Roles of the AGE-RAGE system in vascular injury in diabetes

This study concerns whether advanced glycation endproducts (AGE) are related to microvascular derangement in diabetes, exemplified by pericyte loss and angiogenesis in retinopathy and by mesangial expansion in nephropathy. AGE caused a decrease in viable pericytes cultivated from bovine retina. On the other hand, AGE stimulated the growth and tube formation of human microvascular endothelial cells (EC), this being mediated by autocrine vascular endothelial growth factor. In AGE-exposed rat mesangial cells, type IV collagen synthesis was induced. Those AGE actions were dependent on a cell surface receptor for AGE (RAGE), because they were abolished by RAGE antisense or ribozyme. The AGE-RAGE system may thus participate in the development of diabetic microangiopathy. This proposition was supported by experiments with animal models; several indices characteristic of retinopathy were correlated with circulating AGE levels in OLETF rats. The predisposition to nephropathy was augmented in RAGE transgenic mice when they became diabetic.

Placenta growth factor and vascular endothelial growth factor B and C expression in microvascular endothelial cells and pericytes. Implication in autocrine and paracrine regulation of angiogenesis

We have shown previously that vascular endothelial growth factor (VEGF) synthesized by the cellular constituents of small vessels per se, viz. endothelial cells and pericytes, participates in the hypoxia-driven proliferation of both cell types (Nomura, M., Yamagishi, S., Harada, S., Hayashi, Y., Yamashima, T., Yamashita, J., Yamamoto, H. (1995) J. Biol. Chem. 270, 28316-28324; Yamagishi, S., Yonekura, H., Yamamoto, Y., Fujimori, H., Sakurai, S., Tanaka, N., and Yamamoto, H. (1999) Lab. Invest. 79, 501-509). In this study, we examined the expression of the recently isolated VEGF gene family members (placenta growth factor (PlGF), VEGF-B, and VEGF-C) in human dermal microvascular endothelial cells and bovine retinal pericytes cultured under various oxygen tensions. Quantitative reverse transcription-polymerase chain reaction analyses demonstrated that the two cell types possess not only VEGF (VEGF-A) mRNA, but also VEGF-B, VEGF-C, and PlGF mRNAs. Among them, only VEGF-A mRNA was induced under hypoxia. Competitive reverse transcription-polymerase chain reaction showed that, under normoxic conditions, the rank order of mRNA content in endothelial cells was PlGF > VEGF-B > VEGF-C > VEGF-A and that mRNA coding for PlGF was expressed at >100-fold higher levels than VEGF-A mRNA. In pericytes, the rank order was VEGF-C > VEGF-A > VEGF-B > PlGF, and approximately 7-fold higher levels of VEGF-C mRNA compared with VEGF-A mRNA were noted in this cell type. Furthermore, antisense inhibition of PlGF protein production lowered the endothelial cell synthesis of DNA under hypoxic conditions. The results suggest that these VEGF family members may also take active parts in angiogenesis.

Antisense display--a method for functional gene screening: evaluation in a cell-free system and isolation of angiogenesis-related genes

Presented here is an antisense-oriented method for functional gene screening, which we propose naming 'antisense display'. In principle, it consists of four steps: (i) preparation of phosphorothioate antisense repertoires that would correspond to the Kozak's consensus sequence, (ii) subgroup screening to identify active antisense molecules that could cause changes in the cellular phenotypes concerned and (iii) RT-PCR cloning of cDNA with the 5[prime] sense complement and 3[prime] anchor primers and sequence determination, followed by (iv) functional assays of candidate genes. Cell-free translation in rabbit reticulocyte lysate revealed that 10mer or longer antisense effectively halted protein synthesis. This required the presence of RNase H, and was achieved without prior heat-denaturation of the RNA templates. Then, subpools of the 10mer repertoire were administered to human microvascular endothelial cells in culture, and screened for anti-angiogenic activities. A single species having the sequence 5[prime]-GGCTCATGGT-3[prime] consistently inhibited the endothelial cell growth under hypoxia. Through RT-PCR with the corresponding sense primer, we came across three candidate cDNAs. Experiments employing longer unique antisense reproduced marked growth inhibitions in two of the three cDNAs. One encoded a mitochondrial protein and the other, which encoded a putative type-2 membrane protein containing Rab-GAP/TBC and EF-hand like domains, was a gene previously undescribed in human. The results suggest that the antisense display method is potentially useful for isolating new genes towards elucidating their functions.

A retrospective study of 66 esophageal reconstructions using microvascular anastomoses: problems and our methods for atypical cases

We have studied 66 patients who underwent esophageal reconstruction using microvascular anastomoses. This series comprises 28 patients with reconstruction using a free jejunal interposition between the pharynx and the cervical esophagus following pharyngolaryngoesophagectomy for hypopharyngeal carcinoma and 38 atypical patients in whom other methods of reconstruction were used. Successful transfer was achieved in 98.5 percent (65 of 66). Issues concerning atypical reconstruction and our procedures in these cases are discussed. In order to obtain adequate tension in the jejunum on the anal side, in particular, since the anastomosis is located in a deep or narrow space, autosuture instruments were used. The anastomotic leakage rate was 2.8 percent (1 of 36); the stenosis rate was 2.8 percent (1 of 36). To prevent necrosis in the trachea, a greater omentum flap was used in three patients, a mesenterium flap in two, and a pectoralis major musculocutaneous flap in one. There were no significant complications. In patients with a short gastric pedicle or in those in whom a double cancer occurred in the hypopharynx and thoracic esophagus, a gastric pedicle and a free jejunum flap were used together. As a result of this method, the incidence of any reflux of digestive juice was reduced to 0 percent (0 of 6). To reduce the possibility of an ischemic complication at the oral end of the colonic pedicle, we added a microvascular anastomosis of the colonic pedicle, thereby reducing both leakage [0 percent (0 of 9)] and necrosis [0 percent (0 of 9)]. These procedures involving microvascular anastomoses have reduced the incidence of complications in esophageal reconstructions.

An antigenic determinant on human centromere protein B (CENP-B) available for production of human-specific anticentromere antibodies in mouse

Centromere protein B (CENP-B) is one of the centromere DNA binding proteins constituting centromere heterochromatin throughout the cell cycles. Some components of mammalian centromeres including CENP-B are target antigens for autoimmune disease patients, often those with scleroderma. Recent isolations of CENP-B genes from human and mouse suggested that CENP-B was highly conserved among mammals. From the previous analysis of the reactivity of patient anticentromere sera, two autoepitopes have been located on the DNA binding domain at the amino-terminal region. The amino acid sequences for both the epitopes are perfectly conserved in the two species, human and mouse. In this study, to identify a human-specific antigenic determinant, the remaining two epitopes were further located in separate carboxyl-terminal regions of human CENP-B. Although the amino acid sequence of one epitope is identical to that of the corresponding region in mouse CENP-B, the other has a less homologous sequence. To confirm that the latter epitope was available for production of human-specific anticentromere antibodies, mice were immunized with the recombinant human CENP-B product. One serum that exclusively stained human centromere structure, but not that of other mammals, was identified in the immunofluorescence microscopic observation. The epitope analysis showed that the less conserved one was recognized by this serum. These results suggested that the corresponding region defines the antigenic determinants for the species specificity.

Induction of tumors in the Zymbal gland, oral cavity, colon, skin and mammary gland of F344 rats by a mutagenic compound, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline

A mutagenic compound, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, which was first isolated from broiled sardines and was shown to be carcinogenic to mice, was also found to be carcinogenic to F344 rats. It induced tumors in various organs, such as the Zymbal gland, oral cavity, colon, skin and mammary gland of male and female rats when given at 0.03% in the diet. However, it was noteworthy that tumors were not observed in the liver. Most of the tumors in the Zymbal gland, oral cavity and skin were squamous cell carcinomas, and most of the mammary gland tumors were adenocarcinomas. The colon tumors were identified as adenomas or adenocarcinomas. In control rats no tumors developed in these organs during the 40-week experiment.

Oral bony lesion in a patient with medical history of hyperparathyroidism

Primary hyperparathyroidism is an uncommon disease in which the amount of parathyroid hormone circulating in the bloodstream is increased. Therefore, bony changes are often found in the prolonged or severe cases of hyperparathyroidism. This study describes and discusses the relationship between cystical radiolucent lesion in the left mandible of 29-year-old Japanese male and hyperparathyroidism which has the feature of bony changes.

Ameloblastoma with gingival ulcer

Ameloblastoma usually presents as a painless swelling of the jaw, but the chief complaint is rarely of ulceration. A case of ameloblastoma with a complaint of gingival ulcer in a 75-year-old Japanese male who was treated by an en bloc removal of the tumor with gingival ulcer is described and discussed. There is no evidence of recurrence, and the postoperative course was uneventful.