Three different binding sites of Cks1 are required for p27-ubiquitin ligation

Previous studies have shown that the cyclin-dependent kinase (Cdk) inhibitor p27(Kip1) is targeted for degradation by an SCF(Skp2) ubiquitin ligase complex and that this process requires Cks1, a member of the highly conserved Suc1/Cks family of cell cycle regulatory proteins. All proteins of this family have Cdk-binding and anion-binding sites, but only mammalian Cks1 binds to Skp2 and promotes the association of Skp2 with p27 phosphorylated on Thr-187. The molecular mechanisms by which Cks1 promotes the interaction of the Skp2 ubiquitin ligase subunit to p27 remained obscure. Here we show that the Skp2-binding site of Cks1 is located on a region including the alpha2- and alpha1-helices and their immediate vicinity, well separated from the other two binding sites. All three binding sites of Cks1 are required for p27-ubiquitin ligation and for the association of Skp2 with Cdk-bound, Thr-187-phosphorylated p27. Cks1 and Skp2 mutually promote the binding of each other to a peptide similar to the 19 C-terminal amino acids of p27 containing phosphorylated Thr-187. This latter process requires the Skp2- and anion-binding sites of Cks1, but not its Cdk-binding site. It is proposed that the Skp2-Cks1 complex binds initially to the C-terminal region of phosphorylated p27 in a process promoted by the anion-binding site of Cks1. The interaction of Skp2 with the substrate is further strengthened by the association of the Cdk-binding site of Cks1 with Cdk2/cyclin E, to which phosphorylated p27 is bound.     

A purified green barley extract with modulatory properties upon TNF alpha and ROS released by human specialised cells isolated from RA patients

Based on the finding that reactive oxygen species (ROS) play important roles in mediating proinflammatory cytokine production (e.g. TNF alpha) and that many plant extracts contain substances with antioxidant properties, we examined the antiinflammatory action of a green barley extract, commercially available as "Natural SOD". The results obtained in this study demonstrate that the antiinflammatory properties of "Natural SOD" due to its micromolecular substances, able to scavenge ROS and to down-regulate TNF alpha production, main inflammation mediators produced by specialised cells from peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA). We prepared and tested a purified green barley extract (PE) containing micromolecular substances under 1 kDa, able to inhibit TNF alpha releasing--measured by an bioassay--from LPS stimulated human mononuclear cells (MNC) isolated both from PB and SF of RA patients. Luminol-dependent chemiluminescence has been used to measure the scavenging activity of PE on ROS releasing from activated neutrophils isolated from PB of RA patients. PE, containing high concentrations of substances with antioxidant and antiinflammatory properties, could be a more efficient natural drug for human use than "Natural SOD" in the treatment of RA patients.     

Raphe serotonin neuron‐specific oxytocin receptor knockout reduces aggression without affecting anxiety‐like behavior in male mice only

Serotonin and oxytocin influence aggressive and anxiety‐like behaviors, though it is unclear how the two may interact. That the oxytocin receptor is expressed in the serotonergic raphe nuclei suggests a mechanism by which the two neurotransmitters may cooperatively influence behavior. We hypothesized that oxytocin acts on raphe neurons to influence serotonergically mediated anxiety‐like, aggressive and parental care behaviors. We eliminated expression of the oxytocin receptor in raphe neurons by crossing mice expressing Cre recombinase under control of the serotonin transporter promoter (Slc6a4) with our conditional oxytocin receptor knockout line. The knockout mice generated by this cross are normal across a range of behavioral measures: there are no effects for either sex on locomotion in an open‐field, olfactory habituation/dishabituation or, surprisingly, anxiety‐like behaviors in the elevated O and plus mazes. There was a profound deficit in male aggression: only one of 11 raphe oxytocin receptor knockouts showed any aggressive behavior, compared to 8 of 11 wildtypes. In contrast, female knockouts displayed no deficits in maternal behavior or aggression. Our results show that oxytocin, via its effects on raphe neurons, is a key regulator of resident‐intruder aggression in males but not maternal aggression. Furthermore, this reduction in male aggression is quite different from the effects reported previously after forebrain or total elimination of oxytocin receptors. Finally, we conclude that when constitutively eliminated, oxytocin receptors expressed by serotonin cells do not contribute to baseline anxiety‐like behaviors or maternal care.     

Palestinian prison ontologies

During the first intifada uprising (1987–1993), thousands of Palestinians were arrested annually, and mass incarceration affected as many as 100,000 families. Relying on several recent ethnographies, and other published research including some of my own, this article describes the contests over Palestinian prison ontology as organized by (a) the jailers, (b) the prisoners, (c) the families of prisoners, and (d) a service agency in the emerging Palestinian Authority. What becomes evident is that mass incarceration involves ontological struggles over the framing of justice, agency, and gender. The conclusion asks how these ontological struggles may be part of other modern prisons.     

Mechanics of bone/PMMA composite structures: an in vitro study of human vertebrae

The goal of this study was to provide material property data for the cement/bone composite resulting from the introduction of PMMA bone cement into human vertebral bodies. A series of quasistatic tensile and compressive mechanical tests were conducted using cement/bone composite structures machined from cement-infiltrated vertebral bodies. Experiments were performed both at room temperature and at body temperature. We found that the modulus of the composite structures was lower than bulk cement (p<0.0001). For compression at 37( composite function)C: composite =2.3+/-0.5GPa, cement =3.1+/-0.2GPa; at 23( composite function)C: composite =3.0+/-0.3GPa, cement =3.4+/-0.2GPa. Specimens tested at room temperature were stiffer than those tested at body temperature (p=0.0004). Yield and ultimate strength factors for the composite were all diminished (55-87%) when compared to cement properties. In general, computational models have assumed that cement/bone composite had the same modulus as cement. The results of this study suggest that computational models of cement infiltrated vertebrae and cemented arthroplasties could be improved by specifying different material properties for cement and cement/bone composite.     

Computerized Entry into Medical Care—Its Impact on Doctor-Patient Relationships

A large proportion of cannery workers see a doctor only as a last resort, in time of crisis. The Cannery Workers Multiphasic Screening Program identified workers in need of physician evaluation, and referred each to a physician of his choice, for examination by appointment, while the worker was not acutely ill. In many instances the screening program generated the first encounters between patient and physician. It conducted a follow-up system for workers unaccustomed to methodical health care. The program financed pretesting education of the persons to be tested, multiphasic testing, physician evaluation of abnormal findings, and the follow-up reminder system.Each physician, in advance of the appointment for evaluation, was sent a computerized report calling attention to findings that exceeded limits considered normal. The report included a form facilitating the physician''s report and billing. In counties having foundations for medical care, the foundations reviewed the form for adequacy of follow-up and appropriateness of charges.The effort to bridge the gap between findings, diagnosis and therapy, for a population group newly introduced to modern medical care delivery, was made possible by the use of the computer as a tool for the attainment of specific, preanalyzed components of the total objective.     

Cultures under Siege: Collective Violence and Trauma

Cultures under Siege: Collective Violence and Trauma. Antonius C. G. M. Robben and Marcelo M. Sudrez-Orozco. eds. Cambridge: Cambridge University Press, 2000. 285 pp.     

Resonance Raman spectroscopy of oxoiron(IV) porphyrin pi-cation radical and oxoiron(IV) hemes in peroxidase intermediates

The catalytic cycle intermediates of heme peroxidases, known as compounds I and II, have been of long standing interest as models for intermediates of heme proteins, such as the terminal oxidases and cytochrome P450 enzymes, and for non-heme iron enzymes as well. Reports of resonance Raman signals for compound I intermediates of the oxo-iron(IV) porphyrin pi-cation radical type have been sometimes contradictory due to complications arising from photolability, causing compound I signals to appear similar to those of compound II or other forms. However, studies of synthetic systems indicated that protein based compound I intermediates of the oxoiron(IV) porphyrin pi-cation radical type should exhibit vibrational signatures that are different from the non-radical forms. The compound I intermediates of horseradish peroxidase (HRP), and chloroperoxidase (CPO) from Caldariomyces fumago do in fact exhibit unique and characteristic vibrational spectra. The nature of the putative oxoiron(IV) bond in peroxidase intermediates has been under discussion in the recent literature, with suggestions that the Fe(IV)O unit might be better described as Fe(IV)-OH. The generally low Fe(IV)O stretching frequencies observed for proteins have been difficult to mimic in synthetic ferryl porphyrins via electron donation from trans axial ligands alone. Resonance Raman studies of iron-oxygen vibrations within protein species that are sensitive to pH, deuteration, and solvent oxygen exchange, indicate that hydrogen bonding to the oxoiron(IV) group within the protein environment contributes to substantial lowering of Fe(IV)O frequencies relative to those of synthetic model compounds.