We used flow cytometry to assess the cell cycle kinetics of cultured Maden Darby canine kidney cells after exposure to paraquat. Fluorescein diacetate fluorescence was used as a marker of cell viability, while bromodeoxyuridine incorporation was detected with a monoclonal antibody and propidium iodide staining to assess DNA synthesis. Flow cytometry was performed immediately, 48 h and 96 h after exposure to paraquat for 24 h. Lactate dehydrogenase release was also measured to determine the extent of cytolysis. Flow cytometry of paraquat-treated cells showed a marked increase of the S phase population immediately after exposure, at a time when there was no increase of lactate dehydrogenase release. In contrast, the cell cycle profile returned towards normal at 48 and 96 h after paraquat exposure, but lactate dehydrogenase release increased. These findings indicate that paraquat arrested cells in the S phase and that inhibition of DNA synthesis by this agent appeared to influence cell viability because S phase block occurred before cytolysis. In addition, this method proved useful for assessing the effects of paraquat on DNA synthesis by cultured cells.

Animals↗

PubMedDate not supplied

An approach to the mechanism of the asymmetrical radical formation in yttrium-90-beta-irradiated D- and L-alanines.

Several attempts were made to investigate the mechanism of the asymmetrical radical formation in yttrium-90-beta-irradiated D- and L-alanines which was reported in the preceding paper (1). The experiments demonstrated that the magnitude of the asymmetry was dependent on beta-ray dose, namely the lower the dose the larger the observed difference was, and that no difference could be detected when the alanines were irradiated in aqueous state. The results in the present study seem to that different interaction between the crystal structure of the two enantiomers and polarized beta-rays may be responsible for the observed phenomenon.

Alanine↗

PubMedDate not supplied

Endoscopic ultrasonography in the assessment of colonic wall invasion by adjacent diseases.

For assessing the direct invasion of the colonic wall by pelvic or abdominal tumors, endoscopic ultrasonography was performed prospectively in patients who were suspected of having colonic wall invasion by barium enema. Three patients with ovarian cancer, two with endometriosis, and one with pancreatic cancer were included in this study. Preoperative endoscopic ultrasonography (EUS) revealed the relationship between the tumor and the colon in all cases. A surgical procedure was performed in all patients: resection of the tumor and a portion of the invaded colon (4) and removal of the tumor (only adhesion) (2). A correct preoperative diagnosis of the depth of tumor invasion was obtained in five of the six (83%) cases. In patients with pelvic or abdominal tumors, preoperative EUS may be useful for evaluating the presence and the degree of invasion of the colonic wall by the tumor.

Abdominal Neoplasms↗

PubMedDate not supplied

Intracranial dural cyst.

Intracranial dural cyst is a very rare congenital malformation. The presence of such a cyst was confirmed by means of computed tomography and magnetic resonance findings in a child with an enlargement of the head and developmental retardation and confirmed histologically in surgically obtained specimens of cyst wall.

Arachnoid Cysts↗

PubMedDate not supplied

Preventing human CD8+ cytotoxic T lymphocyte-mediated cytotoxicity against swine endothelial cells by overexpression of human decoy Fas antigen.

Although the birth of homozygous alpha1, 3 galactosyltransferase gene-knockout pigs raised hopes for an imminent breakthrough in the prevention in the antibody-mediated rejection of pig to human discordant xenotransplants, human CD8(+) cytotoxic T lymphocyte (CTL)-mediated killing may represent a new immunological barrier to long-term survival in xenograft recipients. In this study, we demonstrated that the cytotoxicity of human CD8(+) CTL against swine endothelial cells (SEC) is highly detrimental and mediated at least in part by the Fas/FasL pathway. To prevent this CTL-mediated xenocytotoxicity, we overexpressed the human decoy Fas antigen, which does not contain a death domain in its cytoplasmic region, by means of binding competition with endogenous pig Fas antigen on SEC for the common ligand, human FasL. Furthermore, we generated a membrane-bound form of human FasL that cannot be cleaved by a putative metalloproteinase to produce a soluble form, which was assessed as an inhibitor of CTL cytotoxicity. Both human decoy Fas and membrane-bound FasL were effective to prevent CTL-mediated killing, suggesting that these novel molecules may represent a step forward toward preventing CD8(+) CTL-mediated xenograft rejection. The combined expression of both molecules may be more beneficial to protect xenograft cells.

Animals↗

PubMedDate not supplied

Beneficial effects of pancreas transplantation: regeneration of pancreatic islets in the spontaneously diabetic Torii rat.

AIMS: Type 2 diabetes is characterized by a combination of insulin resistance and pancreatic beta-cell dysfunction. Although pancreas transplantation (PTx) is mainly performed in patients with type 1 disease, both clinical and experimental data have demonstrated that PTx improves insulin sensitivity in type 2 diabetic recipients. However, it remains unclear whether PTx has the potential to induce islet neogenesis in a recipient's native pancreas. METHODS: Nondiabetic 10-week-old and diabetic (defined as blood glucose level >250 mg/dL) 25-week-old (average onset age of diabetes) male spontaneously diabetic Torii (SDT; RT1(a)) rats served as donors and recipients, respectively. RESULTS: In nontreated control SDT rats, beta-cell mass gradually decreased and blood glucose levels progressively increased (>600 mg/dL after 40 weeks of age). In PTx rats, however, the onset of diabetes was significantly delayed (>47.5 +/- 18.2 [graft age] versus 25.2 +/- 3.9 weeks in control rats). On immunohistochemical staining, insulin-secreting islets were observed in the naive pancreata of 40-week-old recipients with PTx (PTx40w), whereas no islets were found in 40-week-old control SDT rats. Moreover, the islets in the native pancreata of PTx40w recipients were located close to ductal structures, and PDX-1 (pancreatic duodenal homeobox-1)-positive cells were more clearly visible. These results indicate the possibility of beta-cell regeneration in the recipient native pancreas by avoiding glucose toxicity under normoglycemic condition achieved by PTx. CONCLUSIONS: Pancreas transplantation has beneficial effects on impaired islet, inducing regeneration in the spontaneously diabetic Torii rat.

Aging↗

PubMedDate not supplied

Early primary carcinoma of the duodenal bulb arising from Brunner's glands.

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Adenocarcinoma, Papillary↗