Relationship between cellular ATP content and cellular functions of primary cultured rat hepatocytes in hypoxia

The importance of oxygen in maintaining the functional integrity of hepatocytes has been well established in a variety of experimental models, such as in vivo , perfused liver and isolated hepatocytes. However, one of the shortcomings of these systems is their short life span. Therefore, we have examined the effects of long-term hypoxia on cellular adenine nucleotide content and cellular functions, such as albumin production, urea production and DNA synthesis, in adult rat hepatocytes in primary culture. Hepatocytes were cultured at a density of 11 × 10⁴ and 5 × 10⁴ cells/0.18 mL per cm² for the study of albumin and urea production and DNA synthesis, respectively, at various oxygen tensions (20, 12, 8 and 5%) for 24 h. Cellular ATP content in cultured hepatocytes in hypoxia gradually declined, corresponding to the decrease in oxygen tension, and the cellular ATP level at 5% oxygen was approximately 20% of that at 20% oxygen. Albumin production also decreased in parallel with the decrease in cellular ATP content in cultured hepatocytes in hypoxia. However, even when cellular ATP content gradually declined corresponding with the decrease in oxygen tension in cultured hepatocytes in hypoxia, such as at 8 or 5% oxygen, urea production remained at a high level; in contrast, DNA synthesis was completely suppressed. These results suggest that the cellular ATP content decreases in cultured hepatocytes during long-term hypoxia in relation to oxygen tension and that the relationship between decreased ATP levels and liver function in cultured hepatocytes during hypoxia differs for albumin production, urea production and DNA synthesis.     

Conserved and novel structural characteristics of enantiomorphic Leu-enkephalin

The crystal of the Leu-enkephalin raceinate (L-Tyr-Gly-Gly-L-Phe-L-Leu and d -Tyr-Gly-Gly-D-Phe-D-Leu) was obtained as a centrosymmetric space group. Crystal data: C₂₈H₃₇N₅O₇· 1.5H₂O, M_w, = 582.6, triclinic, space group PI, a = 11.176(3), b = 16.115(3), c = 10.204(4) Å, α= 92.41(3), β= 104.86(2), γ= 85.35(2) °, V= 1770(1) ų, Z= 2; F(000) = 640, μ(CuKα) = 6.50 cm^?1, D_x= 1.081 g cm^?3. The structure was determined by X-ray diffraction. The conformation of the Leu-enkephalin racemate was classified into the extended form which has been often observed in natural enkephalin. The symmetry-related molecules were connected by hydrogen bonds and arranged in an antiparallel fashion. The molecular packing showed a sheet structure similar to that of natural enkephalin.     

Interruption of aortic arch type A in two siblings

The recurrence of interruption of aortic arch (IAA) in siblings is rare. According to previous reports concerning siblings with IAA, all cases were IAA type B according to the classification proposed by Celoria and Patton. In this report we present the first cases of brothers with IAA type A. The type of IAA was confirmed by autopsy findings in the elder brother and by operative findings in the younger brother. The etiology of IAA was unclear. Monogenic inheritance was thought unlikely because congenital heart disease was not recognized in other members of the family. It would seem prudent to separate recurrence risks for IAA type A from IAA type B when genetic counselling is provided, but it must be borne in mind that the recurrence of IAA type A can occur among siblings.     

Estimation of usefulness of N-butyl-2-cyanoacrylate-lipiodol mixture in transcatheter arterial embolization for urgent control of life-threatening massive bleeding from gastric or duodenal ulcer

We estimated the usefulness of a mixture of N-butyl-2-cyanoacrylate (NBCA) with lipiodol for transcatheter arterial embolization (TAE) used to control massive bleeding from gastric or duodenal ulcer. Thirty patients who had gastric or duodenal ulcers and massive bleeding that was uncontrollable by endoscopic procedures were included in this study. All patients were subjected to TAE (without NBCA in 23 and with NBCA in seven patients). Coils and/or gelfoam were also used. The achievement of haemostasis, occurrence of rebleeding and the time taken for TAE were compared between patients who received TAE without and with NBCA. Eighteen of 23 patients (78.3%) who received TAE without NBCA and six of seven patients (85.7%) who underwent TAE with NBCA achieved complete haemostasis without rebleeding. The time for TAE was significantly shorter in patients who received NBCA compared with those who did not (P= 0.0095). TAE using NBCA or a combination of NBCA and coils achieved a rapid, complete embolization regardless of vascular distribution or arterial diameter. Thus NBCA is considered to be useful as a secondary embolization material in TAE that is urgently conducted to control massive bleeding from gastric or duodenal ulcers.     

Histopathologic evidence for cardiomyopathy in a child with mitral valve prolapse

An intriguing relationship between idiopathic mitral valve prolapse (MVP) and cardiomyopathy has been reported in adult cases of MVP. This paper reports a girl with idiopathic MVP, who presented with progressive cardiomegaly and cardiomyopathic findings on cardiac biopsy; right ventricular endomyocardial biopsy at the age of 15 years showed myocardial hypertrophy, disarray, myocardial degeneration, interstitial fibrosis and endocardial thickening. To our knowledge, this is the first case of idiopathic MVP in childhood that has been shown to have positive biopsy findings for cardiomyopathy.     

Long-term administration of natural interferon-α in patients with chronic hepatitis C: Relationship to serum RNA concentration, HCV-RNA genotypes, histological changes and hepatitis C virus

To virologically assess the efficacy of interferon therapy in chronic hepatitis C, either 5 or 10 MU/day natural interferon-α (IFNα) was administered to 57 patients with chronic hepatitis C for 38 weeks. A complete and sustained response (CR-SR), as evidenced by the absence of serum hepatitis C virus (HCV)-RNA during the administration period and at 6 months after the final administration of IFNα and a normal GPT level at 6 months after final administration, occurred in 42.6% (23/54) of subjects. Liver tissue was histologically evaluated using the histological activity index (HAI) score before and after the administration period. In CR-SR cases, significant improvements (P <0.01) occurred in periportal necrosis, intralobular necrosis, portal inflammation and total score. A comparison, by HCV genotypes, revealed that CR-SR occurred in 60% (9/15) of subjects with type 2a and 30.3% (10/33) of subjects with type Ib. A comparison by virus concentration revealed that CR-SR occurred in 71.4% (15/21) of those subjects having a virus concentration of < 10⁵ copies/mL, but in only 24.2% (8/33) of those having a virus concentration of > 10⁵ copies/mL. Analysis by a multiple logistic model revealed a strong correlation between the therapeutic effect of interferon therapy and the pre-administration virus concentration (P=0.0061) and genotype (P=0.0015). These results suggest that the preadministration virus concentration and genotype are both key factors affecting the therapeutic effect of interferon therapy in chronic hepatitis C and that the therapeutic effect of interferon is satisfactorily high, irrespective of virus concentration, in subjects with type 2a HCV, but varies depending on virus concentration in subjects with type 1b.     

Characteristic molecular packing in the crystal structure of tert-butoxycarbonyl-L-phenylalanyl-L-methionine methyl ester

The molecular conformation and association of the peptide Boc-L-Phe-L-Met-OMe have been studied in the solid state by X-ray diffraction. The peptide crystallizes in the orthorhombic system, space group P2₁2₁2₁, with cell parameters of a= 9.821(2), b= 25.394(6), c= 28.714(8) ų, V= 7161(3) ų. The structure has been solved by direct methods and refined to a final R of 0.079 for 5464 independent reflections with F_o≥σ(F_o). The crystal consists of three independent molecular conformations per asymmetric unit. Respective peptide backbones adopt an extended conformation with the side-chains of Phe and Met residues being arranged below and above the backbone chains. Contrary to the sheet structure most frequently observed in the crystal packing of the extended peptide conformations, three independent molecules lie spirally along the c-axis and form a pin-wheel-like crystal packing. The sheet structures formed by two of three independent molecules are almost at right angles to the backbone of the remaining molecule. This molecular packing mode would provide a possible interaction model between the intersecting β-sheet structure and single-strand structure of polypeptide. © Munksgaard 1994.     

Structural versatility of peptides from Cα,α-disubstituted glycines: crystal-state conformational analysis of peptides from Cα-methylhomophenylalanine, (αMe)Hph

The molecular and crystal structures of the C^α-tetrasubstituted, δ-branched α-amino acid C^α-methyl-homophenylalanine, H-d -(αMe)Hph-OH, and three peptides (to the pentamer level), including the homotripeptide, have been determined by X-ray diffraction. The peptides are Z-l -(αMe)Hph-(l -Ala)₂-OMe, pBrBz-[d -(αMe)Hph]₃-OtBu and Ac-(Aib)₂-l -(αMe)Hph-(Aib)₂-OtBu. All the (αMe)Hph residues prefer φ,ψ torsion angles in the helical region of the conformational map. The two terminally blocked tripeptides adopt a β-bend conformation stabilized by a 1→4 C = O?H-N intramolecular H-bond. The terminally blocked pentapeptide is folded in a regular 3₁₀-helix. In general, the relationship between (αMe)Hph α-carbon chirality and helix handedness is the same as that exhibited by protein amino acids. A comparison is also made with the conclusions extracted from published work on peptides from other types of C^α-alkylated aromatic α-amino acids. © Munksgaard 1996.