL(-1)) is characterized by repeated haemarthroses resulting in severe arthropathy in adulthood. In 1958, Professor Nilsson in Sweden introduced prophylactic infusions with clotting factor concentrates at regular intervals in order to maintain clotting factor levels above 0.01 IU mL(-1) and to prevent bleeding. Since then, evidence of the long-term beneficial effects of prophylactic treatment for severe haemophilia has been increasing and it has become the recommended treatment strategy for children with severe haemophilia by both the World Health Organization and the US National Hemophilia Foundation Medical and Scientific Advisory Committee. However, the implementation of this recommendation has been hampered by issues of cost and venous access. The high costs of prophylaxis have largely prevented its use in major parts of the world. The question therefore is whether the current models of replacement of clotting factor concentrates, while certainly being effective, are also optimal. Can the data on outcome at different levels of factor replacement be used to assess their cost-effectiveness?

Adolescent↗
PubMed2004

HLA-B and HLA-C alleles and haplotypes in the Dravidian tribal populations of southern India.

The Dravidians are believed to be the earliest inhabitants of India. Their subsequent migration and admixture with invading racial groups has been of scientific interest for population geneticists. In the present study, seven highly endogamous and extremely isolated colonies of Dravidian tribal populations (n = 105) from Kerala in South India were analysed and compared with random non-tribal Dravidian (RND) samples (n = 78) of southern India using the polymerase chain reaction with sequence-specific primer method for HLA-B and HLA-C typing. The tribal group comprises Adiya, Kanikkar, Kattunaikka, Kuruma, Kurichiya, Malapandaram and Paniya, while the RND group includes Malayalam-speaking individuals from various non-tribal castes of Kerala selected randomly. Some of the most frequent HLA-B alleles in the RND population were similar to the North Indian population and included B*07, B*61 (B*40), B*44, B*51, B*35 and B*52. Although B*61 was the most frequent allele in our total study population, the frequency fluctuated in individual populations. HLA-Cw*14 was one of the most frequent alleles while HLA-Cw*17 was totally absent in all populations studied. The haplotype B*61-Cw*14 was present in all the study groups except in Kurichiya, and the haplotype B*51-Cw*14 was only absent in Kattunaikka. Phylogenetic tree and correspondence analysis indicate that all the Dravidian tribal communities group together as a separate cluster, while the RND group of individuals from South India lie close to the North Indian population. This suggests that the RND population of South India might have a crypto-Dravidian origin, while the smaller Dravidian tribal communities have a distinct Dravidian origin.

Alleles↗
PubMed2004

A randomized study investigating the efficacy and safety of amprenavir in combination with low-dose ritonavir in protease inhibitor-experienced HIV-infected adults.

OBJECTIVES: To compare the safety and efficacy of amprenavir [APV/j Agenerase trade mark; GlaxoSmithKline, [Ware, UK; 600 mg twice a day (bid)] boosted with low-dose ritonavir (RTV, 100 mg bid) with those of other protease inhibitors (PIs) in PI-experienced HIV-infected patients. STUDY DESIGN: Parallel-group, randomized, open-label, multicentre study. METHODS: One hundred and sixty-three patients with HIV predicted to be sensitive to APV, another PI and a nucleoside reverse transcriptase inhibitor (NRTI) were randomly assigned to receive either APV boosted with low-dose RTV (APV/r) or a standard of care (SOC) PI with or without low-dose RTV. The non-inferiority of APV/r to the SOC PIs was assessed by time-weighted average change from baseline (AAUCMB) in plasma viral load (vRNA) at week 16. RESULTS: The antiviral response for APV/r bid was non-inferior to that for the SOC PI group: the vRNA AAUCMB mean treatment difference was 0.043 log(10) HIV-1 RNA copies/mL [95% confidence interval (CI)-0.250, 0.335]. APV/r bid was generally well tolerated. CONCLUSIONS: Results confirm the antiviral activity, short-term safety and tolerability of APV/r bid in PI-experienced patients.

Adolescent↗
PubMed2004

A spontaneous compartment syndrome in a patient with diabetes.

A compartment syndrome is an orthopaedic emergency which can result from a variety of causes, the most common being trauma. Rarely, it can develop spontaneously and several aetiologies for spontaneous compartment syndrome have been described. We describe a patient with diabetes who developed a spontaneous compartment syndrome. The diagnosis was delayed because of the atypical presentation.

Anterior Compartment Syndrome↗
PubMed2004

Greek medicine and Babylonian wisdom: circulation of knowledge and channels of transmission in the archaic and classical periods.

This paper considers questions of transmission and circulation of knowledge between Greeks and Babylonians, and in particular within the medical sphere. It compares evidence for the extensive exchange of goods and ideas with the Near East in the archaic period and considers the channels and means of transmission involved. It suggests, however, that the evidence of Hippocratic medicine and of Herodotus implies that interaction in the medical sphere followed the main areas of contact through trade and colonisation, and above all Egypt, rather than Mesopotamia. Contact with Babylonian wisdom was to reappear only in the late classical and Hellenistic period.

Commerce↗
PubMed2003

Impact of neutropenia on delivering planned adjuvant chemotherapy: UK audit of primary breast cancer patients.

The UK audit was undertaken in primary breast cancer patients receiving adjuvant chemotherapy to: (1) record the incidence of neutropenic events (hospitalisation due to febrile neutropenia, dose delay of > or =1 week or dose reduction of > or =15% due to neutropenia); (2) evaluate the impact of neutropenic events on overall dose intensity (DI) received and (3) review the use of granulocyte colony-stimulating factor (G-CSF) in clinical practice. Data from 422 patients with Stage I-III breast cancer were collected from 15 centres. Cyclophosphamide, methotrexate and 5-fluorouracil(CMF)- or anthracycline-based regimens were the most commonly used. Only 5.2% of patients received G-CSF. Overall, 29% of patients experienced a neutropenic event, most frequently dose delay. Neutropenic events had a significant impact on the ability to deliver planned DI. Out of 422 patients, 17% did not achieve 85% of their planned DI; due to neutropenia in 11% of patients. Of the neutropenic patients receiving CMF- or anthracycline-based regimens, around 40 and 32% of patients, respectively, did not achieve 85% of their planned DI. Patients who experienced one neutropenic event had a higher risk of a second event. During adjuvant chemotherapy of primary breast cancer, neutropenic events are common, likely to occur in subsequent chemotherapy cycles, and have a significant impact on receiving planned DI.

Adult↗
PubMed2003

Enzymatic assay for perfluoro-tagged metabolites of l-DOPA using crude lysate from E. coli transformed with pKKAADCII.

Isomers of l-DOPA and dopamine with a nine-atom 19F atom tag were exposed to aromatic acid decarboxylase (AADC) in the lysate of Escherichia coli JM109 that had been transformed with the plasmid pKKAADCII. The resulting samples were analyzed with HPLC. The first study investigated the conversion of the tagged l-DOPA into tagged dopamine, using the tagged dopamine as a standard. A second study was undertaken to identify the source of peaks seen in the enzymatic assays. l-DOPA with the tag bonded at position 5 served as the best substrate for AADC. Isomers that fit into the active site of AADC are likely to follow the biosynthetic path for dopamine in vivo and are potentially useful in magnetic resonance studies. The enzymatic assay described here provides an efficient and cost-effective tool for screening new compounds for use in the fluorine imaging of neural pathways.

Aromatic-L-Amino-Acid Decarboxylases↗
PubMed2003

Chromosome aberrations in canine multicentric lymphomas detected with comparative genomic hybridisation and a panel of single locus probes.

Recurrent chromosome aberrations are frequently observed in human neoplastic cells and often correlate with other clinical and histopathological parameters of a given tumour type. The clinical presentation, histology and biology of many canine cancers closely parallels those of human malignancies. Since humans and dogs demonstrate extensive genome homology and share the same environment, it is expected that many canine cancers will also be associated with recurrent chromosome aberrations. To investigate this, we have performed molecular cytogenetic analyses on 25 cases of canine multicentric lymphoma. Comparative genomic hybridisation analysis demonstrated between one and 12 separate regions of chromosomal gain or loss within each case, involving 32 of the 38 canine autosomes. Genomic gains were almost twice as common as losses. Gain of dog chromosome (CFA) 13 was the most common aberration observed (12 of 25 cases), followed by gain of CFA 31 (eight cases) and loss of CFA 14 (five cases). Cytogenetic and histopathological data for each case are presented, and cytogenetic similarities with human non-Hodgkin's lymphoma are discussed. We have also assembled a panel of 41 canine chromosome-specific BAC probes that may be used for accurate and efficient chromosome identification in future studies of this nature.

Animals↗
PubMed2003

Adjuvant and neoadjuvant therapy for gastric cancer using epirubicin/cisplatin/5-fluorouracil (ECF) and alternative regimens before and after chemoradiation.

Chemoradiation is now used more commonly for gastric cancer following publication of the US Intergroup trial results that demonstrate an advantage to adjuvant postoperative chemoradiotherapy. However, there remain concerns regarding the toxicity of this treatment, the optimal chemotherapy regimen and the optimal method of radiotherapy delivery. In this prospective study, we evaluated the toxicity and feasibility of an alternative chemoradiation regimen to that used in the Intergroup trial. A total of 26 patients with adenocarcinoma of the stomach were treated with 3D-conformal radiation therapy to a dose of 45 Gy in 25 fractions with concurrent continuous infusional 5-fluorouracil (5-FU). The majority of patients received epirubicin, cisplatin and 5-FU (ECF) as the systemic component given before and after concurrent chemoradiation. The overall rates of observed grade 3 and 4 toxicities were 38 and 15%, respectively. GIT grade 3 toxicity was observed in 19% of patients, while haematologic grade 3 and 4 toxicities were observed in 23%. Our results suggest that this adjuvant regimen can be delivered safely and with acceptable toxicity. This regimen forms the basis of several new studies being developed for postoperative adjuvant therapy of gastric cancer.

Adenocarcinoma↗