Ultrastructural changes of bile duct epithelium in primary biliary cirrhosis in relation to progression of bile duct loss

Summary Using wedge liver biopsies from patients with primary biliary cirrhosis (PBC), ultrastructural features of the intrahepatic bile ducts in livers with slight or no bile duct loss were compared with those in livers with advanced bile duct loss and in extrahepatic cholestasis (EHC).Most changes in the biliary epithelium in PBC were similar to those in EHC. Microvillous loss and bleb formation, mitochondrial damage and increase in endoplasmic reticulum and ribosomes were found in PBC irrespective of the degree of bile duct loss, and also in EHC. These changes were present almost equally at any level of the biliary tree, and are presumed to represent a variety of non-specific lesions of biliary epithelial cells. As the loss of bile ducts in PBC progressed, cytoskeletal filaments and cytophagosomes increased in number and basement membranes were more thickened and reduplicated. These changes were more or less conspicuous in smaller branches of the biliary tree, and were also prominent in EHC. They might be causally related to the bile flow disturbance in the liver. Lateral intercellular spaces were irregularly dilated and contained osmiophilic membranous and/or granular material, similar to that found in duct lumena, within and without the basement membrane, and in the cytoplasm of periductal macrophages. Furthermore, pinocytotic vesicles were increased in the biliary cytoplasm facing periphery. These findings suggest possible alteration of the permeability of biliary epithelial cells, probably in the direction from the lumena to the periductal tissue. Such changes were found in PBC livers with virtual absence of bile duct loss, and the significance of this phenomenon is discussed.     

Isolation of vaccine-derived type 1 polioviruses displaying similar properties to virulent wild strain Mahoney from sewage in Japan

Type 1, 2, and 3 vaccine-derived polioviruses were isolated from a sewage disposal plant located downstream of the Oyabe River in Toyama Prefecture, Japan, between October 1993 and September 1995. Neurovirulence was analyzed in 13 type 1 vaccine-derived strains, using mutant analysis by polymerase chain reaction and restriction enzyme cleavage (MAPREC). Nine strains (69%) were estimated to have marked neurovirulence. Some of the neutralizing antigenic sites, temperature sensitivity, and plaque-forming ability of two virulent vaccine-derived poliovirus strains were similar to Mahoney strain. The neutralizing activity of human sera obtained after oral poliomyelitis vaccine (OPV) administration against one of the virulent vaccine-derived polioviruses was examined. Although all human sera showed sufficient neutralizing activity for the prevention of poliomyelitis by vaccine-derived poliovirus strains, a lower titer than that against Sabin type 1 strain was observed. Vaccination against virulent vaccine-derived poliovirus will be effective. However, the environmental presence of viruses that have properties similar to those Mahoney strain is a threat. The introduction of inactivated poliovirus vaccine (IPV), and well-maintained herd immunity, together with reinforced environmental surveillance is important for the final phase of the polio eradication program by the World Health Organization (WHO).     

Increased expression levels of integrin alphavbeta5 on scleroderma fibroblasts

Integrin alphavbeta5 is a receptor for vitronectin, a plasma glycoprotein that is also distributed in extracellular matrix of various tissues. Matrix-bound vitronectin has the potential to stabilize the active form of plasminogen activator inhibitor-1, resulting in the inhibition of the plasmin-mediated pericellular proteolytic cascade. In this study, we compared the levels of alphavbeta5 and matrix-bound vitronectin between normal and scleroderma fibroblasts and investigated the association with fibrosis. We demonstrated that alphavbeta5 was up-regulated on scleroderma fibroblasts. The up-regulated alphavbeta5 contributed to the increase in vitronectin-binding ability in scleroderma fibroblasts, which led to the vitronectin-dependent activation of plasminogen activator inhibitor-1. In immunohistochemistry, the alphav and beta5 subunits were stained strongly on scleroderma fibroblasts and the amount of vitronectin was increased in the pericellular matrix of those cells. The transient overexpression of alphavbeta5 on normal fibroblasts enhanced the human alpha2(I) collagen promoter activity through Sp-1 and Smad3 as well as the vitronectin-dependent plasminogen activator inhibitor-1 activity. This effect on the promoter activity was also observed in the absence of vitronectin and completely disappeared in the presence of anti-alphavbeta5 antibody. These results indicate that the up-regulated alphavbeta5 may contribute to the phenotypical alteration of scleroderma fibroblasts, while at the same time suppressing the plasmin-mediated pericellular proteolytic cascade.     

Dorfin localizes to the ubiquitylated inclusions in Parkinson's disease,dementia with Lewy bodies,multiple system atrophy,and amyotrophic lateral sclerosis

In many neurodegenerative diseases, the cytopathological hallmark is the presence of ubiquitylated inclusions consisting of insoluble protein aggregates. Lewy bodies in Parkinson's disease and dementia with Lewy bodies disease, glial cell inclusions in multiple system atrophy, and hyaline inclusions in amyotrophic lateral sclerosis (ALS) are representative of these inclusions. The elucidation of the components of these inclusions and the mechanisms underlying inclusion formation is important in uncovering the pathogenesis of these disorders. We hypothesized that Dorfin, a perinuclearly located E3 ubiquitin ligase, participates in the formation of ubiquitylated inclusions in a wide range of neurodegenerative diseases. Here, we report that affinity-purified anti-Dorfin antibody labeled ubiquitylated inclusions of Parkinson's disease, dementia with Lewy bodies disease, multiple system atrophy, and sporadic and familial ALS. A double-immunofluorescence study revealed that Dorfin shows a distribution pattern parallel to that of ubiquitin. Furthermore, by a filter trap assay, we detected that Dorfin is present in the ubiquitylated high-molecular weight structures derived from these diseases. These results suggest that Dorfin plays a crucial role in the formation of ubiquitylated inclusions of alpha-synucleinopathy and ALS. However, because we failed to show the direct binding of alpha-synuclein with Dorfin, future investigations into the binding partner(s) of Dorfin will be needed to deepen our understanding of the pathophysiology of alpha-synucleinopathy and ALS.     

Inhibition of vascular endothelial growth factor (VEGF) signaling in cancer causes loss of endothelial fenestrations, regression of tumor vessels, and appearance of basement membrane ghosts

Angiogenesis inhibitors are receiving increased attention as cancer therapeutics, but little is known of the cellular effects of these inhibitors on tumor vessels. We sought to determine whether two agents, AG013736 and VEGF-Trap, that inhibit vascular endothelial growth factor (VEGF) signaling, merely stop angiogenesis or cause regression of existing tumor vessels. Here, we report that treatment with these inhibitors caused robust and early changes in endothelial cells, pericytes, and basement membrane of vessels in spontaneous islet-cell tumors of RIP-Tag2 transgenic mice and in subcutaneously implanted Lewis lung carcinomas. Strikingly, within 24 hours, endothelial fenestrations in RIP-Tag2 tumors disappeared, vascular sprouting was suppressed, and patency and blood flow ceased in some vessels. By 7 days, vascular density decreased more than 70%, and VEGFR-2 and VEGFR-3 expression was reduced in surviving endothelial cells. Vessels in Lewis lung tumors, which lacked endothelial fenestrations, showed less regression. In both tumors, pericytes did not degenerate to the same extent as endothelial cells, and those on surviving tumor vessels acquired a more normal phenotype. Vascular basement membrane persisted after endothelial cells degenerated, providing a ghost-like record of pretreatment vessel number and location and a potential scaffold for vessel regrowth. The potent anti-vascular action observed is evidence that VEGF signaling inhibitors do more than stop angiogenesis. Early loss of endothelial fenestrations in RIP-Tag2 tumors is a clue that vessel phenotype may be predictive of exceptional sensitivity to these inhibitors.     

Wear properties of alumina/zirconia composite ceramics for joint prostheses measured with an end-face apparatus

While only alumina is applied to all-ceramic joint prostheses at present, a stronger ceramic is required to prevent fracture and chipping due to impingement and stress concentration. Zirconia could be a potential substitute for alumina because it has high strength and fracture toughness. However, the wear of zirconia/zirconia combination is too high for clinical use. Although some investigations on composite ceramics revealed that mixing of different ceramics was able to improve the mechanical properties of ceramics, there are few reports about wear properties of composite ceramics for joint prosthesis. Since acetabular cup and femoral head of artificial hip joint are finished precisely, they indicate high geometric conformity. Therefore, wear test under flat contact was carried out with an end-face wear testing apparatus for four kinds of ceramics: alumina monolith, zirconia monolith, alumina-based composite ceramic, and zirconia based composite ceramic. Mean contact pressure was 10 MPa and sliding velocity was 40 mm/s. The wear test continued for 72 hours and total sliding distance was 10 km. After the test, the wear factor was calculated. Worn surfaces were observed with a scanning electron micrograph (SEM). The results of this wear test show that the wear factors of the both composite ceramics are similarly low and their mechanical properties are much better than those of the alumina monolith and the zirconia monolith. According to these results, it is predicted that joint prostheses of the composite ceramics are safer against break down and have longer lifetime compared with alumina/alumina joint prostheses.     

Liver metastasis from rectal cancer with prominent intrabile duct growth

Intrabiliary growth of liver metastases from colorectal cancer has rarely been studied. A surgically resected case of a metastatic liver tumor with prominent intrabiliary growth derived from rectal cancer is reported. The patient was a 62-year-old man who had received a low anterior resection for rectal cancer in March 2000. He was re-admitted due to obstructive jaundice in January 2003, and was diagnosed with hepatic malignancy in segment II of the liver with an intrabiliary tumor extending from the intrahepatic bile duct of segment II to the common hepatic duct. He underwent a left hepatectomy, a partial resection of segment VI, and an extrahepatic bile duct resection with reconstruction of the biliary tract. In the resected specimen, there were whitish tumors of 3 cm and 1.5 cm in diameter in segments II and VI, respectively, and an intrabiliary tumor originating from the main tumor in segment II extended to the common hepatic duct. Both the liver tumors and the intrabiliary tumor consisted of a well- to moderately differentiated adenocarcinoma, which showed the same histological features as the rectal cancer. The immunohistochemical findings strongly supported that these tumors, including the intrabiliary growth, were liver metastasis from the rectal cancer. The intrabiliary invasion and growth of metastatic liver tumors has generally been overlooked, notwithstanding their frequently observed biological behavior. The present case is informative, and further investigation into this type of metastatic liver tumor may be warranted.     

Administration of thyroxine in treated Graves' disease. Effects on the level of antibodies to thyroid-stimulating hormone receptors and on the risk of recurrence of hyperthyroidism

BACKGROUND. Antibodies to thyroid-stimulating hormone (TSH) receptors that stimulate the thyroid gland cause hyperthyroidism in patients with Graves' disease, and their production during antithyroid drug treatment is an important determinant of the course of the disease. One factor that might contribute to the persistent production of antibodies to TSH receptors is stimulation of the release of thyroid antigens by TSH during antithyroid drug therapy. We therefore studied the effect of the suppression of TSH secretion by thyroxine on the levels of antibodies to TSH receptors after thyroid hormone secretion had been normalized by methimazole. METHODS AND RESULTS. The levels of antibodies to TSH receptors were measured during treatment with methimazole, either alone or in combination with thyroxine, in 109 patients with hyperthyroidism due to Graves' disease. The patients first received 30 mg of methimazole daily for six months. All were euthyroid after six months, and their mean (+/- SD) level of antibodies to TSH receptors decreased from 64 +/- 9 percent to 25 +/- 15 percent (P less than 0.01; normal, 2.9 +/- 1.4 percent). Sixty patients then received 100 micrograms of thyroxine and 10 mg of methimazole and 49 received placebo and 10 mg of methimazole daily for one year. In the thyroxine-treated group, the mean serum thyroxine concentration increased from 108 +/- 16 nmol per liter to 145 +/- 11 nmol per liter (P less than 0.01), and the level of antibodies to TSH receptors decreased from 28 +/- 10 percent to 10 +/- 3 percent after one month of combination therapy. In the patients who received placebo and methimazole, the mean serum thyroxine concentration decreased and the level of antibodies to TSH receptors did not change. Methimazole, but not thyroxine or placebo, was discontinued in each group 1 1/2 years after the beginning of treatment. The level of antibodies to TSH receptors further decreased (from 6.6 +/- 3.2 percent at the time methimazole was discontinued to 2.1 +/- 1.2 percent one year later) in the patients who continued to receive thyroxine, but it increased (from 9.1 +/- 4.8 percent to 17.3 +/- 5.8 percent during the same period) in the patients who received placebo. One patient in the thyroxine-treated group (1.7 percent) and 17 patients in the placebo group (34.7 percent) had recurrences of hyperthyroidism within three years after the discontinuation of methimazole. CONCLUSIONS. The administration of thyroxine during antithyroid drug treatment decreases both the production of antibodies to TSH receptors and the frequency of recurrence of hyperthyroidism.     

An Epstein-Barr virus-producer line Akata: Establishment of the cell line and analysis of viral DNA

An Epstein-Barr virus (EBV)-producer line, designated Akata, was established from a Japanese patient with Burkitt's lymphoma. The Akata line possessed the Burkitt's-type chromosome translocation, t(8q-; 14q+), and was derived from the tumor cell. Akata cells produced a large quantity of transforming virus upon treatment of cells with anti-immunoglobulin antibodies (Takada, 1984). Southern blot analysis of viral DNA indicated that the Akata EBV is nondefective and more representative of wild-type viruses. Akata cells should be useful as a source of EBV.