Crystals in a Gastric Schwannoma

A gastric schwannoma containing large numbers of intracytoplasmic crystals is described. The latter are compared with intracytoplasmic crystals found in the cells of other tumors and their nonneoplastic cell counterparts. The extreme morphologic and histochemical heterogeneity of the different types of crystals is emphasized.     

Increased in vivo frequency of IA-2 peptide-reactive IFNgamma+/IL-4- T cells in type 1 diabetic subjects

Active T cell recognition of islet antigens has been postulated as the pathogenic mechanism in human type 1 diabetes, but evidence is scarce. If T cells are engaged, they are expected to display increased clonal size and exhibit a T helper (Th)1/Th2 differentiation state. We used a peptide library that covers tyrosine phosphatase IA-2, a target antigen expressed in pancreatic beta cells, to probe 8 diabetic patients and 5 HLA-matched controls. When tested in a high resolution IFNgamma/IL-4 double color ELISPOT assay directly ex vivo, the number of IA-2-reactive IFNgamma producing cells was 17-fold higher in patients than in controls and IL-4 producing cells were not present. An average of 9 peptides was recognized in the patients vs. one in the controls. Determinant recognition primarily involved CD4+ cells and showed high variability among the patients. Furthermore, anti-CD28 antibody signal enhances quantitative assessment of effector T cells in T1D patients. In vitro expansion with peptides and IL-2 results in detection of responding cells in the controls and loss of disease specificity of the T cell response. Together these data provide strong evidence for the active targeting of IA-2 by Th1 memory effector cells in human type 1 diabetes.     

Phenotype and functional analysis of human monocyte-derived dendritic cells loaded with biodegradable poly(lactide-co-glycolide) microspheres for immunotherapy

Dendritic cells (DC) are increasingly explored as cellular vaccines for tumor immunotherapy. In most reported DC-based cancer vaccine trials, DC have been pulsed with soluble tumor antigen-derived peptide ligands of MHC molecules. Considering that the half-life of peptide/MHC complexes on the cell surface is relatively short and that soluble exogenous protein antigens cannot be efficiently processed via the MHC class I-processing pathway, the current vaccination procedure is not optimal for the induction of strong T cell responses aiming at tumor rejection. Recently, we have shown that antigen presentation can be prolonged when synthetic peptides were encapsulated in biodegradable poly(D,L-lactide-co-glycolide) (PLGA) microspheres (MS) for uptake by DC. In the present study, we investigated the phenotypic and functional consequences of MS uptake by human monocyte-derived dendritic cells (MoDC) in vitro. We found that immature MoDC that were prepared in serum free media suitable for clinical application were able to phagocytose high numbers of MS, while matured MoDC showed a reduced capacity for phagocytosis of MS. The ingestion of MS did not change the cell surface expression of CD80, CD83, CD86 and HLA-DR of immature and mature DC, suggesting that MS uptake did not induce DC maturation but that maturation by cytokines or LPS was unaltered in the presence of MS. Furthermore, MS-loaded mature MoDC expressed normal levels of the chemokine receptor CCR7 and migrated as efficiently towards CCL19 or CCL21 as unloaded MoDC. DC viability and the secretion of TNF-alpha and IL-12 was not significantly changed by MS loading. Taken together, our data indicate that PLGA-MS loading has no negative effects on the pivotal properties of MoDC in vitro. It should therefore be feasible to further develop this antigen loading strategy for clinical use in immunotherapy against viral infections and tumors.     

APO-1(CD95)-dependent and -independent antigen receptor-induced apoptosis in human T and B cell lines

Certain B and T cell lines respond to activation signals, e.g.through the antigen receptor, by undergoing apoptotlc cell death.In T cells it has been recently shown that TCR-mediated apoptosisinvolves APO-1/Fas (CD95) receptor-ligand interaction. To investigatewhether the TCR-CD3 complex can trigger alternative apoptosispathways we generated subclones of the T cell line Jurkat whichwere completely resistant towards APO-1-mediated apoptosis.These Jurkat^R cells differed phenotypically from sensitive parentalJurkat^S cells only by the lack of APO-1 protein expression.Although Jurkat^R cells responded normally to anti-CD3 stimulationby expression of APO-1 ligand they failed to undergo anti-CD3-inducedapoptosis. Thus, in Jurkat cells APO-1 -mediated apoptosis wasthe main, and might be the only, mechanism for anti-CD3-inducedcell death. However, BL-60 B cells, highly sensitive to anti-IgM-inducedapoptosis, did not use the APO-1 receptor-ligand system becausethey failed to express APO-1 ligand mRNA. Taken together, ourresults suggest that malignant T and B cell lines may use APO-1receptor-ligand-dependent and -independent antigen receptor-inducedapoptosis pathways respectively. Similarly, differential pathwaysmay be used by T and B cell subsets.     

Factors associated with the use of psychiatric consultations in short-term general hospitals

A significant number of patients in general hospitals suffer from psychiatric distress or illness, but not all receive psychiatric consultation. This study examined several potential predictors of such consultation. These included patient characteristics (age, sex, race, insurance, disease stage, and number of medical diagnoses), characteristics of hospital stay (number of procedures, other consultations, length of stay, discharge destination), hospital characteristics (size, percent occupancy, teaching status, presence of a psychiatric unit, type of control), and community characteristics (region, urban/rural setting). Data were derived from a national sample of 327 hospitals. Parallel analyses using stepwise logistic regression were carried out across four samples: patients determined at discharge to have been hospitalized for diabetes, hip fracture, chronic obstructive pulmonary disease, and coronary artery bypass surgery. Results show a wide variation in the use of psychiatric consultations across different subgroups. Longer lengths of stay, urban setting. Northeast region, younger patient age, and other consultations were the most consistent predictors of the probability of psychiatric consultation. These variations may reflect differences in the need for consultation, differential recognition of these needs by providers, or differential availability of psychiatric consultation services. Moreover, they may have implications for equity and/or quality of hospital care.     

Role of the Salmonella pathogenicity island 1 effector proteins SipA, SopB, SopE, and SopE2 in Salmonella enterica subspecies 1 serovar Typhimurium colitis in streptomycin-pretreated mice

Salmonella enterica subspecies 1 serovar Typhimurium (serovar Typhimurium) induces enterocolitis in humans and cattle. The mechanisms of enteric salmonellosis have been studied most extensively in calf infection models. The previous studies established that effector protein translocation into host cells via the Salmonella pathogenicity island 1 (SPI-1) type III secretion system (TTSS) is of central importance in serovar Typhimurium enterocolitis. We recently found that orally streptomycin-pretreated mice provide an alternative model for serovar Typhimurium colitis. In this model the SPI-1 TTSS also plays a key role in the elicitation of intestinal inflammation. However, whether intestinal inflammation in calves and intestinal inflammation in streptomycin-pretreated mice are induced by the same SPI-1 effector proteins is still unclear. Therefore, we analyzed the role of the SPI-1 effector proteins SopB/SigD, SopE, SopE2, and SipA/SspA in elicitation of intestinal inflammation in the murine model. We found that sipA, sopE, and, to a lesser degree, sopE2 contribute to murine colitis, but we could not assign an inflammation phenotype to sopB. These findings are in line with previous studies performed with orally infected calves. Extending these observations, we demonstrated that in addition to SipA, SopE and SopE2 can induce intestinal inflammation independent of each other and in the absence of SopB. In conclusion, our data corroborate the finding that streptomycin-pretreated mice provide a useful model for studying the molecular mechanisms of serovar Typhimurium colitis and are an important starting point for analysis of the molecular events triggered by SopE, SopE2, and SipA in vivo.     

Efficiency of Protection of Guinea Pigs against Infection with Bacillus anthracis Spores by Passive Immunization

The efficacy of passive immunization as a postexposure prophylactic measure for treatment of guinea pigs intranasally infected with Bacillus anthracis spores was evaluated. Antisera directed either against the lethal toxin components (PA or LF) or against a toxinogenic strain (Sterne) were used for this evaluation. All antisera exhibited high enzyme-linked immunosorbent assay titers against the corresponding antigens, high titers of neutralization of cytotoxicity activity in an in vitro mouse macrophages cell line (J774A.1), as well as in vivo neutralization of toxicity when administered either directly to Fisher rats prior to challenge with the lethal toxin or after incubation with the lethal toxin. In these tests, anti-LF antiserum exhibited the highest neutralization efficiency, followed by anti-Sterne and anti-PA. The time dependence and antibody dose necessary for conferring postexposure protection by the various antibodies of guinea pigs infected with 25 50% lethal doses of Vollum spores was examined. Rabbit anti-PA serum was found to be the most effective. Intraperitoneal injections of anti-PA serum given 24 h postinfection protected 90% of the infected animals, whereas anti-Sterne and anti-LF were less effective. These results further emphasizes the importance of anti-PA antibodies in conferring protection against B. anthracis infection and demonstrated the ability of such antibodies to be effectively applied as an efficient postexposure treatment against anthrax disease.     

Different types of aortic stenosis and simulation of their morphological-hydrodynamic interdependence--in vitro study with allografts and stenotic valve models

Biological valves display a dependence of valve resistance and valve area on flow and a phase shift between systolic flow through the valves and pressure difference across the valves. The pressure-flow relations of stenosed valves raise questions about the "best measure of stenosis". There is a need for quantitative evaluation of the hydrodynamic performance of homografts and allografts. In the present paper, we report on in vitro studies of the hydrodynamic behavior of homografts from human donors, allografts from different animal species as well as three valve models. Valve model I was designed to simulate flow-dependence of valve area, valve model II was designed to simulate restricted valve opening independent of flow, and valve model III was designed to simulate a flow-dependent movement of valve root in flow direction. Among other aspects, the effect of increased viscosity of the test fluid on the pressure difference and the effects of water absorption by valve tissue on valve characteristics were investigated. The results of the present studies clearly indicate that any biological valve may be modelled as a serial connection of a model I type valve and a model II type valve. From the results, the dependence of the characteristic pressure-flow relationship of a valve on valve size and valve distensibility can be clearly seen and the clinical significance of the characteristic coefficients of the pressure-flow relationship of a valve can be elucidated. Further, it was shown that the characteristic phase shift between flow and pressure difference displayed by biological valves is due to their movable valve plane similar to that of valve model III.