Altered Transmission of Cardiac Cycles to Ductus Venosus Blood Flow in Fetal Growth Restriction: Why Ductus Venosus Reflects Fetal Circulatory Changes More Precisely.

We aimed to investigate the relation between the time intervals of the flow velocity waveform of ductus venosus (DV-FVW) and cardiac cycles. We defined Delta A as the difference in the time measurements between DV-FVW and cardiac cycles on the assumption that the second peak of ductus venosus (D-wave) starts simultaneously with the opening of the mitral valve (MV). As well, we defined Delta B as the difference of the time measurements between DV-FVW and cardiac cycles on the assumption that the D-wave starts simultaneously with the closure of the aortic valve (AV). We then compared Delta A and Delta B in the control and fetal growth restriction (FGR) groups. In the control group of healthy fetuses, Delta A was strikingly shorter than Delta B. On the other hand, in all FGR cases, no difference was observed. The acceleration of the D-wave is suggested to be generated by the opening of the MV under normal fetal hemodynamics, whereas it precedes the opening of the MV in FGR. Our results indicate that the time interval of DV analysis might be a more informative parameter than the analysis of cardiac cycles.

Time interval analysis of ductus venosus and cardiac cycles in relation with umbilical artery pH at birth in fetal growth restriction.

BACKGROUND: The aims of this study were to evaluate the time intervals of flow velocity waveforms (FVW) of ductus venosus (DV) and cardiac cycles, as well as the pulsatility index of DV-FVW (DV-PI), in correlation with umbilical artery (UA) pH at birth in fetal growth restriction (FGR) complicated with placental insufficiency. METHODS: Data were retrospectively retrieved from pregnancies complicated by FGR. FGR was defined as an estimated fetal weight below - 2.0 S.D. with an elevated UA-PI. Time interval assessments of DV-FVW were as follows: the duration of systolic wave was divided by the duration of diastolic wave and defined as DV-S/D. We also measured the following time intervals of ventricular inflow through tricuspid valve (TV) and mitral valve (MV): (iii), from the second peak of ventricular inflow caused by atrial contraction (A-wave) to the opening of atrio-ventricular valves and: (iv), from the opening of atrio-ventricular valves to the peak of A-wave. (iii)/(iv) was expressed as TV-S/D and MV-S/D, for TV and MV, respectively. The time interval data were transformed into z-scores. RESULTS: Thirty-one FGR fetuses were included in this study. Both DV-PI and DV-S/D showed significant correlation with UA-pH (r = - 0.677, p = < 0.001 and r = 0.489, p = 0.005 for DV-PI and z-score of DV-S/D, respectively) and more significances were observed in FGR ≤ 28 + 6 gestational weeks (r = - 0.819, p < 0.001 and r = 0.726, p = 0.005, for DV-PI and z-score of DV-S/D, respectively) than in FGR > 28 + 6 gestational weeks (r = - 0.634, p = 0.007 and r = 0.635, p = 0.020, for DV-PI and z-score of DV-S/D, respectively). On the other hand, TV-S/D and MV-S/D showed no significant correlation with UA-pH, although these z-scores indicated significant decreases compared with normal references. CONCLUSIONS: Time interval analysis of DV-FVW might be a valuable parameter, as well as DV-PI, for the antenatal prediction of fetal acidemia in the management of FGR fetuses.

Perforin-dependent cell death in skin allograft rejection of the terrestrial slug Incilaria fruhstorferi.

The rejection of allografts in mammals is mainly mediated by cytotoxic T-lymphocytes, whereas no comparable immunoreactive cells have been described in invertebrates. The present study was undertaken to determine whether similar cytotoxic effector cells are present when allograft rejection occurs in the terrestrial slug Incilaria fruhstorferi. A piece of dorsal skin from a donor animal was orthotopically transplanted to a recipient. Immunohistochemistry for perforin, detection of apoptosis by the TUNEL (TdT-mediated dUTP-biotin nick-end labeling) method, and electron microscopy were performed using both donor and recipient tissues. Cellular changes in the rejection process continued over for 40 days. Two functional types of "effector" cells were recognized at the rejection site, but they were observed to be macrophages possessing perforin granules and phagocytosing damaged cells of the allograft. Three days after transplantation, the perforin-positive cells were recognized only in the recipient tissue surrounding the allograft. Five days after transplantation, these cells started to appear in the graft, while they disappeared from the host tissue. However, TUNEL-positive cells were not observed throughout the graft-rejection process. Electron microscopic examination of the graft tissue revealed autophagic degeneration of epithelial cells, mucous cells, pigment cells, fibroblasts, and muscle cells. These observations suggest that the molluscan slug has the capability to recognize differences in cell-surface molecules between the allogeneic and recipient tissues, and that an allograft is chronically rejected due to a type of immunocyte that can induce perforin-dependent cell death.

Characteristics of the promoters derived from the single-stranded DNA components of Milk vetch dwarf virus in transgenic tobacco.

Predicted promoter regions of Milk vetch dwarf virus (MDV) components (C1-C11) were isolated and fused with a beta-glucuronidase (GUS) reporter gene and the characteristics of the promoters were examined. In transgenic tobacco calli, promoters of MDV C4 (encoding a cell-cycle link protein), C5 and C7 (both encoding unknown proteins), C6 (encoding a nuclear-shuttle protein) and C8 (encoding a movement protein) generated a stronger level of GUS expression than the Cauliflower mosaic virus 35S RNA promoter (P35S). In leaves of transgenic tobacco plants, the promoters of C5 and C8 conferred a level of GUS activity comparable to that of P35S. Histochemical GUS analysis showed that the promoters of C4-C9, the latter encoding a capsid protein, were active in phloem and meristematic tissue. The promoter of C8 was also active in mesophyll and cortex cell types. A low level of activity was found for the promoters of C11, which encodes a master replication-initiator protein (Rep), and C1, C2, C3 and C10, which encode additional Reps, in both transgenic tobacco calli and plants.

The promoter of Milk vetch dwarf virus component 8 confers effective gene expression in both dicot and monocot plants.

The activity of a predicted promoter, PMC8, from Milk vetch dwarf virus was evaluated by comparing it with the cauliflower mosaic virus 35S RNA promoter (P35S) and PNCR, a promoter from Soybean chlorotic mottle virus. When the GUS fusion gene was introduced into tobacco, PMC8 showed a similar expression profile to P35S but with a more intense expression in proliferating tissues. The usefulness of PMC8 was confirmed by driving NPTII for selection of kanamycin-resistant tobacco plants with improved transformation efficiency. PMC8 was also effective in transgenic rice plants. Thus, PMC8 is useful as an alternative to P35S in both dicotyledonous and monocotyledonous plants, especially for gene expression in proliferating tissues.

Comparative studies on the internal defense system of schistosome-resistant and -susceptible amphibious snail Oncomelania nosophora 1. Comparative morphological and functional studies on hemocytes from both snails.

Two morphologically distinct blood cell types (hemocytes), Type I and Type II were found coexisting in hemolymph from two kinds of snails, Oncomelania nosophora strain, viz. from the Nirasaki strain (schistosome-resistant snail) and the Kisarazu strain (schistosome-susceptible snail). Ten min after inoculation of SRBC, the majority of Type I cells from Nirasaki strain flattened and spread over the surface of the glass plate by extending pseudopodia. In the Kisarazu strain, Type I cells adhered to the surface of substrate with spike-like filopodia, but did not form spreading lamellipodia. Type I cell from the Nirasaki strain phagocytosed SRBC but that from the Kisarazu strain did not. The starting time of recognition of foreign materials was slightly different in the Type I hemocytes from the two strains. Type II cells from both strains were round and lymphocyte-like. Ten or sixty min after incubation, Type II cells from neither strain adhered to the surface of substrate or SRBC, and did not phagocytose SRBC. Type II cells from the Nirasaki strain were quite similar to those from the Kisarazu strain. We concluded that Type I cells from the schistosome-resistant snail, Nirasaki strain, possessed higher phagocytic activity than those from the susceptible snail, Kisarazu strain, despite the morphological similarities of the hemocytes from both strains.

Release from post-transcriptional gene silencing by cell proliferation in transgenic tobacco plants: possible mechanism for noninheritance of the silencing.

Transgenic tobacco plants that overproduce luciferase (Luc) frequently exhibit post-transcriptional gene silencing (PTGS) of luc. The silencing was observed over five generations and found not to be inherited but acquired by the next generation at a certain frequency. Luc imaging analysis of silenced plants revealed Luc activity only in proliferating tissues such as shoot meristem and developing flower. The luc gene expression has been recovered from silencing before development of germ cells, excluding a possible recovery from the PTGS at meiosis. A systemic silencing signal transferred from older tissue likely induces gene silencing of younger tissues in which cell proliferation has been completed. Only seeds maintained Luc activity, probably because of isolation from the silencing signal by a possible partition from the parent placenta. Calli newly induced from the leaf pieces of silenced plants recovered from the silencing and exhibited strong Luc activity similar to nonsilenced leaves, further indicating that the silencing cannot be maintained in proliferating cells. Thus release from PTGS in proliferating cells is a possible mechanism for noninheritance of silencing.