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Biomedical subjects

Y Satow

Publications and source records attributed to Y Satow.

At least 55 records · Page 3Linked to original sources
PubMed1991

Relation of the distribution of fibronectin to the obliteration of the arch artery in the chick.

Fibronectin has been believed to be involved in vasculogenesis. This study demonstrates by immunohistochemistry the distribution of fibronectin around the systemic arteries of chick embryos during the periods of aortic arch formation, and examines the possible relationship between the distribution of fibronectin and the obliteration of the arch artery. In embryos at stage 23, no obliteration of arch arteries was recognized on sections. At this stage, intense staining with an anti-fibronectin antibody was seen in the developing tunica media of the carotid artery and dorsal aorta. Staining around the arch arteries was much weaker. At stage 26, the intensity of anti-fibronectin antibody staining was weaker around the left arch artery, although the diameter of the 4th arch artery was not different between the left and right. At stage 27, which is the early period for the obliteration of the left 4th arch artery, the intensity of the anti-fibronectin antibody staining for the left arch artery was much less than that for the right arch artery. These results show that fibronectin does not accumulate around the left 4th arch artery during aortic arch formation and suggest the possibility that a smaller amount of fibronectin is responsible for the obliteration of the left 4th arch artery.

Animals↗
PubMed1990

Structure of ribonuclease H phased at 2 A resolution by MAD analysis of the selenomethionyl protein.

Ribonuclease H digests the RNA strand of duplex RNA.DNA hybrids into oligonucleotides. This activity is indispensable for retroviral infection and is involved in bacterial replication. The ribonuclease H from Escherichia coli is homologous with the retroviral proteins. The crystal structure of the E. coli enzyme reveals a distinctive alpha-beta tertiary fold. Analysis of the molecular model implicates a carboxyl triad in the catalytic mechanism and suggests a likely mode for the binding of RNA.DNA substrates. The structure was determined by the method of multiwavelength anomalous diffraction (MAD) with the use of synchrotron data from a crystal of the recombinant selenomethionyl protein.

Amino Acid Sequence↗
PubMed1990

Structure of interleukin 1 alpha at 2.7-A resolution.

The interleukin 1 (IL-1) family of proteins has a central role in modulating immune and inflammatory responses. Two major IL-1 proteins, designated alpha (IL-1 alpha) and beta (IL-1 beta), are produced by activated macrophages and other cell types. In an effort to understand the similarities and differences in the physicochemical and functional properties of these two proteins, a program was initiated to determine their structures. Crystals of IL-1 alpha were grown, and the three-dimensional structure at 2.7-A resolution was solved. The technique of multiple-wavelength anomalous dispersion (MAD) with the selenomethionine form of IL-1 alpha was utilized in combination with a single mercury derivative to provide the starting phases. Partial refinement of the IL-1 alpha model has been performed as well. The overall structure is composed of 14 beta-strands and a 3(10) helix. The core of this structure is a capped beta-barrell that possesses 3-fold symmetry and displays a topology similar to that observed for IL-1 beta [Priestle, J. P., et al. (1988) EMBO J. 7, 339-343] and soybean trypsin inhibitor (STI) [McLachlan, A. D. (1979) J. Mol. Biol. 133, 557-563]. In this paper, the overall structure of IL-1 alpha and the nature and fidelity of the internal 3-fold symmetry are discussed. Comparisons with IL-1 beta and STI are made within these contexts.

Amino Acid Sequence↗
PubMed1990

Distribution of vitronectin in the embryonic chick heart during endocardial cell migration.

In the early phase of heart development, the endocardial cells migrate into the truncal swellings and atrioventricular (AV) cushions, and become mesenchymal cells. Vitronectin is a glycoprotein which is thought to mediate cell migration. The present study demonstrates by immunohistochemistry the distribution of vitronectin in order to elucidate its contribution to endocardial cell migration in the developing chick heart. At Hamburger and Mamilton's stage 23, the network of fibrillar material filled the extracellular space of both truncal swellings and AV cushions. The fibrillar network has been thought to be a matrix for endocardial cell migration. The network was stained with the anti-vitronectin antibody. At stage 29, the swellings and cushions were packed with mesenchymal cells, though immunoreactivity to the antibody was still observed in the extracellular matrix. The myocardium facing the AV cushions reacted to the antibody, but the myocardium surrounding the truncus arteriosus did not. The intensity of the immunohistochemical staining of the myocardium facing the AV cushions increased and reached a peak at stages 24 to 26, and then became weak by stage 29. The endocardial sheet, aortico-pulmonary septum and developing tunica media of the great arteries were not stained by the antibody at any stage. These results strongly suggest that vitronectin is involved in the migration of endocardial cells, and that the myocardium facing the AV cushions produces vitronectin.

Animals↗
PubMed1989

Teratogenic effect of fission neutron and tritium water on rat embryo.

The method employed was to give a single whole body exposure of Cf-252 at various doses to pregnant rats on day 8 or 9 of pregnancy, performing microscopic autopsy of the fetuses at the terminal stage of pregnancy, and examining the external and internal organ anomalies. For comparison, an experiment was also made by irradiating pregnant rats with various doses of Co-60 standard gamma-rays at the same dose rate (1 rad/min.). As a result, relative biological effects (RBE) of 2.3-2.7 was obtained from the straight line that was given by modifying by the method of least squares the curves of the frequency of anomalous fetuses in total implants and survived embryos irradiated from 20 to 120 rad by Cf-252 and from 80 to 220 rad by Co-60 on day 8 of pregnancy. Further, the anomalies of Cf-252 and Co-60 irradiated cases were alike in their types of malformations. Using fetal LD50 as an index, 2.4 was obtained as the RBE of cases irradiated on day 8 of pregnancy and 3.1 as that of cases irradiated on day 9. The teratogenic effects of HTO on rat embryos were also examined and the results obtained were compared with those of tritium simulator (Cs-137 gamma-rays) for determining the RBE for the incidence of malformations. Six groups of pregnant rats were injected intraperitoneally with HTO containing 25, 50, 75, 100, 125 or 150 mCi HTO/300g B.W. on day 9 of pregnancy. To obtain accurate RBE values of HTO in rats, six groups of pregnant rats were exposed to Cs-137 gamma-rays by tritium simulator on days 9-18 of pregnancy at exponentially decreasing doses in accordance with body tritium concentration. The rats were sacrificed on day 18 and the offsprings were examined for external and internal malformations. Malformations were seen at the highest incidence of 100% of the survived embryos and 81.3% of total implants in the group given 100 mCi (accumulated doses were about 451 rad) of HTO on day 9 of pregnancy. Tritium simulator accumulated doses of Cs-137 gamma-rays irradiation at 680 rad induced 98.4% malformation in survived embryos and 71.7% of the total implants on day 9 of pregnancy. Both radiations (HTO and Cs-137 gamma-rays) induced similar anomalies of the cardiovascular system in rat embryos.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormalities, Radiation-Induced↗
PubMed1989

Elevated expression of proto-oncogenes accompany enhanced induction of heat-shock genes after exposure of rat embryos in utero to ionizing irradiation.

We have recently found that the effects of exposing rat embryos in utero to teratogens capable of producing cardiac anomalies were expressed later as enhanced induction of heat-shock proteins (hsp70 family) when embryonic hearts were cultured in vitro. However, it remained to be determined whether heat-shock proteins are induced in vivo after exposure to teratogens. The heat-shock response in some mammalian systems is known to be accompanied by elevated expression of proto-oncogenes. Using gene-specific DNA probes, we examined the levels of the expression (transcription) of heat-shock protein genes and two nuclear proto-oncogenes, c-fos and c-myc, in the embryos removed from irradiated pregnant mother rats 4 or 5 days after the irradiation. We found that the levels of expression in vivo of the hsp70 and c-myc genes in the irradiated embryos increased by approximately twofold as compared with those in the control. The expression in vivo of the c-fos gene was not detected in either the irradiated or non-irradiated embryos. After 0.5-hr incubation in vitro of the embryos, however, the expression of the c-fos gene in the irradiated embryos was highly enhanced whereas the control showed no changes. Although the exact functions of these gene products still remain obscure, the enhanced expression of hsp70 gene(s) and the nuclear proto-oncogenes observed in the present study may reflect repair of intracellular damages and/or regeneration of tissue by compensatory cell proliferation, processes that may disturb the normal program of organogenesis.

Animals↗
PubMed1989

Crystal structure of core streptavidin determined from multiwavelength anomalous diffraction of synchrotron radiation.

A three-dimensional crystal structure of the biotin-binding core of streptavidin has been determined at 3.1-A resolution. The structure was analyzed from diffraction data measured at three wavelengths from a single crystal of the selenobiotinyl complex with streptavidin. Streptavidin is a tetramer with subunits arrayed in D2 symmetry. Each protomer is an 8-stranded beta-barrel with simple up-down topology. Biotin molecules are bound at one end of each barrel. This study demonstrates the effectiveness of multiwavelength anomalous diffraction (MAD) procedures for macromolecular crystallography and provides a basis for detailed study of biotin-avidin interactions.

Bacterial Proteins↗
PubMed1989

Effect of tritiated water on female germ cells: mouse oocyte killing and RBE.

The relative biological effectiveness (RBE) of tritiated water (HTO) was investigated using mouse immature oocytes. Juvenile mice, having immature oocytes that are highly sensitive to radiation killing, were exposed to HTO, 137Cs gamma rays, 60Co gamma rays, or 252Cf fission neutrons. The 137Cs gamma rays were used to simulate the changing dose rate (but not the radiation quality) received from HTO (see section 2). On the 14th day after birth, female ICR strain mice were injected once in the abdominal cavity with HTO at levels of 1.70, 3.40, 6.81, or 10.21 MBq/10g body weight, and their ovaries were removed 2 weeks after the injection. (The cumulative doses are equivalent to 0.039, 0.077, 0.159 and 0.246 Gy, respectively.) The survival rate of oocytes was determined by light microscopy inspection of serial sections, and the results of the different exposures were compared. The number of surviving oocytes decreased exponentially with increasing dose of HTO or 137Cs, and RBEs of HTO compared to 137Cs gamma rays ranged from 1.1 to 3.5. The relative effectiveness of the different types of radiations was compared, and the results of the comparison, in order of increasing effectiveness, was 137Cs, 60Co, HTO, and 252Cf. The RBE of 252Cf compared to 60Co gamma rays ranged from 1.6 to 3.5.

Animals↗
PubMed1989

Teratogenic effect of californium-252 irradiation in rats.

The teratogenicity of californium-252 (Cf-252) irradiation which generates approximately 70% 2.3 MeV fast neutron and 30% gamma rays was evaluated. A single whole body exposure of Cf-252 at various doses was given to pregnant rats on day 8 or 9 of pregnancy, followed by microscopic autopsy of the fetuses at the terminal stage of pregnancy to search for external and internal malformations. For comparison, pregnant rats were irradiated with various doses of cobalt-60 (Co-60) standard gamma rays at the same dose rate (1 rad/min.). The doses were 20-120 rad of Cf-252 and 80-220 rad of Co-60. Using frequency of radiation induced malformations observed on day 8 of pregnancy as an index, relative biological effectiveness (RBE) of 2.3-2.7 was obtained from the straight line obtained by modifying by the least squares method the frequency curves of malformed fetuses in total implants and in surviving fetuses. The types of malformations induced by Cf-252 and Co-60 irradiation were alike. Using fetal LD50 as an index, 2.4 was obtained as RBE when irradiated on day 8 of pregnancy and 3.1 as that when irradiated on day 9. The results showed that Cf-252 had stronger a teratogenic effect than Co-60 gamma rays.

Abnormalities, Radiation-Induced↗
PubMed1989

The localization of fibronectin and 140 Kd fibronectin receptor in the truncus arteriosus of the chick embryonic heart.

The distribution of fibronectin and 140 Kd fibronectin-receptor was examined in the truncus arteriosus of the chick embryonic heart during aortico-pulmonary (AP) septation by immunohistochemistry. In 4-day-old chick embryos, immunoreactivity of both anti-fibronectin and anti-140 Kd fibronectin-receptor was seen in the primordia of the AP septum. In 5-day-old embryos, cells stained with anti-140 Kd fibronectin-receptor antibody were rarely found in the AP septum, though strong immunoreactivity of the anti-fibronectin antibody was observed in the AP septum. In 6-day-old embryos, at a late stage of septation, cells stained with anti-140 Kd fibronectin-receptor antibody were not found in the AP septum, and immunoreactivity of the anti-fibronectin antibody had decreased. In the cushion tissue, immunoreactivity of the anti-fibronectin antibody was seen, but that of the anti-140 Kd fibronectin-receptor antibody was recognizable only on a few cushion cells in the 4-day-old embryos. These findings suggest that fibronectin is involved in the formation of the AP septum primordia, that fibronectin does not promote the development of the AP septum, and that the migration mechanism of cushion cells is different from that of neural crest cells.

Animals↗
PubMed1989

Effects of gamma-ray irradiation in utero on developing hearts of rat embryos: inhibition of accumulation of a 27-kDa protein.

Rat embryos were irradiated in utero with 1.5-Gy (teratogenic dose) of 60Co gamma-rays on Day 9 of gestation, and the protein composition of each embryonic heart was examined by two-dimensional electrophoresis on Day 18. Almost all of about 450 protein species detected were identical to those of the non-irradiated hearts. However, a 27-kDa protein was reproducibly found in decreased amount in the irradiated samples. In the normal development of the heart, this protein accumulates rapidly either during the last several days of gestation or upon birth. Therefore, the irradiation with gamma-rays inhibited the accumulation of this protein.

Animals↗
PubMed1988

Effects of exposing rat embryos in utero to physical or chemical teratogens are expressed later as enhanced induction of heat-shock proteins when embryonic hearts are cultured in vitro.

In order to get more insight into the effects of teratogens on developing embryos, we investigated the protein synthesis patterns of the target organs isolated from teratogen-treated embryos. Rat embryos were either irradiated in utero with either 252Cf fission neutrons or 60Co gamma rays on day 8 of gestation or treated in utero with a bis(dichloroacetyl)diamine (a chemical teratogen) on days 9 and 10. Hearts were removed from the embryos on day 12 and were incubated in vitro at 37 degrees C in the presence of [35S]methionine for up to 8 hr. The newly synthesized labeled proteins were then analyzed qualitatively by two-dimensional polyacrylamide gel electrophoresis. Enhanced and prolonged induction of a family of heat-shock (stress) proteins with a molecular weight of about 70,000 (SP70s) was observed as compared with those of controls. Among the teratogen-treated hearts, those with gross malformations already detectable at this early stage showed especially higher inductions of SP70s than did the others. The abnormal expression of SP70s observed in the present study appears to be a reflection of persisting cellular (tissue) damage inflicted by the teratogens, and the extent of the induction may be indicative of the degree and/or type of the damage. Such persisting defects in surviving cells, manifested by abnormal induction of SP70s in the present study, might be related to malformation of embryonic hearts.

Animals↗
PubMed1988

A case of Ebstein's anomaly with double mitral valve.

A 5-month-old male infant with no history of serious illness died suddenly and unexpectedly. He was found dead under a heavy 'futon', a coverlet, which covered the whole of his body. As it was suspected he may have been smothered, a medicolegal autopsy was performed, and it was discovered that the infant had Ebstein's anomaly with double mitral valve. The cause of death appeared to be due to heart failure caused by this congenital heart disease.

Abnormalities, Multiple↗
PubMed1987

Desmin distribution in the cardiac outflow tract of the chick embryo during aortico-pulmonary septation.

The appearance and distribution of desmin, a muscle type intermediate filament, was examined in the truncus arteriosus of the chick embryonic heart during AP septation by an indirect immunofluorescence method. Prior to septation, on the 4th day of incubation, staining with antidesmin antibody was observed in the AP septum anlagen in the distal truncus. No staining with the antibody was detected in the developing tunica media of the great arteries in the distal truncus at this stage. During septation, on the 5th day of incubation, intense staining with the antidesmin antibody was observed in the cell condensation of the AP septum. In the 6-day-old embryo, the staining in the AP septum was reduced, but fluorescence by staining with the antibody was observed in the developing tunica media. No fluorescence was detected in other mesenchymal cells in the truncal swellings. Because of the time of appearance and the localization of antidesmin reactivity in the developing AP septum, it is suggested that muscle-type cells exist in the AP septum, and that these cells may perform an important function in septation.

Animals↗
PubMed1987

Induction of an hsp70-like protein during organ culture of rat embryonic heart.

Hearts were isolated from rat embryos on Day 12 of gestation and incubated in vitro at 37 degrees C in the presence of [35S]methionine; the labeled proteins were then analyzed by two-dimensional gel electrophoresis. The results showed that an acute and transient synthesis of an hsp70 (heat-shock proteins with a M.W. of about 70,000)-like protein was induced in the isolated rat embryonic hearts, without the concomitant total inhibition of normal cellular protein synthesis usually observed in other heat-shock systems. The significance of the results to the embryonic stress hypothesis of teratogenesis recently proposed is discussed.

Animals↗
PubMed1986

Phosphocholine binding immunoglobulin Fab McPC603. An X-ray diffraction study at 2.7 A.

The crystal structure of the Fab of McPC603, a phosphocholine-binding mouse myeloma protein, has been refined at 2.7 A resolution by a combination of restrained least-squares refinement and molecular modeling. The overall structure remains as previously reported, with an elbow bend angle between the variable and constant modules of 133 degrees. Some adjustments have been made in the structure of the loops as a result of the refinement. The hypervariable loops are all visible in the electron density map with the exception of three residues in the first hypervariable loop of the light chain. A sulfate ion occupies the site of binding of the phosphate moiety of phosphocholine.

Amino Acid Sequence↗
PubMed1986

Craniofacial and oral malformations in an autopsy population of Japanese human fetuses and newborns.

A review of the autopsy records of the Department of Pathology of Nagasaki University and the Department of Geneticopathology of Hiroshima University from 1944 through 1982 revealed that during this period there were 11,050 cases of fetuses and newborns, including 432 cases with craniofacial and oral malformations and 22 cases with amniogenous malformations. Among the cranial malformations, there were 202 (46.8%) anencephaly cases, 38 (8.8%) holoprosencephaly, 28 (6.48%) hydrocephaly, 27 (6.25%) meningoencephalocele, and 13 other cranial malformations (seven microcephaly and two each of macrocephaly, dolichocephaly, and iniencephaly). Among the oral malformations, there were 25 (5.78%) cleft lip cases, 23 (5.32%) cleft palate, and 76 (17.6%) cleft lip and palate. Among the facial malformations, there were 12 (2.78%) anomicrophthalmia cases, 37 (8.56%) ear malformations, 15 (3.47%) micrognathia, and 8 (1.85%) nose malformations. One cranial malformation was found that was complicated with anencephaly and holoprosencephaly. Of 307 cranial malformations, 38 (12.4%) were complicated with oral malformations and 4 (4.6%) with facial malformations. Among the 124 cases of oral malformations, 38 (30.6%) were complicated with cranial malformations. The complicating cranial malformations were anencephaly in 16 cases, holoprosencephaly in seven, hydrocephaly in six, meningoencephalocele in seven, other cranial malformations in two, and with facial malformations in 19 cases. Among the 72 cases of facial malformations, 14 were complicated with cranial malformations and 19 with oral malformations. Four cases showed three or more cranial, facial, and/or oral malformations at the same time. Recently, experimental embryological studies have shown that the neural crest cell-derived mesectoderm participates largely in the morphogenesis of the face and the cardiovascular system. It may be said that neural crest cells are deeply involved in the teratogenesis.

Autopsy↗