Expression of E-cadherin in bone and soft tissue sarcomas: a possible role in epithelial differentiation

The cadherin-mediated cell-cell adhesion system is now known to play a critical role in both the morphogenesis of cancer cells and suppression of their invasion. However, the pattern of expression of E-cadherin, the major cadherin of epithelial cells in bone and soft tissue sarcomas, remains unclear. This prompted us to study E-cadherin expression in a variety of bone and soft tissue sarcomas. Using the monoclonal antibody HECD-1, raised against the extracellular domain of E-cadherin, we observed immunoreactivity in 1 pleomorphic rhabdomyosarcoma, 2 of 5 diffuse mesotheliomas, 4 of 5 clear cell sarcomas, 1 of 5 epithelioid sarcomas, and 10 synovial sarcomas. Other types of bone and soft tissue sarcoma (4 osteosarcomas, 4 chondrosarcomas, 3 primitive neuroectodermal tumors, 1 fibrosarcoma, 4 malignant fibrous histiocytomas, 5 liposarcomas, 4 leiomyosarcomas, 6 alveolar and 5 embryonal rhabdomyosarcomas, 4 angiosarcomas, 4 malignant peripheral nerve sheath tumors, 2 extraskeletal myxoid chondrosarcomas, 2 extraskeletal osteosarcomas, and 3 alveolar soft part sarcomas) were completely negative for E-cadherin. Our findings indicate that E-cadherin is expressed in certain kinds of soft tissue sarcomas, especially those with epithelioid features, suggesting that E-cadherin plays a role in the constitution of their architecture.     

Signal transmission in the catfish retina. IV. Transmission to ganglion cells

1. To characterize the temporal dynamic responses of ganglion cells and to define the possible inputs giving rise to their responses in catfish retina, we recorded the ganglion cell responses evoked by 1) a step of light presented in the dark, 2) an incremental and decremental step from a background illumination, and 3) a white-noise modulated light. 2. For comparison, we recorded the responses of preganglionic cells evoked by the same set of stimuli as used for the ganglion cells. Type-C cells produced on-off transient depolarizations to step stimuli, whether presented in the dark or an illuminated background. Type-N amacrine cells produced complex transient responses to incremental and decremental steps, whereas their step-evoked responses in the dark were sustained polarizations. Bipolar cells produced sustained responses to all step stimuli. 3. Ganglion cells were classified into three types, based on their responses evoked by incremental and decremental steps of light. One class of ganglion cells produced responses similar to those of type-C cells, the second class produced responses similar to those of type-N cells, and the third class resembled bipolar cell responses, although spike discharges accompanied the ganglion cell responses. 4. The analysis of the first-order kernels indicates that the temporal properties of linear dynamic responses are established at the level of bipolar cells and encoded into spike trains of ganglion cells without a major transformation. 5. The second-order nonlinearity appeared at the amacrine cell level. Type-C and type-N cells produced a second-order kernel characteristic of each cell type. The second-order kernels produced in ganglion cells were similar to those produced either by type-C or type-N cells. 6. We conclude that bipolar cells are the major source of linear components of ganglion cell responses and that type-C and type-N amacrine cells are the major source of the nonlinear responses. These linear and second-order nonlinear signals were encoded into spike trains by ganglion cells without a major transformation of the temporal response properties.     

An improved fixation method for transmission electron microscopy for the histological study of the lens.

An improved fixation technique for transmission electron microscopic observation that enables good fixation of all areas of the rat lens was devised. Immersion fixation with 0.1 M phosphate-buffered 1.25% glutaraldehyde at 4 degrees C for 12 hours followed by postosmication produced good results for all areas of the lens--anterior, equatorial, and posterior zones. The technique was particularly suitable for maintenance of the shape of the lens since practically no irregularity, vacuolar degeneration, or expansion of the intercellular spaces was noted. This technique, which requires only a relatively short time, was also useful for the detection of early ultrastructural changes associated with cataract in spontaneously diabetic WBN/Kob rats. We anticipate that our procedure will be widely applied.     

Selective expression of L-serine synthetic enzyme 3PGDH in schwann cells, perineuronal glia, and endoneurial fibroblasts along rat sciatic nerves and its upregulation after crush injury

Non-essential amino acid L-serine functions as a highly potent, glia-derived neurotrophic factor, because it is a precursor for syntheses of proteins, other amino acids, membrane lipids, and nucleotides, and also because its biosynthetic enzyme 3-phosphoglycerate dehydrogenase (3PGDH) is preferentially expressed in particular glial cells within the brain. Here we pursued 3PGDH expression in peripheral nerves and its change after crush injury. In the pathway of rat sciatic nerves, 3PGDH was selectively expressed in non-neuronal elements: Schwann sheaths and endoneurial fibroblasts in sciatic nerves, satellite cells in dorsal root ganglia, and astrocytes and oligodendrocytes in the spinal ventral horn. In contrast, 3PGDH was immunonegative in axons, somata of spinal motoneurons and ganglion cells, and endoneurial macrophages. One week after crush injury, 3PGDH was upregulated in the distal segment of injured nerves, where 3PGDH was intensified in activated Schwann cells and fibroblasts. 3PGDH was still negative in activated macrophages, which were instead associated or surrounded by activated Schwann cells with intensified 3PGDH. These results suggest that in the peripheral nervous system, these non-neuronal cells synthesize and may supply L-serine to satisfy metabolic demands for maintenance and regeneration of peripheral nerves and for proliferation and activation of macrophages upon nerve injury.     

Synthesis of polyaminoquinones by vinylogous nucleophilic substitution polymerization of 2,5-disubstituted p-benzoquinones with diamines

Vinylogous nucleophilic substitution polymerization of 2,5-dihydroxy-p-benzoquinone and 2,5-dimethoxy-p-benzoquinone with various diamines in m-cresol afforded polyaminoquinones with inherent viscosities as high as 0,5 dl.g^?1 in quantitative yields. The polyaminoquinones, except for the polymer derived from 1,3-bis(aminomethyl)benzene, were partially soluble or practically insoluble in organic solvents, but were solubilized by alkaline hydrosulfite reduction. Thermal analyses showed an initial weight loss at around 200°C in both air and nitrogen atmospheres, followed by gradual decomposition.     

Measurement of plasma von Willebrand factor cleaving protease in patients with varied thrombotic microangiopathy

Thrombotic thrombocytopenic purpura(TTP) is a multisystem disorders characterized by thrombocytopenia, microangiopathic hemolytic anemia associated with red cell fragmentation, and neurological and renal symptoms. Plasma of patients with TTP has been shown to contain unusually large von Willebrand factor(vWF) multimers that may cause platelet agglutination in vivo. Recently, a metalloprotease responsible for cleavage of vWF multimers has been isolated from normal human plasma and was found to be deficient in some patients with TTP. We examined the activity of the vWF-cleaving protease(vWF-CP), by modified Furlan's method, in plasma from patients with a familial TTP, 3 acquired TTP, 4 thrombotic microangiopathy(TMA) and 2 veno-occlusive disease(VOD) associated after allo-BMT. Diluted plasma samples of patients were incubated with protease-free vWF purified from normal human plasma, in the presence of urea and barium ions. The extent of vWF degradation was assayed by electrophoresis in SDS-agarose gels and immunoblotting. Activity of vWF-CP from 12 normal plasma have been shown as 77-180%(average 115%), whereas, no vWF-CP(below 5%) was observed in plasma from familial TTP, before and after plasma exchange, although FFP infusion therapy has been effective for this patient to recover thrombocytopenia. In 3 acquired TTP, 2 patients showed lack of vWF-CP activity in plasma, and inhibitors against vWF-CP have been elucidated by plasma cross-mixing test. After extensive plasma exchange and FFP infusion followed by corticosteroid therapy, normal vWF-CP was recovered in plasma from 2 acquired TTP patients. Among BMT patients, plasma from 4 BMT-TMA showed normal vWF-CP activities as 55-111%, whereas plasma from 2 BMT-VOD revealed low vWF-CP activity, as 24% and 37%, respectively. Thus, measurement of vWF-CP is crucial to predict differentiation of primary forms of TMA to establish the pathogenesis in varied endothelial dysfunction.     

Treatment with cathepsin L inhibitor potentiates Th2-type immune response in Leishmania major-infected BALB/c mice

Prior to the activation of CD4 (+) T cells, exogenous proteins must be digested by endo/lysosomal enzymes in antigen-presenting cells (APC) to produce antigenic peptides that are able to be presented on class II molecules of the MHC. Studies described here inspect the functional significance of cathepsin L inhibition for antigen processing and T (h) 1/T (h) 2 differentiation in experimental leishmaniasis. We first demonstrated using in vitro systems that cathepsin L is one of the candidate endo/lysosomal enzymes in processing of soluble Leishmania antigen (SLA) and that its specific inhibitor, CLIK148, modulated the processing of SLA. BALB/c mice are known to be susceptible to infection with Leishmania major. Interestingly, treatment of BALB/c mice with CLIK148 exacerbated the infection by enhancing the development of SLA-specific T (h) 2-type response such as production of IL-4 and generation of T (h) 2-dependent specific IgE/IgG1 antibodies. Moreover, addition of CLIK148 in incubation of a SLA-specific CD4 (+) T cell line with APC up-regulated the production of IL-4. However, CLIK148 did not exert any direct influence on the function of T cells themselves. Taken together, these findings suggest that treatment of host mice with CLIK148 affects the processing of SLA in APC, resulting in the potentiation of T (h) 2-type immune responses and thus leading to exacerbation of the infection. Furthermore, endo/lysosomal cathepsin L was found to be functionally distinct from previously described cathepsins B and D.     

CD34+ stromal cells and hyalinized vascular changes in the anal fibroepithelial polyps

AIMS: To elucidate the pathogenesis of the anal fibroepithelial polyp, we examined surgically resected lesions histopathologically. METHODS AND RESULTS: Twenty-seven surgically resected anal fibroepithelial polyps were investigated histologically with an additional immunohistochemical examination using anti-CD34. For a control study, the surgical specimens of the anal canal showing non-polypoid lesions, obtained from haemorrhoidectomy (18 specimens) and rectectomy (five specimens) due to rectal cancer without anal canal involvement, were also analysed. We demonstrated characteristic spindle or stellate cells immunohistochemically positive for CD34 in the anal fibroepithelial polyps (24/27, 89%). The number of CD34+ cells was statistically related to the size of anal fibroepithelial polyps, although CD34+ stromal cells were recognized in the non-polypoid anal submucosa and haemorrhoids. We also found hyalinized vascular changes in the base of six anal fibroepithelial polyps examined. These features were not detected in the non-polypoid anal canal. CONCLUSIONS: An increase in CD34+ stromal cells may play a role in the enlargement of anal fibroepithelial polyps. CD34+ stromal cells are suggested to be distinctive mesenchymal cells with a capability for tissue repair and overgrowth. The vascular impairment could be secondary change associated with localized tissue damage by abnormal traction.     

Immunopathological similarities between IgA nephropathy and Henoch-Schoenlein purpura (HSP) nephritis

A study on the immunopathological similarities between IgA nephropathy and Henoch-Schoenlein purpura (HSP) nephritis is described. Various examinations were performed as follows. (1) Pathological studies: light microscopic findings and immunofluorescent staining; (2) Measurement of the levels of IgA in pharyngeal washings and sera, and those of IgA quantitated by radial immunodiffusion; (3) Elution studies: renal biopsy specimens obtained from patients with IgA nephropathy and HSP nephritis were treated with citrate buffer (pH 3.2) and the "eluate" was neutralized by sodium hydroxide. The "eluate" was then applied to the acid-treated sections obtained from the same and other patients with IgA nephropathy as well as sections from patients with HSP nephritis and other glomerular diseases. The sections were stained with FITC-conjugated heavy chain specific antihuman IgA antisera and then examined with a fluorescent microscope. There were no differences in pathological findings of IgA nephropathy and HSP nephritis in the light microscopic and immunofluorescent examinations. The levels of IgA in pharyngeal washings and sera were significantly increased in patients with both diseases. IgA antibodies deposited in kidneys from patients with HSP nephritis crossreacted with kidneys from some patients with IgA nephropathy, and vice versa. However, antibodies from patients with IgA nephropathy and HSP nephritis did not react with normal glomeruli or other nephritic glomeruli. It is concluded that there are some immunopathological similarities between IgA nephropathy and HSP nephritis.     

Functionality of chimeric Rev proteins of HIV/SIV

Studies on functional compatibility of various Rev proteins derived from all known human and simian immunodeficiency virus subgroups have shown that this essential gene product is not always exchangeable among the viruses. In an attempt to map the region of Rev proteins responsible for the observed nonreciprocal complementation, hybrid genomic Rev expression vectors were constructed by exchanging the first and second exons ofrev genes, and were examined for their abilities to activate reporter clones by transfection. With one exception, the second coding exon ofrev gene determined the functional specificity of Rev proteins.