Significant association between nonsyndromic oral clefts and arylhydrocarbon receptor nuclear translocator (ARNT)

The etiology of nonsyndromic oral clefts (cleft lip, cleft palate, or cleft lip and palate) is still controversial, but is considered to involve both genetic and environmental factors. One of suspected environmental factors is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) found in tobacco, herbicides, contaminated soil, and food. TCDD administered during organogenesis in mice causes a high incidence of CP in fetuses. There is ample evidence that aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), and cytochrome P450 1A1 (CYP1A1) are involved in TCDD metabolism. We assessed whether there is any association in the Japanese population of nonsyndromic oral clefts with single nucleotide polymorphisms (SNPs) in the AHR, ARNT, and CYP1A1 genes using transmission disequilibrium test (TDT) and case-control study. We identified and investigated three SNPs in ARNT; 567G/C (V189V), IVS12-19T/G, and 2117C/T (P706L). Two amino acid substitutions, R554L in AHR and I462V in CYP1A1, were also investigated. In the TDT, the C allele of ARNT 567G/C was preferentially transmitted to patients (P = 0.033). When a haplotype consisting of 567G/C and IVS12-19T/G in ARNT was considered, the preferential transmission of the CT (567C-IVS12-19T) haplotype was observed (P = 0.0012). In a case-control study, a significant association of IVS12-19T/G in ARNT was observed (P = 0.021). The SNPs studied in AHR and CYP1A1 were not associated with the disease. Our results suggest that ARNT is involved in the development of nonsyndromic oral clefts in the Japanese population.     

Structural basis for distinct roles of Lys63- and Lys48-linked polyubiquitin chains

Ubiquitination, a modification in which single or multiple ubiquitin molecules are attached to a protein, serves as a signalling function that controls a wide variety of cellular processes. To date, two major forms of polyubiquitin chain have been functionally characterized, in which the isopeptide bond linkages involve Lys48 or Lys63. Lys48-linked polyubiquitin tagging is mostly used to target proteins for degradation by the proteasome, whereas Lys63-linked polyubiquitination has been linked to numerous cellular events that do not rely on degradative signalling via the proteasome. Apparently linkage-specific conformations of polyubiquitin chains are important for these cellular functions, but the structural bases distinguishing Lys48- and Lys63-linked chains remain elusive. Here, we report NMR and small-angle X-ray scattering (SAXS) studies on the intersubunit interfaces and conformations of Lys63- and Lys48-linked di- and tetraubiquitin chains. Our results indicate that, in marked contrast to Lys48-linked chains, Lys63-linked chains are elongated molecules with no stable non-covalent intersubunit interfaces and thus adopt a radically different conformation from that of Lys48-linked chains.     

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.     

In vivo study of the effects of cryopreservation on heart valve xenotransplantation.

BACKGROUND: Recent reports have suggested that cryopreservation reduces the immunogenicity of donor tissue. The immunomodulation by cryopreservation might influence on the tissue durability after xenotransplantation. We investigated the in vivo morphologic changes in cryopreserved xenograft (CXG) heart valves. MATERIAL AND METHOD: We transplanted a fresh (fresh xenograft; FXG) and a cryopreserved (CXG) porcine aortic root and a cryopreserved canine (cryopreserved allograft; CAG) aortic root into the abdominal aorta of a dog without any immunosuppressive agents. Explanted grafts on the 21st to 49th days after implantation were analyzed morphologically with light microscopy using some special stains, immunohistochemical analysis, and scanning electron microscopy (SEM). RESULT: Light microscopy showed the absence of smooth muscle cells in the media of the aorta in any group after transplantation. FXG valves did not maintain any cellularity after transplantation. CXG valves contained cellular infiltration in themselves. CAG valves contained numerous fibroblasts, which showed the maintenance of tissue integrity without allowing cellular infiltration. The structure of elastic fibers was well maintained, even in the part of CXG valve with cellular infiltration. Immunohistochemical studies documented the infiltration of T lymphocytes in CXG valves that were labeled by anti-CD3 antibodies. SEM demonstrated that no endothelia were seen on the surface of the valves in any group after transplantation. CONCLUSION: We concluded that the cryopreservation method might provide an immunomodulation of xenogeneic heart valves for transplantation.     

Oral disodium cromoglycate and ketotifen for a patient with eosinophilic gastroenteritis, food allergy and protein-losing enteropathy

We present a case report of a 10 years old boy with protein-losing enteropathy and eosinophilic gastroenteritis who had positive histamine release tests, increased allergen-specific IgE antibodies to some food items, and low levels of total serum protein and albumin. Upper gastrointestinal endoscopy revealed a number of polyps and diffuse gastritis. Biopsy specimens of the stomach and duodenum showed widespread eosinophilia and neutrophilia. Although a restricted diet was recommended, a diet which excluded foods with positive results to both histamine release test and allergen-specific IgE antibodies was poorly tolerated, and the patient rejected systemic administration of corticosteroids. Thus, we initiated an oral disodium cromoglycate (DSCG) and ketotifen therapy. After oral DSCG and ketotifen administration, the patient's condition improved gradually. Therefore, oral DSCG and ketotifen therapy might be considered as treatment option in patients with eosinophilic gastroenteritis and protein-losing enteropathy caused by food allergy.     

Morphological changes in mouse sublingual gland parenchyma subjected to chorda tympani resection

Morphological changes in the mouse sublingual gland parenchyma subjected to parasympathetic nerve block were investigated. Mice were subjected to unilateral resection of the chorda tympani, near its point of joining with the lingual nerve. After 1, 2, 3, 5, 10 or 20 weeks, the mice were killed and their sublingual glands were removed and processed for light and electron microscopy. Two weeks after resection, the space between the adjoining lobules of the glands on the treated side began to be expanded, and by 10 weeks were 10 times the size of the spaces in the glands of the untreated mice. Three weeks after resection, the lobule area decreased to about 72% of the area of glands in the untreated mice and the acinus area to about 52%. However, no significant difference was seen between the numbers of acini in each group. Electron microscopy showed that the glands on the treated side contained fewer secretory granules than the glands in the untreated mice, though there was no difference in size. Neither the lobules of the glands on the treated side nor those of the glands of the untreated mice contained many TUNEL-positive cells. These findings suggest that following parasympathetic nerve resection, mouse sublingual gland acinar cells undergo atrophy with a reduction size rather than cell death.     

Follicular hyperplasia presenting with a marginal zone pattern in a reactive lymph node lesion

Histologically, the marginal zone pattern of the lymph node is characterized by lymphoid follicles with three distinct layers. The inner layer is composed of follicular center zones, the middle layer of darkly stained mantle zones, and the outer layer of marginal zones. However, the marginal zone pattern is rarely seen in reactive lymph nodes except for mesenteric lymph nodes. We describe the clinicopathologic, immunohistochemical and genotypic findings of six cases of reactive follicular hyperplasia exhibiting the marginal zone pattern. The patients comprised three males and three females (age range 24 to 63 years; medium 56 years). Follow-up data were obtained from five patients. None of them developed malignant lymphomas during the follow-up period of from 5 to 204 months (median 68 months). Histologically, the lesion was characterized by numerous lymphoid follicles and partial distortion of lymph node structure. Varying degrees of progressive transformation of the germinal center (PTGC) were noted in the four cases. The marginal zone pattern was observed in some or most of the lymphoid follicles including PTGC. The marginal zone B cells were small to medium-sized lymphocytes with round or slightly indented nuclei and a broad rim of pale cytoplasm. Some of them had a monocytoid appearance. They were CD20+, CD79a+, sIgM+/-, sIgD-, CD5-, CD10-, CD21-, CD23-, CD43-, CD45RO-, Bcl-6-, cyclin D1-, EMA- and p53-. A portion of them were Bcl-2 positive. Occasional large lymphoid cells with round or indented nuclei and moderate amounts of cytoplasm were observed in the marginal zone in four cases. These large lymphoid cells were usually CD20 positive, but Bcl-6 negative. A small number of them contained polytypic intracytoplasmic immunoglobulins. The polytypic nature of B lymphocytes was demonstrated by immunohistochemistry and polymerase chain reaction. Recognition of unusual marginal zone hyperplasia in reactive lymph node lesions is important to avoid confusion with nodal involvement in various low-grade B cell lymphomas presenting a marginal zone distribution pattern.     

Surface photografting, 2. Modification of polypropylene film surface by graft polymerization of acrylamide

The hydrophobic surface of oriented poly(propylene) film (OPP) was modified to a hydrophilic one by a novel photo-grafting procedure using acrylamide (AM) as monomer. A deoxygenated acetone solution containing AM and benzophenone (BP) or other sensitizers was brought into contact with OPP film and the reaction system was photoirradiated from the other side of the polymer film. Within a few minutes, surface photo-grafting resulted. The influences of solvent, sensitizer, and additives revealed that the graft polymerization was initiated by hydrogen abstraction from the polymer surface by the triplet excited state of the sensitizer. IR Spectroscopy as well as ESCA measurements confirmed that the graft polymerization occurred on the film surface. The wettability of the grafted OPP film is discussed and correlated with the relative amount of surface grafting. The contact angle of untreated OPP film to water (101°) decreased to ≈40° after surface photografting. The drastic change of surface properties makes the practical application of the present technique feasible.     

Immunohistochemical study on tissue transglutaminase and copper-zinc superoxide dismutase in human myocardium: Its relevance to apoptosis detected by the nick end labelling method

The influence of free radicals on apoptosis was studied in the human heart; 45 autopsy cases were examined by the nick end labelling method (NELM) that detects DNA fragmentation. Immunostaining for copper-zinc superoxide dismutase (CuZn-SOD) and tissue transglutaminase (tTG) induced frequently during apoptosis were also studied. Positive immunoreaction for tTG was detected in mucinous degeneration of myocardial cells; these same cells were also positive for CuZn-SOD but negative for NELM. Myocardial cells showing basophilic alterations after haematoxylin and eosin staining were also positive for CuZn-SOD but negative for the other markers examined. Positive nuclear reaction by NELM was only observed in myocardial cells showing contraction band necrosis or irregularly shaped nuclei surrounding recent or long-standing infarcted foci. In these the other two markers were negative. Since mucinous degeneration lacks the distinguishing morphological features of apoptosis, immunoreactive tTG in this lesion may not imply that the cells are undergoing apoptosis. tTG can be induced in non-apoptotic conditions and may not be involved in apoptosis induced by infarction. Histological disassociation between CuZn-SOD expression and apoptosis suggests the possibility of a cytoprotective role played by endogenous CuZn-SOD against free radical generation in the human heart.