Assessment of Cross-Reactivity of Chimeric Trypanosoma cruzi Antigens with Crithidia sp. LVH-60A: Implications for Accurate Diagnostics.

This study focuses on developing accurate immunoassays for diagnosing Chagas disease (CD), a challenging task due to antigenic similarities between Trypanosoma cruzi and other parasites, leading to cross-reactivity. To address this challenge, chimeric recombinant T. cruzi antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) were synthesized to enhance specificity and reduce cross-reactivity in tests. While these antigens showed minimal cross-reactivity with leishmaniasis, their performance with other trypanosomatid infections was unclear. This study aimed to assess the diagnostic potential of these IBMP antigens for detecting CD in patients with Crithidia sp. LVH-60A, a parasite linked to visceral leishmaniasis-like symptoms in Brazil. This study involved seven Crithidia sp. LVH-60A patients and three Leishmania infantum patients. The results indicated that these IBMP antigens displayed 100% sensitivity, with specificity ranging from 87.5% to 100%, and accuracy values between 90% and 100%. No cross-reactivity was observed with Crithidia sp. LVH-60A, and only one L. infantum-positive sample showed limited cross-reactivity with IBMP-8.1. This study suggests that IBMP antigens offer promising diagnostic performance, with minimal cross-reactivity in regions where T. cruzi and other trypanosomatids are prevalent. However, further research with a larger number of Crithidia sp. LVH-60A-positive samples is needed to comprehensively evaluate antigen cross-reactivity.

IUPAC project: a glossary of concepts and terms in chemometrics.

A project has been initiated by the International Union of Pure and Applied Chemistry (IUPAC) to create a glossary of concepts and terms in chemometrics. This will be accomplished by consultation with the community through the means of a wiki--a web site that can be modified by users (see http://www.iupacterms.eigenvector.com/index.php?title=Main_Page). Over time new terms can be added, and consensus definitions arrived at. The definitions will be published as IUPAC recommendations.

Epidermolysis bullosa acquisita following bullous pemphigoid, successfully treated with the anti-CD20 monoclonal antibody rituximab.

Epidermolysis bullosa acquisita is a rare autoimmune subepidermal blistering disease, often resisting current treatments, especially systemic corticosteroids. We report a patient having a bullous pemphigoid who relapsed with clinical and immunological features of inflammatory epidermolysis bullosa acquisita. An anti-CD20 monoclonal antibody (rituximab) was proposed because of resistance to high-dose steroids and other immunosuppressive agents. The disease dramatically improved within a few weeks following rituximab infusion allowing the decrease in steroid therapy. Our case illustrates also the possible evolution from bullous pemphigoid to epidermolysis bullosa acquisita that should be suspected when clinical atypia occurs or in case of corticosteroid resistance.

How to avoid over-fitting in multivariate calibration--the conventional validation approach and an alternative.

This paper critically reviews the problem of over-fitting in multivariate calibration and the conventional validation-based approach to avoid it. It proposes a randomization test that enables one to assess the statistical significance of each component that enters the model. This alternative is compared with cross-validation and independent test set validation for the calibration of a near-infrared spectral data set using partial least squares (PLS) regression. The results indicate that the alternative approach is more objective, since, unlike the validation-based approach, it does not require the use of 'soft' decision rules. The alternative approach therefore appears to be a useful addition to the chemometrician's toolbox.

Selecting the optimum number of partial least squares components for the calibration of attenuated total reflectance-mid-infrared spectra of undesigned kerosene samples.

Selecting the correct dimensionality is critical for obtaining partial least squares (PLS) regression models with good predictive ability. Although calibration and validation sets are best established using experimental designs, industrial laboratories cannot afford such an approach. Typically, samples are collected in an (formally) undesigned way, spread over time and their measurements are included in routine measurement processes. This makes it hard to evaluate PLS model dimensionality. In this paper, classical criteria (leave-one-out cross-validation and adjusted Wold's criterion) are compared to recently proposed alternatives (smoothed PLS-PoLiSh and a randomization test) to seek out the optimum dimensionality of PLS models. Kerosene (jet fuel) samples were measured by attenuated total reflectance-mid-IR spectrometry and their spectra where used to predict eight important properties determined using reference methods that are time-consuming and prone to analytical errors. The alternative methods were shown to give reliable dimensionality predictions when compared to external validation. By contrast, the simpler methods seemed to be largely affected by the largest changes in the modeling capabilities of the first components.

Prediction of pork quality attributes from near infrared reflectance spectra.

Near infrared spectroscopy (NIRS) is one of the most promising techniques for large-scale meat quality evaluation. We investigated the potential of NIRS-based models to predict drip loss and shear force of pork samples. Near infrared reflectance spectra (1000-2500 nm), water-holding capacity, shear force, ultimate pH, and colour (L(∗), a(∗), b(∗)-value) of 96 pork longissimus muscles were recorded at 2 days post mortem. Stepwise multiple linear regression (SMLR) and partial least squares regression (PLSR) analyses were used to formulate models for drip loss and shear force. Prediction models for drip loss correlated moderately strong with measured drip loss (R=0.71-0.74), which is similar to the correlation obtained using a combination of ultimate pH, filter paper test, and L(∗)-value (R=0.74). The current results indicate that NIRS enables the classification of pork longissimus muscles with a superior or inferior water-holding capacity as having a drip loss lower than 5% or higher than 7%. No useful models could be constructed for shear force.

Towards a rehabilitation of the generalized rank annihilation method (GRAM).

The trilinear PARAFAC model occupies a central place in multiway analysis, because the components of a data array can often be uniquely resolved. This paper compares the resolution for a large variety of methods, namely the generalized rank annihilation method (GRAM), alternating least squares (ALS), alternating trilinear decomposition (ATLD), alternating coupled vectors resolution (ACOVER), alternating slice-wise diagonalization (ASD), alternating coupled matrices resolution (ACOMAR), self-weighted alternating trilinear decomposition (SWATLD), and pseudo alternating least squares (PALS). The comparison was conducted using Monte Carlo simulations. It was shown that GRAM performs well for moderately and highly overlapped data. These results argue strongly against the previously claimed superiority of the alternatives listed above.

Detection of Leptospira spp. in the aqueous humor of horses with naturally acquired recurrent uveitis.

Leptospiral organisms have long been presumed to be associated with the presence of equine recurrent uveitis. This project was undertaken to determine the presence of Leptospira spp. in the aqueous humor of horses with uveitis to determine if there was an association with inflammation. Thirty horses were determined to have recurrent uveitis based on clinical evaluation or history. Sixteen horses were judged clinically and historically to be free of uveitis and were used as controls. Aqueous humor samples were cultured and evaluated by PCR for the presence of Leptospira DNA. Serum was collected and evaluated for the presence of antibodies against five serovars in a leptospirosis panel. Twenty-one of 30 horses with recurrent uveitis and one of 16 uveitis-free horses were positive by PCR for the presence of Leptospira DNA. Six of these 21 horses with uveitis were culture positive for leptospires from the aqueous humor. Serologic results did not correlate well with the presence of Leptospira DNA or organisms in the aqueous humor. Leptospira spp. are present in a high percentage of horses with naturally occurring recurrent uveitis.

Testicular biopsy in stallions: diagnostic potential and effects on prospective fertility.

Testicular biopsy was performed as a standing procedure on fertile, mature stallions (n=7) under sedation and local anaesthesia. The 'Biopty' instrument was used to collect three samples from the left testis of each stallion. The oestradiol, testosterone and inhibin content in each testis were assessed by validated radioimmunoassay (RIA); protein concentrations were determined and the testes were prepared histologically for haematoxylin and eosin staining. The fertility status of each stallion was assessed before and after testicular biopsy by semen evaluation, changes in total scrotal width, pregnancy rate per oestrous cycle, serum and seminal plasma antisperm antibody concentrations, and determination of plasma LH, FSH, oestradiol, testosterone and inhibin concentrations once a week by validated RIA. Testicular testosterone (3.85 +/- 1.24 ng mg(-1) protein), oestradiol (3.01 +/- 0.95 ng mg(-1) protein) and inhibin (11.06 +/- 1.69 ng mg(-1) protein) content were measured successfully from tissue samples by RIA. Active spermatogenesis was evident in all histological samples. The mean numbers of progressively motile morphologically normal spermatozoa were not significantly different in the last three ejaculates of the 7 day periods of semen collection before (3.37 +/- 0.48 x 10(9) spermatozoa per ejaculate) and after (3.77 +/- 0.48 x 10(9) spermatozoa per ejaculate) testicular biopsy. Total scrotal width varied within normal ranges throughout the year (from 11.7 +/- 0.3 to 10.0 +/- 0.4 cm). Pregnancy rates per oestrous cycle before (50 +/- 6%) and after (63 +/- 9%) testicular biopsy were not significantly different. The concentration of antisperm antibodies in serum and seminal plasma samples did not vary significantly before and after testicular biopsy. Plasma LH, FSH, oestradiol, testosterone and inhibin concentrations fluctuated within normal ranges after biopsy in the expected seasonal pattern. In conclusion, the present study demonstrates that using the 'Biopty' instrument to obtain testicular biopsy samples from stallions has no apparent detrimental effects on prospective stallion fertility and can be used to evaluate testicular factors and structure.

Factors influencing participation in weekly support groups among women completing an HIV/STD intervention program.

Over the past three decades, the influence and importance of social support has been well documented and the findings have suggested a beneficial effect on stress-related situations, mental and physical health, and social functioning. More recently, small group/skills training behavioral interventions have demonstrated success in changing behaviors which affect the transmission of sexually transmitted diseases, including HIV among populations at risk for these diseases. Studies of support groups to date have been conducted exclusively in research settings where women are offered financial incentives for participation. Little is known about the willingness of women to participate in ongoing support groups after successfully completing a skills training intervention. The present study examines the factors that may influence participation among women in a weekly support group after completing a structured, six session HIV/STD intervention. Both quantitative and qualitative data are collected from 265 women in the intervention arm of a multi-site randomized controlled behavioral intervention trial. Results reveal that less than a quarter (22%) of women participated in at least one support group. Participation varied significantly by site, ranging from 34% to 15% (p = .008). Participation was also strongly linked to recent use of domestic violence services. Qualitative data indicated that although monetary incentives play some role in the woman's decision to participate, other factors are also important. These include program outreach, support group size, salience of the group content, consistency of group leadership from the intervention to the support group, and use of peer leaders along with professional facilitators. Implications for design of post-intervention support groups programs are discussed.

Multivariate sensitivity for the interpretation of the effect of spectral pretreatment methods on near-infrared calibration model predictions.

Predictions obtained from a multivariate calibration model are sensitive to variations in the spectra such as baseline shifts, multiplicative effects, etc. Many spectral pretreatment methods have been developed to reduce these distortions, and the best method is usually the one that minimizes the prediction error for an independent test set. This paper shows how multivariate sensitivity can be used to interpret spectral pretreatment results. Understanding why a particular pretreatment method gives good or bad results is important for ruling out chance effects in the conventional process of "trial and error", thus obtaining more confidence in the finally selected model. The principles are exemplified using the transmission near-infrared spectroscopic prediction of oxygenates in ampules of the standard reference material gasoline. The pretreatment methods compared are the multiplicative signal correction, first-derivative method, and second-derivative method. It is shown that for this application the first- and second-derivative methods are successful in removing the background. However, differentiating the spectra substantially reduces multivariate net analyte signal (in the worst case by a factor of 21). Consequently, a significantly smaller multivariate sensitivity is obtained which leads to increased spectral error propagation resulting in a larger uncertainty in the regression vector estimate and larger prediction errors. Differentiating spectra also increases the spectral noise (each time by a factor 2(1/2)) but this effect, which is well-known, is of minor importance for the current application.

Characterization of protein-binding to the spinach chloroplast psbA mRNA 5' untranslated region.

RNA-binding proteins play a major role in regulating mRNA metabolism in chloroplasts. In this work we characterized two proteins, of 43 and 47 kDa, which bind to the spinach psbA mRNA 5' untranslated region (psbA encoding the D1 protein of photosystem II). The 43 kDa protein, which is present in the stroma and in membranes, co-sediments with a complex of 68S. It was purified, and the N-terminal sequence was determined. Upon homology search it was identified as the chloroplast homologue of the Escherichia coli ribosomal protein S1. The 47 kDa protein, which, in contrast with the 43 kDa protein, sediments with a small sedimentation coefficient, is only detected in the stromal fraction. It is soluble in an uncomplexed form. By deletion analysis, an element within the psbA mRNA 5' untranslated region was identified that is necessary but not sufficient for binding of stromal proteins. The 'central protein binding element' ranges from nucleotide -49 to -9 of the psbA mRNA 5' untranslated region. It comprises the Shine-Dalgarno-like GGAG motif and, 7 nucleotides upstream, an endonucleolytic cleavage site involved in psbA mRNA degradation in vitro . The mechanistic impacts of this region in relation to RNA-binding proteins are discussed.

Efficient computation of net analyte signal vector in inverse multivariate calibration models.

The net analyte signal vector has been defined by Lorber as the part of a mixture spectrum that is unique for the analyte of interest; i.e., it is orthogonal to the spectra of the interferences. It plays a key role in the development of multivariate analytical figures of merit. Applications have been reported that imply its utility for spectroscopic wavelength selection as well as calibration method comparison. Currently available methods for computing the net analyte signal vector in inverse multivariate calibration models are based on the evaluation of projection matrices. Due to the size of these matrices (p × p, with p the number of wavelengths) the computation may be highly memory- and time-consuming. This paper shows that the net analyte signal vector can be obtained in a highly efficient manner by a suitable scaling of the regression vector. Computing the scaling factor only requires the evaluation of an inner product (p multiplications and additions). The mathematical form of the newly derived expression is discussed, and the generalization to multiway calibration models is briefly outlined.

Reanalysis of SCOR and anxiety measures in the Israeli High-Risk Study.

In an earlier study, skin conductance orienting response (SCOR) and anxiety measures obtained when the subjects of the Israeli High-Risk Study were 11 years old were analyzed, using adult diagnostic information, when the subjects were 26 years old. The present study considers similar data obtained from most of this sample when the subjects were 16 years old. As in the earlier analysis, those subjects who would receive a schizophrenia spectrum diagnosis at 26 had higher anxiety ratings at age 16. Nondiagnosed index subjects also had significantly higher anxiety ratings than the nondiagnosed controls. The subjects who would receive affective spectrum diagnoses at age 26 had the most hyporesponsive SCORs, as predicted, while the subjects who would later be diagnosed in the schizophrenia spectrum had an unexpected hyperresponsive SCOR to the dishabituation tone in a habituation series. Further consideration of the long-term stability of SCORs seems necessary; they may be related to the developing psychopathological processes.

Squamous cell carcinoma associated with a chronic wound in a horse.

A 13-year-old Belgian stallion developed a squamous cell carcinoma at the site of a neck laceration that had been treated topically with various irritating chemicals for 18 months. Orthovoltage treatments at 3 times over 5 years controlled the tumor. Eight years after the initial hospitalization, the area was healed and the stallion appeared healthy.

Determination of human platelet antigen frequencies in the Dutch population by immunophenotyping and DNA (allele-specific restriction enzyme) analysis.

Platelets from 200 random Dutch blood donors were typed for the human platelet alloantigens HPA-1 to -5 recognized at present and for Naka. Naka is an epitope on glycoprotein IV, not expressed on the platelet of individuals with hereditary GP IV deficiency. Platelet immunofluorescence and monoclonal antibody-specific immobilization of platelet antigens (MAIPA) were applied for this purpose. The observed phenotype frequencies were 97.86% and 28.64% for HPA-1a and -1b, 100% and 13.15% for HPA-2a and -2b, 80.95% and 69.84% for HPA-3a and -3b, 100% and 0% for HPA-4a and -4b, 100% and 19.7% for HPA-5a and HPA-5b, respectively. Platelets from all donors reacted with the anti-Naka antibodies. To determine the gene frequencies for the HPA-1, HPA-2 and HPA-3 systems directly, DNA from 98 of these donors was isolated from peripheral blood mononuclear leucocytes and specific fragments were amplified by polymerase chain reaction (PCR). The fragments were analyzed using allele-specific restriction enzymes (ASRA). In all amplified PCR products an "internal control" for each assay, ie, a restriction site for the applied enzyme independent from the phenotype of the donor was present. In all donors tested, phenotypes, as determined by serological methods and genotypes, directly determined by the ASRA, were identical. Thus, the PCR-ASRA described in this report is a practical and reliable technique for the determination of alleles that code for platelet antigen allotypes, at least in the Dutch population.

Single point mutation in human glycoprotein IIIa is associated with a new platelet-specific alloantigen (Mo) involved in neonatal alloimmune thrombocytopenia.

Here we describe a new platelet-specific alloantigen that was identified in a case of neonatal alloimmune thrombocytopenia. This antigen has provisionally been called "Mo." By studying the Mo family, it was shown to be inherited in an autosomal dominant manner. Immunoprecipitation and Western blot analysis showed that the antigen resides on platelet glycoprotein IIIa (GP IIIa). Genomic analysis, performed by applying polymerase chain reaction and sequencing, showed a C-->G substitution of base pair 1267 of the coding region of the DNA for GP IIIa, resulting in a substitution of Proline407 by Alanine407. That this substitution is associated with the antigen could be demonstrated by restriction fragment length polymorphism analysis of cDNA, prepared from platelet RNA, and of genomic DNA. It was confirmed by dot-blot hybridization with allele-specific oligonucleotides. All family members, also those being Mo antigen-positive, were healthy. None of them appeared to suffer from increased tendency of bleeding or thrombosis. Thus, the Mo mutation does not lead to significant platelet dysfunction in vivo with heterozygous carriers. One of 450 random healthy blood donors who were tested was positive for the Mo antigen. Typing was performed by the classical serologic methods as well as by DNA analysis.