Radiation-induced cancer: a modern view.

Diagnostic medical radiation has been the most rapidly increasing component of population background radiation exposure in Western countries over the past decade. This trend is set to increase as CT scanning is readily available with burgeoning use in everyday clinical practice. Consequently, the issue of cancer induction from the doses received during diagnostic medical exposures is highly relevant. In this review we explain current understanding of potential cancer induction at low doses of sparsely ionising radiation. For cancers that may be induced at low doses, a mechanistic description of radiation-induced cancer is discussed, which, in combination with extrapolation of data based on population cohort studies, provides the basis of the currently accepted linear no-threshold model. We explore the assumptions made in deriving risk estimates, the controversies surrounding the linear no-threshold model and the potential future challenges facing clinicians and policy-makers with regards to diagnostic medical radiation and cancer risk, most notably the uncertainties regarding deriving risk estimates from epidemiological data at low doses.

Evaluation of meglumine gadoterate-enhanced MR angiography (MRA) compared with time-of-flight MRA in the diagnosis of clinically significant non-coronary arterial disease: a pooled analysis of data from two clinical trials.

OBJECTIVES: We analysed pooled data from two clinical trials to assess the diagnostic accuracy and safety of meglumine gadoterate (Gd-DOTA)-enhanced MR angiography (MRA) relative to those of non-enhanced time-of-flight (TOF) MRA for non-coronary arterial disease. Both techniques were compared with X-ray angiography as the gold standard. METHODS: Patients were of both sexes, were aged at least 18 years and had suspected non-coronary arterial disease. Each patient was his/her own control and underwent TOF MRA followed by Gd-DOTA-enhanced MRA, and then X-ray angiography. MRA was performed at 1.5 T (USA study) or 3 T (Republic of Korea study). The primary criterion used to evaluate efficacy was the degree to which the MRA examination agreed with X-ray angiography in assessing non-coronary arterial lesions. The performance of Gd-DOTA over TOF was assessed using a one-sided paired t-test. We also evaluated the specificity, sensitivity, image quality, examination duration and clinical safety of both MRA procedures. RESULTS: In total, 192 patients were enrolled and received Gd-DOTA. In the intent-to-treat population (n=162), within-patient accuracy was significantly greater for Gd-DOTA than for TOF (85.8 ± 19.8% agreement between Gd-DOTA and X-ray angiography compared with 78.3 ± 24.9% agreement between TOF and X-ray angiography; p=0.0001). The sensitivity, specificity, image quality and examination duration were also better for Gd-DOTA than for TOF. There were no serious drug-related adverse events. CONCLUSION: We conclude that Gd-DOTA-enhanced MRA is a safe and accurate procedure for detecting arterial stenosis at both 1.5 T and 3 T.

Generation of 4D access corridors from real-time multislice MRI for guiding transapical aortic valvuloplasties.

Real-time image-guided cardiac procedures (manual or robot-assisted) are emerging due to potential improvement in patient management and reduction in the overall cost. These minimally invasive procedures require both real-time visualization and guidance for maneuvering an interventional tool safely inside the dynamic environment of a heart. In this work, we propose an approach to generate dynamic 4D access corridors from the apex to the aortic annulus for performing real-time MRI guided transapical valvuloplasties. Ultrafast MR images (collected every 49.3 ms) are processed on-the-fly using projections to extract a conservative dynamic trace in form of a three-dimensional access corridor. Our experimental results show that the reconstructed corridors can be refreshed with a delay of less than 0.5ms to reflect the changes inside the left ventricle caused by breathing motion and the heartbeat.

Computational study of haemodynamic effects of entry- and exit-tear coverage in a DeBakey type III aortic dissection: technical report.

OBJECTIVES: Outcome prediction in DeBakey Type III aortic dissections (ADs) remains challenging. Large variations in AD morphology, physiology and treatment exist. Here, we investigate if computational fluid dynamics (CFD) can provide an initial understanding of pressure changes in an AD computational model when covering entry and exit tears and removing the intra-arterial septum (IS). DESIGN: A computational mesh was constructed from magnetic resonance images from one patient (one entrance and one exit tear) and CFD simulations performed (scenario #1). Additional meshes were derived by virtually (1) covering the exit tear (false lumen (FL) thrombus progression) (scenario #2), (2) covering the entrance tear (thoracic endovascular treatment, TEVAR) (scenario #3) and (3) completely removing the IS (fenestration) (scenario #4). Changes in flow patterns and pressures were quantified relative to the initial mesh. RESULTS: Systolic pressures increased for #2 (300 Pa increase) with largest inter-luminal differences distally (2500 Pa). In #3, false lumen pressure decreased essentially to zero. In #4, systolic pressure in combined lumen reduced from 2400 to 800 Pa. CONCLUSIONS: CFD results from computational models of a DeBakey type III AD representing separate coverage of entrance and exit tears correlated with clinical experience. The reported results present a preliminary look at a complex clinical problem.

Hand problems in migrant farmworkers.

PURPOSE: We estimated the self-reported prevalence of hand problems and identified factors associated with them in this cross-sectional study including 390 farmworkers representing 180 migrant farmworker families from Starr County, Texas. METHODS: A two-year cohort study (1999-2001), "Injury and Illness Surveillance in Migrant Farmworkers (MANOS), "provided the data for this study. We calculated the prevalence for the two-year follow-up period, stratified by family member and survey year. The associated work and non-work factors were identified for the entire sample using multilevel mixed-effects logistic regression analysis. RESULTS: Prevalence for hand problems was 29.0% and 17.8% for the first and second study years, respectively. Significant factors (associated odds ratios) included increasing age (1.07), female gender (3.49), duration of sleep while migrating (0.68), participation group working in both study years 1 and 2 (0.21) or year 2 only (0.14), working on average more than 11 hours per day (8.23), moving heavy objects at work (3.97), working with hand-held vibrating tools/machinery (5.16), and working in meat processing (40.48). CONCLUSIONS: The prevalence of hand problems in migrant farmworkers reported by this study was notable for mothers, fathers, and children. Further research with refined ergonomic exposure and outcome assessments for investigating hand injuries in migrant farmworkers is indicated, specifically among youth. The role of sleep in preventing symptoms should also be explored.

Hepatitis B-associated nephrotic syndrome in Jamaican children.

Between December 1984 and November 1996, 171 children under 12 years old presented to the University Hospital of the West Indies with nephrotic syndrome. Hepatitis B surface antigen (HBsAg) was found in ten (6%) of these children, eight of whom had membranous nephropathy (MN), and one each had mesangial proliferative glomerulonephritis (MesN) and minimal change nephrotic syndrome (MCNS). Only those children with MesN and MCNS were steroid-sensitive. The HBsAg-positive status was identified incidentally on screening. At a mean follow-up of 34 months, seven of ten children had experienced complete or partial remission and three had persistent nephrotic syndrome, although none was in renal failure. Six of the ten had biochemical hepatitis. All the children were still HBsAg-positive. Hepatitis B virus (HBV) is a factor contributory to nephrotic syndrome in Jamaican children. As diagnostic clinical markers for HBV-associated nephropathy are usually absent, all children presenting with nephrotic syndrome should be screened for HBsAg. A policy should be implemented in Jamaica for screening pregnant women and at-risk groups for HBsAg, as well as for immunising susceptible neonates, in order to reduce the incidence of HBV-associated pathology.

Human T-cell lymphotropic virus-1-associated renal disease in Jamaican children.

This report documents the clinicopathological features in two Jamaican children who presented with infective dermatitis, glomerulonephritis, renal failure and human T-cell lymphotropic virus (HTLV-1) seropositivity. Severe hypertension with hypertensive encephalopathy was the most impressive clinical feature. Histological findings from renal biopsy specimens in both cases revealed significant glomerulosclerosis with fibrosis, chronic inflammatory cell infiltrates in the interstitium, and arteriolar hypertensive changes. Membranoproliferative glomerulonephritis (MPGN) was demonstrable in case 1 and marked focal glomerulosclerosis in case 2. Case 1 developed end stage renal failure and died within 3 years of diagnosis. Case 2 remains hypertensive and in chronic renal failure. Although a causal relationship between HTLV-1 infection and renal disease cannot be proven by these two cases, it appears that renal involvement in children with HTLV-1 infection is severe, with the potential for chronic renal failure and malignant hypertension. HTLV-1 nephropathy should be suspected in children with infective dermatitis and renal disease.

Thyroid papillary carcinoma arising in a branchial cleft cyst.

We describe the clinico-pathological features and discuss the possible pathogenetic mechanism of thyroid papillary carcinoma arising in a branchial cleft cyst. This has been described only once previously in the literature.

Idiopathic focal and segmental glomerulosclerosis in Jamaica. A 10-year review.

Idiopathic focal and segmental glomerulosclerosis (IFSGS) in a predominantly black population does not appear to behave any differently than in Caucasian patients. Response to steroid therapy and cyclophosphamide had favourable prognostic significance. There may be a subgroup of IFSGS which responds more slowly to steroids. The duration of steroid therapy should extend beyond four months.

Glomerulonephritis after human parvovirus infection in homozygous sickle-cell disease.

Glomerulonephritis with proteinuria of sufficient degree to manifest the nephrotic syndrome followed aplastic crises induced by human parvovirus (B19) in seven patients with homozygous sickle-cell disease, within 7 days in five patients and 6-7 weeks in two. Segmental proliferative glomerulonephritis was found in all four patients who underwent acute renal biopsies and focal segmental glomerulosclerosis was found in the fifth patient who had a biopsy 4 months later. One patient recovered completely, one died in chronic renal failure after 3 months, and the others had impaired creatinine clearance, four with continuing proteinuria.

Splenic cysts--a Jamaican experience.

A total of eleven (11) cases of non-parasitic splenic cysts have been studied at the University Hospital of the West Indies by routine haematoxylin and eosine and immunohistochemical staining, using epithelial markers (cytokeratin, low molecular weight keratin and epithelial membrane antigen). The majority (eight of eleven) were found to be epithelial or true cysts. This is in contrast to findings previously reported in the literature, based on light microscopic examination, that the majority of splenic cysts are non-epithelial in origin. We therefore suggest that immunohistochemical studies should be used routinely to accurately define the nature of all splenic cysts.

Outcome of solid renal tumours in children at the University Hospital of the West Indies.

Of the twenty-nine children with solid renal tumours treated at the University Hospital of the West Indies (UHWI) between January, 1972 and December, 1991, there were twenty-eight cases of nephroblastoma and one of mesoblastic nephroma. Peak incidence was between the ages of two and four years. Twenty-five children had radical nephrectomy while one had bilateral partial nephrectomy. In thirteen cases, pre-operative chemotherapy +/- radiotherapy was used. Post-operative chemotherapy and radiotherapy were used in 24 and 13 cases, respectively. Stage of the tumour was the most decisive factor influencing the outcome. Whereas there was a 100% cure rate in Stages I and II, Stage III had only a 55.5% survival rate and none of the Stage IV survived. Bilateral (Stage V) tumours are curable if individual tumours are localised, as in one of the two cases. The benign mesoblastic nephroma, in a one-month-old infant, was cured by nephrectomy alone. While the present therapy of radical nephrectomy along with combination chemotherapy is satisfactory for early stages, more aggressive adjuvant therapy is needed for improving the results in Stages III and IV.

Inflammatory pseudotumour of the spleen. Report of a case and review of the literature.

A case of inflammatory pseudotumour of the spleen in a 34-year-old female patient is described. We have briefly reviewed the literature on the subject and discussed aetiopathogenesis, pre-operative differential diagnosis and treatment modalities.

Adult T-cell leukemia/lymphoma in a renal transplant recipient: an opportunistic occurrence.

A 42-year-old man with chronic renal failure and homograft transplantation developed adult T cell lymphoma in one native kidney. The role of transfusion in the acquisition of human T-lymphotropic virus type I and its role in the early development of adult T cell lymphoma, particularly on the background of chronic immunosuppression, are discussed. To our knowledge, this is the first such case.

Mortality of Jamaican patients with systemic lupus erythematosus.

A retrospective study of all patients with systemic lupus erythematosus (SLE) who died at the University Hospital of the West Indies over a 14-year period is presented. The major cause of death was infection followed by renal failure. Gram-negative organisms were the major microbiological agents causing infections. Side-effects of therapy were common, in particular bone marrow depression and haemorrhage related to anticoagulants. It appears that controlling severe lupus activity without increasing the risk of lifethreatening complications remains an important goal in the treatment of SLE.