Masaki Nakamura

Dienogest, a synthetic steroid, suppresses both embryonic and tumor-cell-induced angiogenesis

Orally administered dienogest (17alpha-cyanomethyl-17beta-hydroxy-estra-4,9-diene-3-one) is efficacious against human hormone-dependent cancer xenografts in severely immunodeficient mice and in rats with experimental endometriosis, but its mechanisms of action remain unclear. We assessed the effect of dienogest on angiogenesis, because these two diseases that are sensitive to dienogest are known to be angiogenesis-dependent. Topical dienogest treatment dose-dependently inhibited embryonic angiogenesis, the ID(50) value being 6.4 nmol/egg. Oral administration of dienogest (1 mg kg(-1) day(-1)) for 5 consecutive days significantly suppressed angiogenesis induced by S-180 mouse tumor cells in the mouse dorsal air sac assay. In vitro experiments showed that dienogest at concentrations up to 10 microM had little or no effect on the proliferation of plasminogen activator activity or formation of tube-like structures by microvascular endothelial cells. These results suggest that dienogest is a new, orally active antagonist of angiogenesis, and that its anti-angiogenic action may be involved in its therapeutic effects on cancer xenografts and endometriosis that we observed previously.

Improvement of serum amino acid profile in hepatic failure with the bioartificial liver using multicellular hepatocyte spheroids

We designed a bioartificial liver support system in which encapsulated multicellular spheroids of rat hepatocytes were utilized as a bioreactor in a hollow fiber cartridge. The spheroids, formed in a positively charged polystyrene dish that contained hormonally defined medium, were encapsulated into microdroplets of agarose that contained about 9 × 107 rat hepatocytes. The medium, including 150 mL reservoir volume, was circulated in a closed circuit in which the cartridge was inserted. The pH and levels of dissolved oxygen were monitored and automatically regulated so that they were maintained within a constant range for 72 h. Albumin accumulated in the circuit at the rate of 2.0 mg/L/h in this system. When the bioreactor cells in the system were replaced with Hep G2 cells, a human hepatoblastoma cell line, albumin accumulated at the rate of 0.15 mg/L/h. The spheroids of primary culture hepatocytes had 13 times higher albumin‐producing capacity than the aggregates of Hep G2. The serum of a patient with fulminant hepatic failure was circulated in this system with the spheroids of primary culture hepatocytes. The concentration of branched amino acid (BCAA) in the circuit significantly increased during the 48 h circulation, while the concentration of aromatic amino acid (AAA) and methionine decreased. The ratio of BCAA/AAA increased from 0.640 to 0.772, indicating that the hepatocyte spheroids had improved the imbalance of the amino acid profile in the serum. These findings indicate that this system may be a useful model for an artificial liver support.

Diagnostic Accuracy of Laparoscopic Liver Biopsy in Chronic Liver Diseases, Comparison of Laparoscopic and US‐Guided Liver Biopsy Results

Liver biopsies were carried out using three different needles, a Vim‐Silverman needle 2.5 mm in outer caliber, an 18‐Gauge (18G) Majima needle, and a 17‐Gauge (17G) Majima needle. The biopsies were obtained from nearby locations on the liver surface under laparoscopic observation, to ascertain differences in histological diagnosis according to the size of the biopsy specimen. The biopsy specimens obtained with the Vim‐Silverman needle were wider than those obtained with the other two needles. The agreement in histological diagnoses of the liver, obtained with the Vim‐Silverman needle versus the 18G Majima needle, was 26.0%, while that between the Vim‐Silverman needle and the 17G Majima needle was 40.0%. Histological diagnosis tended to be underestimated in small biopsy specimens in advanced chronic liver diseases. A questionnaire survey, conducted in 92 hospitals affiliated with Okayama University Medical School, revealed US‐guided liver biopsy to be the practice of choice in 57 of 92 (62.0%) hospitals, and 18G needles were used in US‐guided liver biopsy in 35 of 78 (45.2%) hospitals.

Transient appearance of perisinusoidal chondroitin sulfate proteoglycans associated with enhanced expression of biglycan gene during d-galactosamine-induced acute liver injury in rats

Abstract The present study investigated the chondroitin sulfate proteoglycan changes in the liver during acute liver injury induced by a one-shot administration of d -galactosamine in rats. Chondroitin sulfate proteoglycans were immunohistochemically stained with monoclonal antibodies, 1B5, 2B6, and 3B3, which recognize different stub structures of chondroitin sulfate chain exposed after treatment with chondroitinase ABC. The presence of biglycan, a dermatan sulfate/chondroitin sulfate proteoglycan, in the chondroitin sulfate proteoglycans was examined by determining the expression of biglycan gene by PCR and RNase protection assay. Immunoreactive chondroitin sulfate proteoglycans were detected in the ECM of portal areas and along the sinusoid, in either a radial or scattered dot pattern, out from the portal area. The positive signals in the portal area were detected in both control and injured rats. However, those along the sinusoid were detected only in injured rats, transiently from day 1 to 4 after the administration of d -galactosamine. The expression of biglycan gene was detected in both control and injured rats, and was four-five-fold the basal level at day 1 to 2 in the injured rats. These results suggest that the appearance of chondroitin sulfate proteoglycan along liver sinusoid is specific to acute liver injury, and biglycan is partially involved.