Role of CD4 molecule in intrathymic T-cell development.

We have investigated the role of CD4 molecules in intrathymic T-cell repertoire selection. The administration of monoclonal antibody (mAb) to CD4 in organ culture of murine foetal thymus (FTOC) completely inhibited the development of CD4+8- cells, and additional treatment with anti-class II MHC (Ia) mAb caused no further effects on this inhibition. On the other hand, when the potentially autoreactive cells in Mls-1a mice were monitored by expression of the Mls-1a-reactive V beta 6 gene product of T-cell receptor alpha beta (TcR alpha beta), the treatment with anti-CD4 resulted in the appearance of V beta 6-bearing cells to some extent, but this effect was considerably reinforced by the combinatory use of anti-Ia mAb with anti-CD4. In a model system where the bacterial superantigen staphylococcal enterotoxin B serves as self-antigen to deplete V beta 8-bearing cells in FTOC, the depletion of V beta 8+ cells was restored partially by anti-CD4 alone but completely by the combination with anti-Ia. These results suggest that CD4 is indispensable for positive selection of all CD4+8- thymocytes, whereas participation of CD4 in negative selection is only partial. It was also observed that the development of TcR alpha beta-bearing cells in the CD4-8- population was inhibited by the treatment with anti-CD4 mAb. In Mls-1a mice, V beta 6-bearing cells were developed in CD4-8+, CD4+8+, and also in CD4-8- populations after anti-CD4 mAb treatment. It is suggested that TcR alpha beta-bearing CD4-8- cells are possibly originated from CD4+ cells and undergo CD4-mediated thymic selection.     

Tumorous deformity of mitral valve leaflet after chordal rupture in a child

A case with tumorous deformity of the posterior mitral valve leaflet after spontaneous chordal rupture in a child is described. A partial rupture in the chordae tendineae of the posterior mitral leaflet was found by echocardiography in a 9-year-old Japanese boy. Tumorous bulging was gradually developed in the leaflet and was surgically excised 5 years later. Multiple nodular tumors were found on the atrial surface of the posterior mitral leaflet. Histological examination revealed that the tumorous bulging consisted of myxomatous materials in which collagen fibrils and very fine elastic fibers were distributed loosely and irregularly. Normal-looking endothelial cells covered the luminal surface of the bulging lesion. Vimentin-positive spindle-shaped mesenchymal cells were scattered in the bulge area. The labeling index of proliferating cell nuclear antigen (PCNA) in these cells was 29.3%. These spindle cells were positive for matrix metalloproteinase (MMP)-1 in the entire bulge area. The cells and matrix were positive for MMP-2 and tissue inhibitor of MMP (TIMP)-1 in the basal area of bulging, but were weakly positive or negative at the surface area. Reactivity for TIMP-2 in the cells in the bulge area was obviously weaker than that in the cells at the spongiosa of the anterior mitral leaflet, which was obtained from the patient at the valve replacement operation 9 months after the initial operation. These findings indicated that the tumorous deformity of the mitral valve was formed by the overgrowth of valve tissue under the stimulation of mitral regurgitation in this child, and the imbalance of MMP and TIMP might play an important role in the bulge formation.     

JC virus genotyping using formalin-fixed, paraffin-embedded renal tissues

Recently genotyping of JC virus (JCV) DNA in renal tissue was reported to be useful to identify the geographic origin of unidentified cadavers. In the above study, autopsied tissue samples without storage or stored in a frozen state were used. This study examined JCV DNA sequence modifications caused by formalin-fixation, in an attempt to elucidate whether formalin-fixed, paraffin-embedded tissue samples can also be used to determine the genotypes of JCV DNA in the kidney. In four cases, a 610 bp typing region of the JCV genome was PCR-amplified from renal tissues stored for 1 year in three different states: frozen at -80 degrees C [Amaker, B.H., Chandler, F.W., Huey, L.O., Colwell, R.M., 1997. Molecular detection of JC virus in embalmed, formalin-fixed, paraffin-embedded brain tissue. J. Forensic Sci., 1157-1159], formalin-fixed, paraffin-embedded [Ault, G.S., Stoner, G.L., 1992. Two major types of JC virus defined in progressive multifocal leukoencephalopathy brain by early and late coding region DNA sequences. J. Gen. Virol. 73, 2669-2678], and soaked in 5% formalin [Baksh, F.K., Finkelstein, S.D., Swalskey, P.A., Stoner, G.L., Ryschkewitsch, C.F., Randhawa, P.R., 2001. Molecular genotyping of BK and JC virus in human polyomavirus-associated interstitial nephritis after renal transplantation. Am. J. Kidney Dis. 38 (2), 354-365]. The amplified fragments were cloned, and the resultant clones were sequenced. In frozen samples, single sequences ('original' sequences) were detected in all cases. In formalin-fixed, paraffin-embedded samples, not only the original sequences but also those with 1-6 base substitutions were detected. From formalin-soaked samples, the original sequences and those with 1-5 and 10-13 substitutions were detected. The genotyping of JCV DNA was not hampered by the presence of 1-6 substitutions, but a shift in JCV genotypes was observed in sequences with 10-13 substitutions. Thus, it was concluded that the genotypes of JCV DNA in the kidney can be determined only with specimens stored in a frozen state or formalin-fixed for a short time.     

Relation between benign prostatic hyperplasia and obesity and estrogen

PURPOSE: There have been few reports on correlations between resection volume of benign prostatic hyperplasia, body mass index (BMI) and estrogen. This study was undertaken to evaluate the correlations. METHOD: In this study, we considered 50 patients who had benign prostatic hyperplasia (BPH) and underwent suprapubic prostatectomy (SPP). Men with prostate cancer or prior prostate surgery were excluded. The relationship between prostate resection volume and BMI was examined. Additionally, patients were divided into two groups according to BMI: less than 25, and more than 25. The two groups were evaluated according to stained estrogen receptors. RESULTS: BMI was correlated positively with prostate volume (p < 0.01). However, positive rates of estrogen receptors showed no significant difference between the two groups. CONCLUSIONS: This was a study describing the relationship between BMI and prostate volume. Obesity has been hypothesized to be associated with BPH because of the endocrine changes in men that occur with age, including increased estrogen and decreased testosterone. Our findings suggest that estrogen may play a pathophysiologic role in benign prostatic hyperplasia. Further studies of large populations are needed to validate this assumption.     

Tolerance to self gangliosides is the major factor restricting the antibody response to lipopolysaccharide core oligosaccharides in Campylobacter jejuni strains associated with Guillain-Barré syndrome

Guillain-Barré syndrome following Campylobacter jejuni infection is frequently associated with anti-ganglioside autoantibodies mediated by molecular mimicry with ganglioside-like oligosaccharides on bacterial lipopolysaccharide (LPS). The regulation of antibody responses to these T-cell-independent antigens is poorly understood, and only a minority of Campylobacter-infected individuals develop anti-ganglioside antibodies. This study investigates the response to gangliosides and LPS in strains of mice by using a range of immunization strategies. In normal mice following intraperitoneal immunization, antibody responses to gangliosides and LPS are low level but can be enhanced by the antigen format or coadministration of protein to recruit T-cell help. Class switching from the predominant immunoglobulin M (IgM) response to IgG3 occurs at low levels, suggesting B1-cell involvement. Systemic immunization results in poor responses. In GalNAc transferase knockout mice that lack all complex gangliosides and instead express high levels of GM3 and GD3, generation of anti-ganglioside antibodies upon immunization with either complex gangliosides or ganglioside-mimicking LPS is greatly enhanced and exhibits class switching to T-cell-dependent IgG isotypes and immunological memory, indicating that tolerance to self gangliosides is a major regulatory factor. Responses to GD3 are suppressed in knockout mice compared with wild-type mice, in which responses to GD3 are induced specifically by GD3 and as a result of polyclonal B-cell activation by LPS. The anti-ganglioside response generated in response to LPS is also dependent on the epitope density of the ganglioside mimicked and can be further manipulated by providing secondary signals via lipid A and CD40 ligation.     

Immunohistochemical localization of transforming growth factor alpha in chemically induced rat hepatocellular carcinomas with reference to differentiation and proliferation

Hepatocellular carcinomas (HCCs) were induced in male Fischer 344 rats with dietary 3'-methyl-4-(dimethylamino)-azobenzene treatment and were classified into solid, glandular (well- or poorly differentiated), and trabecular types. Investigation of cell proliferation kinetics and immunohistochemical localization of transforming growth factor alpha (TGF-alpha) demonstrated all solid (n = 24) and poorly differentiated glandular type (n = 6) HCCs to have TGF-alpha-positive nuclei. Nuclear staining of TGF-alpha was also observed in 13 of 28 (46%) trabecular-type HCCs, whereas 12 (43%) exhibited cytoplasmic staining, and 3 (11%) were negative. As for well-differentiated glandular HCCs, 7 of 20 (35%) were positively stained in their nucleus, another 7 (35%) demonstrated antibody binding in the cytoplasm, and 6 (30%) were negative. The order for growth rate evaluated by bromodeoxyuridine (BrdU) labeling was solid (38.22%), poorly differentiated glandular (26.82%), trabecular (7.98%), and well-differentiated glandular (2.57%) types. For trabecular HCCs with nuclear, cytoplasmic, or negative TGF reactions, values were 13.39% (n = 13), 3.61% (n = 12), and 2.01% (n = 3), respectively. Likewise, BrdU-labeling indices for the counterpart groups of well-differentiated glandular type HCCs were 4.53, 1.91, and 1.29%, respectively. The results indicate that TGF-alpha expression might be linked to histopathological differentiation and cell proliferation in rat HCCs.     

Roles of tyrosine kinase in insulin action on cell volume of fetal rat type II pneumocyte

The aim of the present study was to investigate the roles of tyrosine kinase (TK) in the insulin action on cell volume in fetal rat (20-day gestational age) type II pneumocyte. Insulin (100 nmol/l) increased cell volume, and this insulin (100 nmol/l) action was completely blocked by 50 μmol/l bumetanide (BMT) and 10 μmol/l amiloride (AML). This observation indicates that 100 nmol/l insulin activates BMT-sensitive Na⁺/K⁺/2Cl^? cotransporter and AML-sensitive pathways. The stimulatory action of 100 nmol/l insulin on BMT-sensitive Na⁺/K⁺/2Cl^? cotransporter was completely abolished by 10 μmol/l lavendustin A (LAV-A, an inhibitor of TK), however 100 nmol/l insulin could stimulate AML-sensitive pathways even in LAV-A (10 μmol/l)-treated cells. These observations indicate that the insulin (100 nmol/l) action on the BMT-sensitive Na⁺/K⁺/2Cl^? cotransporter is mediated through TK-dependent pathways, while 100 nmol/l insulin requires a TK-independent pathway to show the stimulatory action on the AML-sensitive pathways. From these observations we conclude that TK-dependent and -independent pathways are involved in the insulin (100 nmol/l) signaling in fetal rat type II pneumocyte.     

Two dinucleotide repeat polymorphisms at the D8S1442 and D8S1443 loci

Two polymorphic dinucleotide (CA) repeat clones were isolated from cosmids, cCI8-1121 and cCI8-1199, mapped to chromosome 8p11.2-p12.