Is there a way for pathologists to decrease interobserver variability in the diagnosis of dysplasia?

Many obstacles interfere with our efforts to screen patients with Barrett esophagus. Probably the largest is choosing the appropriate patient group for screening. Beyond this problem, sampling error on the part of endoscopists is probably more serious a problem than observer variation among pathologists reviewing patient samples. Pathologists agree well on lesions that merit close follow-up or other intervention (high-grade dysplasia and invasive carcinoma), although interobserver agreement between pathologists interpreting lesser lesions is not good. This lack of agreement is not likely to improve substantially, and many adjunct markers are being sought in an attempt to identify patients with lesions of lower grades that are most likely to progress, allowing doctors to identify patients who would benefit from upgraded surveillance.     

The human neural cell adhesion molecule L1 functions as a costimulatory molecule in T cell activation

L1 is a neural cell adhesion molecule (CAM) known to be important for normal neurological development. Despite being described as a neural CAM, we have documented L1 expression by antigen-presenting cells of myelomonocytic origin. Here we demonstrate that L1 can function as a costimulatory molecule in T cell activation. A monoclonal antibody that abrogates L1-L1 homophilic binding significantly reduced mixed leukocyte responses initiated by allogeneic L1+ dendritic cells. Autologous T cell activation in response to phytohemagglutinin was also inhibited by blockade of L1. In accordance with these results, transfection of human L1 into a murine myeloma cell line significantly increased the capacity of these cells to stimulate xenogeneic T cell responses. As a costimulatory ligand L1 could represent a novel target for immunotherapeutic intervention and may act as an important intermediary in neuroimmunological processes and disease.     

A novel method for making "tissue" microarrays from small numbers of suspension cells.

Tissue microarrays (TMAs) are a highly efficient method for large-scale protein expression studies. To date most TMAs have been constructed using paraffin-embedded specimens. The authors developed a method that allows construction of TMAs from small numbers of cells in suspension. Spun pellets of 1x10 to 1x10 cells are directly processed and embedded in paraffin in an Eppendorf tube. Cylindrical cores of 0.6 mm are taken from these tubes and embedded in a recipient paraffin block to create a TMA. This relatively simple but versatile method enables very small numbers of cells in suspension to be analyzed using the TMA technology and allows for the study of hematolymphoid and related disorders of the blood and bone marrow for which solid tissue samples cannot be readily obtained. With the increasing trend toward obtaining small samples for screening and diagnostic purposes, this method provides a means to manipulate small volume samples for high-throughput immunohistochemical analysis. This method is also amenable for use for cultured cells.     

Desensitization protocols improving access and outcome in transplantation

Sensitization to antigens of the HLA and ABO system has been the biggest barrier to access in renal transplantation and, increasingly, in transplantation of other organs. Additionally, antibody to donor antigens has been shown to result in injury to the graft ranging from catastrophic, irreversible hyperacute rejection to the slower, more insidious, chronic form of rejection. The problem of access has been recognized globally and has been the incentive for measures to overcome the disadvantage experienced by the sensitized patient. However, early attempts to reduce sensitization achieved only transient success. Newer immunosuppressive agents that affect B-cell function or viability have permitted the development of treatment protocols to eliminate and, potentially, downregulate donor-specific antibodies. The use of these protocols has achieved successful transplants that were HLA and/or ABO incompatible prior to treatment and, as such, has provided some patients with their only opportunity for transplantation.     

Pathogenesis of Shigella diarrhea: rabbit intestinal cell microvillus membrane binding site for Shigella toxin

This study examined the binding of purified 125I-labeled shigella toxin to rabbit jejunal microvillus membranes (MVMs). Toxin binding was concentration dependent, saturable, reversible, and specifically inhibited by unlabeled toxin. The calculated number of toxin molecules bound at 4 degrees C was 7.9 X 10(10) (3 X 10(10) to 2 X 10(11))/micrograms of MVM protein or 1.2 X 10(6) per enterocyte. Scatchard analysis showed the binding site to be of a single class with an equilibrium association constant, K, of 4.7 X 10(9) M-1 at 4 degrees C. Binding was inversely related to the temperature of incubation. A total of 80% of the labeled toxin binding at 4 degrees C dissociated from MVM when the temperature was raised to 37 degrees C, but reassociated when the temperature was again brought to 4 degrees C. There was no structural or functional change of MVM due to toxin as monitored by electron microscopy or assay of MVM sucrase activity. These studies demonstrate a specific binding site for shigella toxin on rabbit MVMs. The physiological relevance of this receptor remains to be determined.     

Dizygotic twinning is not associated with methylenetetrahydrofolate reductase haplotypes

BACKGROUND: Folate metabolism is critical to embryonic development, influencing neural tube defects (NTD) and recurrent early pregnancy loss. Polymorphisms in 5,10-methylenetetrahydrofolate reductase (MTHFR) have been associated with dizygotic (DZ) twinning through pregnancy loss. METHODS: The C677T and A1298C polymorphisms in MTHFR were genotyped in 258 Australasian families (1016 individuals) and 118 Dutch families (462 individuals) of mothers of DZ twins and a population sample of 462 adolescent twin families (1861 individuals). Haplotypes were constructed from the alleles, and transmission of the MTHFR haplotypes to mothers of DZ twins and from parents to twins in the adolescent twin families analysed. RESULTS: The C677T and A1298C were common in all three populations (frequencies > 0.29). There was strong linkage disequilibrium (D' = 1) between the variants, showing that specific combinations of alleles (haplotypes) were transmitted together. Three haplotypes accounted for nearly all the variation. There was no evidence of any association between MTHFR genotype and twinning in mothers of twins, or of the loss of specific MTHFR genotypes during twin pregnancies. CONCLUSIONS: It is concluded that variation in twinning frequency is not associated with MTHFR genotype.     

The homemaker needs of the rural frail elderly from a client versus agency perspective

The clients, aides, and staff of a homemaker services program for the rural frail elderly were individually interviewed concerning client's met and unmet needs. While the overall response from all three groups suggested a highly effective program, significant differences existed among the three groups with regard to what they considered the most important needs, both met and unmet by the program. It was concluded that although the perceptions of all three groups of participants in such programs might differ, such differences may not necessarily work to undermine the program.     

Quantifying infection risks in incompatible living donor kidney transplant recipients

Desensitization has enabled incompatible living donor kidney transplantation (ILDKT) across HLA/ABO barriers, but added immunomodulation might put patients at increased risk of infections. We studied 475 recipients from our center from 2010 to 2015, categorized by desensitization intensity: none/compatible (n = 260), low (0-4 plasmaphereses, n = 47), moderate (5-9, n = 74), and high (≥10, n = 94). The 1-year cumulative incidence of infection was 50.1%, 49.8%, 66.0%, and 73.5% for recipients who received none, low, moderate, and high-intensity desensitization (P < .001). The most common infections were UTI (33.5% of ILDKT vs. 21.5% compatible), opportunistic (21.9% vs. 10.8%), and bloodstream (19.1% vs. 5.4%) (P < .001). In weighted models, a trend toward increased risk was seen in low (wIRR = _0.771.40_2.56,P = .3) and moderately (wIRR = _0.881.35_2.06,P = .2) desensitized recipients, with a statistically significant 2.22-fold (wIRR = _1.332.22_3.72,P = .002) increased risk in highly desensitized recipients. Recipients with ≥4 infections were at higher risk of prolonged hospitalization (wIRR = _2.623.57_4.88, P < .001) and death-censored graft loss (wHR = _1.154.01_13.95,P = .03). Post–KT infections are more common in desensitized ILDKT recipients. A subset of highly desensitized patients is at ultra-high risk for infections. Strategies should be designed to protect patients from the morbidity of recurrent infections, and to extend the survival benefit of ILDKT across the spectrum of recipients.     

A novel strategy for targeting CD4+ PPD-reactive T cells against tumour cells using PPD monoclonal antibody heteroconjugates.

We have constructed PPD monoclonal antibody heteroconjugates specific for a tumour-associated antigen of C57BL/6 melanomas or for human complement component C3d fixed de novo to murine fibrosarcoma cells (MC6A). The ability of our heteroconjugates to target CD4+ PPD-reactive T cells against the appropriate tumour targets was then determined in vitro. Heteroconjugate-treated B16-F10 and MC6A tumour targets were both able to present PPD to the specific T cells, resulting in activation and concomitant lymphokine secretion. Secreted lymphokines were then demonstrated to cause significant tumour cytolysis and cytostasis in vitro. Preliminary experiments in vivo suggest that this targeting system may provide the basis for a future immunotherapeutic strategy.