Comparison of Birth Weight/Gestation Distribution in Cases of Stillbirth and Neonatal Death According to Lesions Found at Necropsy

The birth weight/gestation distribution of a large series of cases of perinatal death has been analysed according to the lesion (or lesions) present at necropsy. Among the lesions associated with low gestation babies dying with hyaline membranes have a much higher mean birth weight for gestation than either the babies with intraventricular haemorrhage or “no cause found.” Among infants dying of intrapartum asphyxia or cerebral birth trauma it was found that those who were stillborn with trauma had, at term, a significantly higher mean birth weight than the control livebirths, and that, at all gestations, the stillbirths with trauma were, on average, heavier than the babies dying neonatally with this lesion. Cases of intrapartum asphyxia were smaller than the stillbirths with trauma, but those dying during the second stage of labour were larger than those dying during the first stage.Cases of intrauterine pneumonia—that is, stillbirths and first-day deaths—were also shown to be larger for length of gestation than cases of extrauterine pneumonia—that is, deaths between the second and the 28th day. The cases with haemorrhagic pneumonia, however, were, at least at term, smaller than the cases of extrauterine pneumonia, and cases of massive pulmonary haemorrhage showed evidence of growth retardation at all gestations.     

S-100B蛋白在新生儿缺氧缺血性脑病中的临床应用进展

S-100B蛋白是一类钙离子结合蛋白,由神经系统胶质细胞分泌,广泛分布于神经组织中。在正常情况下发挥重要的生理作用,但分泌过高具有神经毒性。血清中S-100B蛋白含量与新生儿缺氧缺血性脑病(HIE)呈正相关,可作为早期诊断HIE脑损伤及判断损伤程度及预后的有效指标。通过动态监测S-100B蛋白含量,了解脑损伤后血清中S-100B蛋白水平变化的时间规律性,S-100B蛋白可作为脑损伤后神经生化新标志物。本文对血清S-100B蛋白在新生儿缺氧缺血性脑病诊断中的价值作一综述。     

Relationship of Urinary Phthalate Metabolites with Serum Thyroid Hormones in Pregnant Women and Their Newborns: A Prospective Birth Cohort in Taiwan

Background

The purpose of this study was to examine the relationship of phthalates exposure with thyroid function in pregnant women and their newborns.

Methods

One hundred and forty-eight Taiwanese maternal and infant pairs were recruited from E-Da hospital in southern Taiwan between 2009 and 2010 for analysis. One-spot urine samples and blood samples in the third trimester of pregnant women and their cord blood samples at delivery were collected. Nine phthalate metabolites in urine were determined by triple quadrupole liquid chromatography tandem mass spectrometry, whereas serum from pregnant women and their cord blood were used to measure thyroid profiles (thyroid-stimulating hormone [TSH], thyroxine, free thyroxine, and triiodothyronine) by radioimmunoassay.

Results

Median levels of urinary mono-n-butyl phthalate, mono-ethyl phthalate, and mono-(2-ethyl-5-oxohexyl) phthalate (μg/g creatinine) were the three highest phthalate metabolites, which were 37.81, 34.51, and 21.73, respectively. Using Bonferroni correction at a significance of < 0.006, we found that urinary mono-benzyl phthalate (MBzP) levels were significantly and negatively associated with serum TSH in cord blood (β = -2.644, p = 0.003).

Conclusions

Maternal urinary MBzP, of which the parental compound is butylbenzyl phthalate, may affect TSH activity in newborns. The alteration of thyroid homeostasis by certain phthalates in the early life, a critical period for neurodevelopment, is an urgent concern.     

S100A6 and S100A11 are specific targets of the calcium- and zinc-binding S100B protein in vivo

In solution, S100B protein is a noncovalent homodimer composed of two subunits associated in an antiparallel manner. Upon calcium binding, the conformation of S100B changes dramatically, leading to the exposure of hydrophobic residues at the surface of S100B. The residues in the C-terminal domain of S100B encompassing Phe(87) and Phe(88) have been implicated in interaction with target proteins. In this study, we used two-hybrid technology to identify specific S100B target proteins. Using S100B as bait, we identify S100A6 and S100A11 as specific targets for S100B. S100A1, the closest homologue of S100B, is capable of interaction with S100B but does not interact with S100A6 or S100A11. S100B, S100A6, and S100A11 isoforms are co-regulated and co-localized in astrocytoma U373 cells. Furthermore, co-immunoprecipitation experiments demonstrated that Ca(2+)/Zn(2+) stabilizes S100B-S100A6 and S100B-S100A11 heterocomplexes. Deletion of the C-terminal domain or mutation of Phe(87) and Phe(88) residues has no effect on S100B homodimerization and heterodimerization with S100A1 but drastically decreases interaction between S100B and S100A6 or S100A11. Our data suggest that the interaction between S100B and S100A6 or S100A11 should not be viewed as a typical S100 heterodimerization but rather as a model of interaction between S100B and target proteins.     

Deletion of STK40 Protein in Mice Causes Respiratory Failure and Death at Birth

STK40 is a putative serine/threonine kinase and was shown to induce extraembryonic endoderm differentiation from mouse embryonic stem cells. However, little is known about its physiological function in vivo. Here, we generate Stk40 knock-out mice and demonstrate that loss of the Stk40 gene causes neonatal lethality at birth. Further examination reveals that the respiratory distress and atelectasis occur in the homozygous mutants. The maturation of lung and alveolar epithelium is delayed in the mutant, as indicated by narrowed air spaces, thickened interstitial septa, and increased glycogen content in the lungs of Stk40^−/− mice. The reduction in levels of T1-α, SP-B, and SP-C indicates delayed maturation of both type I and type II respiratory epithelial cells in Stk40^−/− lungs. Moreover, Stk40 is found to be most highly expressed in lungs of both fetal and adult mice among all organs tested. Mechanistically, a genome-wide RNA microarray analysis reveals significantly altered expression of multiple genes known to participate in lung development. The expression of some genes involved in lipid metabolism, immune response, and glycogen metabolism is also disrupted in the lung of Stk40^−/− mice. Protein affinity purification identifies RCN2, an activator of ERK/MAPK signaling, as an STK40-associated protein. Consistently, Stk40 deficiency attenuates the ERK/MAPK activation, and inhibition of ERK/MAPK activities reduces surfactant protein gene expression in lung epithelial cells. Collectively, this study uncovers an important role of STK40 for lung maturation and neonatal survival. STK40 may associate with RCN2 to activate ERK/MAPK signaling and control the expression of multiple key regulators of lung development.     

The S100B story: from biomarker to active factor in neural injury

The pressure to develop pharmacological therapeutic interventions in the field of the rapidly progressing, fatal disease amyotrophic lateral sclerosis (ALS) is traditionally high. Cannabinoids have been discussed for decades as potential neuroprotective agents for ALS because of their antiexcitatory, anti‐inflammatory, antiapoptotic and anticatabolic properties. This Editorial highlights a study by Urbi et al in the current issue of the Journal of Neurochemistry, in which the authors performed a Systematic Review and come to the conclusion that cannabinoids seem to have a small, but consistent effect on survival and function of the G93A mice, a standard model for ALS. However, some methodological concerns regarding translation of findings made in G93A mice come to mind, and thus the Systematic Review emphasizes the need to critically assess differences between mice and humans.     

A model of full-length RAGE in complex with S100B

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Redox modifications of the C-terminal cysteine residue cause structural changes in S100A1 and S100B proteins

S100 is a family of small, acidic, calcium binding proteins involved in the control of a multitude of intra- and extracellular processes, including many pathologies. The application of the analytical methodology based on the combination of RP HPLC and ESI-MS allowed for the characterization of S-nitrosylation and S-glutathionylation in two representative S100 proteins: S100A1 and S100B. The GSNO related S-nitrosylation of the conserved C-terminal cysteine is strongly activated by the binding of Ca(II) to S100A1 and of Ca(II) and Zn(II) to S100B. This modification results in a global alteration of protein structure, as demonstrated by a variety of techniques. The presented results provide a mechanistic basis for further studies of the function of S100 proteins in the control of redox-based and metal-based signal transduction.     

Accuracy of SenseWear Pro2 Armband to Predict Resting Energy Expenditure in Childhood Obesity

Objective: The accuracy of the SenseWear Pro2 Armband (SWA) in estimating resting energy expenditure (REE) in children and adolescents with obesity, using indirect calorimetry (IC) as a reference was evaluated. Design and Methods: REE was assessed using both the SWA and IC in 40 obese subjects (26 M/14 F, age 11.5 ± 2.57 years, z‐score BMI 3.14 ± 0.53). The agreement between methods was assessed by the Bland‐Altman procedure. The relationship between REE assessments and patients' characteristics was also analyzed. Results : SWA‐ and IC‐derived estimates of REE showed a significant correlation (r = 0.614; P < 0.001), but the SWA overestimated mean REE by 13% (P < 0.001). Age and kilogram of fat‐free mass (kg‐FFM) were significantly correlated with both REE estimation by SWA (r = 0.434 and r = 0.564, respectively) and IC (r = 0.401 and r = 0.518, respectively). Only kg‐FFM was demonstrated to be the main predictor factor of REE variability (r² 79% SWA; 75% IC). Conclusions: The SWA overestimated mean REE in childhood obesity, suggesting that the SWA and IC are not yet interchangeable methods. This would require improving the SWA by developing better algorithms for predicting REE and, probably, bias in each individual REE could be reduced by an adjustment for subjects' kg‐FFM.     

The Administration of 100% Oxygen and Respiratory Drive in Very Preterm Infants at Birth

Aim

To retrospectively investigate the changes of SpO₂ and respiratory drive in preterm infants at birth after administration of 100% oxygen.

Methods

Respiratory parameters, FiO₂ and oximetry of infants <32 weeks gestation before and after receiving FiO₂ 1.0 were reviewed during continuous positive airway pressure (CPAP) or positive pressure ventilation (PPV).

Results

Results are given as median (IQR) or percentages where appropriate. Suitable recordings were made in 50 infants (GA 27 (26–29) weeks), 17 received CPAP and 33 PPV. SpO₂ increased rapidly in the first minute after FiO₂ 1.0 and remained stable. The duration of FiO₂ 1.0 tended to be shorter in the CPAP group than in the PPV group (CPAP vs. PPV: 65 (33–105) vs. 100 (40–280) s; p = 0.05), SpO₂ >95% occurred more often in PPV group (53% vs. 69%) and lasted longer (70(40–95) vs. 120(50–202) s). In CPAP group, minute volume increased from 134 (76–265) mL/kg/min 1 minute before to 240 (157–370) mL/kg/min (p<0.01) 1 minute after start FiO₂ 1.0 and remained stable at 2 minutes (252 (135–376) mL/kg/min; ns). The rate of rise to maximum tidal volume increased (from 13.8 (8.0–22.4) mL/kg/s to 18.2 (11.0–27.5) mL/kg/s; p<0.0001) to 18.8 (11.8–27.8) mL/kg/s; ns). In the PPV group respiratory rate increased from 0(0–4) to 9(0–20) at 1 minute (p<0.001) to 23 (0–34) breaths per minute at 2 minutes (p<0.01).

Conclusion

In preterm infants at birth, a rapid increase in oxygenation, resulting from a transient increase to 100% oxygen might improve respiratory drive, but increases the risk for hyperoxia.     

Oligomerization state of S100B at nanomolar concentration determined by large-zone analytical gel filtration chromatography.

S100B is a Ca(2+)-binding protein known to be a non-covalently associated dimer, S100B(beta beta), at high concentrations (0.2-3.0 mM) under reducing conditions. The solution structure of apo-S100B (beta beta) shows that the subunits associate in an antiparallel manner to form a tightly packed hydrophobic core at the dimer interface involving six of eight helices and the C-terminal loop (Drohat AC, Amburgey JC, Abildgaard F, Starich MR, Baldisseri D, Weber DJ. 1996. Solution structure of rat apo-S100B (beta beta) as determined by NMR spectroscopy. Biochemistry 35:11577-11588). The C-terminal loop, however, is also known to participate in the binding of S100B to target proteins, so its participation in the dimer interface raises questions as to the physiological relevance of dimeric S100B (beta beta). Therefore, we investigated the oligomerization state of S100B at low concentrations (1-10,000 nM) using large-zone analytical gel filtration chromatography with 35S-labeled S100B. We found that S100B exists (> 99%) as a non-covalently associated dimer, S100B (beta beta), at 1 nM subunit concentration (500 pM dimer) in the presence or absence of saturating levels of Ca2+, which implies a dissociation constant in the picomolar range or lower. These results demonstrate for the first time that in reducing environments and at physiological concentrations, S100B exists as dimeric S100B (beta beta) in the presence or absence of Ca2+, and that the non-covalent dimer is most likely the form of S100B presented to target proteins.     

Demonstration of Heterodimer Formation between S100B and S100A6 in the Yeast Two-Hybrid System and Human Melanoma

S100B (S100β) and S100A6 (calcyclin) are two 10-kDa Ca²⁺- and Zn²⁺-binding proteins coexpressed in melanoma and cell-cycle regulated. These proteins are members of the S100 subfamily and are thought to exert their function through interaction with intracellular target proteins. In order to search for potential target proteins interacting with S100B, we used a yeast two-hybrid strategy with human S100B as bait to screen a human brain cDNA library. The fusion proteins interacting with the S100B bait were identified as S100B, S100A1, and S100A6. This indicates the potential of S100B to form homodimers and heterodimers with other members of the S100 subfamily. By Northern and Western blotting, S100B and S100A6 were shown to be expressed at high levels in a panel of human melanoma cell lines. S100B and S100A6 were coimmunoprecipitated from melanoma cell lysates in the presence of 100 μM Zn²⁺. Confocal microscopy demonstrated that both proteins were distributed throughout the cytoplasm and concentrated in the nucleus. The demonstration of an association and colocalization of S100B and S100A6 in melanoma supports the possibility that an S100B/S100A6 heterodimer plays a functional role in these cells.     

Birth and Death Rate Estimates of Cats and Dogs in U.S. Households and Related Factors

Studies report variable factors associated with dog and cat surpluses in the United States. Estimates of cat and dog birth and death rates help understand the problem. This study collected data through a commercial survey company, distributing questionnaires to 7,399 cat- and dog-owning households (HHs) in 1996. The study used an unequal probability sampling plan and reported estimates of means and variances as weighted averages. The study used estimates of HHs and companion animals for national projections. More than 9 million owned cats and dogs died during 1996-yielding crude death rates of 8.3 cat deaths/100 cats in HHs and 7.9 dog deaths/100 dogs in HHs. The study reported twice as many kitten as puppy litters, with an average litter size of 5.73 and 7.57, respectively. The study reported data on planned versus unplanned litters, reasons caregivers did not spay females, disposition of litters, and sources of animals added to HHs. These first national estimates indicate the magnitude of, and reasons for, animals leaving HHs. The crude birth rate was estimated to be 11.2 kittens/100 cats in HHs and 11.4 puppies/100 dogs in HHs.     

RAGE recycles at the plasma membrane in S100B secretory vesicles and promotes Schwann cells morphological changes

RAGE is a multiligand receptor of the immunoglobulin superfamily involved in regeneration of injured peripheral nerve and cell motility. RAGE is implicated in the development of various chronic diseases, such as neurodegenerative disorders, inflammatory responses, and diabetic complications. The correlation between RAGE endocytic trafficking and RAGE function is still uninvestigated. S100B is one of the ligands of RAGE. The molecular mechanisms responsible of S100B translocation in exocytic vesicles are still poorly investigated. In the present study we elucidate the role of RAGE endocytic trafficking in promoting S100B secretion in Schwann cells. Here we show that RAGE-induced secretion of S100B requires phosphorylated caveolin1-dependent endocytosis of RAGE. Endocytosis of RAGE in response to ligand binding promotes the fusion of endosomes with S100B-positive secretory vesicles. Src promotes the fusion of endosomes with S100B-secretory vesicles. Inhibition of src induces RAGE degradation. RAGE-mediated src activation induces cav1 phosphorylation and relocalization in the perinuclear compartment. RAGE signaling and recycling are required for S100-induced Schwann cells morphological changes and are inhibited by high-glucose, suggesting a possible link between diabetes and peripheral nerve injury. Indeed, high glucose inhibits RAGE-mediated src activation. Src inhibition blocks RAGE recycling, S100B secretion, and morphological changes. In summary, we identified a novel pathway of vesicular trafficking required for the amplification of RAGE signaling and cytoskeleton dynamics that is potentially involved in the regeneration of injured peripheral nerve.     

Solution NMR structure of S100B bound to the high-affinity target peptide TRTK-12

The solution NMR structure is reported for Ca(2+)-loaded S100B bound to a 12-residue peptide, TRTK-12, from the actin capping protein CapZ (alpha1 or alpha2 subunit, residues 265-276: TRTKIDWNKILS). This peptide was discovered by Dimlich and co-workers by screening a bacteriophage random peptide display library, and it matches exactly the consensus S100B binding sequence ((K/R)(L/I)XWXXIL). As with other S100B target proteins, a calcium-dependent conformational change in S100B is required for TRTK-12 binding. The TRTK-12 peptide is an amphipathic helix (residues W7 to S12) in the S100B-TRTK complex, and helix 4 of S100B is extended by three or four residues upon peptide binding. However, helical TRTK-12 in the S100B-peptide complex is uniquely oriented when compared to the three-dimensional structures of other S100-peptide complexes. The three-dimensional structure of the S100B-TRTK peptide complex illustrates that residues in the S100B binding consensus sequence (K4, I5, W7, I10, L11) are all involved in the S100B-peptide interface, which can explain its orientation in the S100B binding pocket and its relatively high binding affinity. A comparison of the S100B-TRTK peptide structure to the structures of apo- and Ca(2+)-bound S100B illustrates that the binding site of TRTK-12 is buried in apo-S100B, but is exposed in Ca(2+)-bound S100B as necessary to bind the TRTK-12 peptide.     

Analysis of the structure of human apo-S100B at low temperature indicates a unimodal conformational distribution is adopted by calcium-free S100 proteins

S100B is one of the best-characterized members of the calcium-signaling S100 protein family. Most S100 proteins are dimeric, with each monomer containing two EF-hand calcium-binding sites (EF1, EF2). S100B and other S100 proteins respond to calcium increases in the cell by coordinating calcium and undergoing a conformational change that allows them to interact with a variety of cellular targets. Although several three dimensional structures of S100 proteins are available in the calcium-free (apo-) state it has been observed that these structures appear to adopt a wide range of conformations in the EF2 site with respect to the positioning of helix III, the helix that undergoes the most dramatic calcium-induced conformational change. In this work, we have determined the structure of human apo-S100B at 10 degrees C to examine whether temperature might be responsible for these structural differences. Further, we have used this data, and other available apo-S100 structures, to show that despite the range of interhelical angles adopted in the apo-S100 structures, normal Gaussian distributions about the mean angles found in the structure of human apo-S100B are observed. This finding, only obvious from the analysis of all available apo-S100 proteins, provides direct structural evidence that helix III is a loosely packed helix. This is likely a necessary functional property of the S100 proteins that facilitates the calcium-induced conformational change of helix III. In contrast, the calcium-bound structures of the S100 proteins show significantly smaller variability in the interhelical angles. This shows that calcium binding to the S100 proteins causes not only a conformational change but results in a tighter distribution of helices within the EF2 calcium binding site required for target protein interactions.