Testis size, sperm characteristics and testosterone concentrations in four species of shrews (Mammalia, Soricidae)

The aim of this study was to establish and compare the sperm characteristics in four shrew species in the context of the sperm competition hypothesis. As expected, the large relative testis size in promiscuous species was associated with a high number of cauda epididymal spermatozoa and a high concentration of circulating testosterone. In addition, in Sorex and Neomys, species with high intensity of sperm competition, the spermatozoa stored in cauda epididymis were characterized by high percentage of progressive motility whereas in Crocidura and Suncus, the cauda epididymal spermatozoa were motile but with very low percentage of progressive motility. This capability is achieved only following the passage through the vas gland, a specialized region for sperm storage located along the vas deferens in these shrew species. The hypothesis that sperm competition is positively correlated with spermatozoa length could not be confirmed. In Crocidura and Suncus, the total sperm length is increased by the large sperm head due to a big acrosome. This trait, specific to the subfamily Crocidurinae, may results from a selective pressure independent of the context of sperm competition, related to a specific, but as yet unclear role, for the acrosome during the fertilization.

Ocular albinism and hypopigmentation defects in Slc24a5-/- mice

As part of a high-throughput mutagenesis and phenotyping process designed to discover novel drug targets, we generated and characterized mice with a targeted mutation in Slc24a5, a gene encoding a putative cation exchanger. Upon macroscopic examination, Slc24a5-/- mice were viable, fertile, and indistinguishable by coat color from their heterozygous and wild-type litter mates. Ophthalmoscopic examination revealed diffuse retinal hypopigmentation, and a histologic examination of the eye confirmed the presence of moderate-to-marked hypopigmentation of the retinal pigmented epithelium (RPE), ciliary body, and iris pigment epithelium (IPE). Hypopigmentation was most severe in the anterior layer cells of the IPE, where melanosomes were smaller, paler, and more indistinct than those of the anterior stroma and posterior IPE. The pigment granules of the posterior IPE appeared to be nearly as dark as those in stromal melanocytes; however, both cell layers were thinner and paler than corresponding layers in wild-type mice. Ultrastructural analysis of the RPE, IPE, and ciliary body pigmented cells confirmed that mutation of Slc24a5 results in marked hypopigmentation of melanosomes in optic cup-derived pigmented neuroepithelium in the eyes. Milder reductions in melanosome size and pigmentation were noted in neural crest-derived melanocytes. The severe hypopigmentation of neuroepithelium-derived cells in the eyes resulted in a novel form of ocular albinism in Slc24a5-/- mice. Our findings suggest that SLC24A5 may be a candidate gene for some forms of ocular albinism and for the BEY1/EYCL2 locus previously associated with central brown eye color in humans.

Total Asymmetric Synthesis of Glycomimetics and Polypropionates of Biological Interest

Using readily available chiral auxiliaries such as (+)- and (?)-camphanic acid, (R,R)- and (S,S)-tartaric acid derivatives (e.g. RADO(R)-COCl, SADO(R)-COCl) efficient diastereoselective syntheses of rare sugars and glycomimetics have been developed. They engage the 'naked sugar' (enantiomerically pure 7-oxanorbornene) methodologies in which the chiral auxiliaries are recovered at an early stage of the multistep syntheses. A new reaction cascade starting with the hetero-Diels-Alder addition of sulfur dioxide to 1-(1-phenylethoxy)-1,3-dienes derived from inexpensive (+)- and (?)-1-phenylethanol allows the one-pot, four-component synthesis of polyfunctional sulfones, sulfonamides and sulfonic esters containing up to three stereogenic centers. The method ensures a high molecular and stereochemical diversity. The reaction cascade can also produce polyketide and polypropionate fragments in one-pot operations. The latter contain up to three contiguous stereogenic centers and do not have to be modified (deprotection, activation) before using them as nucleophilic partners in diastereoselective cross-aldol reactions, thus permitting the quick access to complicated polypropionate antibiotics such as Baconipyrones, Ryfamicyn S and Apoptolidines.

Precision measurement of neutrino oscillation parameters with KamLAND

The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06.

Preparation and Synthetic Applications of 8-Oxabicyclo[3.2.1]oct-6-en-3-one Derivatives

The development of efficient routes to multi-gram quantities of chiral synthons is a key issue in the total synthesis of natural products and analogues. The conformationally defined and rigid 8-oxabicyclo[3.2.1]oct-6-en-3-one template is an appealing starting material for the development of non-iterative approaches to polyoxygenated fragments that are found in a large variety of biologically relevant natural compounds. Desymmetrization and resolution procedures, stereoselective functionalizations and double-chain elongations represent attractive strategies for such synthetic challenges.

Recent synthetic approaches toward non-anomeric spiroketals in natural products

Many natural products of biological interest contain [6,5]- and [6,6]-spiroketal moieties that can adopt various configurations, benefiting or not from anomeric conformation stabilizing effects. The spiroketal fragments are often important for the biological activity of the compounds containing them. Most stable spiroketal stereoisomers, including those benefiting from conformational anomeric effects (gauche conformers can be more stable than anti conformers because of a contra-steric stabilizing effect), are obtained easily under acidic conditions that permit acetal heterolysis (formation of tertiary oxycarbenium ion intermediates). The synthesis of less stable stereoisomers requires stereoselective acetal forming reactions that do not permit their equilibration with their most stable stereoisomers or, in the case of suitably substituted derivatives, concomitant reactions generating tricyclic products that quench the less stable spiroketal conformers. Ingenuous approaches have been recently developed for the synthesis of naturally occurring [6,6]- and [5,6]-nonanomeric spiroketals and analogues. The identification of several parameters that can influence the stereochemical outcome of spirocyclization processes has led to seminal improvements in the selective preparation of the non-anomeric isomers that are discussed herein. This review also gives an up-dated view of conformational anomeric effect which represents a small fraction of the enthalpic anomeric effect that makes gem-dioxy substituted compounds much more stable that their 1,n-dioxy substituted isomers (n > 1). Although models assuming sp3-hybridized oxygen atoms have been very popular (rabbit ears for the two non-bonding electron pairs of oxygen atom), sp2-hybridized oxygen atoms are used to describe the conformational anomeric effect.

New efficient route to an advanced precursor of the AB spiroketal of spongistatins

A sequence of highly diastereoselective functionalizations allowed transformation of a meso-methylenebis(cyclohept-3-ene-1,6-diyl diester) into an advanced precursor of the AB spiroketal of spongistatins. This route illustrates the potential of this bis-cycloheptene derivative for the synthesis of a key fragment of complex bioactive natural compounds.

Short synthesis of the C16-C28 polyketide fragment of apoptolidin A aglycone

Starting from (E,E)-1-[(1R)-(phenylethyl)oxy]-2-methylpenta-1,3-diene and triethylsilyl enol ether of butanone rapid access to Koert's advanced C10-C28 polyketide fragment of apoptolidin A is now possible.

Mediterranean populations of the lesser white-toothed shrew (Crocidura suaveolens group): an unexpected puzzle of Pleistocene survivors and prehistoric introductions

An earlier study revealed the strong phylogeographical structure of the lesser white-toothed shrew (Crocidura suaveolens group) within the northern Palaearctic. Here, we aim to reconstruct the colonization history of Mediterranean islands and to clarify the biogeography and phylogeographical relationships of the poorly documented Middle East region with the northern Palaearctic. We performed analyses on 998-bp-long haplotypes of the mitochondrial cytochrome b gene of 143 samples collected around the Mediterranean basin, including islands and the Middle East. The analyses suggest that the Cypriot shrew belongs to the rare group of relict insular Pleistocene mammal taxa that have survived to the present day. In contrast, the Cretan, Corsican and Menorcan populations were independently introduced from the Middle East during the Holocene. The phylogeographical structure of this temperate Palaearctic species within the Middle East appears to be complex and rich in diversity, probably reflecting fragmentation of the area by numerous mountain chains. Four deeply divergent clades of the C. suaveolens group occur in the area, meaning that a hypothetical contact zone remains to be located in central western Iran.

New organic chemistry of sulfur dioxide

Simple 1,3-dienes undergo highly stereoselective hetero-Diels-Alder additions with SO2 at low temperature giving sultines. These reactions that are faster than the more exothermic cheletropic additions of SO2-producing sulfolenes. This has led to the invention of a new C-C bond-forming reaction combining electron-rich dienes and alkenes with SO2. The reaction cascade has been exploited to develop combinatorial, one-pot, four-component syntheses of polyfunctional sulfones, sulfonamides, and sulfonic esters. It also allows us to generate, in one-pot operations, enantiomerically enriched polypropionate fragments containing up to three contiguous stereogenic centers and a (E)-alkene unit. These fragments can be used directly in further C-C bond-forming reactions, such as cross-aldol condensations, thus permitting the expeditious construction of complicated natural products of biological interest (e.g., Baconipyrones, Rifamycin S, Apoptolidinone) and analogues. New ene reactions of SO2 have also been discovered; they open new avenues to organic synthesis.

Mechanism of the diphenyldisulfone-catalyzed isomerization of alkenes. Origin of the chemoselectivity: experimental and quantum chemistry studies

Polysulfone- and diphenyldisulfone-catalyzed alkene isomerizations are much faster for 2-alkyl-1-alkenes than for linear, terminal alkenes. The mechanism of these reactions has been investigated experimentally for the isomerization of methylidenecyclopentane into 1-methylcyclopentene, and theoretically [CCSD(T)/6-311++G(d,p)//B3LYP/6-311++G(d,p) calculations] for the reactions of propene and 2-methylpropene with a methanesulfonyl radical, MeSO2*. On heating, polysulfones and (PhSO2)2 equilibrate with sulfonyl radicals, RSO2*. The latter abstract allylic hydrogen atoms in one-step processes giving allylic radical/RSO2H pairs that recombine within the solvent cage producing the corresponding isomerized alkene and RSO2*. The sulfinic acid, RSO2H, can diffuse out from the solvent cage (H/D exchange with MeOD,D2O) and reduce an allyl radical. Calculations did not support other possible mechanisms such as hydrogen exchange between alkenes, electron transfer, or addition/elimination process. Kinetic deuterium isotopic effects measured for the (PhSO2)2-catalyzed isomerization of methylidenecyclopentane and deuterated analogues and calculated for the H abstraction from 2-methylpropene and deuterated analogues by CH3SO2* are consistent also with the one-step hydrogen transfer mechanism. The high chemoselectivity for this reaction is not governed by an exothermicity difference but by a difference in ionization energies of the alkenes. Calculations for CH3SO2* + propene and CH3SO2* + 2-methylpropene show a charge transfer of 0.34 and 0.38 electron, respectively, from the alkenes to the sulfonyl radical in the transition states of these hydrogen abstractions.

Molecular evidence of Pleistocene bidirectional faunal exchange between Europe and the Near East: the case of the bicoloured shrew (Crocidura leucodon, Soricidae)

We sequenced 1077 bp of the mitochondrial cytochrome b gene and 511 bp of the nuclear Apolipoprotein B gene in bicoloured shrew (Crocidura leucodon, Soricidae) populations ranging from France to Georgia. The aims of the study were to identify the main genetic clades within this species and the influence of Pleistocene climatic variations on the respective clades. The mitochondrial analyses revealed a European clade distributed from France eastwards to north-western Turkey and a Near East clade distributed from Georgia to Romania; the two clades separated during the Middle Pleistocene. We clearly identified a population expansion after a bottleneck for the European clade based on mitochondrial and nuclear sequencing data; this expansion was not observed for the eastern clade. We hypothesize that the western population was confined to a small Italo-Balkanic refugium, whereas the eastern population subsisted in several refugia along the southern coast of the Black Sea.

Inflammatory and locally advanced breast cancer respond similar to operable breast cancer to neoadjuvant chemotherapy: Results from 278 patients with cT4a-d tumors of the GeparTRIO trial

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Background: Neoadjuvant chemotherapy is the treatment of choice in patients with T4a-c and inflammatory (T4d) breast cancer. However, data on large-scale, multicentre, prospective trials are missing. In the GeparTRIO study (SABCS 2006, abstr. 42) 278 of 2,090 patients with cT4a-c or T4d tumors were included as a separate stratum for inoperable disease for a prospectively planned analysis. Methods: Patients were treated with 2 cycles TAC (docetaxel 75 mg/m2, doxorubicin 50 mg/m2, cyclophosphamide 500 mg/m2, q d 21). If tumor reduction was >50%, patients were randomized to receive 4 or 6 additional TAC cycles. If tumor reduction was less, patients were randomized to 4 additional TAC cycles or to 4 NX cycles (vinorelbine 25 mg/m2 day 1 + 8, capecitabine 2,000 mg/m2 day 1 14, q21). Efficacy endpoints were pCR-rate (no invasive and no non-invasive residuals in breast and lymph nodes) (primary), clinical response before surgery and breast conserving therapy (BCT) rate (secondary). Results: 95 (4.6%) T4d, 183 (8.9%) cT4a-c, and 1,767 (86.4%) T1–3 tumors were registered in GeparTRIO within 36 months. Patients with inoperable/operable tumors had a median age of 53.9/49.0 years, median cT size: 7.0/4.0cm, cN+: 75.6/52.0%, ductal: 76.3/78.4%, lobular: 14.0/13.5%, multiple lesions: 28.5/19.5%, grade 3: 34.8/39.9%, hormone receptor (HR) neg: 24.7/36.6%, HER-2 pos: 41.0/35.5%. Response rates for T4d, T4a-c, T1–3 were 8.4, 10.9, 17.5% (pCR, p=0.007), 36.7, 59.4, 72.6% (palpation after 2 cycles TAC, p<0.0001), 64.2, 62.3, 77.8% (palpation before surgery, p<0.0001), 52.6, 51.9, 67.4% (ultrasound before surgery, p<0.0001). BCT was performed in 12.6, 31.7, 69.5% (p<0.0001). Response after two cycles, negative HR content, young age, high grade, ductal type, but not tumor stage or size, were independent predictors for pCR in the total population. Conclusions: Inflammatory and cT4a-c breast carcinomas, compared to cT1–3 tumors, show less favorable tumor characteristics but a comparable pattern of response to TAC/NX. These patients do not need separate neoadjuvant trials.

[Table: see text]

Tandem Staudinger-azaWittig mediated ring expansion: rapid access to new isofagomine-tetrahydroxyazepane hybrids

New seven-membered iminosugars with potent and selective inhibition towards glycosidases have been prepared as 1-N-iminosugar homologues via a tandem Staudinger-azaWittig mediated ring expansion.

Search for α-glucosidase inhibitors: New N-substituted valienamine and conduramine F-1 derivatives

A solid-phase synthesis of new N-substituted valienamines has been developed and new synthesis of (+/-)-conduramine F-1, (-)-conduramine F-1, and (+)-ent-conduramine F-1 is presented, together with the preparation of N-benzylated conduramines F-1. N-Benzylation of both valienamine and (+)-ent-conduramine F-1 improves their inhibitory activity toward alpha-glucosidases significantly. The additional hydroxymethyl group makes valienamine derivatives more active than their (+)-ent-conduramine F-1 analogues.

The use of levoglucosenone and isolevoglucosenone as templates for the construction of C-linked disaccharides

Because of their functionalities (enone, ketone, and acetal) and their bicyclic structure (steric factors), levoglucosenone (1,6-anhydro-3,4-dideoxy-beta-D-glycero-hex-3-enopyran-2-ulose) and isolevoglucosenone (1,6-anhydro-2,3-dideoxy-beta-D-glycero-hex-3-enopyran-4-ulose) are useful templates for the convergent and combinatorial synthesis of (1-->2), (1-->3), and (1-->4)-linked C-disaccharides in reactions combining them with sugar-derived carbaldehydes. Synthetic methods relying on conjugate nucleophilic additions of these enones, their combination with aluminum reagents and aldehydes (Baylis-Hillman reaction) and modified Takai-Hiyama-Nozaki-Kishi couplings of enol triflates derived from them with sugar-derived aldehydes are reviewed. Highly stereoselective methods have thus been developed. These allow the generation of disaccharide mimetics with a high molecular diversity.

Comparison of neoadjuvant 6 vs 8 cycles of docetaxel/doxorubicin/cyclophosphamide (TAC) in patients early responding to TACx2-the GEPARTRIO Study

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Background: Primary breast cancer (BC) patients (P) with early response to neoadjuvant TACx2 (75mg/m, 50 mg/m, 500 mg/m, day 1, q21, supported with (pegylated) G-CSF and epoetin) experience a high pathologic complete remission (pCR) rate after further TACx4 (von Minckwitz et al, Ann Oncol 2005) compared to patients without early response (SABCS 2005, Abst 38). We compared prolongation to 8 cycles of TAC with conventional 6 cycles TAC in the chemosensitive subgroup. Methods: P with operable (T 2 cm by palpation) or locally advanced (T4 or N3, M0) BC were treated with TACx2. If tumor reduction was exceeding 50% according to breast ultrasound, P were randomized to receive either 4 or 6 additional cycles. Endpoints were pCR-rate (no invasive and no non-invasive residuals) (primary), sonographic response before surgery, breast conservation rate, safety and compliance (secondary). To detect an increase in pCR-rate from 20 to 26%, 606 evaluable patients were requested for each arm (α=0.05, β=0.2, one-sided). Results: 2106 P were recruited into the multi-centre, prospective, open-label, randomized GEPARTRIO-trial within 36 months. 1400 P with an early response to TACx2 were randomized with the last patient having surgery in Dec 05. Median clinical tumor size was 4.0 (1.0 - 30.0) cm at study entry. A planned safety and blinded efficacy interim analysis was performed on the first 600 patients (306 TACx6, 294 TACx8). Main toxicities (grade I-IV %TACx6 vs %TACx8) were: anemia (91 vs 93), thrombopenia (39 vs 49), neutropenia (65 vs 75), febrile neutropenia (10 vs 16), infection (29 vs 30), vomiting (42 vs 44), diarrhea (59 vs 52), stomatitis (66 vs 67), conjunctivitis (51 vs 57), allergic reactions (20 vs 14), edema (40 vs 47), asthenia (90 vs 93), hand-foot-syndrome (25 vs 28), nail (43 vs 50), dyspnea (33 vs 37), sensory neuropathy (51 vs 61). Treatment was discontinued early in 165 P (31.0%), 53 (19.8%) P during TACx6 and 112 (42.3%) P during TACx8. Overall pCR was reported in 102 (17.0%) of these patients. Conclusions: TACx8 is associated with moderate increase in toxicity and treatment discontinuations compared to TACx6. Final results on the primary and secondary endpoints will be presented.

[Table: see text]

Spirocyclopropyl pyrrolidines as a new series of α-l-fucosidase inhibitors

Polyhydroxy 4-azaspiro[2.4]heptane derivatives (spirocyclopropyl iminosugars) were prepared in four to six steps from readily available protected aldoses. The key step of the reaction sequence involves a titanium-mediated aminocyclopropanation of glycononitriles with subsequent cyclization. Five new polyhydroxypyrrolidines so-obtained have been evaluated for their ability to inhibit 16 glycosidases. One of them exhibits selective inhibition of alpha-L-fucosidase from bovine kidney (Ki=1.6 microM, competitive).