Suppressive role of B cells in chronic colitis of T cell receptor alpha mutant mice

The role of antibodies (Abs) in the development of chronic colitis in T cell receptor (TCR)-alpha-/- mice was explored by creating double mutant mice (TCR-alpha-/- x immunoglobulin (Ig)mu-/-), which lack B cells. TCR-alpha-/- x Ig mu-/- mice spontaneously developed colitis at an earlier age, and the colitis was more severe than in TCR-alpha-/- mice. Colitis was induced in recombination-activating gene-1 (RAG-1-/-) mice by the transfer of mesenteric lymph node (MLN) cells from TCR-alpha-/- x Ig mu-/- mice. When purified B cells from TCR-alpha-/- mice were mixed with MLN cells before cell transfer, colitis did not develop in RAG-1-/- mice. Administration of the purified Ig from TCR-alpha-/- mice and a mixture of monoclonal autoAbs reactive with colonic epithelial cells led to attenuation of colitis in TCR-alpha-/- x Ig mu-/- mice. Apoptotic cells were increased in the colon, MLN, and spleen of TCR-alpha-/- x Ig mu-/- mice as compared to Ig mu-/- mice and TCR-alpha-/- mice. Administration of the purified Ig from TCR-alpha-/- mice into TCR-alpha-/- x Ig mu-/- mice led to decrease in the number of apoptotic cells. These findings suggest that although B cells are not required for the initiation of colitis, B cells and Igs (autoAbs) can suppress colitis, presumably by affecting the clearance of apoptotic cells.     

Monoallelic expression of the interleukin-2 locus

The lymphokine interleukin-2 (IL-2) is responsible for autocrine cell cycle progression and regulation of immune responses. Uncontrolled secretion of IL-2 results in adverse reactions ranging from anergy, to aberrant T cell activation, to autoimmunity. With the use of fluorescent in situ hybridization and single-cell polymerase chain reaction in cells with different IL-2 alleles, IL-2 expression in mature thymocytes and T cells was found to be tightly controlled by monoallelic expression. Because IL-2 is encoded at a nonimprinted autosomal locus, this result represents an unusual regulatory mode for controlling the precise expression of a single gene.     

Surgical experience with intracardiac myxomas: long-term follow-up

BACKGROUND: Myxomas are the most common benign intracardiac tumors. This report summarizes our 20-year experience with these tumors. METHODS: Sixty-six patients (25 male) with a median age of 39 years (range, 6 to 70 years) underwent surgical excision of primary or recurrent intracardiac myxomas during the years 1976 to 1996. Symptom duration ranged from 2 to 8 months. There were 55 left atrial myxomas, 10 right atrial myxomas, and 1 biatrial myxoma. Three of the patients were in one family. The surgical approach comprised complete wide excision. RESULTS: There were two early deaths. Late follow-up is 89% (57/64) complete. There was one late death, which was not due to a cardiac cause. Echocardiography at a mean follow-up of 66.9 months (range, 7 to 241 months) showed no recurrence of sporadic myxomas. However, 2 of the 3 patients with familial myxomas had recurrence. CONCLUSIONS: Surgical excision of atrial myxoma gives excellent short-term and long-term results leading to eventual cure of nonfamilial myxomas. However, familial myxomas retain a strong tendency to recur even 20 years after excision.     

Consequences of Fas-ligand and perforin expression by colon T cells in a mouse model of inflammatory bowel disease

Cardiotrophin-1 (CT-1) was originally identified as a molecule capable of inducing cardiac hypertrophy. We show here that treatment of cultured neonatal cardiocytes with CT-1 induces enhanced synthesis of the heat shock proteins hsp70 and hsp90, with hsp70 levels being enhanced three-fold and hsp90 levels being enhanced seven-fold. Such CT-1-treated cells are protected against subsequent exposure to severe thermal or ischaemic stress, as assayed both by measures of total cell death, such as trypan blue exclusion and LDH release, and by measures of apoptosis, such as propidium-iodide-staining and TUNEL-labelling. Hence, CT-1 can induce the protective hsps and protect cardiac cells from diverse stresses.     

Aneurysm of sinus of Valsalva dissecting into interventricular septum

PURPOSE: We developed an algorithm using unenhanced computerized tomography (CT) for the management of acute flank pain and suspected ureteral obstruction. MATERIALS AND METHODS: During a 25-month interval 417 patients with acute flank pain underwent unenhanced helical CT. The final diagnosis was confirmed by additional imaging or clinical followup. For all patients who underwent additional imaging studies the official dictated radiology reports were used to determine whether the studies were recommended based on CT findings. Cases requiring intervention were evaluated to determine whether additional imaging was performed before the procedure. Medical records were reviewed and/or patients were interviewed to document the course of therapy and long-term outcome. RESULTS: Unenhanced helical CT diagnosed ureteral stone disease with 95% sensitivity, 98% specificity and 97% accuracy. Of the 38 patients requiring intervention, including nephrostomy catheters in 18, lithotripsy in 3 and ureteroscopic stone extraction in 7, additional imaging (excretory urography) was performed in only 1. Additional imaging studies generated by CT were done in 3 cases in which the dictated reports were indeterminate for ureteral stones, including negative excretory urography in 2 and retrograde urography in 1. In 1 patient in whom CT misdiagnosed a ureteral stone unnecessary retrograde urography revealed the calcification to be a gonadal vein phlebolith. Seven patients with false-negative examinations reported spontaneous stone passage with no complications. CONCLUSIONS: Unenhanced helical CT accurately determines the presence or absence of ureterolithiasis in patients with acute flank pain. CT precisely identifies stone size and location. When ureterolithiasis is absent, other causes of acute flank pain can be identified. In most cases additional imaging is not required.     

A new method for measurement of threshold voltage non-uniformity in CCD multiplexers for hybrid focal plane arrays

A new, simple and rapid method for determining threshold voltage (V_T) non-uniformity in two-dimensional CCD multiplexers (MUXs) for hybrid focal plane arrays is presented. The method is based on simple oscilloscopic measurement of non-uniformity in the output signal of CCD MUX. The non-uniformity in V_T, measured by this method, is compared with conventional current forcing method. The results of the proposed new method agree within 7.8% with the conventional method. Additionally, intrinsic non-uniformity due to processing and material variations is also measured by this method.     

Immunohistochemical characterization of intraepithelial and subepithelial mononuclear cells of the upper airways

The upper airway is the first site of exposure to inhaled antigens and the site of initiation of mucosal immunity to certain antigens; however, the intraepithelial lymphoid populations of this region have not been well characterized. We studied 6-mu frozen tissue sections from tonsils, adenoids, and nasal mucosae using immunohistochemistry and a panel of antibodies to mononuclear antigens to determine whether nasal mucosa contained distinctive populations of mononuclear cells. Intraepithelial lymphocytes (IELs) of nasal mucosa were CD3+, CD8+, and mainly CD5+. Tonsil and adenoid both showed diffuse CD8+ IELs; clusters of CD4+ IELs were associated with B cells within the crypt epithelium. All nasal IELs were uniformly negative for Leu8 (homing receptor analog of Mel14). Scattered Leu8-positive cells were present within tonsil and adenoid crypt epithelium only. Nasal IELs rarely expressed HML1 and were often CD7-, whereas the majority of tonsillar and adenoidal IELs were HML1+ and variably CD7+. In nasal mucosa and in deep submucosa of tonsil and adenoid, 80 to 90% of T cell receptor expression was of alpha/beta type. There was a concentration of gamma/delta T cell receptor-positive cells in intraepithelial and subepithelial zones of tonsil and adenoid, with areas of up to 30% gamma/delta T cell receptor positivity. A population of intraepithelial dendritic cells was identified in all three tissues expressing mononuclear phagocyte system antigens CD14 and KiM1P, but lacking CD1a. Virtually no B cells and no organized subepithelial lymphoid tissue were identified in nasal mucosa. Nasal mucosal lymphoid tissue seems to differ from that of endodermally derived mucosae, tonsil, and adenoids to share similarities with both mucosa-associated lymphoid tissue and peripheral lymph nodes.     

Inhibitory effect of parthenium (Parthenium hysterophorus L.) residue on growth of water hyacinth (Eichhornia crassipes mart solms.) I. Effect of leaf residue

The allelopathic effect of parthenium (Parthenium hysterophorus L.) leaf residue (dry leaf powder, DLP) on water hyacinth (Eichhornia crassipes Mart Solms.) was studied. The treatment caused wilting starting from the margins of the older leaves and desiccation of above-water plant parts (shoot). Appearance, persistence, and disappearance of symptoms depended on the level and duration of the treatment and recovery of the treated plants, if it occurred. The treatment drastically reduced the number of healthy leaves (HLN) and the plant biomass at 0.25% (w/v) DLP; the treated plants recovered in about one month. At and above 0.50% (w/v) DLP, the plants were killed in about one month, resulting in sinking of the dead mass in water. Physiological effects of the treatment included deterioration of membrane integrity, loss of dehydrogenase activity with concurrent drastic reduction or total failure of water absorption by the roots, and reduction of chlorophyll contents in the leaves. The results indicate that the inhibitors leached out of the DLP affected the water hyacinth plants through changes in macromolecules: protein, lipid, and nucleic acid, resulting in root dysfunction and other inhibitory activities both in the root and shoot. Phenolic and other inhibitors including those found in the parthenium plant (except sesquiterpene lactones which have not been tested) at 50 ppm, exceptp-hydroxybenzoic acid, did not affect the treated plants. Such a high concentration of the allelochemicals is unlikely to be present in the medium at the lethal dose (0.50% w/v) of the DLP. Even withp-hydroxybenzoic acid, the plants recovered subsequently and grew normally. Thus, it appears that other allelochemicals including sesquiterpene lactones were mainly responsible for the inhibitory activity of the DLP on water hyacinth plants.     

A hybrid genetic algorithm for efficient parameter estimation of large kinetic models

The development of predictive models is a time consuming, knowledge intensive, iterative process where an approximate model is proposed to explain experimental data, the model parameters that best fit the data are determined and the model is subsequently refined to improve its predictive capabilities. Ascertaining the validity of the proposed model is based upon how thoroughly the parameter search has been conducted in the allowable range. The determination of the optimal model parameters is complicated by the complexity/non-linearity of the model, potentially large number of equations and parameters, poor quality of the data, and lack of tight bounds for the parameter ranges. In this paper, we will critically evaluate a hybrid search procedure that employs a genetic algorithm for identifying promising regions of the solution space followed by the use of an optimizer to search locally in the identified regions. It has been found that this procedure is capable of identifying solutions that are essentially equivalent to the global optimum reported by a state-of-the-art global optimizer but much faster. A 13 parameter model that results in 60 differential-algebraic equations for propane aromatization on a zeolite catalyst is proposed as a more challenging test case to validate this algorithm. This hybrid technique has been able to locate multiple solutions that are nearly as good with respect to the “sum of squares” error criterion, but imply significantly different physical situations.