Biomedical subjects
Publications and source records attributed to A Darnell.
We report on 8 years of imaging and clinical follow-up of a confirmed hepatic angiomyolipoma (AML) undergoing notable growth over this period. The tumor grew considerably in the first 5 years, and its growth especially affected the fatty component; in the last 3 years, growth occurred more slowly. Radiologists should be aware that tumor growth of a hepatic AML can occur.
We report a case of primary biliary tract malignant melanoma occurring in a 47-year-old male. Ultrasonography and computed tomography showed multiple masses in the gallbladder and distal common bile duct that caused biliary tract dilatation. Magnetic resonance imaging showed that the polypoid masses in the gallbladder and common bile duct were of low signal intensity on T2-weighted images and of high signal intensity on unenhanced T1-weighted images.
Although ultrasonography (US) remains the most widely used diagnostic imaging modality for routine evaluation of the fetus, magnetic resonance (MR) imaging has become an invaluable complement to US in all cases in which additional information is desirable. While the ability of US to detect fetal abnormalities is limited in cases such as maternal obesity, oligohydramnios, and in certain fetal positions, MR using fast and ultrafast pulse sequences enables high-quality fetal images to be acquired regardless of the mother's physical condition or fetal position. Fetal genitourinary disorders are the most common intrauterine abnormalities detected by US, accounting for approximately 30% of all antenatally detected anomalies. Although they usually occur in isolation, these defects can form part of more complex syndromes or chromosomopathies, and MR is indicated to rule out associated abnormalities. In some severe genitourinary disorders, there is a severe deficit of amniotic fluid; these cases are associated with other fetal anomalies such as pulmonary hypoplasia and very poor prognosis. In other cases, the amniotic fluid is not compromised, yet the further detection, localization, and characterization of prenatal disorders will have an impact on postnatal follow-up. This article reviews the role of fetal MR in urogenital tract disorders.
Serum soluble interleukin-2 receptor (sIL-2R) concentrations were determined using the ELISA method in 19 cases of ANCA-associated vasculitis. These patients were classified as 7 cases of Wegener's granulomatosis (WG) and 12 cases of microscopic polyangiitis (MPA). Elevated levels of sIL-2R were present in the sera of these patients. Levels of serum sIL-2R were not significantly different in patients with WG and MPA either in the active or inactive phase, so the results were expressed as a unified ANCA associated vasculitis group. Concentrations of serum sIL-2R were significantly higher in ANCA-associated vasculitis during the active phase than during the inactive phase (p<0.05), and serum sIL-2R levels were significantly increased in these patients, in the active or inactive stage, compared with a group of healthy subjects (p<0.05). In patients with vasculitis, serum sIL-2R levels correlated with serum levels of C-reactive protein (p<0.05). In the active phase, concentrations of serum sIL-2R correlated to creatinine concentrations. No correlation was found between sIL-2R and ANCA levels in any of the stages of the disease. These findings suggest cellular immune activation in ANCA associated vasculitis.
Anti-glomerular basement membrane antibody (anti-GBM Ab)-mediated disease and autoimmune thyroiditis are characterized by the presence of organ-specific antibodies. The diagnosis of autoimmune thyroiditis is usually based on the presence of serum antithyroid antibodies. Few studies have addressed the relationship between anti GBM-Ab mediated disease and autoimmune thyroid pathology. Given that this disorder is often asymptomatic, associations of the two pathologies may be under-diagnosed. This study investigated the prevalence of serum antithyroid antibodies (antithyroglobulin (anti-TG) and anti-thyroid peroxidase (anti-TPO)) in patients with anti-GBM Ab-mediated disease. Antithyroid antibodies presence was investigated in sera from 35 patients in whom anti-GBM Ab-mediated disease had been diagnosed. Anti-glomerular basement membrane antibodies and anti-thyroid antibodies (anti-TG and anti-TPO) were assayed using an enzyme-linked immunosorbent assay. Forty-five percent of patients with anti-GBM Ab-mediated disease (16/35) had positive antithyroid antibody titers. Eighteen percent (3/16) suffered from subclinical hypothyroidism. In conclusion, the high prevalence of antithyroid antibodies in these patients suggests a possible pathogenic link between autoimmune thyroiditis and anti GBM Ab-mediated disease.
Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. It is caused by mutations in at least two different genes: PKD1 and PKD2. The study of mutations in these genes is very difficult nowadays. In this study we have analyzed the non reiterated region of the PKD1 gene and all the exons and intron exon boundaries of the PKD2 gene. The technique used to study these genes have been single strand conformation analysis and heteroduplex. We have found 25 differences within the DNA sequence of the PKD1 gene with respect to the published sequence. Seven of these changes correspond to nonsense, missense, frameshifting and splicing mutations. The rest of changes correspond to polymorphisms or rare DNA variants. In the PKD2 gene we have identified 8 new mutations and one polymorphism. Six of these mutations are frameshifting, one is missense and the other one is a large deletion of the PKD2 gene. The rate of mutation detection within the PKD1 gene has been 4% and the rate for PKD2 has been 100%. We have not observed any correlation between genotype and phenotype either in the PKD1 nor in the PKD2 gene. The mutation analysis of ADPKD genes is very difficult, specially for the PKD1 gene. The rate of mutation detection is higher in the PKD2 gene but the global efficacy of the technique is very low as PKD2 represents only 15% of ADPKD patients. Nowadays linkage analysis is still the most useful technique for the molecular diagnosis of ADPKD patients.
Antiglomerular basement membrane disease is an autoimmune disorder characterized by the presence of antibodies directed against glomerular basement membrane. Pyrexia of unknown origin (PUO) is defined as temperatures higher than 38.3 degrees C on several occasions, with a duration of more than 3 weeks, and failure to reach a diagnosis despite 1 week of in-patient investigation. There is a large list of causes of PUO including infections, malignancies and autoimmune diseases, but antiglomerular basement disease has not been described as a cause. We present the first case of antiglomerular basement disease which presented with PUO.
Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder mainly characterized by renal cyst formation. Cysts in ADPKD are focal in nature, since only a small fraction of nephrons become cystic. The hypothesis that a second hit may be required for cyst formation has been proposed. This hypothesis suggests that inactivation of the inherited wild-type allele by a somatic mutation triggers cyst formation. In some cases, this second hit eliminates the normal allele and the affected cells remain with a single allele, which is the inherited mutated copy, and we only visualize one allele after the amplification by polymerase chain reaction; this is called loss of heterozygosity (LOH). In this study we have analysed the DNA isolated from epitehlial cells from 164 cysts of 8 kidneys affected by ADPKD type I and 30 cysts form a kidney affected by ADPKD type II. We have demonstrated the presence of LOH in 20.1% of PKD1 cysts and in 10% of PKD2 cysts. We have also found eight other different mutations in PKD2 cysts without LOH; so the percentage of somatic mutations in the PKD2 kidney reaches 36.6% of cysts. In conclusion, our data suggest that a recessive mechanism at the cellular level is implicated in cyst formation in the PKD1 and the PKD2 disease. The loss of both copies of the gene triggers the proliferation of a single cell, resulting in the cyst formation.
Fever is one of the most frequent causes of hospital admission in patients with end-stage renal disease. Lack of an identified source of infection and/or lack of clinical response to the first empirical antibiotic treatment favour the use of broader spectrum antibiotics. The availability of fourth-generation cephalosporins (e.g. cefepime) and the increasing incidence of bacterial resistances to classical antibiotics has increased their use in the clinical practice. We present two cases of non-convulsive status epilepticus in patients with advanced chronic renal failure who received cefepime at doses corrected for the degree of renal function according to the manufacturer's instrument as. The clinical symptoms included shouthough, processes, disorientation, loss of attention, and the later appearance of myoclonus. In both cases the electroencephalogram (EEG) was compatible with non-convulsive epileptic status. After cefepime withdrawal there was a clinical remission of symptoms and normalization of the EEG. It is concluded that cefepime treatment can induce a non-convulsive epileptic status in patients with advanced chronic renal failure. Pharmacokinetic studies are urgently needed to clearly define the appropriate dose of cefepime in patients with advanced chronic renal failure.
Rapidly progressive glomerulonephritides (RPGN) are forms of necrotizing glomerulonephritis associated with anti-glomerular basement membrane (anti-GBM) and anti-neutrophil cytoplasmic antibodies (ANCA) against the antigens proteinase-3 (anti-PR3) and myeloperoxidase (anti-MPO). RPGN have a course of rapid progression to renal failure. We compared the results from the semiquantitative ELISAs for anti-GMB antibodies, PR3-ANCA and MPO-ANCA and the indirect immunofluorescence technique (IIF) against a new rapid assay (30 minutes) for the same antibodies in patients with clinically suspected RPGN. The semiquantitative ELISAs for anti-GBM antibodies and PR3-ANCA and MPO-ANCA have a proven diagnostic significance in patients with RPGN I and III. There were no significant differences between the ANCA-GBM screening test and the results from the semiquantitative ELISAs (p > 0.05). We did not find significant differences between the results for PR3-ANCA and MPO-ANCA from the ANCA-GBM screening test with C-ANCA and P-ANCA IIF values (p > 0.05). We also corroborated that the ANCA-GBM screening test is a diagnostic tool for RPGN I and III as useful as the semiquantitative ELISAs and the IFF technique. The ANCA-GBM ELISA screening test is a tool as useful as the semiquantitative ELISA against anti-GBM antibodies for diagnosis of RPGN I. The comparison of the screening ELISA with the IIF technique and the semiquantitative ELISAs against PR3-ANCA and MPO-ANCA showed similar utility for diagnosis of RPGN III. The advantages of the new screening assay are that three antibodies are tested at the same time, yielding results in only 30 minutes.
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