Rolandic type cerebral palsy in children as a pattern of hypoxic-ischemic injury in the full-term neonate

Magnetic resonance images (MRIs) of the brains of 11 patients aged from 1 week to 12 years with a distinctive type of cerebral palsy were selected based on distribution of cerebral lesions, which were restricted to bilateral perirolandic cortical and subcortical regions, including frequent symmetric involvement of basal ganglia and ventrolateral nucleus of thalami. Retrospectively, the perinatal history and clinical features were reviewed to correlate clinical data with this distinctive pattern of brain injury. Clinically affected neonates had an encephalopathy associated with a severe perinatal asphyxial event. Older children with cerebral palsy survived a similar perinatal course and demonstrated spastic quadriparesis with bulbar or pseudobulbar involvement, lack of verbal speech and variable delays in cognitive development. The distribution of hypoxic-ischemic lesions involving bilateral perirolandic regions, basal ganglia, and thalami, appears to correlate with increased metabolic areas of primary myelination in full-term neonates, but not with arterial border zones nor a single cerebral artery distribution. Myelination is a critical process in maturing brain associated with marked increase in tissue respiration and thus greater susceptibility to oxygen deprivation. It is believed that the extent of hypoxic-ischemic brain injury is determined principally by brain maturity and regional metabolic rates at time of insult and this correlates with active myelination in full-term neonates. This study confirms previous data from neuropathologic literature and recent reports of neuroimaging studies of asphyxiated neonates. In addition, retrospective analysis of the clinical data enables recognition of a type of cerebral palsy that might be the hallmark of hypoxic-ischemic injury in term neonates.     

Cdc2-cyclin B phosphorylates p70 S6 kinase on Ser411 at mitosis

The carboxyl terminus of p70 S6 kinase (p70(s6k)) has a set of Ser and Thr residues (Ser411, Ser418, Ser424, and Thr421) phosphorylated in vivo by an unidentified kinase(s). These Ser/Thr sites are immediately followed by proline, a motif that is commonly seen in the substrates of cyclin-dependent kinases (Cdk) and mitogen-activated protein kinases. A previous study has shown that Cdc2 (Cdk1) indeed phosphorylates these p70(s6k) Ser/Thr residues in vitro. Here, we demonstrate that Cdc2-cyclin B complex phosphorylates Ser411 in the KIRSPRR sequence, whereas other Cdk-cyclin complexes including those containing Cdk2, Cdk4, or Cdk6 do not. Additionally, Ser411 phosphorylation in vivo was increased at mitosis in parallel with Cdc2 activation, and it was suppressed by a dominant negative form of Cdc2. These data indicate that p70(s6k) is a physiological substrate of Cdc2-cyclin B in mitosis. Since the activity of p70(s6k) is low during mitosis, Cdc2-cyclin B may play a role in inactivating p70(s6k) during mitosis, where protein synthesis is suppressed.     

Activated polo-like kinase Plx1 is required at multiple points during mitosis in Xenopus laevis

Entry into mitosis depends upon activation of the dual-specificity phosphatase Cdc25C, which dephosphorylates and activates the cyclin B-Cdc2 complex. Previous work has shown that the Xenopus polo-like kinase Plx1 can phosphorylate and activate Cdc25C in vitro. In the work presented here, we demonstrate that Plx1 is activated in vivo during oocyte maturation with the same kinetics as Cdc25C. Microinjection of wild-type Plx1 into Xenopus oocytes accelerated the rate of activation of Cdc25C and cyclin B-Cdc2. Conversely, microinjection of either an antibody against Plx1 or kinase-dead Plx1 significantly inhibited the activation of Cdc25C and cyclin B-Cdc2. This effect could be reversed by injection of active Cdc25C, indicating that Plx1 is upstream of Cdc25C. However, injection of Cdc25C, which directly activates cyclin B-Cdc2, also caused activation of Plx1, suggesting that a positive feedback loop exists in the Plx1 activation pathway. Other experiments show that injection of Plx1 antibody into early embryos, which do not require Cdc25C for the activation of cyclin B-Cdc2, resulted in an arrest of cleavage that was associated with monopolar spindles. These results demonstrate that in Xenopus laevis, Plx1 plays important roles both in the activation of Cdc25C at the initiation of mitosis and in spindle assembly at late stages of mitosis.     

Dwelling performance and adaptive summer comfort in low-income Australian households

Increasing reliance on air-conditioning to improve summertime comfort in dwellings results in higher energy bills, peak electricity demand and environmental issues. In pursuit of social equity, society needs to develop ways of improving cooling that are less reliant on air-conditioning. Designing homes to emphasize adaptive thermal comfort can reduce this reliance, particularly when combined with improved dwelling thermal performance. A multi-method evaluation of 10 low-income dwellings in the state of Victoria in Australia is presented, including low-energy and ‘standard-performance’ houses. The combination of performance monitoring and householder interviews reveals new insights for achieving summertime comfort. The low-energy houses without air-conditioning were both measured and perceived as more comfortable than the ‘standard-performance’ houses with air-conditioning. The low-energy households achieved improved personal thermal comfort through a combination of improved fabric performance augmented with adaptive comfort activities (e.g., opening/closing windows). This outcome reduces reliance on air-conditioning, reduces living costs and energy consumption, and improves environmental outcomes. There is a need to integrate lessons from adaptive thermal comfort theory and strategies into minimum building performance requirements and standards, as well as wider design strategies. It is evident that adaptive comfort has a role to play in a transition to a low-carbon housing future.     

Prebreakdown Process in Freon-Nitrogen Mixtures at Low Gas Pressures

Steady-state prebreakdown currents were measured under a uniform field in freon-nitrogen mixtures over the range 110? E/p?240 (E = electric field in V.cm -1torr -1, and p = gas pressure in torr) and at pressures ranging from 1-20 torr for different concentrations of freon. From the measured currents, the values of ionization and attachment coefficients and the ratio of diffusion coefficients to mobility for electrons (mean energy), were determined. The addition of a small concentration of freon (?10 percent) to nitrogen at high E/p values is found to increase the ionization rate considerably with a corresponding reduction in sparking potentials. A peak in the value of mean energy for electrons was also observed under this condition. This is attributed to a significant difference in the ionization potentials of freon and nitrogen molecules, which is capable of ionizing molecules.     

Heredity and experience: Their relative importance in the development of taste preference in man.

Heritability estimates for sucrose, lactose, and sodium chloride taste preferences were uniformly low in a total of 311 pairs of monozygotic and like-sex dizygotic twins between 9 and 15 yrs of age. Black Ss preferred more concentrated solutions of all 3 tastants than did Caucasian Ss. This effect was independent of socioeconomic status in the total sample. Males preferred more concentrated solutions of sucrose and lactose than did females, but there were no sex differences in sodium chloride preference. The possibility that early intake experiences may play a role in the determination of enduring taste preferences in humans is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cloning and characterization of the Xenopus cyclin-dependent kinase inhibitor p27XIC1

We have isolated a gene encoding Xic-1, a 27-kDa cyclin-dependent kinase (Cdk) inhibitor from Xenopus ovary that shares significant homology with both mammalian CIP1 and Kip1/Kip2. The N- and C-terminal halves of Xic-1 are sufficient for interacting with Cdks and proliferating cell nuclear antigen, respectively. Recombinant Xic-1 inhibits Xenopus cyclin E/Cdk2, cyclin A/Cdk2 and cyclin B/Cdc2 activities, although with quite different IC50 values. Truncation of the N terminus of Xic-1 increases the IC50 value for cyclin A/Cdk2 50-fold with no effect on the inhibition of cyclin E/Cdk2 or cyclin B/Cdc2.Xic-1 inhibits both single-stranded and nuclear DNA synthesis in egg extracts, an effect reversed by proliferating cell nuclear antigen or cyclin E/Cdk2, respectively. These results suggest a function for Xic-1 in the control of DNA synthesis by cyclin E/Cdk2.     

Single toxin detection is inadequate to diagnose Clostridium difficile diarrhea in pediatric patients

BACKGROUND & AIMS: Clostridium difficile is an important cause of symptomatic diarrhea in pediatric patients. The bacterium produces two toxins, although many laboratories assay for only one. We questioned this diagnostic approach when patients had positive results for C. difficile at our institution, but initially had tested negative at outside laboratories. METHODS: We retrospectively analyzed relative frequencies of C. difficile toxin A alone, toxin B alone, and toxins A and B from pediatric patients with diarrhea. Results were stratified according to toxin detection and patient age. RESULTS: Of 1061 specimens, 276 (26.8%) were positive for C. difficile toxin(s). Fifty-one (18.5%) were positive for toxin A alone, 133 (48.2%) for toxin B alone, and 92 (33.3%) for both toxins. Assaying for toxin B identified C. difficile infection more frequently than did assaying for toxin A (P < 0.0001). The frequency of toxin B detection was significantly higher for older children but not for infants. CONCLUSIONS: Testing for C. difficile toxin A or toxin B alone will result in more frequent misdiagnosis than testing for both toxins. This practice may lead to inappropriate further invasive investigations in children, although this finding may not be applicable to adults.     

Encountering the Multiplicity of Community in Planning and Designing New Neighbourhoods

In contrast to recent understandings of community beyond place, urban partnerships of developers and policymakers focus on creating place-based communities in new neighbourhoods such as master-planned housing estates. These efforts are critiqued for ignoring the multiple ways community is experienced in everyday life as physical places take precedence over social relations and processes. Drawing on the example of a master-planned community (MPC) in Australia, this article explores some of the complexities involved in attempting to create community in these and other new neighbourhoods by comparing conceptualisations of community depicted in marketing materials with future residents' expectations and lived experience. Although some notions of community portrayed in the marketing of the estate resonated with future residents' expectations, their everyday experiences of community were broad and varied, and not confined to one particular place. In concluding, the article suggests there is greater scope for the multiplicity of community to be incorporated in the planning and design of MPCs. Specifically, policymakers could make more of partnerships with developers to advocate for the acknowledgement and inclusion of broader experiences of community in everyday life.