Pain in Paget's disease: a retrospective study of treatment efficacy

The authors addressed the role and the management of pain in Paget's disease by a retrospective study. The objectives were: to assess the presence of pain in Paget's disease; to look for a relationship between pain and the levels of total alkaline phosphatase (total ALP); to verify if the most commonly used drugs in Paget's disease, calcitonin and bisphosphonates, were able to reduce the pain and the levels of total ALP. The study analyzed 107 Italian patients with Paget's disease who were hospitalized at the same Institute between 1970 and 2010; all patients affected by severe arthritis were excluded. From the analysis of the clinical records it emerged that as many as 85% of patients had pain and that total ALP was also increased in most of the patients with pain in comparison with patients without pain. The clinical and metabolic effects of different therapies were then assessed: many patients had not received any specific therapy (58%), others had been treated with calcitonin (25%) and others with bisphosphonates (17%). In fact, the patients treated with bisphosphonates had significantly lower levels both of pain and total ALP. The authors hypothesize that the pain in Paget's disease has a primary origin and is correlated to the degree of bone metabolic hyperactivity. Finally, treatment with bisphosphonates appeared to be the most appropriate treatment, having been able to control both the pain and the metabolic hyperactivity.     

Reactive Astrocytes as Therapeutic Targets for Brain Degenerative Diseases: Roles Played by Metabotropic Glutamate Receptors

Astrocytes are well known to play critical roles in the development and maintenance of the central nervous system (CNS). Moreover, recent reports indicate that these cells are heterogeneous with respect to the molecules they express and the functions they exhibit in the quiescent or activated state. Because astrocytes also contribute to pathology, promising new results raise the possibility of manipulating specific astroglial populations for therapeutic roles. In this mini-review, we highlight the function of metabotropic glutamate receptors (mGluRs), in particular mGluR3 and mGluR5, in reactive astrocytes and relate these to three degenerative CNS diseases: multiple sclerosis, Alzheimer’s disease and Amyotrophic Lateral Sclerosis. Previous studies demonstrate that effects of these receptors may be beneficial, but this varies depending on the subtype of receptor, the state of the astrocytes, and the specific disease to which they are exposed. Elucidating the role of mGluRs on astrocytes at specific times during development and disease will provide novel insights in understanding how to best use these to serve as therapeutic targets.

     

Use of Formalin-Fixed Paraffin-Embedded Samples for Gene Expression Studies in Breast Cancer Patients

To obtain gene expression profiles from samples collected in clinical trials, we conducted a pilot study to assess feasibility and estimate sample attrition rates when profiling formalin-fixed, paraffin-embedded specimens. Ten matched fresh-frozen and fixed breast cancer samples were profiled using the Illumina HT-12 and Ref-8 chips, respectively. The profiles obtained with Ref 8, were neither technically nor biologically reliable since they failed to yield the expected separation between estrogen receptor positive and negative samples. With the use of Affymetrix HG-U133 2.0 Plus chips on fixed samples and a quantitative polymerase chain reaction -based sample pre-assessment step, results were satisfactory in terms of biological reliability, despite the low number of present calls (M = 21%±5). Compared with the Illumina DASL WG platform, Affymetrix data showed a wider interquartile range (1.32 vs 0.57, P<2.2 E-16,) and larger fold changes. The Affymetrix chips were used to run a pilot study on 60 fixed breast cancers. By including in the workflow the sample pre-assessment steps, 96% of the samples predicted to give good results (44/46), were in fact rated as satisfactory from the point of view of technical and biological meaningfulness. Our gene expression profiles showed strong agreement with immunohistochemistry data, were able to reproduce breast cancer molecular subtypes, and allowed the validation of an estrogen receptor status classifier derived in frozen samples. The approach is therefore suitable to profile formalin-fixed paraffin-embedded samples collected in clinical trials, provided that quality controls are run both before (sample pre-assessment) and after hybridization on the array.     

Biochemical evidence of a physical interaction between <Emphasis Type="Italic">Sulfolobus solfataricus</Emphasis> B-family and Y-family DNA polymerases

The hyper-thermophilic archaeon Sulfolobus solfataricus possesses two functional DNA polymerases belonging to the B-family (Sso DNA pol B1) and to the Y-family (Sso DNA pol Y1). Sso DNA pol B1 recognizes the presence of uracil and hypoxanthine in the template strand and stalls synthesis 3–4 bases upstream of this lesion (“read-ahead” function). On the other hand, Sso DNA pol Y1 is able to synthesize across these and other lesions on the template strand. Herein we report evidence that Sso DNA pol B1 physically interacts with DNA pol Y1 by surface plasmon resonance measurements and immuno-precipitation experiments. The region of DNA pol B1 responsible for this interaction has been mapped in the central portion of the polypeptide chain (from the amino acid residue 482 to 617), which includes an extended protease hyper-sensitive linker between the N- and C-terminal modules (amino acid residues Asn482-Ala497) and the α-helices forming the “fingers” sub-domain (α-helices R, R′ and S). These results have important implications for understanding the polymerase-switching mechanism on the damaged template strand during genome replication in S. solfataricus.     

Circadian changes in microtubules,synaptic ribbons and synaptic ribbon fields in the pinealocytes of the baboon (Papio ursinus)

Summary In baboons kept under controlled lighting conditions, microtubules (MT) are readily seen in the perikaryal cytoplasm and in the perivascular processes of pinealocytes. A significant increase in the number of MT, single synaptic ribbons (SR) and the formation of synaptic ribbon fields (RF, i.e. organelles which consist of multiple dense rodlets or plates, and vesicles), occur during the dark phase of a circadian light-dark cycle. MT may act as tracks for the oriented flow of vesicles derived from the smooth endoplasmic reticulum, to cytoplasmic sites where RF are being formed. The origin of the dense rodlets of RF remains unknown. Structural differences between SR and RF indicate that the latter organelles are not directly involved in impulse propagation between adjacent baboon pinealocytes. RF may function as storage organelles for some of the pineal secretory products which are formed in large amounts during the dark phase.     

Collective properties of hydration: long range and specificity of hydrophobic interactions.

We report results of molecular dynamics (MD) simulations of composite model solutes in explicit molecular water solvent, eliciting novel aspects of the recently demonstrated, strong many-body character of hydration. Our solutes consist of identical apolar (hydrophobic) elements in fixed configurations. Results show that the many-body character of PMF is sufficiently strong to cause 1) a remarkable extension of the range of hydrophobic interactions between pairs of solute elements, up to distances large enough to rule out pairwise interactions of any type, and 2) a SIF that drives one of the hydrophobic solute elements toward the solvent rather than away from it. These findings complement recent data concerning SIFs on a protein at single-residue resolution and on model systems. They illustrate new important consequences of the collective character of hydration and of PMF and reveal new aspects of hydrophobic interactions and, in general, of SIFs. Their relevance to protein recognition, conformation, function, and folding and to the observed slight yet significant nonadditivity of functional effects of distant point mutations in proteins is discussed. These results point out the functional role of the configurational and dynamical states (and related statistical weights) corresponding to the complex configurational energy landscape of the two interacting systems: biomolecule + water.     

A statistical light scattering approach to separating fast and slow dynamics

Light scattering is a powerful technique to study the structural and dynamical properties of biomolecular systems or other soft materials such as polymeric solutions and blends or gels. An important application of this technique is the study of the kinetics of formation of supramolecular structures. However, in such cases, the system under study is rapidly changing, and consequently the integration time for each measurement is limited. In order to overcome this difficulty, a statistical approach has been developed based on the analysis of the scattered light intensity distribution (Manno et al. 2006, 2004). Indeed the intensity distribution depends upon the ratio between the integration time of each measurement and the coherence time of scattered radiation. This method has been applied to protein aggregation (Manno et al. 2006) and to sol-gel transition (Manno et al. 2004), to obtain information on the heterogeneity of morphological and dynamical features during such processes. In the present work, we accurately test the validity of this approach by analyzing the statistical properties of the light scattered by a model system: a solution of polystyrene spherical macromolecules of different sizes. Each molecular size is related to a given diffusion coefficient and to a given coherence time of the scattered intensity. The effect of changing the experimental integration time is systematically investigated. A mixture of particles of two different sizes is also analyzed to test the validity and robustness of the model based on the convolution of a gaussian with an exponential distribution. Proceedings of the XVIII Congress of the Italian Society of Pure and Applied Biophysics (SIBPA), Palermo, Sicily, September 2006.