Analysis of the antibody response to an immunodominant epitope of the envelope glycoprotein of a lentivirus and its diagnostic potential

The envelope glycoprotein of small ruminant lentiviruses (SRLV) is a major target of the humoral immune response and contains several linear B-cell epitopes. We amplified and sequenced the genomic segment encoding the SU5 antigenic site of the envelope glycoprotein of several SRLV field isolates. With synthetic peptides based on the deduced amino acid sequences of SU5 in an enzyme-linked immunosorbent assay (ELISA), we have (i) proved the immunodominance of this region regardless of its high variability, (ii) defined the epitopes encompassed by SU5, (iii) illustrated the rapid and peculiar kinetics of seroconversion to this antigenic site, and (iv) shown the rapid and strong maturation of the avidity of the anti-SU5 antibody. Finally, we demonstrated the modular diagnostic potential of SU5 peptides. Under Swiss field conditions, the SU5 ELISA was shown to detect the majority of infected animals and, when applied in a molecular epidemiological context, to permit rapid phylogenetic classification of the infecting virus.

Evaluation of colonoscopic allergen provocation as a diagnostic tool in dogs with proven food hypersensitivity reactions

OBJECTIVE: To evaluate the colonoscopic allergen provocation (COLAP) test as a new tool for the diagnosis of IgE-mediated food allergy. METHODS: Oral food challenges as well as COLAP testing were performed in a colony of nine research dogs with proven immediate-type food allergic reactions. In addition, COLAP was performed in five healthy dogs. RESULTS: When compared with the oral challenge test, COLAP accurately determined 18 of 23 (73 per cent) positive oral challenge reactions (73 per cent) in dogs with food allergies and was negative in the healthy dogs. CLINICAL SIGNIFICANCE: The accuracy of this new test may be higher than that for gastric sensitivity testing. Therefore, COLAP holds promise as a new test to confirm the diagnosis of suspect IgE-mediated food allergy in dogs.

The diagnostic yield of vitrectomy specimen analysis in chronic idiopathic endogenous uveitis

PURPOSE: The low diagnostic yield of vitrectomy specimen analysis in chronic idiopathic uveitis (CIU) has been related to the complex nature of the underlying disease and to methodologic and tissue immanent factors in older studies. In an attempt to evaluate the impact of recently acquired analytic methods, the authors assessed the current diagnostic yield in CIU. METHODS: Retrospective analysis of consecutive vitrectomy specimens from patients with chronic endogenous uveitis (n = 56) in whom extensive systemic workup had not revealed a specific diagnosis (idiopathic) and medical treatment had not resulted in a satisfying clinical situation. Patients with acute postoperative endophthalmitis served a basis for methodologic comparison (Group 2; n = 21). RESULTS: In CIU, a specific diagnosis provided in 17.9% and a specific diagnosis excluded in 21.4%. In 60.7% the laboratory investigations were inconclusive. In postoperative endophthalmitis, microbiological culture established the infectious agent in 47.6%. In six of eight randomly selected cases, eubacterial PCR identified bacterial DNA confirming the culture results in three, remaining negative in two with a positive culture and being positive in three no growth specimens. A double negative result never occurred, suggesting a very high detection rate, when both tests were applied. CONCLUSIONS: The diagnostic yield of vitrectomy specimen analysis has not been improved by currently routinely applied methods in recent years in contrast to the significantly improved sensitivity of combined standardized culture and PCR analysis in endophthalmitis. Consequently, the low diagnostic yield in CIU has to be attributed to insufficient understanding of the underlying pathophysiologic mechanisms.

[Disorders of the origin of the suspensory ligament in the horse: a diagnostic challenge]

Lameness in horses due to pain originating from the proximal metacarpal/metatarsal region remains a diagnostic challenge. In cases of obvious lameness the pain can be localised to this region by diagnostic anaesthesia. Because a variety of disorders can cause lameness in this region different imaging modalities including radiography, ultrasonography and scintigraphy should be used to arrive at an accurate diagnosis. Even though a precise anatomic-pathologic diagnosis can still be an enigma, because not only bone and joints, but also soft tissue structures including the proximal suspensory ligament, its origin at the proximal metacarpus/ metatarsus, its fascia, the superficial fascia, as well as the intermetacarpal/metatarsal ligaments, the accessory ligament of the deep digital flexor tendon and both digital flexor tendons may be involved. Magnet resonance tomography (MRT) shows a high diagnostic sensitivity in imaging soft tissue structures and bone. In horses MRT is still at the beginning. The MRT appearance of the proximal metacarpal/metatarsal region has not yet been evaluated in detail and there are only few anatomic studies of the origin of the suspensory ligament in horses. The first experiences showed, that more gross and histologic examinations are necessary to fully interpret MRT-images and to differentiate pathologic alterations from clinically not relevant variations.

Diagnostic significance of Neospora caninum DNA detected by PCR in cattle serum

A nested PCR that successfully detected Neospora caninum DNA in serum of cattle was used for investigation of selected abortion cases and in a study of healthy pregnant cows at an abattoir. N. caninum DNA was not detected in serum from antibody positive dams that aborted due to N. caninum, but was present in serum of some antibody negative dams that aborted due to other causes. N. caninum DNA was also found in the serum of about half of the animals that aborted of undetermined cause, but was not detected in cow sera from two beef cattle herds in Western Australia with no recent history of abortion. In the abattoir study of 79 dams and their foetuses N. caninum DNA was found in serum of 3 dams and in material from 11 foetuses. The majority of the cows and all foetuses were antibody negative. Our findings suggest that there is no obvious relationship between the presence or absence of N. caninum DNA in serum and the presence of antibodies to N. caninum in dams, the presence of N. caninum DNA in foetuses or abortion due to N. caninum. This is the first report of the detection of N. caninum DNA in serum of cattle rather than the white blood cell fraction. It indicates the presence of free tachyzoites and/or parasite DNA in circulation. The results suggest that persistent infection in the absence of antibodies is a possible outcome of N. caninum infection. Infection of foetuses in the absence of antibodies supports the possibility of persistent infection due to immunotolerance to an early in utero infection. It is therefore important to test for N. caninum DNA as well as antibodies for the detection of exposed and/or infected animals. However, the presence or absence of N. caninum antibodies or DNA did not support nor exclude N. caninum as the cause of abortion. Additional criteria are required for a positive diagnosis of abortion caused by N. caninum.

Leydig-cell tumour in children: variable clinical presentation, diagnostic features, follow-up and genetic analysis of four cases

BACKGROUND: Testicular tumours are relatively uncommon in infants and children, accounting for only 1-2% of all paediatric solid tumours. Of these approximately 1.5% are Leydig-cell tumours. Further, activating mutations of the luteinizing hormone receptor gene (LHR), as well as of the G protein genes, such as Gsalpha (gsp) and Gialpha (gip2) subunits, and cyclin-dependent kinase gene 4(CDK4) have been associated with the development of several endocrine neoplasms. AIMS/METHODS: In this report, the clinical variability of Leydig-cell tumours in four children is described. The LHR-, gsp-, gip2- and CDK4 genes were investigated to establish the possible molecular pathogenesis of the variable phenotype of the Leydig-cell tumours. RESULTS: No activating mutations in these genes were found in the four Leydig-cell tumours studied. Therefore, the absence of activating mutations in LHR, as well as in both the 'hot spot' regions for activating mutations within the G-alpha subunits and in the regulatory 'hot spot' on the CDK4 genes in these tumours indicates molecular heterogeneity among Leydig-cell tumours. CONCLUSION: Four children with a variable phenotype caused by Leydig-cell tumours are described. A molecular analysis of all the 'activating' genes and mutational regions known so far was performed, but no abnormalities were found. The lessons learnt from these clinically variable cases are: perform ultrasound early and most importantly, consider discrepancies between testicular swelling, tumour size and androgen production.

Sample sizes of studies on diagnostic accuracy: literature survey

OBJECTIVES: To determine sample sizes in studies on diagnostic accuracy and the proportion of studies that report calculations of sample size. DESIGN: Literature survey. DATA SOURCES: All issues of eight leading journals published in 2002. METHODS: Sample sizes, number of subgroup analyses, and how often studies reported calculations of sample size were extracted. RESULTS: 43 of 8999 articles were non-screening studies on diagnostic accuracy. The median sample size was 118 (interquartile range 71-350) and the median prevalence of the target condition was 43% (27-61%). The median number of patients with the target condition--needed to calculate a test's sensitivity--was 49 (28-91). The median number of patients without the target condition--needed to determine a test's specificity--was 76 (27-209). Two of the 43 studies (5%) reported a priori calculations of sample size. Twenty articles (47%) reported results for patient subgroups. The number of subgroups ranged from two to 19 (median four). No studies reported that sample size was calculated on the basis of preplanned analyses of subgroups. CONCLUSION: Few studies on diagnostic accuracy report considerations of sample size. The number of participants in most studies on diagnostic accuracy is probably too small to analyse variability of measures of accuracy across patient subgroups.

Treatment of hyperactive children: increased efficiency through modifications of homeopathic diagnostic procedure

BACKGROUND: The rigorous test to which homeopathy was subject in our recent double-blind clinical trail of homeopathic treatment of attention deficit hyperactivity disorder (ADHD) necessitated optimized treatment meeting the highest standards. METHODS: Optimization was performed in three steps: (1) In successfully treated children, prescriptions leading to an insufficient response were analysed by a general questionnaire to identify unreliable symptoms. (2) Polarity analysis, a further development of Bönninghausen's concept of contraindications, was introduced in response to the frequently one-sided symptoms. This enabled us to use few but specific symptoms to identify the medicine whose genius symptoms exhibit the closest match to the patient's characteristic symptoms. (3) We investigated the influence of the primary perception symptoms on the result of the repertorization. Perception symptoms are not normally recorded during a patient interview even though they are among the most reliable facts related by the patients. At the same time we were able to improve the continuity of improvement of ADHD symptoms using liquid Q-potencies. RESULTS: Introducing the questionnaire, polarity analysis, and including perception symptoms, lead to an improvement in the success rate of the first prescription from 21% to 54%, of the fifth prescription from 68% to 84%.

Diagnostic efficacy of SonoVue, a second generation contrast agent, in the assessment of extracranial carotid or peripheral arteries using colour and spectral Doppler ultrasound: a multicentre study

The purpose of this study was to demonstrate the improvement in diagnostic quality and diagnostic accuracy of SonoVue microbubble contrast-enhanced ultrasound (CE-US) versus unenhanced ultrasound imaging during the investigation of extracranial carotid or peripheral arteries. 82 patients with suspected extracranial carotid or peripheral arterial disease received four SonoVue doses (0.3 ml, 0.6 ml, 1.2 ml and 2.4 ml) with Doppler ultrasound performed before and following each dose. Diagnostic quality of the CE-US examinations was evaluated off-site for duration of clinically useful contrast enhancement, artefact effects and percentage of examinations converted from non-diagnostic to diagnostic. Accuracy, sensitivity and specificity were assessed as agreement of CE-US diagnosis evaluated by an independent panel of experts with reference standard modality. The median duration of clinically useful signal enhancement significantly increased with increasing SonoVue doses (p< or =0.002). At the dose of 2.4 ml of SonoVue, diagnostic quality evaluated as number of inconclusive examinations significantly improved, falling from 40.7% at baseline down to 5.1%. Furthermore, SonoVue significantly (p<0.01) increased the accuracy, sensitivity and specificity of assessment of disease compared with baseline ultrasound. SonoVue increases the diagnostic quality of Doppler images and improves the accuracy of both spectral and colour Doppler examinations of extracranial carotid or peripheral arterial disease.

Autofluorescence endoscopy in surveillance of Barrett's esophagus: a multicenter randomized trial on diagnostic efficacy

BACKGROUND AND STUDY AIMS: The reference surveillance method in patients with Barrett's esophagus is careful endoscopic observation, with targeted as well as random four-quadrant biopsies. Autofluorescence endoscopy (AFE) may make it easier to locate neoplasia. The aim of this study was to elucidate the diagnostic accuracy of surveillance with AFE-guided plus four-quadrant biopsies in comparison with the conventional approach. PATIENTS AND METHODS: A total of 187 of 200 consecutive Barrett's esophagus patients who were initially enrolled (73 % male, mean age 67 years, mean Barrett's segment length 4.6 cm), who underwent endoscopy for Barrett's esophagus in four study centers, were randomly assigned to undergo either AFE-targeted biopsy followed by four-quadrant biopsies or conventional endoscopic surveillance, also including four-quadrant biopsies (study phase 1). After exclusion of patients with early cancer or high-grade dysplasia, who underwent endoscopic or surgical treatment, as well as those who declined to participate in phase 2 of the study, 130 patients remained. These patients were examined again with the alternative method after a mean of 10 weeks, using the same methods described. The main study parameter was the detection of early cancer/adenocarcinoma or high-grade dysplasia (HGD), comparing both approaches in study phase 1; the secondary study aim in phase 2 was to assess the additional value of the AFE-guided approach after conventional surveillance, and vice versa. Test accuracy measures were derived from study phase 1. RESULTS: In study phase 1, the AFE and conventional approaches yielded adenocarcinoma/HGD rates of 12 % and 5.3 %, respectively, on a per-patient basis. With AFE, four previously unrecognized adenocarcinoma/HGD lesions were identified (4.3 % of the patients); with the conventional approach, one new lesion (1.1 %) was identified. Of the 19 adenocarcinoma/HGD lesions detected during AFE endoscopy in study phase 1, eight were visualized, while 11 were only detected using untargeted four-quadrant biopsies (sensitivity 42 %). Of the 766 biopsies classified at histology as being nonneoplastic, 58 appeared suspicious (specificity 92 %, positive predictive value 12 %, negative predictive value 98.5 %). In study phase 2, AFE detected two further lesions in addition to the initial alternative approach in 3.2 % of cases, in comparison with one lesion with conventional endoscopy (1.7 %). CONCLUSIONS: In this referral Barrett's esophagus population with a higher prevalence of neoplastic lesions, the AFE-guided approach improved the diagnostic yield for neoplasia in comparison with the conventional approach using four-quadrant biopsies. However, AFE alone was not suitable for replacing the standard four-quadrant biopsy protocol.

Acute testicular torsion in children: the role of sonography in the diagnostic workup

Acute testicular torsion in children is an emergency and has to be diagnosed urgently. Doppler sonography is increasingly used in imaging the acute scrotum. Nevertheless, in uncertain cases, surgical exploration is required. In this study, we attempted to define the role of Doppler sonography in the diagnostic workup of the acutely painful scrotum. All patients admitted between 1999 and 2005 with acute scrotal pain were included. After clinical assessment, patients were imaged by Doppler sonography with a ''high-end'' instrument. In cases of absent arterial perfusion of the testis in Doppler sonography, surgical exploration was carried out. Patients with unaffected perfusion were followed clinically by ultrasound for up to 2 years. Sixty-one infants and children aged 1 day to 17 years (median: 7.9 years) were included. In 14 cases, sonography demonstrated absent central perfusion, with abnormal parenchymal echogenicity in six. Absence of venous blood flow together with reduction of central arterial perfusion was found in one infant. In these 15 patients, surgical exploration confirmed testicular torsion. Among the other 46 patients, we found four cases with increased testicular perfusion and 27 with increased perfusion of the epididymis. In one infant, a testicular tumour was found sonographically, and orchiectomy confirmed diagnosis of a teratoma. Follow-up examinations of the conservatively treated patients showed good clinical outcome with physiologic central perfusion as well as normal echogenic pattern of both testes. No case of testicular torsion was missed. By means of Doppler sonography, an unequivocal statement regarding testicular perfusion was possible in all cases. The initial Doppler diagnosis was confirmed by operative evaluation and follow-up ultrasound. Testicular torsion can therefore be excluded by correctly performed ultrasound with modern equipment.

[The importance of clinical information in diagnostic imaging in the febrile patient]

From conventional radiography to cross-sectional imaging methods, modern radiology offers a wide range of diagnostic tools for investigating patients with fever. To achieve the best results and to yield a correct diagnosis, the radiologist must tailor the diagnostic protocol individually for every patient. The decision on the most suitable imaging method, and the type and timing of contrast media strongly depends on the suspected diagnosis. Based on patient history and laboratory data, some modalities may be contraindicated or the patient may need a premedication. The authors give a short overview of diagnostic strategies in evaluating the most important causes of fever and point to the need of discussion and co-operation between clinicians and radiologists.

Diagnostic accuracy of coronary in-stent restenosis using 64-slice computed tomography: comparison with invasive coronary angiography

OBJECTIVES: This study sought to evaluate the diagnostic accuracy of coronary binary in-stent restenosis (ISR) with angiography using 64-slice multislice computed tomography coronary angiography (CTCA) compared with invasive coronary angiography (ICA). BACKGROUND: A noninvasive detection of ISR would result in an easier and safer way to conduct patient follow-up. METHODS: We performed CTCA in 81 patients after stent implantation, and 125 stented lesions were scanned. Two sets of images were reconstructed with different types of convolution kernels. On CTCA, neointimal proliferation was visually evaluated according to luminal contrast attenuation inside the stent. Lesions were graded as follows: grade 1, none or slight neointimal proliferation; grade 2, neointimal proliferation with no significant stenosis (<50%); grade 3, neointimal proliferation with moderate stenosis (> or =50%); and grade 4, neointimal proliferation with severe stenosis (> or =75%). Grades 3 and 4 were considered binary ISR. The diagnostic accuracy of CTCA compared with ICA was evaluated. RESULTS: By ICA, 24 ISRs were diagnosed. Sensitivity, specificity, positive predictive value, and negative predictive value were 92%, 81%, 54%, and 98% for the overall population, whereas values were 91%, 93%, 77%, and 98% when excluding unassessable segments (15 segments, 12%). For assessable segments, CTCA correctly diagnosed 20 of the 22 ISRs detected by ICA. Six lesions without ISR were overestimated as ISR by CTCA. As the grade of neointimal proliferation by CTCA increases, the median value of percent diameter stenosis increased linearly. CONCLUSIONS: Binary ISR can be excluded with high probability by CTCA, with a moderate rate of false-positive results.