Perinatal development of styrene monooxygenase and epoxide hydrolase in rat liver microsomes and nuclei

Nuclear enzymes were found to develop earlier than the corresponding microsomal activities. In fact styrene monooxygenase enzymatic activity at 18 days gestational age reached about half the values of adult animals, whereas fetal microsomal activity was only about $\text{1}\text{20}$ the adult level at the same age. In microsomes and nuclei the ontogenic development of epoxide hydrolase is slightly slower than styrene monooxygenase. This suggests that fetuses and newborn animals are exposed to higher risk of accumulation of styrene-7,8-oxide, a toxic and possibly teratogenic product of styrene monooxygenase.     

Immunocytochemical localisation of prolactin and growth hormone in the perinatal sheep pituitary

Summary The peroxidase anti-peroxidase immunocytochemical staining technique has been used to identify prolactin and growth hormone cells in pituitaries from fetal and neonatal sheep. The size of the secretory granules in these cell types has been measured using the image analysing computer Quantimet 720. The area size distributions of the fetal prolactin and growth hormone granules were compared with those in the neonate and the adult. It appears that the gestational age of the fetus may influence the size range of prolactin secretory granules.     

Perinatal stem cells: A promising cell resource for tissue engineering of craniofacial bone

In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongoing research of regenerative medicine using stem cells and concurrent advancement in biotechnology have shifted the focus from surgical reconstruction to a novel stem cell-based tissue engineering strategy for customized and functional craniofacial bone regeneration. Given the unique ontogenetical and cell biological properties of perinatal stem cells, emerging evidence has suggested these extraembryonic tissue-derived stem cells to be a promising cell source for extensive use in regenerative medicine and tissue engineering. In this review, we summarize the current achievements and obstacles in stem cell-based craniofacial bone regeneration and subsequently we address the characteristics of various types of perinatal stem cells and their novel application in tissue engineering of craniofacial bone. We propose the promising feasibility and scope of perinatal stem cell-based craniofacial bone tissue engineering for future clinical application.     

Gene Trap Mice Reveal an Essential Function of Dual Specificity Phosphatase Dusp16/MKP-7 in Perinatal Survival and Regulation of Toll-like Receptor (TLR)-induced Cytokine Production

MAPK activity is negatively regulated by members of the dual specificity phosphatase (Dusp) family, which differ in expression, substrate specificity, and subcellular localization. Here, we investigated the function of Dusp16/MKP-7 in the innate immune system. The Dusp16 isoforms A1 and B1 were inducibly expressed in macrophages and dendritic cells following Toll-like receptor stimulation. A gene trap approach was used to generate Dusp16-deficient mice. Homozygous Dusp16tp/tp mice developed without gross abnormalities but died perinatally. Fetal liver cells from Dusp16tp/tp embryos efficiently reconstituted the lymphoid and myeloid compartments with Dusp16-deficient hematopoietic cells. However, GM-CSF-induced proliferation of bone marrow progenitors in vitro was impaired in the absence of Dusp16. In vivo challenge with Escherichia coli LPS triggered higher production of IL-12p40 in mice with a Dusp16-deficient immune system. In vitro, Dusp16-deficient macrophages, but not dendritic cells, selectively overexpressed a subset of TLR-induced genes, including the cytokine IL-12. Dusp16-deficient fibroblasts showed enhanced activation of p38 and JNK MAPKs. In macrophages, pharmacological inhibition and siRNA knockdown of JNK1/2 normalized IL-12p40 secretion. Production of IL-10 and its inhibitory effect on IL-12 production were unaltered in Dusp16tp/tp macrophages. Altogether, the Dusp16 gene trap mouse model identifies an essential role in perinatal survival and reveals selective control of differentiation and cytokine production of myeloid cells by the MAPK phosphatase Dusp16.     

Rat liver glycogen metabolism in the perinatal period

The correlation between blood glucose levels, the concentration of glycogen, the activities of glycogen sythase and phosphorylase and their respective kinases and phosphatases was examined in liver of rat fetuses between day 18 of gestation and one day after birth. Between day 18 and 21 there is a rapid increase in the concentration of glycogen and in the activity of synthase a and a much slower increase in the activity of phosphorylase a. The activity of the respective kinases increased rapidly during this period and reached maximun on day 21. The activity of synthase phosphatase and phosphorylase phosphatase increased after day 18, to reach a maximum on day 19 and 20, respectively, but decreased again towards day 21. The possibility that the changes in glycogen concentration and enzyme activities were related to an effect of glucose of AMP on the respective phosphatases was considered. It was found that the Km of phosphatase for glucose in the prenatal period was 5–7 mM, as in the adult. Since the level of blood glucose during this period was constant (2.8 mM), an effect of glucose on phosphatase activity seems unlikely. AMP concentration increased between day 18 and 21 from 6–15 nmol/g. In view of the low level of phosphorylase a activity during this period, the increase in AMP concentration is not considered to be important in the regulation of glycogen breakdown at this time.Immediately after birth blood glucose levels dropped to 5 mg/dl. This was accompanied by a rapid decrease in glycogen concentration and in the activity of glycogen synthase and a rise in phosphorylase activity. Blood glucose levels returned to the initial level within 1 h after birth, whereas the changes in glycogen concentration and enzyme activities continued for at least 3 h after birth. On day 22 all parameters examined had reached the level found in adult rat liver.It is suggested that the rapid changes observed immediately after birth are due to an effect of hypoglycemia mediated by hormones and cannot be ascribed to direct effects of metabolites on the enzyme systems involved.     

妊娠合并血小板减少136例临床研究

目的：探讨妊娠合并血小板减少的原因及围生期处理方法。方法：回顾性分析2005年10月-2011年4月产科分娩的136例妊娠合并血小板减少患者临床资料。结果：妊娠合并血小板减少的主要原因有妊娠相关性血小板减少症（PAT）79例（58．09％）、妊娠期高血压疾病（PIH）21例（15．44％）、特发性血小板减少性紫癜（ITP）18例（13．24％）、妊娠期肝内胆汁瘀积症（ICP）16例（11．76％）;阴道分娩52例,剖宫产84例;产后出血16例,产褥感染1例。结论：多种原因可以导致妊娠妇女血小板减少。PAT是最常见类型。治疗采用针对病因治疗的基础上给予糖皮质激素、丙种球蛋白、输血小板等综合治疗。分娩方式视血小板多少及有无产科指征而定。     

Perinatal Hypoxia-Ischemia Disrupts Striatal High-Affinity [3H]Glutamate Uptake into Synaptosomes

We examined the impact of hypoxia-ischemia on high-affinity [3H]glutamate uptake into a synaptosomal fraction prepared from immature rat corpus striatum. In 7-day-old pups the right carotid artery was ligated, and pups were exposed to 8% oxygen for 0, 0.5, 1, or 2.5 h, and allowed to recover for up to 24 h before they were killed. High-affinity glutamate uptakes in striatal synaptosomes derived from tissue ipsilateral and contralateral to ligation were compared. After 1 h of hypoxia plus ischemia, high-affinity glutamate uptake in the striatum was reduced by 54 +/- 13% compared with values from the opposite (nonischemic) side of the brain (p less than 0.01, t test versus ligates not exposed to hypoxia). There were similar declines after 2.5 h of hypoxia-ischemia. Activity remained low after a 1 h recovery period in room air, but after 24 h of recovery, high-affinity glutamate uptake was equal bilaterally. Kinetic analysis revealed that loss of activity could be attributed primarily to a 40% reduction in the number of uptake sites. Hypoxia alone had no effect on high-affinity glutamate uptake although it reduced synaptosomal uptake of [3H]3,4-dihydroxyphenylethylamine. Addition of 1 mg/ml of bovine serum albumin to the incubation medium preferentially stimulated high-affinity glutamate uptake in hypoxic-ischemic brain compared with its effects in normal tissue. These studies demonstrate that hypoxia-ischemia reversibly inhibits high-affinity glutamate uptake and this occurs earlier than the time required to produce neuronal damage in the model.     

A freeze-fracture study of perinatal changes of intramembranous particles in microvilli of absorptive cells in mouse small intestine

Summary Perinatal changes in the appearance of intramembranous particles (IMPs) of microvilli of enterocytes were analyzed quantitatively. In both the jejunum and the ileum, the IMP density on the P-face showed no significant changes from day 17 of gestation to day 5 of postnatal life. It increased between day 5 and day 12, reached a maximum at day 21, and thereafter decreased slightly. The IMP density on the E-face remained almost constant during the perinatal period in both intestinal parts. Measurements of particle diameters proved that neither the P-face nor the E-face membrane showed significant differences in either mean value or size distribution among different age groups.This study has revealed that the perinatal change in the IMP density on the P-face of microvilli correlates well with changes in the activity of certain enzymes found in the membranes of microvilli, e.g. disaccharidase and aminopeptidase.This study was supported by a Grant-in-Aid for Scientific Research to T. Yamamoto from the Ministry of Education, Science and Culture of Japan     

Changing patterns of placental hexokinase isozymes during the course of gestation.

Hexokinase, an enzyme that is capable of regulating the entry of glucose into metabolic sequences, is known to exist in four isozyme forms in a variety of mammalian tissues. Each of these isozymes possesses different kinetic properties, suggesting that they may serve in different regulatory capacities. In addition, the proportions of the four isozymes are characteristically different for various differentiated tissues, presumably reflecting different metabolic capabilities of the tissues.Extracts of rabbit and human placentas from early gestational age and term pregnancies were chromatographed and assayed for hexokinase activity. Four peaks of activity were observed. Elution positions of the four placental hexokinase isozymes were comparable to those from liver; however, the relative proportions were considerably different. In both rabbit and human placentas, the proportion of Type I hexokinase increased during gestation and Type III decreased, while Types II and IV remained essentially unchanged. Implications of the gestational changes for placental carbohydrate metabolism are discussed.     

Effect of thyroid deficiency on Go α-subunit isoforms in developing rat cerebral cortex

Postnatal development of G_o isoforms in rat cerebral cortex was studied by SDS-PAGE and immunoblotting. When rat cerebral cortical membranes were resolved on separating gels containing 9% acrylamide and 8 M urea, three electrophoretically distinct G_o-immunoreactive proteins were evident. Comparison of their electrophoretic mobilities and partial tryptic digest pattern with recombinant G_o1 or G_o1-specific antibody revealed that the slowest and intermediate-migrating bands represent unmodified and fatty acylated forms of G_o1 protein, respectively. The fastestmigrating band corresponds to G_o2. While the fatty acylated form of G_o1 is the predominant species, its appearance paralleled that observed for G_o2 in developing rat cortex. Perinatal hypothyroidism induced by methimazole treatment did not significantly alter the appearance of cerebral cortical G_o1 and G_o2 between days 1 and 22 postpartum. Our findings support the earlier idea that heterogeneity of G_o proteins in mammalian brain is likely the result of different co- or post-translational processings of each splice variant of G_o. While the appearance of G_o isoforms is developmentally regulated, they likely do not play an obligatory role in neonatal brain development. Alternatively, the expression of G_o isoforms in developing rat cortex may be controlled by an intrinsic signal(s) that is independent of the thyroid status.