Immunologic risk stratification of pediatric heart transplant patients by combining HLA-EMMA and PIRCHE-II

Human leukocyte antigen (HLA) molecular mismatch is a powerful biomarker of rejection. Few studies have explored its use in assessing rejection risk in heart transplant recipients. We tested the hypothesis that a combination of HLA Epitope Mismatch Algorithm (HLA-EMMA) and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE-II) algorithms can improve risk stratification of pediatric heart transplant recipients. Class I and II HLA genotyping were performed by next-generation sequencing on 274 recipient/donor pairs enrolled in the Clinical Trials in Organ Transplantation in Children (CTOTC). Using high-resolution genotypes, we performed HLA molecular mismatch analysis with HLA-EMMA and PIRCHE-II, and correlated these findings with clinical outcomes. Patients without pre-formed donor specific antibody (DSA) (n=100) were used for correlations with post-transplant DSA and antibody mediated rejection (ABMR). Risk cut-offs were determined for DSA and ABMR using both algorithms. HLA-EMMA cut-offs alone predict the risk of DSA and ABMR; however, if used in combination with PIRCHE-II, the population could be further stratified into low-, intermediate-, and high-risk groups. The combination of HLA-EMMA and PIRCHE-II enables more granular immunological risk stratification. Intermediate-risk cases, like low-risk cases, are at a lower risk of DSA and ABMR. This new way of risk evaluation may facilitate individualized immunosuppression and surveillance.

Sources of information and factual knowledge in Europeans with inflammatory bowel diseases: a cross-cultural comparison between German and Irish patients

BACKGROUND

Disease related knowledge may be associated with quality of life, coping skills and medication adherence. However, little is known of cross-cultural variations regarding inflammatory bowel disease knowledge or sources of information and no study has assessed knowledge in diverse European IBD populations.

AIM

To assess sources of information and patient knowledge in Irish and German inflammatory bowel disease patients.

METHODS

Three hundred and three disease, gender, age and education matched German and Irish patients completed a previously validated knowledge questionnaire. Additional data were collected on age, gender, education, disease type and duration, family history, smoking habits, medication use, previous surgery and quality of life.

RESULTS

German patients obtained knowledge from a wider range of sources than Irish patients (p<0.001), most notably from the internet (p<0.001), newspapers and magazines (p=0.002). Both cohorts answered a similar number of questions correctly (Irish, mean 4.4 questions (Standard deviation (S.D.) 2.4); German, mean 4.3 (S.D. 2.2); p=0.67). In addition, both nationalities answered "don't know" to a similar number of questions (Irish, mean 3.3 (S.D. 3.1); German, mean 2.7 (S.D. 2.8); p=0.12) while Irish patients answered slightly fewer questions wrongly (Irish, mean 2.4 (S.D. 1.8); German, mean 3.1 (S.D. 1.9); p=0.002). A multivariate analysis included only Crohn's disease, female gender, young age and higher educational status as being significantly and independently associated with knowledge.

CONCLUSIONS

Our data suggest few differences between German and Irish IBD patients, despite cultural and linguistic differences, with regard to disease related knowledge of IBD.

Proteomic analysis of the supernatant of red blood cell units: the effects of storage and leucoreduction

BACKGROUND

Red blood cell (RBC) transfusion is a life-saving intervention for critically ill patients; however, it has been linked to increased morbidity and mortality. We hypothesize that a number of important proteins accumulate during routine storage of RBCs, which may explain some of the adverse effects seen in transfused patients.

STUDY DESIGN

Five RBC units were drawn and divided (half prestorage leucoreduced (LR-RBC) and half left as an unmodified control (RBC). The supernatant was separated on days 1 and 42 of storage and proteomic analyses completed with in-gel tryptic digestion and nano-liquid chromatography tandem mass spectrometry.

RESULTS

In RBC supernatants, 401 proteins were identified: 203 increased with storage, 114 decreased, and 84 were unchanged. In LR-RBC supernatant, 231 proteins were identified: 84 increased with storage, 30 decreased, and 117 were unchanged. Prestorage leucoreduction removed many platelet- and leucocyte-derived structural proteins; however, a number of intracellular proteins accumulated including peroxiredoxins (Prdx) 6 and latexin. The increases were confirmed by immunoblotting, including the T-phosphorylation of Prdx-6, indicating that it may be functioning as an active phospholipase. Active matrix metalloproteinase-9 also increased with a coinciding decrease in the metalloproteinase inhibitor 1 and cystatin C.

CONCLUSION

We conclude that a number of proteins increase with RBC storage, which is partially ameliorated with leucoreduction, and transfusion of stored RBCs may introduce mediators that result in adverse events in the transfused host.

Silicon optical fiber

Described herein are initial experimental details and properties of a silicon core, silica glass-clad optical fiber fabricated using conventional optical fiber draw methods. Such semiconductor core fibers have potential to greatly influence the fields of nonlinear fiber optics, infrared and THz power delivery. More specifically, x-ray diffraction and Raman spectroscopy showed the core to be highly crystalline silicon. The measured propagation losses were 4.3 dB/m at 2.936 microm, which likely are caused by either microcracks in the core arising from the large thermal expansion mismatch with the cladding or to SiO(2) precipitates formed from oxygen dissolved in the silicon melt. Suggestions for enhancing the performance of these semiconductor core fibers are provided. Here we show that lengths of an optical fiber containing a highly crystalline semiconducting core can be produced using scalable fiber fabrication techniques.

Supramolecular Behavior of the Amphiphilic Drug (2R)-2-Ethylchromane-2-Carboxylic Acid Arginine Salt (a Novel PPARα/γ Dual Agonist)

PURPOSE

This study was conducted to evaluate the aggregation properties of an amphiphilic drug.

METHODS

Aggregation of the drug was studied by various methods including phase-contrast and polarized microscopy, spectrophotometry, surface tensiometry, atomic force microscopy, and dynamic light scattering. Lymph-cannulated rats were used to assess fractions of drug that were absorbed into lymphatics.

RESULTS

During the pharmaceutical development of an alpha/gamma dual PPAR agonist, a derivative of a chromane-2-carboxylic acid (compound 1), it was discovered that the compound was able to form various aggregates in aqueous media from pH 6.5 to 7.1, whereas aggregating predominantly into micelles at higher pH values. Critical micelle concentrations seemed to be quite low, about 0.25 mM (0.17 mg/mL) in deionized water as determined by spectrophotometric (dye) and surface tensiometry (du Nuoy) methods. Aggregation of compound 1 into large supramolecular aggregates was visualized via phase-contrast microscopy and atomic force microscopy. The observed aggregates ranged from 250 nm to greater than 10 microm in size. Formation of liquid crystalline phases was observed by polarized microscopy as the material was gradually hydrated with water. Lymph studies in rats indicated that up to 6.9% of the orally administered dose of compound 1 in pH 6.5 buffer appeared in lymph, suggesting that supramolecular aggregation may also occur in vivo leading to partitioning between the portal and the lymph routes.

CONCLUSIONS

The aforementioned supramolecular aggregation was found to have a profound effect on the pharmaceutical development of the drug and potentially on in vivo absorption of the drug.

Effects of overlapping parametric resonances on the particle diffusion process

The evolution of the beam distribution in a double-rf system with a phase modulation on either the primary or secondary rf cavity was measured. We find that the particle diffusion process obeys the Einstein relation if the phase space becomes globally chaotic. When dominant parametric resonances still exist in the phase space, particles stream along the separatrices of the dominant resonance, and the beam width exhibits characteristic oscillatory structure. The particle-tracking simulations for the double-rf system are employed to reveal the essential diffusion mechanism. Coherent octupolar motion has been observed in the bunch beam excitation. The evolution of the longitudinal phase space in the octupole mode is displayed.

Differential targeting of nicotinic acetylcholine receptors by novel alphaA-conotoxins

We describe the isolation and characterization of two peptide toxins from Conus ermineus venom targeted to nicotinic acetylcholine receptors (nAChRs). The peptide structures have been confirmed by mass spectrometry and chemical synthesis. In contrast to the 12-18 residue, 4 Cys-containing alpha-conotoxins, the new toxins have 30 residues and 6 Cys residues. The toxins, named alphaA-conotoxins EIVA and EIVB, block both Torpedo and mouse alpha1-containing muscle subtype nAChRs expressed in Xenopus oocytes at low nanomolar concentrations. In contrast to alpha-bungarotoxin, alphaA-EIVA is inactive at alpha7-containing nAChRs even at micromolar concentrations. In this regard, alphaA-EIVA is similar to the previously described alpha-conotoxins (e.g. alpha-MI and alpha-GI) which also selectively target alpha1- versus alpha7-containing nAChRs. However, alpha-MI and alpha-GI discriminate between the alpha/delta versus alpha/gamma subunit interfaces of the mouse muscle nAChR with 10,000-fold selectivity. In contrast, alphaA-conotoxin EIVA blocks both the alpha/gamma site and alpha/delta site with equally high affinity but with distinct kinetics. The alphaA-conotoxins thus represent novel probes for the alpha/gamma as well as the alpha/delta binding sites of the nAChR.

Who gets a heart? Rationing and rationalizing in heart transplantation

National policy on organ transplantation is made by the United Network for Organ Sharing (UNOS), a representative body composed of health care professionals and patients. Standardized criteria for determining when a patient should be placed on the waiting list for heart transplantation are now in effect nationwide. Current and future directions to maximize the utilization of available donated organs are explored.

Molecular activation-deactivation of xanthine oxidase in human milk

Enzymic activity and protein levels of xanthine oxidase were measured in serial samples of breast milk donated by each of 14 mothers, starting, in all but two cases, within 7 days following parturition. Enzyme activity varied widely, usually reaching peak values during the first 15 days and falling thereafter, by as much as 98%, to basal levels that were subsequently largely maintained. Corresponding changes in xanthine oxidase protein levels were not observed and, consequently, the specific activity of xanthine oxidase followed the above pattern. The capacity of human xanthine oxidase to undergo activation-deactivation cycles at the molecular level has important implications, not only for its role in breast milk, but also for its potential as a source of reactive oxygen species in other human tissues.

Content of the neurotoxins cycasin (methylazoxymethanol beta-D-glucoside) and BMAA (beta-N-methylamino-L-alanine) in cycad flour prepared by Guam Chamorros

Exposure to cycad seed kernel is an etiologic factor for the western Pacific amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC). Traditionally processed cycad flours (n = 17) obtained from Chamorro residents of Guam and the adjacent island of Rota at risk for neurodegenerative disease were extracted and analyzed by high-performance liquid chromatography for content of beta-N-methylamino-L-alanine (BMAA) and methyl-azoxymethanol beta-D-glucoside (cycasin). Cycasin (detection limit: picomole) was present in concentrations of 0.004 to 75.93 micrograms/g (mean, 12.45 +/- 5.0 micrograms/g), and levels of BMAA (detection limit: subpicomole) ranged from 0.00 to 18.39 micrograms/g (mean, 5.44 +/- 1.56 micrograms/g). On average, cycasin content was approximately 10 times higher than that of BMAA. The largest concentrations of cycasin were found in samples from villages with a high reported prevalence of ALS/PDC. Ingestion of cycad-derived food would result in estimated human exposure to milligram amounts of cycasin per day. The cytotoxic properties of cycasin merit consideration in relation to the etiology of western Pacific ALS/PDC.

Impotence following pelvic fracture

A group of 42 men (mean age, 26.7 years) with pelvic fractures as the result of motor vehicle accidents were evaluated for impotence 48 hours after injury. Hormone levels were normal in all patients tested. One half (21/42) of the patients had abnormal penile:brachial arterial ratios. Of this group, 13/21 had abnormal bulbocavernosus reflex (BCR): four patients were paraplegic and nine had urethral injuries. Followup of available patients to 20 months reflects persistent impotence in those who experienced vasculogenic trauma. Only 2/21 patients with normal tests (vascular, hormonal, neurologic) complain of impotence (followup at 23 months); one of these patients is in litigation.

Production of beta-human chorionic gonadotrophin by human squamous carcinoma cell lines

Eight out of 9 human squamous carcinoma cell lines ectopically secrete the beta subunit of human chorionic gonadotrophin (beta-HCG) in amounts detectable by radioimmunoassay. In contrast, both normal and SV40-transformed keratinocytes show no such evidence of beta-HCG secretion. Ectopic beta-HCG is identical in its gel exclusion and high-performance liquid chromatographic properties to placental beta-HCG and, in radioimmunoassay, yields a dilution curve parallel to that of placental beta-HCG. Dibutyryl cyclic AMP, but not sodium butyrate, stimulates beta-HCG secretion by the one human cell line examined, LICR-LON-HN-5, suggesting that ectopic production by these cells is similar to trophoblastic beta-HCG secretion, and differs from most other non-trophoblastic cell lines previously examined.

A monoclonal antibody detecting neural and neuroendocrine differentiation

A monoclonal antibody, named LICR-LON-E36, has been produced to the acidic fraction of soluble protein extracts of human brains. Using immunocytochemistry, it stained normal peripheral nerves, adrenal medulla, pancreatic islets, and enterochromaffin cells, in addition to recognizing an intracytoplasmic epitope in phaeochromocytomas, carcinoid tumors, some small-cell anaplastic lung, and a few breast carcinomas. Microenzyme-linked immunosorbent assay and electrophoretic nitrocellulose blotting experiments confirmed that the antibody is not directed at neuron-specific enolase. Its potential use as an immunological probe for neural and neuroendocrine differentiation is discussed.

Distribution of myoepithelial cells and basement membrane proteins in the normal breast and in benign and malignant breast diseases

An immunocytochemical method for fixed and paraffin-embedded human breast biopsies is reported for the detection of myoepithelial and epithelial cells using antibodies to myosin and keratin, respectively, and of basement membranes using antibodies to laminin and type IV collagen. Using these markers, myoepithelial cells can be clearly distinguished in the normal breast and in the benign breast diseases sclerosing adenosis, epitheliosis, and fibroadenoma. In sclerosing adenosis, myoepithelial cells form a major cellular component. A stromally derived spindle cell is identified which stains with myosin but not with keratin antibodies (myofibroblast). These cells are seen in one-fifth of the fibroadenomas. Although cells staining with myosin antibodies are seen in the infiltrating component of all 18 carcinomas examined, elongated cells staining with both myosin and keratin antibodies (myoepithelial-like) are seen in only one infiltrating carcinoma where they are interposed at the stromal-epithelial junction of the infiltrating tumor cells. In contrast to the situation in benign breast diseases, mature myoepithelial cells form a very minor component of the majority of infiltrating ductal carcinomas. Basement membrane proteins, laminin, and type IV collagen are present in normal breast, benign breast disease, and grade I infiltrating ductal carcinomas but are absent in carcinomas of grades II and III.

Role of copper in collagen cross-linking and its influence on selected mechanical properties of chick bone and tendon

Day-old White Leghorn cockerels were fed skim-milk-based diets containing 0, 2, 4, 8, or 16 ppm added copper as CuSO4 for 21 days. Lysyl oxidase was extracted from bone and tendon. The recovery of activity from the extracts was linearly correlated with dietary copper (r greater than 0.90). Tests of the mechanical properties of tendon and bone indicated that tendon viscoelasticity (as measured by stress--relaxation) may not be significantly influenced by copper, whereas the ultimate torsional strength of bone is markedly decreased when the dietary copper level is below 1 ppm. Furthermore the torsional fracture characteristics of bone from copper-deficient birds demonstrated a lack of plastic deformation prior to failure that was normally seen in bone from control birds. The change in the mechanical properties of bone from copper-deficient birds appeared to be related to a decrease in the amounts of dihydroxylysinonorleucine and other lysine-derived cross-linking amino acids in bone collagen. The data indicate that the requirement for optimal growth of chicks fed skim-milk-based diets is 6--8 ppm copper, however, the requirement for normal cross-link formation in bone is less than 2 ppm copper.

The human tumour xenograft--a valid model in experimental chemotherapy?

The chemotherapeutic response of a series of patients with bronchial carcinoma has been compared with the response of their xenografts established in immune-suppressed mice. The in situ endpoint of growth delay in subcutaneous tumours was the main parameter used to assess xenograft response, but clonogenic cell survival studies were also performed to assess the extent of cell kill associated with in vivo responses. Histology, chromosome analysis and demonstration of ectopic hormone production indicated that the xenografts retained human morphology and functional behaviour. Clinical response was assessed by serial measurement of metastases. The chemotherapeutic validity of xenografts is supported by this study in which 21 separate responses in 16 patients and their respective xenografts were similar. Metastases regressed completely in 5 out of 7 patients with oat cell carcinoma. Xenografts derived from these were also highly responsive to similar chemotherapy. In contrast, minimal responses were observed in xenografts established from two chemoresistant patients. One large cell anaplastic, 3 squamous and 4 adenocarcinomas were universally chemoresistant in patients and their xenografts. It is concluded that the bronchial carcinoma xenografts broadly retained human morphology and functional behaviour, and reproduced the pattern of chemotherapeutic response of their source tumours. The present work suggests that the incorporation of human tumour xenografts into drug development programmes is justified, although their usefulness in a predictive capacity to select appropriate chemotherapy for individual patients remains limited.