Painless aortic dissection late after aortic valve replacement, presenting as superior vena cava syndrome

A 68-year-old man, who had underwent aortic valve replacement (AVR) with Björk-Shiley disc valve for aortic regurgitation 17 years ago, was transferred to our hospital complaining of facial ruddiness and swelling, without chest or back pain. Preoperative examination revealed DeBakey type II aortic dissection, which caused superior vena cava syndrome (SVC syndrome). Emergent ascending aortic replacement was performed, postoperatively central venous pressure (CVP) decreased from 33 to 9 mmHg, and SVC syndrome was relieved. Painless aortic dissection after AVR, presenting as SVC syndrome, is a rare case, and close follow-up should be performed under consideration of painless aortic dissection late after AVR.     

Analysis of mRNA with microsomal fractionation using a SAGE-based DNA microarray system facilitates identification of the genes encoding secretory proteins

In the regulation of host defense responses such as inflammation and immunity, the secretory proteins, including membrane proteins, play central roles. Although many secretory proteins have been identified by using methods such as differential display, random screening, or the signal sequence trap method, each method suffers from poor reproducibility, low sensitivity, or time-consuming or laborious work. Therefore, the strategy for facilitating the selection of the genes encoding the secretory proteins is desired. In this paper, we describe a system for isolating the genes encoding secretory proteins by analyzing mRNAs with microsomal fractionation on serial analysis of gene expression (SAGE)-based DNA microarray system. This system succeeded in discriminating the genes encoding secretory proteins from ones encoding nonsecretory proteins with 80% accuracy. We applied this system to human T lymphocytes. As a result, we were able to identify the genes that are not only encoding secretory proteins but also expressing selectively in a specific subset of T lymphocytes. The SAGE-based DNA microarray system is a promising system to identify the genes encoding specific secretory proteins.     

Changes in T,B, and NK Lymphocyte Subsets During and After Normal Pregnancy

PROBLEM: Pregnancy affects the maternal immune system and the clinical course of maternal diseases. Here we report the changes in the detailed lymphocyte subsets of helper T cells, suppressor T cells, CD5⁺ B cells, T cell receptor (TCR) αβ-positive T cells (Tαβ cells), TCRαβ-negative T cell (Tγδ cells), and others during and after pregnancy through to one year postpartum, and discuss the significance of the changes. METHOD: The absolute numbers of helper T cells, suppressor T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), CD5^— B cells, CD5⁺ B cells, and NK cell subsets were examined by two-color flow cytometry in peripheral blood from 51 healthy non-pregnant women, 106 healthy pregnant women, and 148 healthy postpartum women. RESULTS: In early pregnancy, the numbers of suppressor T cells and NK cells with strong cytotoxicity (NK⁺⁺⁺ cells) increased, and the number of cytotoxic T cells decreased. In late pregnancy, the helper T cell and NK⁺⁺⁺ cell numbers decreased. Tαβ, CD5^— B and CD5⁺ B cells decreased during pregnancy. After delivery, helper T cells and cytotoxic T cells increased from 1 to 4 months postpartum, and suppressor T cells increased at 7 months postpartum. TCRαβ-negative T cells increased at 4 to 10 months postpartum. Both CD5^— and CD5⁺ B cells decreased further at 1 month postpartum, but CD5⁺ B cells increased markedly at 7 to 10 months postpartum. CONCLUSIONS: These data indicate that 1) early increases of suppressor T cells and NK⁺⁺⁺ cells during pregnancy may be related to the mechanism to accept or reject the fetus in early pregnancy, respectively; 2) late decreases of helper T cells and NK⁺⁺⁺ cells may be related to the maintenance of pregnancy: 3) postpartum increases of helper T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), and CD5⁺ B cells may be related to the postpartum aggravation of autoimmune diseases; and 4) the immunological effects of pregnancy remains until about 1 year after delivery.     

Interleukin-1 receptor antagonist attenuates airway hyperresponsiveness following exposure to ozone

The role of an interleukin (IL)-1 receptor antagonist (IL-1Ra) on the development of airway hyperresponsiveness (AHR) and airway inflammation following acute O(3) exposure in mice was investigated. Exposure of C57/BL6 mice to O(3) at a concentration of 2.0 ppm or filtered air for 3 h resulted in increases in airway responsiveness to inhaled methacholine (MCh) 8 and 16 h after the exposure, and an increase in neutrophils in the bronchoalveolar lavage (BAL) fluid. IL-1beta expression, assessed by gene microarray, was increased 2-fold 4 h after O(3) exposure, and returned to baseline levels by 24 h. Levels of IL-1beta in lung homogenates were also increased 8 h after O(3) exposure. Administration of (human) IL-1Ra before and after O(3) exposure prevented development of AHR and decreased BAL fluid neutrophilia. Increases in chemokine levels in lung homogenates, tumor necrosis factor-alpha, MIP-2, and keratinocyte chemoattractant following O(3) exposure were prevented by IL-1Ra. Inhalation of dexamethasone, an inhibitor of IL-1 production, blocked the development of AHR, BAL fluid neutrophilia, and decreased levels of IL-1 following O(3) exposure. In summary, acute exposure to O(3) induces AHR, neutrophilic inflammation, epithelial damage, and IL-1. An IL-1Ra effectively prevents the development of altered airway function, inflammation, and structural damage.     

Significance of aberrant (cytoplasmic/nuclear) expression of beta-catenin in pancreatoblastoma

This study concerns the significance of aberrant (nuclear/cytoplasmic) expression of beta-catenin in pancreatoblastoma (PBL). On immunohistochemistry, all seven PBLs examined showed nuclear/cytoplasmic expression of beta-catenin, predominantly in the squamoid corpuscles (SCs). In areas with acinar/ductular differentiation, few tumour cells displayed nuclear/cytoplasmic expression of beta-catenin and more than half of the tumour cells showed membranous expression. Two out of five (40%) tumours examined showed missense mutations in codons 33 and 37 of exon 3 of the beta-catenin gene. No mutation of the adenomatous polyposis coli (APC) gene was detected in two of the remaining three tumours. Amplifiable DNA for APC analysis was not obtained from the one other tumour. Immunoreactivity for cyclin D1, one of the nuclear targets of beta-catenin, was found predominantly in the SCs of the seven tumours. In contrast, the Ki-67 labelling index was 2-4% (median 3%) in the SCs and 8-18% (median 12%) in the other areas, indicating a negative correlation with nuclear cyclin D1 reactivity. These results imply that in PBLs, nuclear/cytoplasmic accumulation of beta-catenin and overexpression of its target gene cyclin D1 are not associated with the induction of tumour cell proliferation. Nuclear/cytoplasmic accumulation of beta-catenin may be related to the morphogenesis of the SCs that are considered most characteristic for PBL.     

Thromboxane A2 modulates interaction of dendritic cells and T cells and regulates acquired immunity

Physical interaction of T cells and dendritic cells (DCs) is essential for T cell proliferation and differentiation, but it has been unclear how this interaction is regulated physiologically. Here we show that DCs produce thromboxane A2 (TXA2), whereas naive T cells express the thromboxane receptor (TP). In vitro, a TP agonist enhances random cell movement (chemokinesis) of naive but not memory T cells, impairs DC-T cell adhesion, and inhibits DC-dependent proliferation of T cells. In vivo, immune responses to foreign antigens are enhanced in TP-deficient mice, which also develop marked lymphadenopathy with age. Similar immune responses were seen in wild-type mice treated with a TP antagonist during the sensitization period. Thus, TXA2-TP signaling modulates acquired immunity by negatively regulating DC-T cell interactions.     

Evidence of Delayed Mesangial Transport of Human IgA in Glomeruli of ddY Mice Pretreated with Sheep Anti-type IV Collagen Serum

In order to investigate whether mesangial transport by glomeruli is delayed in ddY mice pretreated with sheep anti type IV collagen serum, the mice were administered an overload of human IgA myeloma serum. Non pretreated ddY mice used as controls and both experimental and control BALB/c mice were also processed in a similar manner. The intensities of mesangial deposition of human IgA were examined periodically and were found to correlate well with deposition of mouse IgA. Both mouse and human IgAs showed a gradual increase for up to 8 experimental weeks. In the control young ddY mice, however, the overloaded mesangial human IgA quickly disappeared, presenting no appreciable mesangial deposition of autologous IgA. In sharp contrast, both the experimental and control BALB/c mice showed an initially prolonged and rather heavy mesangial deposition of human IgA, followed by a gradual decrease and somewhat light mesangial deposition of autologous mouse IgA. These results obtained using experimental ddY mice appear to confirm the possibility that non immunological local trapping, due to retardation of mesangial transport function, causes mesangial deposition of autologous mouse IgA in this particular strain. Acta Pathol Jpn 39: 289 295, 1989.     

Immunolocalization of 3β-hydroxysteroid dehydrogenase in human adrenal cortex and in its disorders

Immunohistochemical localization of 3β-hydroxysteroid dehydrogenase/Δ^5→4-isomerase (3β-HSD), which converts Δ⁵-3β-hydroxysteroids to Δ⁴-3-ketosteroids, was performed in the human adrenal gland and in its disorders by employing a specific antibody raised against the enzyme purified from human placenta. Immunoreactivity of 3β-HSD was present in all three cortical zones of the adrenal glands obtained at autopsy, while in surgically removed adrenal glands, immunoreactivity was dominant in the zona fasciculata (ZF), with faint immunoreactivity in the zona glomerulosa (ZG) and the zona reticularis (ZR). Intracortical localization of 3β-HSD in the adrenal glands obtained at autopsy may represent an adrenal adaptation to antemortem stress, with shifting of adrenal pregnenolone- a substrate of 3β-HSD - as well as steroid 17α-hydroxylase from adrenal androgen synthesis to glucocorticoid synthesis. In adrenocortical hyperplasia, marked immunoreactivity was observed in the ZG and outer ZF in adrenal glands with idiopathic hyperaldosteronism and in the ZF and ZR, especially in cortical micronodules, in the adrenal glands associated with Cushing’s disease. In aldosteronoma and Cushing’s adenoma, immunoreactivity of the enzyme was much more intense in large clear tumor cells than in small compact tumor cells. Immunolocalization of 3β-HSD can yield important information toward an understanding of adrenal steroid metabolism in both physiological and pathological processes.     

Colocalization of a carnosine-splitting enzyme,tissue carnosinase (CN2)/cytosolic non-specific dipeptidase 2 (CNDP2), with histidine decarboxylase in the tuberomammillary nucleus of the hypothalamus

Carnosine is a naturally occurring dipeptide (β-alanyl-l-histidine) present in mammalian tissues such as the brain and skeletal muscles. Carnosine is not only a radical scavenger but also a possible neurotransmitter-like molecule that regulates neuronal functions such as hypothalamic control of the autonomic nervous system. CN2 (CNDP2) is a cytosolic enzyme that can hydrolyze carnosine to yield l-histidine and β-alanine. In order to understand the functions of carnosine and CN2 in the brain, we have investigated the immunohistochemical localization of CN2 in the hypothalamus. CN2-immunoreactivity was highly concentrated in neuronal cells in the dorsal part of the tuberomammillary nucleus of the posterior hypothalamus. Since the tuberomammillary nucleus is the exclusive origin of histaminergic neurons, we further investigated whether CN2 is present in the histaminergic neurons. We found that CN2-immunoreactivity was colocalized with that of histidine decarboxylase, which is the key enzyme for histamine biosynthesis specifically expressed in the histaminergic neurons of the tuberomammillary nucleus. These results suggest that CN2 is highly expressed in the histaminergic neurons in the tuberomammillary nucleus, implying that it may supply histidine to histaminergic neurons for histamine synthesis.