Artifacts and pitfalls in MR imaging of the pelvis

Artifacts are intimately intertwined with MRI. For the practicing radiologist, effective supervision, troubleshooting, and interpretation of diagnostic MR studies require a solid knowledge of the pertinent artifacts. This article seeks to familiarize the reader with commonly encountered artifacts and pitfalls in pelvic imaging, the mechanism behind their generation, and methods of minimizing their negative impact or maximizing their diagnostic yield. It also serves as an exciting tool to learn many aspects of basic and advanced MR physics. Artifacts are categorized into patient- and sequence-related artifacts. Various manifestations of motion and vascular artifacts, susceptibility, altered tissue contrast, blurring, chemical shift artifact, volume averaging, and gadolinium (Gd) pseudolayering are explained, along with their proposed remedies.     

Effect of exercise on learning and memory in a rat model of developmental stress

Adverse life events occurring in early development can result in long-term effects on behavioural, physiological and cognitive processes. In particular, perinatal stressors impair neurogenesis in the hippocampus which consequently impairs memory formation. Exercise has previously been shown to have antidepressant effects and to increase cognitive functioning by increasing neurogenesis and neurotrophins in the hippocampus. The current study examined the effects of maternal separation, which has been shown to model anxiety in animals, and the effects of exercise on learning and memory. Forty-five male Sprague-Dawley rats were divided into four groups, maternally separated / non-runners, maternally separated / runners, non-separated / runners and non-separated / non-runners. Maternal separation occurred from postnatal day 2 (P2) to 14 (P14) for 3 h per day. Exercised rats were given voluntary access to individual running wheels attached to their cages from P29 to P49. Behavioural testing (Morris water maze (MWM) and object recognition tests) took place from P49 to P63. Maternally separated rats showed no significant difference in anxiety levels in the elevated plus maze and the open field compared to the normally reared controls. However, rats that were allowed voluntary access to running wheels showed increased levels of anxiety in the elevated plus maze and in the open field. Maternal separation did not have any effect on memory performance in the MWM or the object recognition tasks. Exercise increased spatial learning and memory in the MWM with the exercised rats displaying a decreased latency in locating the hidden platform than the non-exercised rats. The exercised rats spent significantly less time exploring the most recently encountered object in the temporal order task in comparison to the non-exercised controls, therefore showing improved temporal recognition memory. All groups performed the same on the other recognition tasks, with all rats showing intact memory performance. Results indicate that maternal separation had little effect on the rats whereas exercise enhanced both spatial and recognition memory.     

Peripheral and bone marrow plasmacytosis in dengue fever: report of a case

We report a case of dengue fever with plasma cells in the blood (3980 per cubic millimeter) and bone marrow (30%) in a 55-year-old woman hospitalized for fever, arthralgias and thrombocytopenia (66,000 per cubic millimeter) on returning from the West Indies. Serological testing confirmed the diagnosis. Plasmacytosis is rare in dengue fever and its frequency and correlation with the different forms of the disease remain to be determined.     

Long-term sequelae of spontaneous axillary-subclavian venous thrombosis.

BACKGROUND: The frequency and severity of post-thrombotic sequelae after spontaneous axillary-subclavian venous thrombosis remain poorly known. OBJECTIVE: To determine the late sequelae of conventionally treated spontaneous axillary-subclavian venous thrombosis. DESIGN: Cross-sectional study. SETTING: University department of vascular medicine. PATIENTS: 54 patients seen during an 18-year period (mean follow-up, 5 years). MEASUREMENTS: Scores for the severity of post-thrombotic symptoms were graded on a numerical rating scale ranging from 0 to 10 and on a 6-point verbal rating scale. Ultrasonographic sequelae were classified as grade 0, normal flow; grade 1, moderate obstruction; or grade 2, severe obstruction or occlusion. RESULTS: Verbal scores were "nil/negligible" in 47% of patients and "severe/intolerable" in 13%; numerical scores were 0 to 3 in 78% of patients and 7 to 10 in 9%. Grade 2 ultrasonographic sequelae were found in 22% of cases. No relation was seen between ultrasonographic sequelae and symptom severity scores. CONCLUSION: The overall clinical outcome of spontaneous axillary-subclavian venous thrombosis is good, and there is no relation between the severity of late symptoms and ultrasonographic sequelae.     

Antibody responses to MAP 1B and other Cowdria ruminantium antigens are down regulated in cattle challenged with tick-transmitted heartwater

Serological diagnosis of heartwater or Cowdria ruminantium infection has been hampered by severe cross-reactions with antibody responses to related ehrlichial agents. A MAP 1B indirect enzyme-linked immunosorbent assay that has an improved specificity and sensitivity for detection of immunoglobulin G (IgG) antibodies has been developed to overcome this constraint (A. H. M. van Vliet, B. A. M. Van der Zeijst, E. Camus, S. M. Mahan, D. Martinez, and F. Jongejan, J. Clin. Microbiol. 33:2405-2410, 1995). When sera were tested from cattle in areas of endemic heartwater infection in Zimbabwe, only 33% of the samples tested positive in this assay despite a high infection pressure (S. M. Mahan, S. M. Samu, T. F. Peter, and F. Jongejan, Ann. N.Y. Acad. Sci 849:85-87, 1998). To determine underlying causes for this observation, the kinetics of MAP 1B-specific IgG antibodies in cattle after tick-transmitted C. ruminantium infection and following recovery were investigated. Sera collected weekly over a period of 52 weeks from 37 cattle, which were naturally or experimentally infected with C. ruminantium via Amblyomma hebraeum ticks, were analyzed. MAP 1B-specific IgG antibody responses developed with similar kinetics in both field- and laboratory-infected cattle. IgG levels peaked at 4 to 9 weeks after tick infestation and declined to baseline levels between 14 and 33 weeks, despite repeated exposure to infected ticks and the establishment of a carrier state as demonstrated by PCR and xenodiagnosis. Some of the serum samples from laboratory, and field-infected cattle were also analyzed by immunoblotting and an indirect fluorescent-antibody test (IFAT) to determine whether this observed seroreversion was specific to the MAP 1B antigen. Reciprocal IFAT and immunoblot MAP 1-specific antibody titres peaked at 5 to 9 weeks after tick infestation but also declined between 30 and 45 weeks. This suggests that MAP 1B-specific IgG antibody responses and antibody responses to other C. ruminantium antigens are down regulated in cattle despite repeated exposure to C. ruminantium via ticks. Significantly, serological responses to the MAP 1B antigen may not be a reliable indicator of C. ruminantium exposure in cattle in areas of endemic heartwater infection.     

Y chromosome microdeletion screening in infertile men in France: a survey of French practice based on 88 IVF centres

Y chromosome microdeletion screening is advised in cases of severely impaired spermatogenesis. Improvements in molecular biological techniques have made diagnosis more accessible in routine analysis. However, Y chromosome microdeletions are not diagnosed in all IVF centres. The aim of the present study was to determine the regulatory (indications, financing) and performance (methods, invoicing) conditions required for this analysis, in France. Microdeletion detection was found to be spreading fast and consistantly. It therefore seems necessary for a consensus to be reached on indications, with a view to a standardized technique, with a common effort of experts in the field. Financial management by the French Health Insurance bodies (Sécurité Sociale) would be an essential step towards routine adoption. Lastly, the answers to our questionnaire revealed a strong demand for information concerning this analysis.     

Lipid transfer proteins from fruit: cloning, expression and quantification

BACKGROUND: Lipid transfer proteins (LTP) are stable, potentially life-threatening allergens in fruits and many other vegetable foods. The aim of this study was to clone and express recombinant apple LTP (Mal d 3), as has previously been done for peach LTP (Pru p 3) and set up quantitative tests for measuring fruit LTPs. METHODS: cDNA for Mal d 3 and Pru p 3 was cloned, expressed in the yeast Pichia pastoris and the resulting proteins were purified via cation exchange chromatography. The immune reactivity of rMal d 3 was compared to nMal d 3 by RAST (inhibition), immunoblotting and basophil histamine release testing. To obtain monoclonal and monospecific polyclonal antibodies, mice and rabbits were immunized with purified nMal d 3. RESULTS: The deduced amino acid sequence of Mal d 3 was identical to the published sequence, Pru p 3 differed at two positions (S9A and S76H). The rMal d 3 had an IgE-binding potency and biological activity close to its natural counterpart. One sandwich ELISA selectively detecting apple LTP and another cross-reactive with cherry, nectarine and hazelnut LTP were developed. In addition, a competitive RIA was developed with polyclonal rabbit antiserum and labeled nMal d 3. CONCLUSION: rMal d 3 (as shown before for rPru p 3) may be a useful tool for application in component-resolved diagnosis of food allergy. Assays for the measurement of LTP will increase the traceability of this potentially dangerous allergen.     

Venous vascular malformations and their treatment with Ethibloc]

The use of Ethibloc must be contemplated as a first-intention treatment for venous malformations of the face. This sclerosing agent has transformed the functional, esthetic and psychological prognosis for these vascular malformations.     

Metastatic carcinoma of oral soft tissue

Metastatic carcinomas to the oral region are rare. Most of the lesions are located in the bones of the jaw. The medical literature contains quite a few examples of metastatic lesions located strictly in the oral soft tissue. We present two cases of oral soft tissue metastatic carcinoma of urogenital origin.