Non-hinge-binding pyrazolo[1,5-a]pyrimidines as potent B-Raf kinase inhibitors

As part of our research effort to discover B-Raf kinase inhibitors, we prepared a series of C-3 substituted N-(3-(pyrazolo[1,5-a]pyrimidin-7-yl)phenyl)-3-(trifluoromethyl)benzamides. X-ray crystallography studies revealed that one of the more potent inhibitors (10n) bound to B-Raf kinase without forming a hinge-binding hydrogen bond. With basic amine residues appended to C-3 aryl residues, cellular activity and solubility were enhanced over previously described compounds of this class.     

Caldesmon structure and function: sequence analysis of a 35 kilodalton actin- and calmodulin-binding fragment from the C-terminus of the turkey gizzard protein

We have determined the amino acid sequence of a 35 kDa proteolytic fragment ("CaD35") derived from the C-terminus of turkey gizzard caldesmon. This 239-residue peptide contains binding sites for actin and calmodulin. Residues 1-96 of CaD35 comprise "CaD15", an actin-binding subfragment which we previously showed to resemble the tropomyosin-binding segment of troponin T. The remainder of the CaD35 sequence shows no significant similarity to other proteins. Residues 111-128 may form a basic, amphipathic helix which interacts with calmodulin.     

The synthesis of some methy 4,6-O-Benzylidene-α-D-erythro-Hexopyranosid-2,3-Diulose derivatives

Methyl 4,6-O-benzylidene-3-deoxy-3-phenylazo-α-D-glucopyranoside (1) has been oxidised with the Pfitzner—Moffat reagent to the 2,3-diulose 3-phenylhydrazone derivative (2) which has been characterised as the phenylosazone (3) and oxime (4). An unstable 2-imino derivative (10) of the same diulose has been produced by base-catalysed elimination of nitrogen from methyl 2-azido-4,6-O-benzylidene-2-deoxy-α-D-ribo-hexopyranosid-3-ulose (8). The imino intermediate was trapped as a quinoxaline derivative (9). The base-catalysed reactions of certain other hydrazone derivatives of methyl hexosiduloses have also been examined.     

Effect of Tetanus Toxin on Transmitter Release from the Substantia Nigra and Striatum In Vitro

Abstract: The effect of tetanus toxin on the uptake and release of radiolabelled transmitters from slices prepared from substantia nigra (SN) and striatum of rats has been investigated. Tetanus toxin-500–750 mouse lethal doses (MLD)-injected into the SN 6 h before preparing the slices significantly reduced the calcium-dependent, potassium-evoked release of [³H]GABA. Endogenous GABA levels in the SN and [³H]GABA uptake by nigral slices were unaffected by pretreatment with the toxin. Injections of tetanus toxin (1000–2000 MLD) into the striatum significantly reduced the calcium-dependent, potassium-evoked release of [¹⁴C]GABA and also [³H]dopamine, but had no effect on the K⁺-evoked release of [³H]5-hydroxytryptamine or [¹⁴C]acetylcholine. It is concluded that tetanus toxin inhibits GABA release directly and not by interference with synthesis or inactivation processes.     

Effects of DNA replication inhibitors on UV excision repair in synchronised human cells.

When HeLa cells are irradiated with UV and treated with the DNA synthesis inhibitors hydroxyurea (HU) and 1-beta-D-arabinofuranosylcytosine (ara C), DNA strand breaks accumulate at sites where excision repair of DNA damage has been inhibited after the incision step. This break accumulation occurs in mitotic, G1 and S phase cells. But UV-induced repair synthesis of DNA, as measured by [3H]thymidine incorporation into unreplicated DNA, is not inhibited by HU and ara C in G1 or S phase cells, even though replicative synthesis is virtually abolished. Repair and replication must therefore utilise different DNA precursor pools, or different DNA synthetic systems; and the action of Hu and ara C in causing strand break accumulation may occur at the ligation step of excision repair.     

The Genome-wide Patterns of Variation Expose Significant Substructure in a Founder Population

Although high-density SNP genotyping platforms generate a momentum for detailed genome-wide association (GWA) studies, an offshoot is a new insight into population genetics. Here, we present an example in one of the best-known founder populations by scrutinizing ten distinct Finnish early- and late-settlement subpopulations. By determining genetic distances, homozygosity, and patterns of linkage disequilibrium, we demonstrate that population substructure, and even individual ancestry, is detectable at a very high resolution and supports the concept of multiple historical bottlenecks resulting from consecutive founder effects. Given that genetic studies are currently aiming at identifying smaller and smaller genetic effects, recognizing and controlling for population substructure even at this fine level becomes imperative to avoid confounding and spurious associations. This study provides an example of the power of GWA data sets to demonstrate stratification caused by population history even within a seemingly homogeneous population, like the Finns. Further, the results provide interesting lessons concerning the impact of population history on the genome landscape of humans, as well as approaches to identify rare variants enriched in these subpopulations.     

Somatic embryogenesis in soybean via somatic embryo cycling

Summary The objectives of the present research were: a) to develop an efficient soybean embryogenic regeneration system characterized by a high frequency of explant response and a large number of somatic embryos per explant; b) to evaluate the factors affecting somatic embryogenesis via somatic embryo cycling; and c) to identify the origin of somatic embryos in the system. A highly improved and efficient system for soybean somatic embryogenesis was established using somatic embryo cotyledons and somatic embryo hypocotyl/radicle explants plated on α-naphthaleneacetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D) supplemented MS basal media. The system included somatic embryo cycling between liquid and solid medium and it consistently gave rise to a much higher frequency of explant response and a larger number of embryos per responding explant than those obtained from zygotic cotyledon explant tissues. Genotype, differences were observed for response in some of the treatments with cv “Fayette” being more responsive than “J103”. Histological studies revealed that somatic embryos induced in the somatic embryo cycling system originated almost exclusively from epidermal cells on both 2,4-D and NAA inductive media. The cells of the epidermis proliferated to produce somatic embryos directly without an intervening callus phase. A single-cell origin of somatic embryos was observed in cultures on a 40 mg/liter 2,4-D treatment. A large number of responding cells in the epidermis was also observed in the 10 mg/liter NAA treatment. The single-cell origin of somatic embryos from epidermal layers of the explant tissues should facilitate development of an efficient transformation system for soybean.     

Intraoperative breast radiotherapy: survival,local control and risk factors for recurrence

BackgroundWhole breast irradiation reduces loco-regional recurrence and risk of death in patients submitted to breast-conserving treatment. Data show that radiation to the index quadrant alone may be enough in selected patients.AimTo report the experience with intra-operative radiotherapy (IORT) with Electron-beam Cone in Linear Accelerator (ELIOT) and the results in overall survival, local control and late toxicity of patients submitted to this treatment.Materials and Methods147 patients treated with a median follow up of 6.9 years (0.1?11.5 years). The actuarial local control and overall survival probabilities were estimated using the Kaplan Meier method. All tests were two-sided and p ? 0.05 was considered statistically significant.ResultsOverall survival of the cohort in 5 years, in the median follow up and in 10 years was of 98.3%, 95.1% and 95.1%, respectively, whereas local control in 5 years, in the median follow up and in 10 years was of 96%, 94.9% and 89.5%, respectively. Two risk groups were identified for local recurrence depending on the estrogen or progesterone receptors, axillary or margin status and lymphovascular invasion (LVI) (p = 0.016).ConclusionsIORT is a safe and effective treatment. Rigorous selection is important to achieve excellent local control results.     

Dynamic hydration numbers for biologically important ions

The role of ionized groups in biological systems is determined by their affinity for water [Biophys. J. 72 (1997) 65-76]. The tightly bound water associated with biologically important ions increases their apparent size. We define the apparent dynamic hydration number of an ion here as the number of tightly bound water molecules that must be assigned to the ion to explain its apparent molecular weight on a Sephadex G-10 size exclusion column, and report the first accurate determination of tightly bound water for 23 ions of biological significance, including H(+) and HO(-). We also calculate the radius of the equivalent hydrated sphere (r(h)) for each ion. We find that the ratio of the hydrated volumes of two ions approximates the ratio of the square of the charges of the same two ions. Since the 'ionic strength' of the solution also depends upon the square of the charges on the ions, our results suggest that ionic strength effects may largely arise from local effects related to the hydrated volume of the ion--that is, from space filling, osmotic, water activity, surface tension and hydration shell overlap effects rather than from long-range electric field effects.