Potential prevention of stillbirth caused by placental abruption: a regional population-based study in Japan

OBJECTIVE

Placental abruption is associated with adverse perinatal outcomes including intrauterine fetal demise, which subsequently results in stillbirth. However, few studies have demonstrated the preventability of stillbirth due to placental abruption. Therefore, we evaluated the possibility of preventing stillbirth caused by placental abruption by reviewing all stillbirths in our region.

METHODS

This study reviewed all stillbirths after 22 weeks of gestation in Shiga Prefecture, Japan from 2010 to 2019, excluding lethal disorders. We evaluated 350 stillbirth cases, with and without placental abruption.

RESULTS

There were 32 stillbirths with PA and 318 without placental abruption. The probability of preventing stillbirth was significantly higher in patients with placental abruption than in those without (30% vs. 8%, p < 0.001). We also determined the recommendations for preventing stillbirths with placental abruption.

CONCLUSION

Some stillbirths caused by placental abruption can be prevented. We recommend improvements to perinatal maternal-fetal care and perinatal emergency transport systems.

Insufficient antenatal identification of fetal growth restriction leading to intrauterine fetal death: a regional population-based study in Japan

OBJECTIVE

Fetal growth restriction (FGR) is associated with perinatal adverse outcomes including intrauterine fetal death. Antenatally unidentified FGR has a higher risk of intrauterine fetal death than that identified antenatally. We, therefore, investigated the antenatal identification of FGR among intrauterine fetal deaths, and assessed the perinatal factors associated with the identification of FGR.

METHODS

This retrospective and population-based study reviewed all stillbirths in Shiga Prefecture, Japan, from 2007 to 2016 with exclusion criteria of multiple births, births at unidentified gestational weeks or < 22 gestational weeks, and lethal disorders. We analyzed cases of FGR, using the Japanese clinical definition: Z-score of estimated fetal weight for gestational age <-1.5 standard deviations (SD).

RESULTS

We identified 94 stillbirths with FGR among 429 stillbirths. Thirty-seven cases were antenatally identified during pregnancy management (39%). Dividing cases by a Z-score of -2.5 SD, 51 cases were classified as ≤-2.5 SD. Twenty-eight of the 51 cases (55%) with a Z-score <-2.5 SD were antenatally identified as having FGR, whereas 9 of the 43 cases (21%) with a Z-score ≥-2.5 SD were antenatally identified as having FGR (p = .002). Among cases with a Z-Score <-2.5 SD, 16 of 21 (76%) beyond 28 weeks' gestation and 12 of 30 (40%) before 28weeks' gestation were antenatally identified as having FGR (p = .023).

CONCLUSION

Fetal growth restriction leading to intrauterine fetal death in Japan was antenatally identified in less than half of cases. Antenatal identification of FGR was associated with the severity of growth restriction.

Significant improvement in survival outcomes of trisomy 18 with neonatal intensive care compared to non-intensive care: a single-center study

Background

Trisomy 18 syndrome, also known as Edwards syndrome, is a chromosomal trisomy. The syndrome has historically been considered lethal owing to its poor prognosis, and palliative care was primarily indicated for trisomy 18 neonates. Although there have been several reports on the improvement of survival outcomes in infants with trisomy 18 syndrome through neonatal intensive care, few studies have compared the impact of neonatal intensive care on survival outcomes with that of non-intensive care. Therefore, we compared the survival-related outcomes of neonates with trisomy 18 between intensive and non-intensive care.

Methods

Seventeen infants of trisomy 18 admitted to our center between 2007 and 2019 were retrospectively studied. We divided the patients into a non-intensive group (n = 5) and an intensive group (n = 12) and evaluated their perinatal background and survival-related outcomes of the two groups.

Results

The 1- and 3-year survival rates were both 33% in the intensive group, which was significantly higher than that in the non-intensive group (p < 0.001). Half of the infants in the intensive care group were discharged alive, whereas in the non-intensive care group, all died during hospitalization (p = 0.049).

Conclusions

Neonatal intensive care for neonates with 18 trisomy significantly improved not only survival rates but also survival-discharge rates. Our findings would be helpful in providing 18 trisomy neonates with standard neonatal intensive care when discussing medical care with their parents.

Chronological changes of serum exosome in preterm infants: A prospective study

BACKGROUND

Exosomes, which are observed in all human fluid, including serum, are nanosized extracellular vesicles with a mechanism of intercellular communication. Potential clinical applications of exosomes in neonatal diseases have recently been discussed. However, the characteristics of exosomes in serum during early infancy is unclear.

METHODS

In this prospective study, we evaluated the chronological changes in the concentration of serum-derived exosomes of 20 infants for 12 months after birth.

RESULTS

The average concentration of serum-derived exosomes was 4.6 × 10¹⁰ particles/mL at birth and increased significantly until the age of 48 weeks. There was a moderate correlation between the gestational age and the concentration of serum-derived exosomes both at birth (r = 0.54, P = 0.01) and during the 8 weeks after birth (r = 0.48, P < 0.001). A multivariable analysis showed that gestational age at birth was associated with the concentration of serum-derived exosomes at birth (partial regression coefficient, 0.86; 95% confidence interval, 0.37-1.37; P = 0.002).

CONCLUSIONS

The concentration of serum-derived exosomes in preterm infants increased both chronologically and by gestational age after birth. These basic data may help to further understand physiology of exosomes in preterm infants.

Highest concentration of breast-milk-derived exosomes in colostrum

BACKGROUND

Exosomes are nanosized extracellular vesicles, that play important roles in intercellular immune regulation. They have potential therapeutic utility for neonatal diseases including necrotizing enterocolitis. Breast-milk-derived exosomes have recently shown beneficial effects on intestinal damage in vitro and in vivo. However, the chronological change in breast-milk-derived exosome concentrations after delivery are unclear.

METHODS

In this prospective study, we enrolled 17 mothers who delivered premature infants admitted to a neonatal intensive care unit in Japan. We measured the consecutive concentrations of breast-milk-derived exosomes in the mothers for 48 weeks after delivery.

RESULTS

The median concentration of breast-milk-derived exosomes was 1.62 × 10⁸ particles/ml in colostrum, showing a significant decrease after 2 weeks (P < 0.01). There was no association between the exosome concentration in colostrum and maternal perinatal factors including parity, mode of delivery, maternal age, and gestational age at delivery.

CONCLUSIONS

We concluded that breast-milk-derived exosomes were the richest in colostrum. Our basic data regarding breast-milk-derived exosomes are expected to aid in the clinical application of exosomes for treating neonatal diseases.

Fetal movement counting is associated with the reduction of delayed maternal reaction after perceiving decreased fetal movements: a prospective study

Maternal perception of decreased fetal movement is associated with adverse perinatal outcomes. Although there have been several studies on interventions related to the fetal movements count, most focused on adverse perinatal outcomes, and little is known about the impact of the fetal movement count on maternal behavior after the perception of decreased fetal movement. We investigated the impact of the daily fetal movement count on maternal behavior after the perception of decreased fetal movement and on the stillbirth rate in this prospective population-based study. Pregnant women in Shiga prefecture of Japan were asked to count the time of 10 fetal movements from 34 weeks of gestation. We analyzed 101 stillbirths after the intervention compared to 121 stillbirths before the intervention. In multivariable analysis, maternal delayed visit to a health care provider after the perception of decreased fetal movement significantly reduced after the intervention (aOR 0.31, 95% CI 0.11–0.83). Our regional stillbirth rates in the pre-intervention and post-intervention periods were 3.06 and 2.70 per 1000 births, respectively. Informing pregnant women about the fetal movement count was associated with a reduction in delayed maternal reaction after the perception of decreased fetal movement, which might reduce stillbirths.

Impact of the recommendation for embryo transfer limitation on multiple pregnancy: A population-based study in Japan

OBJECTIVE

Limitations on the number of embryos transferred have been recommended worldwide to reduce the number of medically assisted multiple births. Our aim was to evaluate the impact of this recommendation for embryo transfer limitation on perinatal outcomes of multiple births.

STUDY DESIGN

A retrospective and population-based study compared all multiple births in Shiga prefecture of Japan in 2014-2015 (2015 group) with those in 2007-2008 (2008 group). The perinatal background and neonatal outcomes of multiple births were compared.

RESULTS

The number of multiple pregnancies in the 2015 group (n = 251) was almost the same as in the 2008 group (n = 245). The proportion of multiple pregnancies conceived through assisted reproductive technology significantly decreased to 23% in the 2015 group compared to 31% in the 2008 group. In contrast, the rate of ovulation induction significantly increased to 24% in the 2015 group from 15% in the 2008 group. There was no significant difference in the outcome of multiple-birth infants between the two groups.

CONCLUSION

The method of conception in multiple pregnancies markedly shifted from in vitro fertilization to non-in vitro fertilization after the issuance of a recommendation for limits on embryo transfer. It should be necessary for the assessment of the impact of this recommendation to monitor closely multiple pregnancies via non-in vitro fertilization as well as via in vitro fertilization.

Fetal movement frequency and the effect of associated perinatal factors: Multicenter study

BACKGROUND

Decreased fetal movements are associated with adverse perinatal outcomes, including stillbirth. Delayed maternal visits to a health care provider after perceiving decreased fetal movements are frequently observed in stillbirths. Informing pregnant women of the normal range of fetal movement frequency is essential in their earlier visits in order to prevent stillbirth.

AIM

To investigate the fetal movement frequency in late pregnancy and the effects of associated perinatal factors.

METHODS

This prospective multicenter study was conducted in 20 obstetric facilities in our region of Japan. A total of 2337 pregnant women were asked to record the time it took to perceive 10 fetal movements by the modified 'count to 10' method every day from 34weeks of gestation until delivery.

FINDINGS

The 90th percentile of the time for the maternal perception of 10 fetal movements was 18-29min, with a gradually increasing trend toward the end of pregnancy. The numbers of both pregnant women giving birth after 39weeks' gestation and infants with a birth weight exceeding 3000g were significantly higher in mothers who took ≥30min to count 10 fetal movements than in those who took <30min.

CONCLUSION

The maternal perception time of fetal movements shows a gradually increasing trend within 30min for 10 fetal movements by the modified 'count to 10' method. Informing pregnant women of the normal range of the fetal movement count time will help improve the maternal recognition of decreased fetal movements, which might prevent fetal death in late pregnancy.

Possible Prevention of Neonatal Death: A Regional Population-Based Study in Japan

PURPOSE

The neonatal mortality rate in Japan has currently been at the lowest level in the world. However, it is unclear whether there are still some potentially preventable neonatal deaths. We, therefore, aimed to examine the backgrounds of neonatal death and the possibilities of prevention in a region of Japan.

MATERIALS AND METHODS

This is a population-based study of neonatal death in Shiga Prefecture of Japan.

RESULTS

The 103 neonatal deaths in our prefecture between 2007 and 2011 were included. After reviewing by a peer-review team, we classified the backgrounds of these neonatal deaths and analyzed end-of-life care approaches associated with prenatal diagnosis. Furthermore, we evaluated the possibilities of preventable neonatal death, suggesting specific recommendations for its prevention. We analyzed 102 (99%) of the neonatal deaths. Congenital malformations and extreme prematurity were the first and the second most common causes of death, respectively. More than half of the congenital abnormalities (59%) including malformations and chromosome abnormality had been diagnosed before births. We had 22 neonates with non-intensive care including eighteen cases with congenital abnormality and four with extreme prematurity. Twenty three cases were judged to have had some possibility of prevention with one having had a strong possibility of prevention. Among specific recommendations of preventable neonatal death, more than half of them were for obstetricians.

CONCLUSION

There is room to reduce neonatal deaths in Japan. Prevention of neonatal death requires grater prenatal care by obstetricians before birth rather than improved neonatal care by neonatologists after birth.

Recommendations for preventing stillbirth: a regional population-based study in Japan during 2007-2011

The perinatal mortality rate in Japan has recently been at the lowest level in the world. However, the perinatal mortality rate of Shiga prefecture has been continuously higher than the Japanese average. The reason for this has not yet been explained. The perinatal mortality rate comprises both stillbirths and neonatal deaths. As stillbirths were almost double neonatal deaths, we focused on the stillbirths to determine how they might be prevented. All of the stillbirth certificates in Shiga Prefecture during 2007-2011 were inspected. On the basis of that information, we designed the original questionnaire and sent it to each obstetrician submitting a death certificate to obtain further information associated with the stillbirth. Reviewing retrospectively returned questionnaires by a peer-review team, we evaluated the possibility of preventing stillbirth along with recommendations for prevention. There were 252 stillbirths among 66,682 deliveries in Shiga during this period. We were able to analyze 188 stillbirths (75%). The audit conference judged that 47 cases of them (25%) were determined to have had some possibility of prevention with seven cases (4%) having strong possibility. We identified major causes of preventable stillbirths, including substandard obstetrical management, delayed referral of high-risk women from primary obstetrical clinics to higher perinatal centers, and delayed visits of pregnant women with decreased fetal movements to clinics or hospitals. Based on the results of this study, we conclude that education for pregnant women is required as well as the necessity of improving obstetric care to prevent stillbirths.

Neonatal Meckel diverticulum: Obstruction due to a short mesodiverticular band

This is the first report of symptomatic Meckel diverticulum in a newborn, in which direct compression by a short mesodiverticular band (MDB) caused intestinal obstruction. A short MDB can cause intestinal obstruction due to direct compression. There are two mechanisms by which Meckel diverticulum with MDB can cause intestinal obstruction: internal hernia and direct compression. Onset of intestinal obstruction due to direct compression by a short MDB might be earlier than that for internal hernia with long MDB.

Suspected fetal onset of neonatal transient eosinophilic colitis and development of respiratory distress

Neonatal transient eosinophilic colitis (NTEC) is a new disease concept within eosinophilic gastroenteritis, which was proposed by Ohtsuka et al. It causes hematochezia as a result of eosinophilia, in neonates who have not yet started to receive enteral nutrition, although the whole-body status of the infant is in fact relatively good. To date, there have been no reports of this disease in which abnormalities were noted during gestation, and the clinical phenomena surrounding it, along with any complications, are not yet clear. We encountered a suspected case of NTEC causing respiratory distress with aspiration of hematochezia, in which dilated bowel was noted during gestation. This case indicates that NTEC may occur at the fetal stage and be complicated by respiratory distress.

Efficacy of bronchial fiberscope in esophageal fistula caused by necrotizing bronchitis

Neonatal necrotizing bronchitis is a disease that occurs in premature and low-birthweight infants who are subject to artificial respiratory management, and which has a poor prognosis, because it progresses suddenly and can result in death. There have been no reports of survival to date in cases of tracheo-esophageal fistula caused by necrotizing bronchitis, and no swift and effective management method has yet been reported. This report describes a case in which the use of a bronchial fiberscope in making an early diagnosis facilitated appropriate management and survival. The proactive use of a bronchial fiberscope in regard to this disease, which has a high fatality rate, may save lives.

Neonatal urethral polyps associated with Beckwith-Wiedemann syndrome

We report the first case of Beckwith-Wiedemann syndrome without urinary obstruction, but with a congenital urethral polyp as a tumor protruding from the external urinary meatus. The present case suggests a possible relation between Beckwith-Wiedemann and the onset of fibroepithelial polyps in the reno-urinary system during the neonatal period.

Hallopeau-Siemens dystrophic epidermolysis bullosa due to homozygous 5818delC mutation in the COL7A gene

Epidermolysis bullosa (EB) is a group of inherited mechanobullous skin disease. The dystrophic EB (DEB), one subtype of EB, is inherited in an autosomal dominant DEB or in an autosomal recessive (RDEB). DEB is caused by mutations in the COL7A1 gene encoding type VII collagen, the major component of anchoring fibrils. Over 300 pathogenic mutations have been detected within COL7A in DEB. Patients with the Hallopeau-Siemens type (HS-RDEB), most severe form of DEB, frequently have premature termination codon (PTC) mutations on both alleles. PTC mutations on both alleles result in depleted mRNA and α1 helix, and failure to form the triple helix structure characteristic of type VII collagen. As patients with HS-RDEB usually have a pair of heterozygous PTC mutations, there have been rarely reported homozygous ones in HS-RDEB. We report the first case of HS-RDEB homozygous PTC mutations of 5818delC in both COL7A1 alleles. This case report suggests the positional effect of PTC mutations and vigilance against early infantile death in EB including HS-RDEB.

Lower extremity biomechanics during kendo strike-thrust motion in healthy kendo athletes

AIM

The aim of this study was to demonstrate the kinematics and kinetics of the lower extremity during the kendo strike-thrust motion in experienced kendo athletes.

METHODS

Fifteen experienced kendo athletes (age 20.4±1.2 years; height 171.5±4 cm; weight 73.9±9.1 kg; the kendo experience 11.1±3.1 years) volunteered to participate in the study. The three-dimensional kinematic and kinetic data was collected by the motion analysis system with eight cameras and with a force platform. We instructed the participants to perform three sets of kendo motion at the distances of 1.8 m, 2 m, and 2.2 m to the target. We then obtained the joint kinematic and kinetic data of the ankle dorsiflexion-planterflexion, foot pronation-supination, knee flexion-extension, and hip flexion-extension during the single support phase. The peak foot pronation angle and the range of motion (ROM) of foot pronation were also calculated.

RESULTS

The result demonstrated the high intra-subject repeatability of the joint angle and the torque curve of the left lower extremity during the single support phase in the kendo motion. Our result also showed that as for the peak foot pronation angle and the pronation ROM there was no significant difference between different distances to the target.

CONCLUSION

We provided the basic biomechanical information during the kendo strike-thrust motion, and the result will help us to understand the Achilles tendon injury occurrence in kendo athletes.

The common mechanisms of anterior cruciate ligament injuries in judo: a retrospective analysis

BACKGROUND

Although high prevalence of anterior cruciate ligament injuries (ACL) in judokas has been reported, there has been very little research concerning events preceding the injury.

OBJECTIVE

To determine the common situations and mechanisms of ACL injury in judo.

METHODS

A total of 43 cases of ACL injuries that had occurred during judo competition or practice were investigated, using questionnaires with interviews conducted by a single certified athletic trainer who has 20 years of judo experience to obtain information regarding the situation and mechanism in which the ACL injury occurred.

RESULTS

The number of ACL injuries when the participant's grip style was different from the style of the opponent (ie, kenka-yotsu style) (28 cases) was significantly greater than when the participant's grip style was the same as that of the opponent (ie, ai-yotsu style) (15 cases; p<0.001). The number of ACL injuries was significantly higher when the participant was attacked by the opponent than when counterattacked or when attempting the attack (p<0.001). In addition, being attacked with osoto-gari was revealed as the leading cause of ACL injury incidence among the participants (16.8%).

CONCLUSIONS

Grip style may be associated with ACL injury occurrence in judo. In addition, direct contact due to the opponent's attack may be a common mechanism for ACL injuries in judo.

Expression of pericyte, mesangium and muscle markers in malignant rhabdoid tumor cell lines: differentiation-induction using 5-azacytidine

Malignant rhabdoid tumor (MRT) has been considered to have multiphenotypic diversity characteristics. Some MRTs exhibit a neural phenotype. However, it is still unclear whether MRT cells can display a skeletal muscle, smooth muscle or smooth muscle-like cell phenotype, like those of pericytes and mesangial cells. To determine if MRTs exhibit skeletal muscle cell or smooth muscle-like cell phenotypes, six MRT cell lines (TM87-16, STM91-01, TTC549, TTC642, YAM-RTK1 and TTC1240) were examined for markers of skeletal muscle (MyoD, myogenin, myf-5, myf-6, acetylcholine receptor-alpha, -beta and -gamma), smooth muscle (alpha-smooth muscle actin, SM-1 and SM22), and smooth muscle-like cells, such as pericytes (angiopoietin-1 and -2) and mesangial cells (megsin), using conventional RT-PCR, semi-quantitative PCR, western blotting and immunocytochemistry before and after differentiation-induction with 5-azacytidine. alpha-Smooth muscle actin and SM22 were detected in all six MRT cell lines, while MyoD and myf-5, crucial markers for skeletal myogenic determination, were not. The TM87-16 cell line expressed SM-1 and angiopoietin-1. TTC1240 also expressed angiopoietin-1. Interestingly, STM91-01 expressed megsin, a novel marker for mesangial cells, in addition to angiopoietin-1. Our results indicated that some MRTs exhibited smooth muscle and/or smooth muscle-like cell phenotypes and some renal MRTs might be of mesangial origin. Recently, smooth muscle and also smooth muscle-like cells have been considered to be of neuroectodermal origin. MRT can thus considered to belong to the category of primitive neuroectodermal tumors (PNETs) in the broad sense.

Peters' anomaly with bilateral perisylvian polymicrogyria and abdominal calcification

We report a neonatal case of Peters' anomaly with bilateral perisylvian polymicrogyria and abdominal calcification. The male infant was born after a normal labor. Bilateral central corneal opacities with iridocorneal strands indicated Peters' anomaly. The X-ray and abdominal computed tomography demonstrated multiple calcifications beneath the diaphragma around the liver and the spleen. TORCH serology was negative. Intracranial calcification was not detected. Brain magnetic resonance imaging demonstrated bilateral perisylvian polymicrogyria. Abdominal calcification was suspected to be related to vascular disruption. Bilateral perisylvian polymicrogyria has been thought to result from ischemic events such as intrauterine hypotension or vascular occlusions. Based on these considerations, we conclude that a vascular disruption sequence may an important pathogenetic mechanism of Peters' anomaly.

TRAIL/Apo2L ligands induce apoptosis in malignant rhabdoid tumor cell lines

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a potent inducer of apoptosis in various cancer cells, whereas normal cells are not sensitive to TRAIL-mediated apoptosis. Four TRAIL/Apo2L receptors (DR4, DR5, DcR1, and DcR2) have been identified. DR4 and DR5 have a death domain, whereas DcR1 and DcR2 are called decoy receptors because of their incomplete or lack of a death domain. Malignant rhabdoid tumor (MRT) is an aggressive neoplasm showing a poor prognosis because of its resistance to chemotherapeutic agents. In this study, we examined whether TRAIL could induce apoptotic cell death in MRT cell lines. We found that although half of the MRT cell lines examined were sensitive to TRAIL/Apo2L, Western blot analysis revealed that the expression of DcR2 was low in TRAIL-sensitive MRT cells. We examined the effect of doxorubicin on the expression levels of TRAIL receptors and its enhancement on the susceptibility of MRT cell lines to TRAIL. Western blot and flow cytometric analyses revealed that doxorubicin significantly increased the expression of DR5, and somewhat up-regulated the expression of DR4 and DcR2. Moreover, doxorubicin, NF-kappaB inhibitor (SN50), and PI3-kinase/Akt inhibitor (wortmannin, LY294002) enhanced the susceptibility of MRT cell lines to TRAIL/Apo2L-induced apoptosis. These results suggest that TRAIL/Apo2L may provide the basis for clinical trials of TRAIL-based treatment to improve the outcome of MRT patients.

Estrogen receptor expression and estrogen receptor-independent cytotoxic effects of tamoxifen on malignant rhabdoid tumor cells in vitro

Recent studies have shown that the antiestrogen tamoxifen (TAM) can be used in the treatment of malignant neoplasms other than breast cancer. In the present study, we investigated the expression of estrogen receptor (ER) in six malignant rhabdoid tumor (MRT) cell lines. Alterations in MRT cell growth in response to estrogen or antiestrogens (4-hydroxytamoxifen (4-OHT), TAM, and ICI 182 780) were also investigated. RT-PCR and western blotting showed that ER-alpha was expressed in three of the six MRT cell lines. While 17-beta-estradiol (E2) did not significantly alter MRT cell line proliferation, the hydroxylated tamoxifen metabolite 4-OHT significantly inhibited the growth of all 6 MRT cell lines. However, the steroidal antiestrogen ICI 182 780 did not alter the proliferation of any of the MRT cell lines. 4-OHT induced apoptosis in both ER-alpha-negative and ER-alpha-positive MRT cell lines, as assessed by nuclear morphology and DNA fragmentation. Neither growth inhibition nor induction of apoptosis due to 4-OHT was blocked by the addition of excess E2. Our data suggested that 4-OHT induced cytotoxic effects against MRT cells, and that these effects were independent of ER expression.

Fgf signalling through MAPK cascade is required for development of the subpallial telencephalon in zebrafish embryos

The telencephalon is formed in the most anterior part of the central nervous system (CNS) and is organised into ventral subpallial and dorsal pallial domains. In mice, it has been demonstrated that Fgf signalling has an important role in induction and patterning of the telencephalon. However, the precise role of Fgf signalling is still unclear, owing to overlapping functions of Fgf family genes. To address this, we have examined, in zebrafish embryos, the activation of Ras/mitogen-activated protein kinase (MAPK), one of the major downstream targets of Fgf signalling. Immunohistochemical analysis reveals that an extracellular signal-regulated kinase (ERK), a vertebrate MAPK is activated in the anterior neural boundary (ANB) of the developing CNS at early segmentation stages. Experiments with Fgf inhibitors reveal that ERK activation at this stage is totally dependent on Fgf signalling. Interestingly, a substantial amount of ERK activation is observed in ace mutants in which fgf8 gene is mutated. We then examine the function of Fgf signalling in telencephalic development by use of several inhibitors to Fgf signalling cascade, including dominant-negative forms of Ras (RasN17) and the Fgf receptor (Fgfr), and a chemical inhibitor of Fgfr, SU5402. In treated embryos, the induction of telencephalic territory normally proceeded but the development of the subpallial telencephalon was suppressed, indicating that Fgf signalling is required for the regionalisation within the telencephalon. Finally, antisense experiments with morpholino-modified oligonucleotides suggest that zebrafish fgf3, which is also expressed in the ANB, co-operates with fgf8 in subpallial development.

Synthesis of heparin partial structures and their binding activities to platelets

A synthetic pentasaccharide corresponding to the antithrombin III-binding region in heparin was also found to bind to human platelets. To identify the platelet-binding site in the pentasaccharide which is expected to be a novel sequence in heparin responsible for its platelet-binding, five partial structures of this particular pentasaccharide were synthesized. In a competitive assay using [3H]-heparin, a trisaccharide, O-(2-deoxy-2-sulfamido-3,6-di-O-sulfo-alpha-D-glucopyranosyl)-1--> 4)-O-(2-O-sulfo-alpha-L-idopyranosyluronic acid)-(1-->4)-2-deoxy-2-sulfamido-6-O-sulfo-alpha-D-glucopyranose, was concluded to be a high-affinity site for heparin's binding to platelets.

Induction of the mesendoderm in the zebrafish germ ring by yolk cell-derived TGF-beta family signals and discrimination of mesoderm and endoderm by FGF

The endoderm forms the gut and associated organs, and develops from a layer of cells which emerges during gastrula stages in the vertebrate embryo. In comparison to mesoderm and ectoderm, little is known about the signals which induce the endoderm. The origin of the endoderm is intimately linked with that of mesoderm, both by their position in the embryo, and by the molecules that can induce them. We characterised a gene, zebrafish gata5, which is expressed in the endoderm from blastula stages and show that its transcription is induced by signals originating from the yolk cell. These signals also induce the mesoderm-expressed transcription factor no tail (ntl), whose initial expression coincides with gata5 in the cells closest to the blastoderm margin, then spreads to encompass the germ ring. We have characterised the induction of these genes and show that ectopic expression of activin induces gata5 and ntl in a pattern which mimics the endogenous expression, while expression of a dominant negative activin receptor abolishes ntl and gata5 expression. Injection of RNA encoding a constitutively active activin receptor leads to ectopic expression of gata5 and ntl. gata5 is activated cell-autonomously, whereas ntl is induced in cells distant from those which have received the RNA, showing that although expression of both genes is induced by a TGF-beta signal, expression of ntl then spreads by a relay mechanism. Expression of a fibroblast growth factor (eFGF) or a dominant negatively acting FGF receptor shows that ntl but not gata5 is regulated by FGF signalling, implying that this may be the relay signal leading to the spread of ntl expression. In embryos lacking both squint and cyclops, members of the nodal group of TGF-beta related molecules, gata5 expression in the blastoderm is abolished, making these factors primary candidates for the endogenous TGF-beta signal inducing gata5.

A novel crosslinking reagent and its application for the detection and isolation of heparin-binding protein(s) on the platelet surface

A new hetero-bifunctional photo crosslinking reagent, 2-(4-azidoanilyl)-4-(4-azabicyclo-[2,2, 2]hexylammonio)-6-morpholino-1,3,5-triazine chloride, was designed to detect and isolate heparin-binding protein(s) that may act as heparin-receptor(s) on the platelet surface. In a preliminary study using ethanol as a model substrate, the reagent was shown to react with the alcoholic hydroxy group under mild conditions and its crosslinking photoreactivity was high. The reagent effectively formed similar covalent bonds with heparin, while preserving its anticoagulant anti-Xa activity. [3H]Heparin labeled with this reagent crosslinked to antithrombin III very specifically but not to ovalbumin, as analyzed by the Bio-imaging Analyzer System (BAS, Fuji Photo Film, Tokyo). Affinity crosslinking of [3H]heparin was then used to detect heparin-binding proteins on the surface of intact platelets. Several discrete protein bands were detected by the BAS-imaging of SDS-PAGE.

Differential expression of C-protein isoforms in developing and degenerating mouse striated muscles

With the aim of clarifying the roles of C-protein isoforms in developing mammalian skeletal muscle, we cloned the complementary DNA (cDNAs) encoding mouse fast (F) and slow (S) skeletal muscle C-proteins and determined their entire sequences. Northern blotting with these cDNAs together with mouse cardiac (C) C-protein cDNA was performed. It revealed that in adult mice, C, F, and S isoforms are expressed in a tissue-specific fashion, although the messages for both F and S isoforms are transcribed in extensor digitorum longus muscle, which has been categorized as a fast muscle. In addition, although C isoform is expressed first and transiently during development of chicken skeletal muscles, C isoform is not expressed in mouse skeletal muscles at all through the developmental stages; S isoform is first expressed, followed by the appearance of F isoform. Finally, in dystrophic mouse skeletal muscles, the expression of S isoform is increased as it is in dystrophic chicken muscle. These observations suggest that mutations in C isoform (MyBP-C) do not lead to any disturbance in skeletal muscle, although they may lead to familial hypertrophic cardiomyopathy. We also suggest that the expression of S isoform may be stimulated in degenerating human dystrophic muscles.

Initial anteroposterior pattern of the zebrafish central nervous system is determined by differential competence of the epiblast

Analyses using amphibian embryos proposed that induction and anteroposterior patterning of the central nervous system is initiated by signals that are produced by the organizer and organizer-derived axial mesoderm. However, we show here that the initial anteroposterior pattern of the zebrafish central nervous system depends on the differential competence of the epiblast and is not imposed by organizer-derived signals. This anteroposterior information is present throughout the epiblast in ectodermal cells that normally give rise both to neural and non-neural derivatives. Because of this information, organizer tissues transplanted to the ventral side of the embryo induce neural tissue but the anteroposterior identity of the induced neural tissue is dependent upon the position of the induced tissue within the epiblast. Thus, otx2, an anterior neural marker, was only ever induced in anterior regions of the embryo, irrespective of the position of the grafts. Similarly, hoxa-1, a posterior neural marker was induced only in the posterior regions. Furthermore, the boundary of each ectopic expression domain on the ventral side was always at an equivalent latitude to that of the endogenous expression of the dorsal side of the embryo. The anteroposterior specification of the epiblast is independent of the dorsoventral specification of the embryo because neural tissues induced in the ventralized embryos also showed anteroposterior polarity. Cell transplantation and RNA injection experiments showed that non-axial marginal mesoderm and FGF signalling is required for anteroposterior specification of the epiblast. However, the requirement for FGF signalling is indirect in that cells with compromised ability to respond to FGF can still respond to anteroposterior positional information.

Zebrafish wnt11: pattern and regulation of the expression by the yolk cell and No tail activity

This study analyzed the spatial and temporal expression pattern of zebrafish wnt11 and the regulation of the expression during zebrafish early development, focusing on the interaction with the no tail (ntl) gene, a zebrafish orthologue of mouse Brachyury (T). Zygotic expression of wnt11 was first detected at the late blastula stage in the blastoderm margin, a presumptive mesoderm region. wnt11 expression coincided with mesoderm induction, and the expression was induced by mesoderm inducers such as the yolk cell (Mizuno, T., Yamaha, E., Wakahara, M., Kuroiwa, A., Takeda, H., 1996. Mesoderm induction in zebrafish. Nature 383, 131-132) or FGFs, indicating that, like ntl, wnt11 is one of the immediate-early genes in mesoderm induction. Initial expression domains of wnt11 and ntl overlapped, and these genes showed a similar response to mesoderm inducers. However, analysis of the ntl mutant embryos suggested that wnt11 and ntl are placed in distinct genetic pathways; the ntl mutation had no effect on wnt11 expression in the blastoderm margin. This was further supported by the result of RNA injection experiments showing that overexpression of Wnt11 did not affect ntl expression in the margin. Thus, wnt11 and ntl expression are induced and maintained independently in their initial phase of expression. In later stages, wnt11 was expressed in various organs, such as the somites, particularly in the developing notochord. Since no wnt gene has been reported to be expressed in the axial mesoderm, which is known to act as a signaling source that patterns the neural tube and somites, zebrafish wnt11 is the first wnt gene expressed in the notochord. Furthermore, in contrast to early expression, wnt11 expression in the notochord depended on Ntl activity. In the ntl mutant in which somite patterning is severely affected, wnt11 expression was completely lost, while another signaling molecule, sonic hedgehog is expressed in the mutant notochord precursor cells (Krauss, S., Concordet, J.-P., Ingham, P.W., 1993. A functionally conserved homolog of the Drosophila segment polarity gene hh is expressed in tissues with polarizing activity in zebrafish embryos. Cell 75, 1431-1444). wnt11 expression in the somite also shows a characteristic pattern, correlated with the migration and differentiation of slow muscle precursors. These observations suggest a role for wnt11 in patterning the somites.

Epimorphin functions as a key morphoregulator for mammary epithelial cells

Hepatocyte growth factor (HGF) and EGF have been reported to promote branching morphogenesis of mammary epithelial cells. We now show that it is epimorphin that is primarily responsible for this phenomenon. In vivo, epimorphin was detected in the stromal compartment but not in lumenal epithelial cells of the mammary gland; in culture, however, a subpopulation of mammary epithelial cells produced significant amounts of epimorphin. When epimorphin-expressing epithelial cell clones were cultured in collagen gels they displayed branching morphogenesis in the presence of HGF, EGF, keratinocyte growth factor, or fibroblast growth factor, a process that was inhibited by anti-epimorphin but not anti-HGF antibodies. The branch length, however, was roughly proportional to the ability of the factors to induce growth. Accordingly, epimorphin-negative epithelial cells simply grew in a cluster in response to the growth factors and failed to branch. When recombinant epimorphin was added to these collagen gels, epimorphin-negative cells underwent branching morphogenesis. The mode of action of epimorphin on morphogenesis of the gland, however, was dependent on how it was presented to the mammary cells. If epimorphin was overexpressed in epimorphin-negative epithelial cells under regulation of an inducible promoter or was allowed to coat the surface of each epithelial cell in a nonpolar fashion, the cells formed globular, alveoli-like structures with a large central lumen instead of branching ducts. This process was enhanced also by addition of HGF, EGF, or other growth factors and was inhibited by epimorphin antibodies. These results suggest that epimorphin is the primary morphogen in the mammary gland but that growth factors are necessary to achieve the appropriate cell numbers for the resulting morphogenesis to be visualized.

Identification of cellular recognition sequence of epimorphin and critical role of cell/epimorphin interaction in lung branching morphogenesis

A mesenchymal protein, epimorphin, is known to bind directly to the cell surface through its central portion and to act as a signaling molecule for epithelial morphogenesis. Utilizing several recombinant polypeptides and synthetic peptides, we identified the cellular recognition sequence of epimorphin in the central portion of this molecule (amino acids 105-123, NGNRTSVDLRIRRTQHSVL; termed NL-peptide sequence). Interestingly, although a model cell type bound to the NL-peptide as strong as to the full-length epimorphin, this peptide itself didn't induce the cellular functional responses so far tested. We found that the NL-peptide behaved as an antagonist for the endogenous epimorphin and severely perturbed lung branching morphogenesis in organ culture. These results not only revealed a part of the functional mechanism of epimorphin but also demonstrated that cell/ epimorphin interaction through the NL-peptide sequence is a critical step for lung epithelial morphogenesis.

Complete primary structure of chicken cardiac C-protein (MyBP-C) and its expression in developing striated muscles

C-protein (MyBP-C) is a myosin binding protein of about 140 kDa which is known to modulate myosin assembly in striated muscles. A cardiac-type isoform of C-protein appears not only in cardiac muscle but also in skeletal muscle before skeletal muscle-type isoforms become detectable during myogenesis, suggesting that the cardiac isoform is involved in the early phase of myofibrillogenesis (Bähler et al., 1985; Kawashima et al., 1986). In this study, in order to understand the structure and functional domains of the cardiac-type C-protein, we cloned and sequenced full-length cDNAs encoding chicken cardiac C-protein from lambda gt11 cDNA libraries which were prepared with poly (A)+ RNA from embryonic chicken cardiac muscle as well as embryonic chicken skeletal muscle by using antibodies specific for cardiac C-protein. Two cDNA variants, probably generated by alternative RNA splicing and encoding different C-protein isoforms, were detected. As judged by the cDNA sequences determined, overall homology of the peptide sequence between cardiac and skeletal muscle C-proteins (Einheber et al., 1990; Fürst et al., 1992, Weber et al., 1994) was about 50-55%. Like other myosin binding proteins, skeletal C-proteins, 86 kDa protein and M-protein, cardiac C-protein contains several copies of fibronectin type III motifs and immunoglobulin C2 motifs in the molecule, but their number and arrangements differed somewhat from those in the other proteins. Northern blot analysis with the cloned cDNA as a probe demonstrated that mRNA of 5.0 kb is transcribed in both cardiac and embryonic skeletal muscle, and that it is specifically expressed in cardiac muscle among adult tissues.

Assembly of cardiac C-protein during myofibrillogenesis in myogenic cells in culture

To examine the function of C-protein, a thick filament-associated protein of vertebrate striated muscles, during myofibrillogenesis, the cDNA encoding chicken cardiac C-protein and the truncated cDNA were subcloned into a expression vector and introduced into mouse C2 myogenic cells. The expression and assembly of the C-protein was investigated by immunofluorescence methods. When the cDNA containing the entire open reading frame was introduced, in C2 myoblasts, the transiently expressed exogenous cardiac C-protein existed only diffusely in the cytoplasm, but it became localized in striated structures together with sarcomeric myosin heavy chains (MHC) in myotubes. To clarify the functional domains of C-protein, the cDNA constructs that lack the regions encoding the C-terminal immunoglobulin (Ig) C2 motif or the N-terminal Ig C2 motif were introduced into C2 cells to produce mutant proteins. The truncated chicken cardiac C-protein, which lacked the C-terminal Ig C2 motif, apparently lost the ability to bind to myosin filaments; the protein was not assembled into myofibrils but diffused in the cytoplasm even in the myotubes. The protein without N-terminal Ig C2 motif, however, was assembled into sarcomeric structures just as complete protein molecules. From these results, we conclude that 1) the assembly of sarcomeric MHC into myofibrils in myotubes is accompanied with that of cardiac C-protein, and 2) the C-terminal Ig C2 motif is necessary for assembly of cardiac C-protein in sarcomeric structures in the cytoplasm.