Review: Exploration of placentation from human beings to ocean-living species.

This review covers four topics. 1) Placental pathology in Himalayan mountain people. To determine morphological changes of the placenta at high altitude, pathological examination was made of 1000 Himalayan placentas obtained in Nepal and Tibet and the results compared with Japanese placentas delivered at sea level. Characteristic findings in the placental villi of the Himalayan group included high incidences of villous chorangiosis and chorangioma. These processes were clarified by ultrastructural observation. 2) Placentation in Sirenians. The giant Takikawa sea cow, which lived 5 million years ago, was discovered on Hokkaido, Japan. It was an ancestor of the dugong as well as the manatees. Sirenia, the sea cow group, shares a common ancestor with Proboscidea, the elephants, even though they now inhabit quite different environments. A comparison was made of their zonary endothelial type of placentation. 3) Placentation in sharks and rays. The remarkable placentation of hammerhead sharks and manta rays is described. 4) Placentation in the Antarctic minke whale. Placental tissue samples of this whale were obtained from the Japan Institute of Cetacean Research. In an ultrastructural study of the utero-placental junction, microfilamental processes of the allantochorionic zone and crypt formation were visualized.

Identification of Tetrahymena hsp60 as a 14-nm filament protein/citrate synthase-binding protein and its possible involvement in the oral apparatus formation.

BACKGROUND: Tetrahymena 14-nm filament protein (14FP) is bifunctional, with roles as a citrate synthase in mitochondria and as a cytoskeletal protein in nuclear events during fertilization and in oral morphogenesis. In this study, to further our understanding of the bifunctional property of 14FP, we attempted to screen 14FP-binding proteins using affinity column chromatography. RESULTS: Through the screening of 14FP-binding proteins using 14FP-affinity chromatography, we detected 65 kDa and 70 kDa proteins that bound to 14FP in an ATP dependent manner. From the N-terminal amino acid sequence, these proteins were identified as the Tetrahymena mitochondrial chaperones, hsp60 and mthsp70, respectively. Tetrahymena hsp60 was recognized with a monoclonal antibody raised against human hsp60. Immunofluorescence and immunoelectron microscopy using the monoclonal antibody showed that Tetrahymena hsp60 was localized to mitochondria. Moreover, Tetrahymena hsp60 was also present at extramitochondrial sites including basal bodies of cilia and oral apparatus, and particularly at the developing oral apparatus during cell division. CONCLUSION: These results suggest that Tetrahymena hsp60 is localized in basal bodies and is involved in cortical patterning such as the formation of the oral apparatus as well as having a role in the folding of mitochondrial proteins in mitochondria.

Participation of Bcl-2/Bax-alpha in glutamate-induced apoptosis of human glioblastoma cells.

Glutamate has been shown to function as a toxic agent in neuronal and glial cells, as well as an excitatory neurotransmitter throughout the central nervous system. In the present study, we examined the effect of increasing glutamate concentration on the induction of apoptosis in the two human glioblastoma cell lines GB-4 and GB-12. Glutamate exposure caused cell death of GB-4 and GB-12 in a dose-dependent manner. The cells were found to die via apoptosis in response to glutamate based on the following criteria: propidium iodide (PI) staining, H-E staining, electron microscopic analysis, and the TdT-mediated dUTP-biotin nick end labeling (TUNEL) method. The glutamate-induced apoptosis appears to involve the modulation of Bcl-2 family gene products such as Bcl-2, Bcl-xL, and Bax-alpha. Both Bcl-2 and Bcl-xL were down-regulated by glutamate at 24 h and further at 48 h. The apoptosis-promoting product p21 Bax-alpha was also down-regulated in GB-12 but slightly up-regulated in GB-4, accompanied by generation of variant form of p18 Bax-alpha in both cell lines. These findings suggest that glutamate toxicity results in cellular death via an apoptotic mechanism which appears to involve the Bcl-2/Bax-alpha molecular complex.

Participation of Bax-alpha in IFN-alpha-mediated apoptosis in Daudi B lymphoma cells.

Although interferon-alpha (IFN-alpha) has proved beneficial in the treatment of some tumors, the basis for this is still uncertain. In this study, we examined the effects of IFN-alpha on the growth of tumor cells in vitro, using the Daudi line of B lymphoma cells as a model. There was a dose-dependent accumulation of these cells in the G1 phase of the cell cycle 24-48 h from the time of exposure to IFN-alpha. This was followed between 48 h and 96 h by an increasing degree of apoptosis, as assessed by cell survival, propidium iodine staining, and transmission electron microscopy. Concomitantly with the apoptosis, there was the appearance of pl8 Bax-alpha, an apparently novel variant low molecular weight form of the p21 Bax-alpha found in normal cells. There was also a slight diminution in Bcl-xL, with a resultant drop in the Bcl-xL:Bax-alpha ratio. Treatment of cells with CD40-L partially inhibited the development of apoptosis in response to IFN-alpha. At the same time, generation of p18 Bax-alpha was reduced, which suggests that this plays a part in the apoptotic process. These findings may throw light on the development of lymphomas and perhaps point to future ways of improving therapy with IFN-alpha.

[Thermal effect on alpha 1-adrenoceptors in the guinea-pig vas deferens: histological and binding studies].

OBJECTIVE: To study the mechanism of thermotherapy on benign prostatic hyperplasia, we examined thermal effects on alpha 1-adrenoceptors in the guinea-pig vas deferens. The histological changes in the muscle cells after thermal exposure were also examined by electron microscopy. METHODS: The guinea-pig vasa deferentia were pretreated at 4 degrees C (control group), 43 degrees C, 50 degrees C, and 55 degrees C (heated group) for 1 hour and returned to 37 degrees C for 1 hour or 2 hours. Radioligand binding assay for alpha 1-adrenoceptors was performed by an incubation of [3H]prazosin with the crude membrane fraction from vasa deferentia. The dissociation constant (Kd) and the number of binding sites (NBS) of alpha 1-adrenoceptors were calculated from Scatchard analysis. The histological changes in the muscle cells were also examined at 4 degrees C, 40 degrees C, 50 degrees C, and 55 degrees C for 1 hour by electron microscopy. RESULTS: Kd and NBS did not change at 43 degrees C, but declined significantly above 50 degrees C for 1 hour. The changes in Kd and NBS above 50 degrees C for 1 hour did not recover after returning to 37 degrees C for 1 hour or 2 hours. Electron microscopic observations revealed a loss of myofilaments and dark staining of nuclear chromatin of the smooth muscle cells after thermal exposure above 50 degrees C. CONCLUSION: The binding ability of [3H]prazosin to alpha 1-adrenoceptors declined after thermal exposure above 50 degrees C. Also, the muscular damages were observed histologically after thermal exposure above 50 degrees C. These results indicated that the irreversible decrease in NBS and the disruption of smooth muscle fibers were associated with the thermotherapy.

Glial uptake system of GABA distinct from that of taurine in the bullfrog sympathetic ganglia.

The kinetics and specificity of GABA and taurine uptake were studied in the bullfrog sympathetic ganglia. GABA uptake system consisted of simple saturable component and taurine uptake system consisted of two saturable components exclusive of non-saturable influx. Taurine unaffected GABA uptake while GABA inhibited taurine uptake competitively with the Ki/Km ratio of 38. GABA (5.14 microM) uptake was inhibited by delta- aminovaleric acid and slightly by 2,4-diaminobutyric acid (5 mM, each) among ten structural analogs. Taurine uptake under high-affinity conditions was most strongly suppressed by hypotaurine and beta-alanine competitively with the Ki/Km ratio of 1.0 and 1.9, respectively. Autoradiography showed that glial cells were heavily labeled by both [3H]GABA and [3H]taurine. These results suggest that GABA is transported by a highly specific carrier system distinct from the taurine carrier and that taurine, hypotaurine, and beta-alanine may share the same high-affinity carrier system in the glial cells of the bullfrog sympathetic ganglia.

Taurine uptake by glial cells in the bullfrog sympathetic ganglia.

Taurine uptake was studied in the bullfrog sympathetic ganglia. High- and low-affinity components were detected after subtraction of nonsaturable influx from total uptake in a concentration range from 34 nM to 8mM. Taurine uptake was strictly sodium dependent and the sodium dependency curve was sigmoidal, with a Hill number of 1.6, indicating that at least two sodium ions are required for the transport of one taurine molecule. External sodium ion affected both K(m) and V(max) for taurine uptake. Taurine uptake was inhibited by ouabain, but not by tetrodotoxin. These results suggest that sodium concentration gradient across plasma membrane may be the main driving force for taurine uptake. Electron and light microscopic autoradiography showed that glial cells were heavily labeled by [(3)H]taurine while ganglion cells were slightly labeled. The present data suggest that glial uptake may contribute to terminating the effect of taurine in the bullfrog sympathetic ganglia.