Microbiological Challenges in the Diagnosis of Chronic Q Fever

Diagnosis of chronic Q fever is difficult. PCR and culture lack sensitivity; hence, diagnosis relies mainly on serologic tests using an immunofluorescence assay (IFA). Optimal phase I IgG cutoff titers are debated but are estimated to be between 1:800 and 1:1,600. In patients with proven, probable, or possible chronic Q fever, we studied phase I IgG antibody titers at the time of positive blood PCR, at diagnosis, and at peak levels during chronic Q fever. We evaluated 200 patients, of whom 93 (46.5%) had proven, 51 (25.5%) had probable, and 56 (28.0%) had possible chronic Q fever. Sixty-five percent of proven cases had positive Coxiella burnetii PCR results for blood, which was associated with high phase I IgG. Median phase I IgG titers at diagnosis and peak titers in patients with proven chronic Q fever were significantly higher than those for patients with probable and possible chronic Q fever. The positive predictive values for proven chronic Q fever, compared to possible chronic Q fever, at titers 1:1,024, 1:2,048, 1:4,096, and ≥1:8,192 were 62.2%, 66.7%, 76.5%, and ≥86.2%, respectively. However, sensitivity dropped to <60% when cutoff titers of ≥1:8,192 were used. Although our study demonstrated a strong association between high phase I IgG titers and proven chronic Q fever, increasing the current diagnostic phase I IgG cutoff to >1:1,024 is not recommended due to increased false-negative findings (sensitivity < 60%) and the high morbidity and mortality of untreated chronic Q fever. Our study emphasizes that serologic results are not diagnostic on their own but should always be interpreted in combination with clinical parameters.     

Pathogenesis of cognitive dysfunction in phenylketonuria: Review of hypotheses

In untreated phenylketonuria (PKU), deficiency of phenylalanine hydroxylase (PAH) results in elevated blood phenylalanine (Phe) concentrations and severe mental retardation. Current dietary treatment prevents mental retardation, but cognitive outcome remains suboptimal. The mechanisms by which elevated blood Phe concentrations disturb cerebral metabolism and cognitive function have not been fully elucidated.In this review, we discuss different hypotheses on the pathogenesis of PKU, focusing on the effects of disturbed large neutral amino acid (LNAA) transport from blood to brain on cerebral neurotransmitter and protein synthesis. Although the definitive roles of these processes in PKU pathogenesis are not fully understood yet, both substantially influence clinical outcome.     

Left ventricular function in the post-infarct failing mouse heart by magnetic resonance imaging and conductance catheter: a comparative analysis

Aim: Murine myocardial infarction (MI) models are increasingly used in heart failure studies. Magnetic resonance imaging (MRI) and pressure–volume loops by conductance catheter (CC) enable physiological phenotyping. We performed a comparative analysis of MRI vs. CC to assess left ventricular (LV) function in the failing mouse heart. Methods: MI was created by LAD ligation. MRI (day 14) and CC (day 15) were used to determine LV end‐diastolic volume (EDV), end‐systolic volume (ESV) and ejection fraction (EF). Results: Pooled data yielded moderate‐to‐strong linear correlations: EDV: R = 0.61; ESV: R = 0.72; EF: R = 0.81. We analysed three groups, no MI (sham, n = 10), small MI (<30% of LV, n = 14) and large MI (>30%, n = 20). Volumes and EF were consistently lower by CC than by MRI, but group differences were evident for both techniques. Receiver‐operating characteristic analysis indicated good sensitivity and specificity for both techniques, with superior results for MRI. Conclusions: CC and MRI are highly valuable for evaluation of LV volume and function. MRI is recommended for longitudinal studies, accurate absolute volumes and anatomical information. Unique features of CC are its online signal with high temporal resolution, and advanced analysis of LV function and energetics.     

Cranial translation of the humeral head on radiographs in rotator cuff tear patients: the modified active abduction view

Cranial translation of the humeral head is related to massive rotator cuff tears; however, it may be unapparent in early-stage tears. The goal of this study was to investigate whether active abduction leads to increased active cranial humeral translation in early-stage tears. We assessed 20 consecutive patients (9 full-thickness supraspinatus tears, 11 posterosuperior tears) using the newly introduced modified active abduction view: acromiohumeral (AH) distance was measured on radiographs acquired during rest and active isometric abduction and adduction tasks with the arm alongside the body. Rest AH was 7.5 mm (SD = 1.53); during abduction and adduction, it decreased to 2.1 mm (95 % CI 1.28–3.01, p < 0.001) and 1.1 mm (95 % CI 0.46–1.65, p = 0.001), respectively. Cranial translation during abduction was more severe in shoulders with posterosuperior cuff tears (?AH = 3 mm, SD = 1.5) compared to supraspinatus tears (?AH = 1 mm, SD = 1.6), with a mean difference of 2 mm (95 % CI 0.64–3.58, p = 0.007). Both active isometric abduction and adduction leads to active cranial translation in cuff tear patients. Cranial translation is largest during active abduction. Furthermore, there is significant more cranial translation in posterosuperior cuff tear patients compared to supraspinatus cuff tear patients. Possibly, radiographs combined with active tasks offer new possibilities in diagnosing early-stage rotator cuff tears.     

A further evaluation of the clinical use of specific IgE antibody testing in allergic diseases

BACKGROUND: The evaluation and interpretation of the results from blood tests measuring specific immunoglobulin E (IgE) antibody concentration is currently made using the dichotomized result from the test despite a quantitative result is obtained. It has been shown that different levels of IgE antibodies, assessed by blood test and skin prick test, may have a relation to presence of symptoms, implying that there is more information in a quantitative result than in the dichotomous--positive or negative. OBJECTIVE: To investigate the clinical utility of quantification of IgE antibodies in the diagnosis of allergic patients and whether such procedure has any advantage to the presently dichotomously used sensitivity and specificity at a fixed cut-off. METHODS: Data from a previously published study (R. Paganelli, I.J. Ansoteugi, J. Sastre, C.-E. Lange, M.H.W.M. Roovers, H. de Groot, N.B. Lindholm, P.W. Ewan, Allergy, 1998; 53) analysing diagnosis of allergic patients in four different clinics were re-evaluated. In the original study consecutive patients with suspected IgE-mediated allergy had been examined and evaluated according to the clinical routine at each clinic, using case history, physical examination, skin tests and laboratory tests, except the test to be evaluated, and given a "doctors' allergen-specific diagnosis" as positive or negative. In the present study the relation between "doctors' allergen-specific diagnosis", expressed as pos/neg, and the quantitative levels of specific IgE antibody concentration was analysed using a logistic regression model. This presentation of results was also compared with the more common characteristics of sensitivity and specificity, and also with Receiver-operator characteristics (ROC) curves. RESULTS: The used logistic model described the relationship between allergen-specific diagnosis in each study and the levels of IgE antibodies. The shape of the curve illustrated the physicians' disposition for a positive diagnose in the study, in relation to the specific IgE antibody level. Differences in the shape of the curve was found both between allergens within clinics and between clinics for the same allergen. No association could be demonstrated between prevalence and shape of the curve. CONCLUSIONS: Conventional sensitivity/specificity figures or ROC concepts only use the qualitative statement of whether IgE is present or not. A risk assessment using the quantitative level of IgE antibody to an allergen increases the utility of the information in clinical context compared with a qualitative statement of whether IgE is present or not. The quantification demonstrated the link between specific IgE antibodies and allergic reactions. The use of objective, well performing quantitative tests should help improve diagnostic accuracy and might provide a way for the patient to understand and manage his or her daily situation and risk for reactions.     

Evaluation of A-V Impulse Technology as a Treatment for Oedema Following Polytetrafluoroethylene Femoropopliteal Surgery in a Randomised Controlled Trial

ObjectiveTo investigate the efficacy of A-V impulse technology (A-V) for oedema prevention and treatment following PTFE femoropopliteal surgery.DesignProspective randomized clinical trial.Materials36 patients undergoing PTFE femoropopliteal bypass reconstructions, either being treated postoperatively with a compression stocking (CS) (Group-1, n = 19) or with A-V (Group-2, n = 17).MethodsPatients in treatment group-1 used a CS postoperatively during 1 week day and night, patients in group-2 were treated with A-V postoperatively at night during one week. The lower leg circumference was measured preoperatively and at five postoperative time points.ResultsLimb circumference has increased postoperatively on day 1 (CS 1.5%/A-V 1.4%), on day 4 (5.7%/6.3%), on day 7 (6.6%/6.1%), on day 14 (7.9%/7.7%) and on day 90 (5.8%/5.2%). Differences between treatment groups were not significant. A re-operation gives a significant 3.9% increase in circumference as compared to a first operation (95% CI: 1.5–6.4%; p = 0.002).ConclusionNo significant differences were found in the extent of developed edema between the groups following PTFE femoropopliteal bypass surgery. A redo peripheral bypass operation results in significantly more postoperative oedema than a first-time performed bypass operation.     

Characterization, expression and complex formation of the murine Fanconi anaemia gene product Fancg

BACKGROUND: Fanconi anaemia (FA) is an autosomal recessive chromosomal instability disorder. Six distinct FA disease genes have been identified, the products of which function in an integrated pathway that is thought to support a nuclear caretaker function. Comparison of FA gene characteristics in different species may help to unravel the molecular function of the FA pathway. RESULTS: We have cloned the murine homologue of the Fanconi anaemia complementation group G gene, FANCG/XRCC9. The murine Fancg protein shows an 83% similarity to the human protein sequence, and has a predicted molecular weight of 68.5 kDa. Expression of mouse Fancg in human FA-G lymphoblasts fully corrects their cross-linker hypersensitivity. At mRNA and protein levels we detected the co-expression of Fancg and Fanca in murine tissues. In addition, mouse Fancg and Fanca proteins co-purify by immunoprecipitation. Upon transfection into Fanca-deficient mouse embryonic fibroblasts EGFP-Fancg chimeric protein was detectable in the nucleus. CONCLUSIONS: We identified a murine cDNA, Fancg, which cross-complements the cellular defect of human FA-G cells and thus represents a true homologue of human FANCG. Spleen, thymus and testis showed the highest Fancg expression levels. Although Fancg and Fanca are able to form a complex, this interaction is not required for Fancg to accumulate in the nuclear compartment.     

Prevalence of occupational allergy to Chrysanthemum pollen in greenhouses in the Netherlands

BACKGROUND: An increasing number of allergic complaints appear to have occurred among Chrysanthemum greenhouse employees. The aim of this study was to estimate the prevalence of work-related allergic symptoms and the prevalence of sensitization to pollen of different members of the Chrysanthemum family. METHODS: We studied 104 employees who were invited to answer an extensive questionnaire and to complete a rhinitis quality of life questionnaire. In addition, they were skin prick tested on location with inhalant allergens and home-made pollen extracts of seven different members of the Chrysanthemum family. Radio-allergo-sorbent tests were performed to confirm IgE-mediated reactions. RESULTS: Work-related symptoms were reported in 56.7% of all cases, with the main symptom being rhinitis. Sensitization to Chrysanthemum pollen was found in 20.2% of the employees without one member of the Chrysanthemum family in particular being most prevalent. Sensitization to Chrysanthemum pollen was considered to be an important risk factor for the occurrence of work-related symptoms of the upper airways. Furthermore, inhalant atopy as well as sensitization to common airborne pollen including mugwort were closely associated with sensitization to Chrysanthemum what might be suggestive for cross-sensitization. CONCLUSIONS: There is a high prevalence of work-related symptoms in Chrysanthemum greenhouses. In one-third of the employees these symptoms were caused by an IgE-mediated allergy caused by the pollen of the flowers. Inhalant atopy appeared to have a great impact on the development of such a sensitization. Measurements to reduce the pollen exposure are necessary to prevent a further increase of this occupational allergy.     

Use of pooled urine samples and automated DNA isolation to achieve improved sensitivity and cost-effectiveness of large-scale testing for Chlamydia trachomatis in pregnant women

The success of large-scale screening for Chlamydia trachomatis depends on the availability of noninvasive samples, low costs, and high-quality testing. To evaluate C. trachomatis testing with pregnant women, first-void urine specimens from 750 consecutive asymptomatic pregnant women from the Rotterdam area (The Netherlands) were collected. Initially, we investigated the performance of three different DNA isolation methods with 350 of these urines and 70 pools of 5 of the same subset of urine samples. The routinely used COBAS AMPLICOR test was compared to the COBAS AMPLICOR test with prior DNA isolation by use of the MagNA Pure large-volume kit and the MagNA Pure bacterial DNA isolation kit. The latter combination provided the best DNA test for pooled urines, with a sensitivity twice that of the other methods. Next, using all 750 urines, the COBAS AMPLICOR performance for individual testing was compared to pooled testing with the standard COBAS AMPLICOR procedure and subsequently to pooled testing with COBAS AMPLICOR in combination with the MagNA Pure bacterial DNA isolation kit. The sensitivity of COBAS AMPLICOR was 65% on individual and 42% on pooled urines but improved to 92% on pooled urines with the MagNA Pure bacterial DNA isolation kit, making this combination the best screening method. The C. trachomatis prevalence in this population appeared to be 6.4%. Additionally, the cost of the combined MagNA Pure bacterial DNA isolation kit and COBAS AMPLICOR method on pooled urines was only 56% of the cost of the standard COBAS AMPLICOR test applied to individual urines. Costs per positive case detected in the combined method were 39% of standard costs.     

The product of the imprinted H19 gene is an oncofetal RNA.

AIMS/BACKGROUND: The H19 gene is an imprinted, maternally expressed gene in humans. It is tightly linked and coregulated with the imprinted, paternally expressed gene of insulin-like growth factor 2. The H19 gene product is not translated into protein and functions as an RNA molecule. Although its role has been investigated for more than a decade, its biological function is still not understood fully. H19 is abundantly expressed in many tissues from early stages of embryogenesis through fetal life, and is down regulated postnatally. It is also expressed in certain childhood and adult tumours. This study was designed to screen the expression of H19 in human cancer and its relation to the expression of H19 in the fetus. METHODS: Using in situ hybridisation with a [35S] labelled probe, H19 mRNA was detected in paraffin wax sections of fetal tissues from the first and second trimesters of pregnancy and of a large array of human adult and childhood tumours arising from these tissues. RESULTS: The H19 gene is expressed in tumours arising from tissues which express this gene in fetal life. Its expression in the fetus and in cancer is closely linked with tissue differentiation. CONCLUSIONS: Based on these and previous data, H19 is neither a tumour suppressor gene nor an oncogene. Its product is an oncofetal RNA. The potential use of this RNA as a tumour marker should be evaluated.