Use of Personalized Biomarkers in Metastatic Colorectal Cancer and the Impact of AI

Colorectal cancer is a major cause of cancer-related death worldwide and is correlated with genetic and epigenetic alterations in the colonic epithelium. Genetic changes play a major role in the pathophysiology of colorectal cancer through the development of gene mutations, but recent research has shown an important role for epigenetic alterations. In this review, we try to describe the current knowledge about epigenetic alterations, including DNA methylation and histone modifications, as well as the role of non-coding RNAs as epigenetic regulators and the prognostic and predictive biomarkers in metastatic colorectal disease that can allow increases in the effectiveness of treatments. Additionally, the intestinal microbiota’s composition can be an important biomarker for the response to strategies based on the immunotherapy of CRC. The identification of biomarkers in mCRC can be enhanced by developing artificial intelligence programs. We present the actual models that implement AI technology as a bridge connecting ncRNAs with tumors and conducted some experiments to improve the quality of the model used as well as the speed of the model that provides answers to users. In order to carry out this task, we implemented six algorithms: the naive Bayes classifier, the random forest classifier, the decision tree classifier, gradient boosted trees, logistic regression and SVM.

Classification Algorithms Used in Predicting Glaucoma Progression

In this paper, various machine learning algorithms were used in order to predict the evolution of open-angle glaucoma (POAG). The datasets were built containing clinical observations and objective measurements made at the Countess of Chester Hospital in the UK and at the "St. Spiridon" Hospital of Iași, Romania. Using these datasets, different classification problems were proposed. The evaluation of glaucoma progression was conducted based on parameters such as VFI (Visual field index), MD (Mean Deviation), PSD (Pattern standard deviation), and RNFL (Retinal Nerve Fiber Layer). As classification tools, the following algorithms were used: Multilayer Perceptron, Random Forest, Random Tree, C4.5, k-Nearest Neighbors, Support Vector Machine, and Non-Nested Generalized Exemplars. The best results, with an accuracy of over 90%, were obtained with Multilayer Perceptron and Random Forest algorithms. The NNGE algorithm also proved very useful in creating a hierarchy of the input values according to their influence (weight) on the considered outputs. On the other hand, the decision tree algorithms gave us insight into the logic used in their classification, which is of practical importance in obtaining additional information regarding the rationale behind a certain rule or decision.

Viscosity Deviation Modeling for Binary and Ternary Mixtures of Benzyl Alcohol-N-Hexanol-Water

Knowing the thermodynamic and transport properties of liquid systems is very important in engineering for the development of theoretical models and for the design of new technologies. Models that allow accurate predictions of thermodynamic and transport properties are needed in chemical engineering calculations involving fluid, heat, and mass transfer. In this study, the modeling of viscosity deviation for binary and ternary systems containing benzyl alcohol, n-hexanol, and water, less studied in the literature, was carried out using Redlich and Kister (R-L) models, multiple linear regression (MLR) models and artificial neural networks (ANN). The viscosity of the binary and ternary systems was experimentally determined at the following temperatures: 293.15, 303.15, 313.15, and 323.15 K. Viscosity deviation was calculated and then correlated with mole fractions, normalized temperature, and refractive index. The neural model that led to the best performance in the testing and validation stages contains 4 neurons in the input layer, 12 neurons in the hidden layer, and one neuron in the output layer. In the testing stage for this model, the standard deviation is 0.0067, and the correlation coefficient is 0.999. In the validation stage, a deviation of 0.0226 and a correlation coefficient of 0.996 were obtained. The MLR model led to worse results than those obtained with the neural model and also with the R-L models. The standard deviation for this model is 0.099, and the correlation coefficient is 0.898. Its advantage over the R-L type models is that the influence of both composition and temperature are included in a single equation.

Positive selection over the mitochondrial genome and its role in the diversification of gentoo penguins in response to adaptation in isolation

Although mitochondrial DNA has been widely used in phylogeography, evidence has emerged that factors such as climate, food availability, and environmental pressures that produce high levels of stress can exert a strong influence on mitochondrial genomes, to the point of promoting the persistence of certain genotypes in order to compensate for the metabolic requirements of the local environment. As recently discovered, the gentoo penguins (Pygoscelis papua) comprise four highly divergent lineages across their distribution spanning the Antarctic and sub-Antarctic regions. Gentoo penguins therefore represent a suitable animal model to study adaptive processes across divergent environments. Based on 62 mitogenomes that we obtained from nine locations spanning all four gentoo penguin lineages, we demonstrated lineage-specific nucleotide substitutions for various genes, but only lineage-specific amino acid replacements for the ND1 and ND5 protein-coding genes. Purifying selection (dN/dS < 1) is the main driving force in the protein-coding genes that shape the diversity of mitogenomes in gentoo penguins. Positive selection (dN/dS > 1) was mostly present in codons of the Complex I (NADH genes), supported by two different codon-based methods at the ND1 and ND4 in the most divergent lineages, the eastern gentoo penguin from Crozet and Marion Islands and the southern gentoo penguin from Antarctica respectively. Additionally, ND5 and ATP6 were under selection in the branches of the phylogeny involving all gentoo penguins except the eastern lineage. Our study suggests that local adaptation of gentoo penguins has emerged as a response to environmental variability promoting the fixation of mitochondrial haplotypes in a non-random manner. Mitogenome adaptation is thus likely to have been associated with gentoo penguin diversification across the Southern Ocean and to have promoted their survival in extreme environments such as Antarctica. Such selective processes on the mitochondrial genome may also be responsible for the discordance detected between nuclear- and mitochondrial-based phylogenies of gentoo penguin lineages.

Absolute Bioavailability and Pharmacokinetic Comparability of Sirukumab Following Subcutaneous Administration by a Prefilled Syringe or an Autoinjector

This phase 1, randomized, open-label study assessed the absolute bioavailability and pharmacokinetic comparability of sirukumab, a human anti-interleukin-6 monoclonal antibody, following subcutaneous (SC) administration via Prefilled Syringe-UltraSafe Passive® Delivery System (PFS-U) or Prefilled Syringe-SmartJect® Autoinjector (PFS-AI; Janssen Research & Development, LLC, Spring House, Pennsylvania). A total of 144 healthy male subjects were randomized to 5 single-dose treatment groups: sirukumab 50 mg and 100 mg (each by PFS-U and PFS-AI) and sirukumab 100 mg intravenous (IV) infusion. Pharmacokinetic parameters were calculated using noncompartmental analysis. Following SC administration, maximum serum concentrations (C_max ) and area under the concentration-vs-time curve (AUC) increased in an approximately dose-proportional manner. Median time to reach C_max was 5 days, and mean half-life ranged from 16 to 19 days. Mean absolute bioavailability of sirukumab by PFS-AI and PFS-U, respectively, was estimated at 92.4% and 81.4% with 100 mg and 88.4% and 94.7% with 50 mg. Ratios of geometric means (90% confidence intervals) of C_max and AUC_0-77d for PFS-AI:PFS-U were 1.13 (1.03, 1.25) and 1.14 (1.05, 1.24), respectively, indicating comparable systemic exposures of sirukumab following a single 100-mg SC dose by PFS-U or PFS-AI. The incidence of antibodies to sirukumab was low (1.4%). No new safety concerns associated with sirukumab were identified at either dose.

Serologic microbial associated markers can predict Crohn's disease behaviour years before disease diagnosis

BACKGROUND

Patients with Crohn's disease (CD) have serologic responses to various microbial antigens. Serologic markers are associated with aggressive forms of disease and can be detected before onset of symptoms. Their utility in pre-clinical disease or prediction of complicated disease course before diagnosis is unclear.

AIM

To evaluate the pattern of serologic anti-microbial antibodies long prior to diagnosis and the subsequent risk of complicated Crohn's disease at diagnosis.

METHODS

Sera from 100 US military personnel with Crohn's disease were obtained from the Department of Defense Serum Repository. For each patient, four samples were obtained at different time points before and around diagnosis, and were tested for 6 microbiota-directed antibodies (ASCA-IgA, ASCA-IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2 and anti-FlaX). Associations between the presence and accumulation of Crohn's disease anti-microbial antibodies before diagnosis and with the later development of complications were evaluated.

RESULTS

Overall, 65 patients were positive for at least one Crohn's disease associated anti-microbial antibody in the earliest available sample, at a median of 6 years before Crohn's disease diagnosis (interquartile range, 5.6-8.2). The number of positive anti-microbial antibodies increased up to the time of Crohn's disease diagnosis. Complicated disease developed around the time of diagnosis in 24 patients. The proportion of positive antimicrobial antibodies before diagnosis was higher in patients with complicated vs. noncomplicated Crohn's disease. There was an inverse relationship between the time to first complication and the magnitude of serologic response before diagnosis.

CONCLUSION

The presence and accumulation of circulating anti-microbial antibodies years before Crohn's disease diagnosis was associated with complicated Crohn's disease at or shortly after diagnosis.

Larazotide acetate in patients with coeliac disease undergoing a gluten challenge: a randomised placebo-controlled study

BACKGROUND

Coeliac disease, an autoimmune disorder triggered by gluten ingestion, is managed by a gluten-free diet (GFD), which is difficult for many patients. Larazotide acetate is a first-in-class oral peptide that prevents tight junction opening, and may reduce gluten uptake and associated sequelae.

AIM

To evaluate the efficacy and tolerability of larazotide acetate during gluten challenge.

METHODS

This exploratory, double-blind, randomised, placebo-controlled study included 184 patients maintaining a GFD before and during the study. After a GFD run-in, patients were randomised to larazotide acetate (1, 4, or 8 mg three times daily) or placebo and received 2.7 grams of gluten daily for 6 weeks. Outcomes included an experimental biomarker of intestinal permeability, the lactulose-to-mannitol (LAMA) ratio and clinical symptoms assessed by Gastrointestinal Symptom Rating Scale (GSRS) and anti-transglutaminase antibody levels.

RESULTS

No significant differences in LAMA ratios were observed between larazotide acetate and placebo groups. Larazotide acetate 1-mg limited gluten-induced symptoms measured by GSRS (P = 0.002 vs. placebo). Mean ratio of anti-tissue transglutaminase IgA levels over baseline was 19.0 in the placebo group compared with 5.78 (P = 0.010), 3.88 (P = 0.005) and 7.72 (P = 0.025) in the larazotide acetate 1-, 4-, and 8-mg groups, respectively. Adverse event rates were similar between larazotide acetate and placebo groups.

CONCLUSIONS

Larazotide acetate reduced gluten-induced immune reactivity and symptoms in patients with coeliac disease undergoing gluten challenge and was generally well tolerated; however, no significant difference in LAMA ratios between larazotide acetate and placebo was observed. Results and design of this exploratory study can inform the design of future studies of pharmacological interventions in patients with coeliac disease.

A randomized, double-blind study of larazotide acetate to prevent the activation of celiac disease during gluten challenge

OBJECTIVES

In patients with celiac disease, enteropathy is caused by the entry of gluten peptides into the lamina propria of the intestine, in which their immunogenicity is potentiated by tissue transglutaminase (tTG) and T-helper type 1-mediated immune responses are triggered. Tight junction disassembly and paracellular permeability are believed to have an important role in the transport of gluten peptides to the lamina propria. Larazotide acetate is a tight-junction regulator peptide that, in vitro, prevents the opening of intestinal epithelial tight junctions. The aim of this study was to evaluate the efficacy and tolerability of larazotide acetate in protecting against gluten-induced intestinal permeability and gastrointestinal symptom severity in patients with celiac disease.

METHODS

In this dose-ranging, placebo-controlled study, 86 patients with celiac disease controlled through diet were randomly assigned to larazotide acetate (0.25, 1, 4, or 8 mg) or placebo three times per day with or without gluten challenge (2.4 g/day) for 14 days. The primary efficacy outcome was the urinary lactulose/mannitol (LAMA) fractional excretion ratio. Secondary endpoints included gastrointestinal symptom severity, quality-of-life measures, and antibodies to tTG.

RESULTS

LAMA measurements were highly variable in the outpatient setting. The increase in LAMA ratio associated with the gluten challenge was not statistically significantly greater than the increase in the gluten-free control. Among patients receiving the gluten challenge, the difference in the LAMA ratios for the larazotide acetate and placebo groups was not statistically significant. However, larazotide acetate appeared to limit gluten-induced worsening of gastrointestinal symptom severity as measured by the Gastrointestinal Symptom Rating Scale at some lower doses but not at the higher dose. Symptoms worsened significantly in the gluten challenge-placebo arm compared with the placebo-placebo arm, suggesting that 2.4 g of gluten per day is sufficient to induce reproducible gluten toxicity. Larazotide acetate was generally well tolerated. No serious adverse events were observed. The most common adverse events were headache and urinary tract infection.

CONCLUSIONS

LAMA variability in the outpatient setting precluded accurate assessment of the effect of larazotide acetate on intestinal permeability. However, some lower doses of larazotide acetate appeared to prevent the increase in gastrointestinal symptom severity induced by gluten challenge.

Successful granulocyte-colony stimulating factor treatment of Crohn's disease is associated with the appearance of circulating interleukin-10-producing T cells and increased lamina propria plasmacytoid dendritic cells

Granulocyte-colony stimulating factor (G-CSF) has proved to be a successful therapy for some patients with Crohn's disease. Given the known ability of G-CSF to exert anti-T helper 1 effects and to induce interleukin (IL)-10-secreting regulatory T cells, we studied whether clinical benefit from G-CSF therapy in active Crohn's disease was associated with decreased inflammatory cytokine production and/or increased regulatory responses. Crohn's patients were treated with G-CSF (5 microg/kg/day subcutaneously) for 4 weeks and changes in cell phenotype, cytokine production and dendritic cell subsets were measured in the peripheral blood and colonic mucosal biopsies using flow cytometry, enzyme-linked immunosorbent assay and immunocytochemistry. Crohn's patients who achieved a clinical response or remission based on the decrease in the Crohn's disease activity index differed from non-responding patients in several important ways: at the end of treatment, responding patients had significantly more CD4(+) memory T cells producing IL-10 in the peripheral blood; they also had a greatly enhanced CD123(+) plasmacytoid dendritic cell infiltration of the lamina propria. Interferon-gamma production capacity was not changed significantly except in non-responders, where it increased. These data show that clinical benefit from G-CSF treatment in Crohn's disease is accompanied by significant induction of IL-10 secreting T cells as well as increases in plasmacytoid dendritic cells in the lamina propria of the inflamed gut mucosa.

Spontaneous collapse of the tibial plateau: radiological staging

OBJECTIVE

This paper proposes a radiological staging system for necrosis of the tibial plateau, similar to those already developed for the hip and the medial femoral condyle.

DESIGN AND PATIENTS

We retrospectively studied the clinical case histories and radiographic findings of 14 patients (15 affected knees) with histologically proven osteonecrosis of the tibial plateau.

RESULTS

Stage I was marked by normal radiograph, but increased uptake in bone scan and subchondral areas of abnormal marrow signal intensity in magnetic resonance imaging (MRI), as reported in other osteonecrosis sites. Stage II was characterised by cystic and sclerotic changes, and stage III fracture of the medial rim of the medial tibial plateau and tibial plateau collapse were present. Stage IV was marked by joint narrowing. These changes appeared earlier and were more pronounced when there was genu varum/valgum or involvement of the lateral tibial plateau.

CONCLUSIONS

The radiological evolution of the disease appears to follow a four-stage course over a period of roughly one year from the onset of symptoms.

Stress fractures of the femoral neck and coxa vara

BACKGROUND

Theoretically, coxa vara substantially modifies the biomechanical conditions of the femoral neck, increasing the effect of direct muscle pull and leading to fatigue of opposing muscle groups; such modifications would appear to favour the appearance of stress fractures.

METHODS

We studied 22 stress fractures of the femoral neck, 12 in patients with coxa vara (group A) and 10 in patients with a normal neck-shaft angle (group B), to assess the possible influence of the femoral angle in the production of stress fractures.

RESULTS

Intergroup differences were found for age at the appearance of the fracture (younger patients in the coxa vara group) and symptom duration (longer in group A).

CONCLUSIONS

It is suggested that coxa vara predisposes to femoral neck stress-fracture.

Steroidal management and serum cytokine profile of a case of alcoholic hepatitis with leukemoid reaction

Leukemoid reactions (LRs) are rare in alcoholic hepatitis (AH), but they are a sign of poor prognosis. The treatment of AH with corticosteroids is controversial, though several reports suggest that these should be used in severe cases of AH. We report a case of AH-associated LRs that presented with an increase of the serum concentrations of the proinflammatory cytokines interleukin (IL)-18 (an initiator of inflammation) and IL-1beta (likely responsible for the neutrophilia of the LRs). These findings provided a pathogenic indication for the use of corticosteroids (that block the transcription of IL-1beta), and this approach achieved a clinical and analytical recovery in our patient. This pathogenic mechanism might also underlie other cases of LRs and other complications of AH, thus providing a rationale for the benefits of corticotherapy in these rare but severe conditions.

Anti-transglutaminase IgA ELISA: clinical potential and drawbacks in celiac disease diagnosis

BACKGROUND

Since the identification of tissue transglutaminase (tTG) as the antigen for the anti-endomysial antibodies (EMA), several antigen-specific immunoassays have been reported for celiac disease (CD) screening. A first objective was to evaluate the suitability for CD screening of three different IgA tTG ELISAs, two of them based on guinea pig liver tTG (gp-tTG) (an in-house ELISA with a partially purified extract and a commercial ELISA with purified gp-tTG antigen) and a third recombinant human tTG (rh-tTG) ELISA. The results are compared with EMA and with the final clinical diagnosis. A second objective was to analyze antibody reactivities in those patients with anti-tTG and EMA discrepancies.

METHODS

ELISA and EMA tests were used to measure IgA anti-tTG levels in sera from 259 patients (107 had CD and 72 had Type I diabetes mellitus).

RESULTS

The purified gp-tTG ELISA was highly sensitive (97.7%) and specific (98.8%) in the detection of CD, almost equaling EMA. Rh-tTG ELISA did not improved the sensitivity of EMA, but its specificity was slightly superior. Immunoblot analysis with partially purified gp-tTG extract, the antigen most frequently used for anti-tTG detection, showed that the majority of false positives were due to IgA reactivities to contaminant proteins present in the liver antigenic extract. This low specificity was particularly problematic in diabetics.

CONCLUSION

Purified tTG ELISAs, either with purified guinea pig liver or recombinant human antigens, can be used as quantitative and observer-independent alternatives to the traditional and time-consuming EMA in the screening of CD.

Intestinal intraepithelial lymphocytes contain a CD3- CD7+ subset expressing natural killer markers and a singular pattern of adhesion molecules

Intestinal intraepithelial lymphocytes (i-IEL) represent one of the largest, non-organized lymphoid population in the body. They are located outside the epithelial basement membrane among the mucosal epithelial cells. We, and previously other groups, have reported the presence of a CD7+CD3-IEL subset in the epithelium of human small intestine. This subset is drastically reduced in coeliac disease (CD) patients. In the present work we accomplish a better phenotypic characterization of this CD3-IEL subset and demonstrate the expression of typical natural killer (NK) cell markers. Most, if not all, CD3-CD7+ cells express NKPR1 (CD161)[98% +/- 2] and CD122[92% +/- 6]. In addition, a variable percentage express CD2[55% +/- 16], CD94[24% +/- 18], CD56[44% +/- 21] and CD16[12% +/- 4], however, no CD57 expression was observed. Moreover, these cells contain perforin granules[75% +/- 5], supporting a potential cytolytic ability. Regarding adhesion molecules, CD18 and CD44 expression is absent, which is consistent with a limited capacity of migration. Altogether, these data suggest the presence of intraepithelial NK cells in human intestinal epithelium, a compartment where cytotoxic effectors have not been clearly defined.

Intraepithelial lymphocytes and coeliac disease: permanent changes in CD3-/CD7+ and T cell receptor gammadelta subsets studied by flow cytometry

Permanent changes in intestinal intraepithelial lymphocytes have been observed in coeliac patients. The aim of this investigation was to study small intestinal intraepithelial lymphocytes by using flow cytometry and to evaluate its diagnostic value in coeliac disease. Three-colour flow cytometry analyses were performed on isolated epithelial cells of 117 intestinal biopsies obtained from 113 children (54 coeliac disease, 4 other enteropathies, 18 Helicobacter pylori associated gastritis and 37 normal controls). A multiple logistic regression model was developed to select the best intraepithelial lymphocytes subset predictor of coeliac disease. Coeliac patients had significant higher levels of T cell receptor gammadelta intraepithelial lymphocytes than control patients (p < 0.01), H. pylori patients (p < 0.01) and other enteropathies (p < 0.05). The density of CD3-/CD7+ intraepithelial lymphocytes, a intraepithelial lymphocyte subset poorly characterized by immunohistochemical methods, was significantly lower in coeliac patients than in the control group (p < 0.01). H. pylori group (p < 0.01) and other enteropathies (p < 0.01). Both changes remained altered independent of the coeliac patient's diet. The data were used on a logistic regression analysis in order to calculate sensitivity [94.4%; 95% confidence interval (CI) 83.7-98.6%], specificity (94.9%; 95% CI 84.9-98.7%) and likelihood ratio for a positive test 18.5 (95% CI 6.1-55.8) in the diagnosis of coeliac disease.

CONCLUSION

Changes in T cell receptor gammadelta and CD3-/CD7+ intraepithelial lymphocytes subsets are permanently observed in paediatric coeliac disease. Their assessment, by three-colour flow cytometry on routine diagnostic biopsies, permits a better characterization of coeliac enteropathy and represents a valuable procedure to identify coeliac patients with different clinical presentations.

Hemispheric specialization using SPECT and stimulation tasks in children with dysphasia and dystrophia

Developmental dysphasia, a severe childhood learning disorder, is thought to result from problems in hemispheric specialization involving both left and right cerebral hemispheres. Regional cerebral blood flow (rCBF) was measured at rest and during stimulation of both hemispheres independently: dichotic listening for the left, dichaptic palpation for the right. Eight right-handed boys with expressive dysphasia, aged 8 to 12 years, were investigated using SPECT and compared with eight right-handed age-matched boys with Duchenne muscular dystrophy with reading disorders but normal speech. rCBF values at rest were also compared with those of five right-handed age-matched normal boys. In the dichotic task, children with dysphasia differed from children with dystrophia by failure to increase rCBF in the left hemisphere, in Broca's area, but rCBF increased in the right hemisphere, in the region homologous to Broca's area. In the dichaptic task, rCBF increased bilaterally for children with dysphasia whereas in children with dystrophia rCBF increased only in the right hemisphere. At rest the physiological asymmetry was reversed in favor of the right hemisphere in all areas except Broca's area. Surprisingly, the same applied at rest and for all areas in children with dystrophia. These results confirm that functional specialization of both hemispheres is impaired in developmental dysphasia. Moreover, they suggest that learning disabilities associated with Duchenne muscular dystrophy could also be related to abnormal hemispheric specialization.

Differential expression of major histocompatibility complex class II variants in cells infiltrating the meth A sarcoma

CD4+ T cells are involved in immune responses against the Meth A sarcoma and infiltrate tumours arising from Meth A cells inoculated intradermally in (BALB/c x C57BL/6)F1 (H-2d/b) mice. In order to investigate whether the prerequisites for tumour antigen presentation to CD4+ T cells are fulfilled within the malignant lesion, expression of class II major histocompatibility complex (MHC) molecules and the costimulatory ligand B7 were examined. The I-Ab and I-Ed allomorphs were abundantly expressed by virtually all B cells and 50% of macrophages infiltrating the tumours. In striking contrast, the I-Ad variant was hardly detectable. This pattern of class II expression appeared to be unique for the tumour microenvironment. Thus the proportion of I-Ad+ spleen B cells and peritoneal macrophages did not significantly differ from the proportion expressing I-Ab and I-Ed, and these extratumoral I-Ad+ cells stained as brightly as did cells from healthy mice. Expression of B7 was weak by tumour-infiltrating cells. The profound capacity of the Meth A sarcoma to confer low local I-Ad and B7 expression might preclude T-cell-dependent anti-tumour immune responses and thus promote survival of malignant cells. Whereas MHC class II genes are generally found to be co-ordinately transcribed, this study demonstrates that the expression of MHC class II allelic variants can be differentially regulated in vivo.

N-terminal elongation of a peptide determinant beyond the first primary anchor improves binding to H-2 I-Ad and HLA-DR1 by backbone-dependent and aromatic side chain-dependent interactions, respectively

The IgG2a(b) heavy chain allopeptide determinant gamma2a(b) 436-451 (Kabat numbering) presented by the major histocompatibility complex (MHC) class II molecule I-Ad is recognized by T cells which cross-react with a corneal self antigen and with the UL6 protein of the herpes simplex virus which induce autoimmune keratitis, and is the target of Th1 clones that suppress IgG2a(b) production in vivo. In the gamma2a(b) peptide/l-Ad complex, tyrosine438 is the first primary anchor (P1) and residues 440-445 encompass the T cell receptor contact residues. Amino-terminal elongation of gamma2a(b) 437-451 by a single residue (P-2) augmented the I-Ad binding capacity 10-fold and the antigenicity 55-195-fold. This was a function of the peptide main chain, since non-conservative substitutions were accepted. The gamma2a(b) peptide also bound HLA-DR1, and amino-terminal extension by a single aromatic amino acid at P-3 augmented binding 15-fold. The interaction between HLA-DR1 and P-3 specifically required an aromatic peptide side chain, and computer simulations indicated that the aromatic ring at P-3 engaged conserved HLA-DR1 phenylalanine residues at the edge of the peptide binding groove. Thus, these data demonstrate that residues amino terminal to P1 may substantially increase peptide affinity for MHC class II by main chain-dependent as well as side chain-dependent interactions, and imply that the HLA-DR1 motif should be extended to include an aromatic amino acid at P-3.

A novel first primary anchor extends the MHC class II I-Ad binding motif to encompass nine amino acids

The MHC class II molecule I-Ad has been reported to bind peptides containing a motif of six consecutive amino acids. We demonstrate that binding of the murine IgG2ab heavy chain allopeptide gamma 2ab 435-451 (Kabat numbering) to I-Ad is strongly enhanced by a novel first primary anchor (P1) three residues N-terminal to this hexamer. This is based on flow cytometric assessment of the I-Ad binding capacity of gamma 2ab peptide analogues, their antigenicity for I-Ad-restricted T cell clones and molecular modelling. The P1 pocket is broadly specific since allphatic, aromatic, acidic, the basic histidine and small polar side chains all allowed good binding. By contrast, asparagine, arginine and glycine reduced the binding capacity 10-, 16- and > 100-fold respectively. Truncation or glycine substitution at P1 decreased antigenicity by a factor > 1000. Nevertheless, I-Ad-restricted T cells are not completely dependent on this anchor since high concentrations of a peptide with glycine-substituted P1 elicited maximal responses. Additional anchoring side chains are found at P4, P6 and P9. The autologous IgG2aa heavy chain shares prominent epitopic residues with gamma 2ab 435-451 at P3, P5 and P8. However, the lysine of gamma 2aa at P9 impairs binding to I-Ad, which may explain why the gamma 2ab allopeptide-reactive T cells escaped negative selection. The data rationalize our observation (Bartnes, K. and Hannestad, K. 1997. Eur. J. Immunol. 27:1124) that these T cells recognize a syngeneic B cell lymphoma, provided its presentation of intrinsic gamma 2aa is enhanced by surface IgG2aa ligation.

Cholera and myocarditis--a case report

The authors describe the case of a fifty-nine-year-old white man, previously in good health, who initiated his present illness with acute episode of enterocolitis characterized by mild fever and, in the next eight hours, twenty-four episodes of watery diarrhea, nausea and vomiting, as well as generalized sweating and severe weakness secondary to hypovolemia and electrolyte disorder. These complications were corrected in seventy-two hours in the intensive care unit. Two days later, when the patient was stable hemodynamically, under cardiac monitoring and with normal laboratory studies including serum electrolytes, he developed electrocardiographic changes characterized by trifascicular block (prolonged P-R interval, complete right bundle branch block [CRBBB] and left posterior hemiblock [LPH]) with a cardiac rate of thirty beats per minute, for which a temporary pacemaker was inserted. Endomyocardial biopsy showed histopathologic signs of myocarditis and the immunologic study of the cardiac tissue revealed positive polymerize chain reaction (PCR+) with the presence of antitoxine choleric antibodies (AcTCA). After three weeks, the same conduction disturbances remained, for which a permanent pacemaker was inserted. On top of intravenous fluid replacement and electrolyte supplements, the patient was managed with tetracycline 2 g a day for one week and sulfamethoxazole-trimethoprim 800/160 mg a day for two weeks. The purpose of this study is to present a rare and very well-documented myocarditis by cholera in a patient with enteric disease, in whom several cardiac complications occurred.

Acute myocardial infarction with normal coronary arteries in a patient with dermatomyositis. Case report

The authors present a forty-year-old man, with a history of dermatomyositis for the past twelve years, managed intermittently with prednisone. During an exacerbation of his illness he developed an acute anterior wall myocardial infarction with normal coronary arteries. A literature review indicates this represents a rare association.

SPECT of the brain in childhood autism: evidence for a lack of normal hemispheric asymmetry

Autism is thought to be associated with abnormal hemispheric specialization and left-hemispheric dysfunction. Brain functional imaging using 133Xe-SPECT (single photon emission computed tomography) was used to measure left/right asymmetry and absolute values of regional cerebral blood flow (rCBF) in 18 children with autism aged from four to 17 years and 10 age-matched controls. All controls but only 10 children with autism were right-handed. The left-to-right indices, both hemispheric and regional, were positive in controls, indicating higher left than right rCBF values, but were negative in patients with autism. This inversion was statically significant for total hemispheres, sensorimotor and language-related cortex and was explained by a significant decrease of the left absolute rCBF values in these regions in the patients with autism. The inversion was independent of handedness, sex and age. These results confirm the existence of left-hemispheric dysfunction in childhood autism, especially in the cortical areas devoted to language and handedness, leading to anomalous hemispheric specialization.

Blood pressure in the sow: an attempt of indirect measuring ante partum

Farrowing disorders in the sow have detrimental consequences in pig farming and many points of the condition still remain obscure. It was suggested to investigate blood pressure since this might provide an early indication of farrowing disturbances. A first study involved 29 pregnant sows. Blood pressure was measured indirectly using a pediatric occlusive cuff unrolled around the base of the tail and connected to a manometer. The recordings were made on resting sows in recumbent position. The disposal was considered suitable. The values obtained showed a good repeatability. Then a prospective survey involving 122 sows was undertaken. Blood pressure was measured at the 111th day of pregnancy. Systolic values ranged from 89 to 142 mm Hg (mean: 112.4). Physical profile of the sows (weight, backfat thickness) slightly influenced systolic level. On the other hand the sows obtaining the lowest values for systolic pressure were more prone to develop a prolonged farrowing. According to the lack of a parallel direct blood pressure measurement, these results have to be taken with caution. The perspective of early detection of "at risk" individuals with respect to MMA through blood pressure measurement, needs further work.