Advance in animal experiments with the undulation pump total artificial heart: 50 and 54 day survival periods with 1/R control

The undulation pump total artificial heart (UPTAH) is a unique, implantable, total artificial heart (TAH) that uses undulation pumps. To achieve long-term survival in animals with physiologic hemodynamic conditions, a control method based on conductance and arterial pressure was applied to UPTAH. With this control method, called 1/R control, survival periods of 50 days (No. 0016, 49.6 kg) and 54 days (No. 0030, 42.5 kg) were obtained in adult female goats. In No. 0016, 1/R control was applied to the left pump, whereas in No. 0030, it was applied to the right pump. Another pump was used for left-right balance control. The control stability was better in No. 0030 than in No. 0016. The sucking effect of the left atrium was remarkable in No. 0016, possibly because of a time delay when left-right balance control was performed with the right pump. In No. 0016, the cause of death was probably a thrombus flown from a panus in the left atrium. It is possible that the left atrial suction effect influenced the thrombus and panus formation in the left atrium. In No. 0030, the cause of death was a small rupture of the membrane in the right pump. The rupture may have been caused by excessive negative pressure inside the pump. This pressure resulted from suction of the right atrium because of an unexpected control excursion, which was probably caused by a software bug. It will be necessary to redesign the undulation pump and improve the software to achieve longer survival periods for animals with physiologic hemodynamic conditions.     

Bcl11b is required for differentiation and survival of alphabeta T lymphocytes

The gene Bcl11b, which encodes zinc finger proteins, and its paralog, Bcl11a, are associated with immune-system malignancies. We have generated Bcl11b-deficient mice that show a block at the CD4-CD8- double-negative stage of thymocyte development without any impairment in cells of B- or gammadelta T cell lineages. The Bcl11b-/- thymocytes showed unsuccessful recombination of V(beta) to D(beta) and lacked the pre-T cell receptor (TCR) complex on the cell surface, owing to the absence of Tcrb mRNA expression. In addition, we saw profound apoptosis in the thymus of neonatal Bcl11b-/- mice. These results suggest that Bcl11b is a key regulator of both differentiation and survival during thymocyte development.     

Temperature-dependent Cu2+-Cu2+ paired structure in ethylene/methacrylic acid copolymer neutralized with Cu(II). Ionic crystallite disordering and polyethylene crystallite melting

Temperature-dependent ESR spectra of Cu²⁺-Cu²⁺ pairs in ethylene/methacrylic acid copolymer neutralized with Cu(II) were reexamined in detail. The resonance positions and the linewidths of one of the ESR fine-structure lines showed thermal distension of the Cu²⁺-Cu²⁺ distance, and the slopes in the temperature variations changed at the temperature associated with melting of the polymer crystallites. No meaningful anomalies were observed around the temperature at which the preceding endothermic transition takes place. In this transition, the Cu²⁺-Cu²⁺ pairs seems to enter a disordered state, keeping almost the same paired structure. In contrast to this irreversible order-disorder transition, the melting process in the most part of the polyethylene crystallite phases starts to impose stress upon the Cu²⁺-Cu²⁺ pairs, accompanying the slope changes of the ESR parameters. These reversible variations with remarkable thermal hysteresis are compatible with the DSC analyses.     

Biological activities of Bacteroides forsythus lipoproteins and their possible pathological roles in periodontal disease

Bacteroides forsythus is a gram-negative, anaerobic, fusiform bacterium and is considered to be an etiological agent in periodontal disease. A lipoprotein fraction prepared from B. forsythus cells by Triton X-114 phase separation (BfLP) activated human gingival fibroblasts and a human monocytic cell line, THP-1, to induce interleukin-6 production and tumor necrosis factor alpha production. BfLP was found to be capable of inducing nuclear factor-kappaB translocation in human gingival fibroblasts and THP-1 cells. By using Chinese hamster ovary K1 cells transfected with Toll-like receptor genes together with a nuclear factor-kappaB-dependent CD25 reporter plasmid, it was found that signaling by BfLP was mediated by Toll-like receptor 2 but not by CD14 or Toll-like receptor 4. BfLP induced apoptotic cell death in human gingival fibroblasts, KB cells (an oral epithelial cell line), HL-60 cells (a human myeloid leukemia cell line), and THP-1 cells but not in MOLT4 cells (a T-cell leukemia cell line). Caspase-8, an initiator caspase in apoptosis, was found to be activated in these cells in response to BfLP stimulation. Thus, this study suggested that BfLP plays some etiological roles in oral infections, especially periodontal disease, by induction of cell activation or apoptosis.     

Werner Syndrome

Werner syndrome is a premature aging disease caused by the mutation in the WRN gene. The cloning andcharacterization of the WRN gene and its product allows investigators to study the disease and the human aging process atmolecular level. This review summarizes the recent progresses on various aspects of the WRN research including functionalanalysis of the protein, interactive cloning, complexes formation, mouse models, and SNPs (single nucleotidepolymorphisms). These in depth investigations have greatly advanced our understanding of the disease and elucidated futureresearch direction for Werner syndrome and the human aging process.     

Clostridium sordellii phospholipase C: gene cloning and comparison of enzymatic and biological activities with those of Clostridium perfringens and Clostridium bifermentans phospholipase C

The gene encoding Clostridium sordellii phospholipase C (Csp) was cloned and expressed as a histidine-tagged (His-tag) protein, and the protein was purified to compare its enzymatic and biological activities with those of Clostridium perfringens phospholipase C (Cpa) and Clostridium bifermentans phospholipase C (Cbp). Csp was found to consist of 371 amino acid residues in the mature form and to be more homologous to Cbp than to Cpa. The egg yolk phospholipid hydrolysis activity of the His-tag Csp was about one-third of that of His-tag Cpa, but the hemolytic activity was less than 1% of that of His-tag Cpa. His-tag Csp was nontoxic to mice. Immunization of mice with His-tag Cbp or His-tag Csp did not provide effective protection against the lethal activity of His-tag Cpa. These results indicate that Csp possesses similar molecular properties to Cbp and suggest that comparative analysis of toxic and nontoxic clostridial phospholipases is helpful for characterization of the toxic properties of clostridial phospholipases.     

DIISOPROPANOLNITROSAMINE (DIPN) INDUCED RAT THYROID LESIONS

DIPN induced localized lesions of the rat thyroid gland are described histologically and classified into three major types: type 1, foci of cellular alteration; type 2, proliferative nodules; and type 3, overt carcinomas. Follicular, papillary and mixed papillofollicular subtypes are recognized in the type 2 lesions, and follicular, papillary, anaplastic and mixed subtypes in the type 3 lesions. The nature of the individual lesions is discussed.     

Characterization of the UL4 gene product of herpes simplex virus type 2

Summary.  We have identified the herpes simplex virus type 2 (HSV-2) UL4 gene product using a rabbit polyclonal antiserum raised against a recombinant 6xHis-UL4 fusion protein expressed in Escherichia coli. The antiserum reacted specifically with a 27-kDa protein in HSV-2 186-infected cell lysates. The protein was not detectable in the presence of the viral DNA synthesis inhibitor, suggesting that the UL4 gene was expressed as a γ₂ gene. Indirect immunofluorescence studies localized the UL4 protein within the nucleus as discrete punctate forms at late times postinfection. However, when expressed in the absence of other viral proteins, the UL4 protein was limited to the cytoplasm, indicating that an interaction with one or more other virus-induced proteins was responsible for the nuclear localization during infection. Subnuclear fractionation studies showed that the protein was released from the nuclear structure of infected cells by high salt treatment. Moreover, the UL4 protein was detected in purified virions and light particles. Received December 24, 1997 Accepted February 4, 1998