Review: Pig-based bioconversion: the use of former food products to keep nutrients in the food chain.

The primary challenge of agriculture and livestock production is to face the growing competition between food, feed, fibre, and fuel, converting them from resource-intensive to resource-efficient. A circular economy approach, using agricultural by-products/co-products, in the livestock production system would allow to reduce, reuse, and redistribute the resources. Former food products (FFPs), also named ex-foods, could represent a valid option in strengthening resilience in animal nutrition. FFPs have a promising potential to be included regularly in animal diets due to their nutritive value, although their potential in animal nutrition remains understudied. A thorough investigation of the compositional and dietary features, thus, is essential to provide new and fundamental insights to effectively reuse FFPs as upgraded products for swine nutrition. Safety aspects, such as the microbial load or the presence of packaging remnants, should be considered with caution. Here, with a holistic approach, we review several aspects of FFPs and their use as feed ingredients: the nutritional and functional evaluation, the impact of the inclusion of FFPs in pigs' diet on growth performance and welfare, and further aspects related to safety and sustainability of FFPs.

Diagnostic accuracy of in-house PCR for pulmonary tuberculosis in smear-positive patients: meta-analysis and metaregression.

In-house PCR (hPCR) could speed differential diagnosis between tuberculosis (TB) and nontuberculous mycobacterial disease in patients with positive smears and pulmonary infiltrates, but its reported accuracy fluctuates across studies. We conducted a systematic review and meta-analysis of hPCR sensitivity and specificity for smear-positive TB diagnosis, using culture as the reference standard. After searching English language studies in MEDLINE and EMBASE, we estimated cumulative accuracy by means of summary receiver operating characteristic analysis. The possible influence of hPCR procedures and study methodological features on accuracy was explored by univariate metaregression, followed by multivariate adjustment of items selected as significant. Thirty-five articles (1991 to 2006) met the inclusion criteria. The pooled estimates of the diagnostic odds ratio, sensitivity, and specificity (random-effect model) were, respectively, 60 (confidence interval [CI], 29 to 123), 0.96 (CI, 0.95 to 0.97), and 0.81 (CI, 0.78 to 0.84), but significant variations (mainly in specificity) limit their clinical applicability. The quality of the reference test, the detection method, and real-time PCR use explained some of the observed heterogeneity. Probably due to the limited study power of our meta-analysis and to the wide differences in both laboratory techniques and methodological quality, only real-time PCR also displayed a positive impact on accuracy in the multivariate model. Currently, hPCR can be confidently used to exclude TB in smear-positive patients, but its low specificity could lead to erroneous initiation of therapy, isolation, and contact investigation. As the inclusion of samples from treated patients could have artificially reduced specificity, future studies should report mycobacterial-culture results for each TB and non-TB sample analyzed.

Avidity of islet cell autoantibodies in non-diabetic children and children with insulin-dependent diabetes.

Low-avidity immunoglobulin G antibodies, which commonly occur after microbial infections and form unstable complexes with the antigen, are within weeks replaced by high-avidity antibodies, which bind the antigen tightly and characterise mature immune response. We hypothesised that avidity of islet cell autoantibodies (ICA), found in the sera of patients with insulin-dependent diabetes mellitus (IDDM) usually months or years before disease onset, might reflect the stage of progression towards overt IDDM. ICA were quantitated before and after treatment of antigen-antibody complexes with 5 M urea in a new assay, in which the fluorescence intensity of europium chelate-labelled detecting antibody is measured from a digital time-resolved fluorescence image. The proportion of urea-resistant ICA of all ICA was defined as the avidity index. The median avidity indices (range) of 119 children with recent-onset IDDM and 64 non-diabetic ICA-positive children were 74% (23-100%) and 11% (0-100%), respectively (p = 0.0001). The avidity indices of only 3 children with IDDM (2.5%), but of 55 non-diabetic ICA-positive children (86%) were < 40%. In conclusion, our data show that ICA avidity indices of ICA-positive non-diabetic children and children with IDDM differ, suggesting that measurement of ICA avidity may improve prediction of the time of onset of clinical IDDM.

Time-resolved fluorescence imaging in islet cell autoantibody quantitation.

The prodromal period of insulin-dependent diabetes mellitus (IDDM) is characterized by circulating islet cell autoantibodies (ICA) and other beta cell specific autoantibodies. Despite biochemical characterization of the major beta cell autoantigens insulin, glutamic acid decarboxylase and protein tyrosine phosphatase and development of the respective antibody assays, ICA has remained the standard in IDDM prediction. Conventional ICA quantitation using classic fluorochromes is prone to errors since fluorescence intensity is estimated subjectively using the human eye, which is also unable to differentiate specific signals from non-specific signals and autofluorescence. Using Eu(3+)-chelate labelled anti-human polyclonal IgG (decay time 1000 microseconds) as the secondary antibody in time-resolved fluorescence imaging (TRFI), the chelate and autofluorescence signals (typical decay time < 100 ns) are fully separated. The image is recorded using an optically gated cooled digital CCD camera. The specificity of the ICA signal is further improved by interactive analysis of the image. Signal detection is objective, the signal-to-background ratio improves, and ICA quantitation is possible using undiluted serum. Of 57 consecutive new-onset IDDM patients, 55 (96.5%) were ICA positive in the new assay while 51 (89.5%) were positive in the conventional assay suggesting that the sensitivity of TRFI exceeds that of the IAA, GAD65 and IA-2 autoantibody assays combined. For later comparisons, the stained slides may be stored in the light for years without any decrease in specific fluorescence.

Appearance of cells expressing CD80 and CD86 costimulatory antigens in the pancreas of nonobese diabetic mice.

The immunopathogenetic mechanisms that lead to type I diabetes in the nonobese diabetic mouse are poorly defined. The immunoregulatory effects of the costimulatory CD80/B7-1 and CD86/B7-2 antigens expressed by the antigen-presenting cells may be crucial for the development of immune responses and their absence may lead to clonal anergy, which is important in the prevention of autoimmune reactivity. To evaluate the role of the CD80 and CD86 antigens in the development of insulin-dependent diabetes mellitus, expression of these antigens in the pancreas of normal and nonobese diabetic mice was studied. The pancreata of normal BALB/c mice and young nonobese diabetic mice contained no CD80- or CD86-positive cells. CD80- and CD86-positive cells appeared in the pancreas of nonobese diabetic mice by 6 weeks of age. Double immunostaining at the age of 12 weeks showed that CD80-positive cells accumulated around the islets of Langerhans but no insulin-containing cells expressed the costimulatory molecules. The morphology of the CD80- and CD86-positive cells was heterogeneous. Many were Mac-1 integrin (CD11b/CD18) positive, suggesting that macrophages expressing the costimulatory antigens are present in the pancreas of all nonobese diabetic mice by 12 weeks of age and that CD80- and CD86-expressing macrophages may be involved in the local regulation of antiislet immune responses.