Brain architecture: a design for natural computation

Fifty years ago, John von Neumann compared the architecture of the brain with that of the computers he invented and which are still in use today. In those days, the organization of computers was based on concepts of brain organization. Here, we give an update on current results on the global organization of neural systems. For neural systems, we outline how the spatial and topological architecture of neuronal and cortical networks facilitates robustness against failures, fast processing and balanced network activation. Finally, we discuss mechanisms of self-organization for such architectures. After all, the organization of the brain might again inspire computer architecture.

Simulation of robustness against lesions of cortical networks

Structure entails function, and thus a structural description of the brain will help to understand its function and may provide insights into many properties of brain systems, from their robustness and recovery from damage to their dynamics and even their evolution. Advances in the analysis of complex networks provide useful new approaches to understanding structural and functional properties of brain networks. Structural properties of networks recently described allow their characterization as small-world, random (exponential) and scale-free. They complement the set of other properties that have been explored in the context of brain connectivity, such as topology, hodology, clustering and hierarchical organization. Here we apply new network analysis methods to cortical interareal connectivity networks for the cat and macaque brains. We compare these corticocortical fibre networks to benchmark rewired, small-world, scale-free and random networks using two analysis strategies, in which we measure the effects of the removal of nodes and connections on the structural properties of the cortical networks. The structural decay of the brain networks is in most respects similar to that of scale-free networks. The results implicate highly connected hub-nodes and bottleneck connections as a structural basis for some of the conditional robustness of brain systems. This informs the understanding of the development of connectivity of the brain networks.

Bortezomib inhibits human osteoclastogenesis

In multiple myeloma, the overexpression of receptor activator of nuclear factor kappa B (NF-kappaB) ligand (RANKL) leads to the induction of NF-kappaB and activator protein-1 (AP-1)-related osteoclast activation and enhanced bone resorption. The purpose of this study was to examine the molecular and functional effects of proteasome inhibition in RANKL-induced osteoclastogenesis. Furthermore, we aimed to compare the outcome of proteasome versus selective NF-kappaB inhibition using bortezomib (PS-341) and I-kappaB kinase inhibitor PS-1145. Primary human osteoclasts were derived from CD14+ precursors in presence of RANKL and macrophage colony-stimulating factor (M-CSF). Both bortezomib and PS-1145 inhibited osteoclast differentiation in a dose- and time-dependent manner and furthermore, the bone resorption activity of osteoclasts. The mechanisms of action involved in early osteoclast differentiation were found to be related to the inhibition of p38 mitogen-activated protein kinase pathways, whereas the later phase of differentiation and activation occurred due to inhibition of p38, AP-1 and NF-kappaB activation. The AP-1 blockade contributed to significant reduction of osteoclastic vascular endothelial growth factor production. In conclusion, our data demonstrate that proteasomal inhibition should be considered as a novel therapeutic option of cancer-induced lytic bone disease.

In vitro antiprotozoal activities and cytotoxicity of some selected Cameroonian medicinal plants

Eight extracts from seven selected Cameroonian medicinal plants, traditionally used to treat malaria and other protozoal diseases, were tested in vitro for their antiprotozoal activities against Plasmodium falciparum K1 chloroquine-resistant strain, Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei rhodesiense, protozoa responsible for malaria, visceral leishmaniasis, Chagas disease and African trypanosomiasis, respectively. The most active extract against Plasmodium falciparum K1 strain and Trypanosoma brucei rhodesiense was the methanolic extract of Albizia zygia (Fabaceae) stem bark with IC(50) values of 1.0 microg/ml and 0.2 microg/ml, respectively. Five extracts showed IC(50) values below 5mug/ml against Leishmania donovani, with the methanolic seed extract of Harungana madagascarensis showing the highest activity, but only the methanolic extract of Albizia zygia showed activity against Trypanosoma cruzi. Cytotoxicity and selectivity indexes were estimated for the most active extracts. The best ratio of cytotoxicity to antiplasmodial activity (SI(a)=14) was established for the methanolic leaf extract of Symphonia globulifera (Clusiaceae), while the methanolic stem bark extract of Albizia zygia showed the best ratio of cytotoxicity to antitrypanosomal activity (SI(b)=22.5).

Predicting the connectivity of primate cortical networks from topological and spatial node properties

Background

The organization of the connectivity between mammalian cortical areas has become a major subject of study, because of its important role in scaffolding the macroscopic aspects of animal behavior and intelligence. In this study we present a computational reconstruction approach to the problem of network organization, by considering the topological and spatial features of each area in the primate cerebral cortex as subsidy for the reconstruction of the global cortical network connectivity. Starting with all areas being disconnected, pairs of areas with similar sets of features are linked together, in an attempt to recover the original network structure.

Results

Inferring primate cortical connectivity from the properties of the nodes, remarkably good reconstructions of the global network organization could be obtained, with the topological features allowing slightly superior accuracy to the spatial ones. Analogous reconstruction attempts for the C. elegans neuronal network resulted in substantially poorer recovery, indicating that cortical area interconnections are relatively stronger related to the considered topological and spatial properties than neuronal projections in the nematode.

Conclusion

The close relationship between area-based features and global connectivity may hint on developmental rules and constraints for cortical networks. Particularly, differences between the predictions from topological and spatial properties, together with the poorer recovery resulting from spatial properties, indicate that the organization of cortical networks is not entirely determined by spatial constraints.

Proteasome as an Emerging Therapeutic Target in Cancer

The 26S proteasome is a multicatalytic intracellular protease expressed in eukaryotic cells. It is responsible for selective degradation of intracellular proteins that are responsible for cell proliferation, growth, regulation of apoptosis and transcription of genes involved in execution of key cellular functions. Thus proteasome inhibition is a potential treatment option for cancer and diseases due to aberrant inflammation condition. Treatment with proteasome inhibitors results in stabilization and accumulation proteasome substrates, a phenomenon that may result in confounding signals in cells, cell cycle arrest and activation of apoptotic programs. The inhibition of the transcriptional factor nuclear factor kappaB (NF-kappaB) activation was found as one of crucial mechanisms in induction of apoptosis, overcoming resistance mechanisms and inhibition of immune response and inflammation mechanisms. Bortezomib (PS-341) and PS-519 are the first proteasome inhibitors that have entered clinical trials. In multiple myeloma, both the FDA (United States Food and Drug Administration) and EMEA (European Medicine Evaluation Agency) granted an approval for the use of bortezomib (Velcade) for the treatment of relapsed multiple myeloma. At present, several phase II and phase III trials in hematological malignancies and solid tumors are ongoing. PS-519 that focuses on inflammation, reperfusion injury and ischemia is currently under evaluation for the indication of acute stroke.

Does neonatal brain ischemia induce schizophrenia-like behavior in young adult rats?

Perinatal cerebral hypoxia represents a major cause of obstetric complications and the resulting transient oxygen deficiency might belong to early risk factors for schizophrenia. The aim of this study was to evaluate possible long-term behavioral changes induced by one hour of continuous bilateral common carotid artery occlusion in 12-day-old male rats. Post-ischemic behavioral disturbances were evaluated in social (play) behavior on postnatal day 22 (PND 22), open field test (PND 35 and 50) and prepulse inhibition of the acoustic startle reflex (PND 50). Transient ischemia in neonatal rats was not significantly altered in social dyadic interactions evaluated in pre-weaning pups, but resulted in enhanced locomotor activity in pubertal rats (PND 35) and impaired prepulse inhibition of the startle reflex in post-pubertal males (PND 50). These behavioral alterations suggest that perinatal hypoxic/ischemic insults may represent a risk factor for later manifestation of specific features relevant to schizophrenia in predisposed individuals.

The fate of object features during perisaccadic mislocalization

Visual objects flashed before a saccade appear compressed toward the saccade target. Simultaneously flashed objects merge perceptually into one. To better understand cortical interactions in perisaccadic processing, we study the perception of features of mislocalized objects. We report four new findings: First, when multiple objects of different colors are compressed onto a single position, their color attributes remain distinguishable. Second, color attributes of objects compressed onto the same position compete for access to visual awareness. Third, objects presaccadically mislocalized onto a static background of identical color and luminance appear visible on top of that background. Object shape can be determined. Fourth, objects flashed during a saccade become invisible when a larger object is present at the mislocalized position. Thus, perisaccadic mislocalization affects the position of objects but retains other object features. Mislocalization must either occur in parallel to color and shape processing or at late stages of the visual pathway.

In vitro antiprotozoal activity of the lipophilic extracts of different parts of Turkish Pistacia vera L

Thirteen lipophilic extracts prepared with n-hexane from various parts of Pistacia vera L. tree (Anacardiaceae) growing in Turkey were screened for their in vitro activity against four parasitic protozoa, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum. Melarsoprol, benznidazole, miltefosine, artemisinin and chloroquine were used as reference drugs. The cytotoxic potentials of the extracts on rat skeletal myoblast (L6) cells were also assessed and compared to that of podophyllotoxin. The screening method employed was medium-throughput, where the extracts were tested at two concentrations, at 0.8 and 4.8 microg/ml (T. brucei rhodesiense, L. donovani and Plasmodium falciparum), or at 1.6 and 9.7 microg/ml (T. cruzi and L6 cells). At 4.8 microg/ml concentration, the branch extract of Pistacia vera (PV-BR) significantly inhibited (77.3%) the growth of L. donovani, whereas the dry leaf extract (PV-DL) was active against Plasmodium falciparum (60.6% inhibition). The IC50 values of these extracts were determined as 2.3 microg/ml (PV-BR, L. donovani) and 3.65 microg/ml (PV-DL, Plasmodium falciparum). None of the extracts possessed cytotoxicity on mammalian cells.

Nonoptimal component placement, but short processing paths, due to long-distance projections in neural systems

It has been suggested that neural systems across several scales of organization show optimal component placement, in which any spatial rearrangement of the components would lead to an increase of total wiring. Using extensive connectivity datasets for diverse neural networks combined with spatial coordinates for network nodes, we applied an optimization algorithm to the network layouts, in order to search for wire-saving component rearrangements. We found that optimized component rearrangements could substantially reduce total wiring length in all tested neural networks. Specifically, total wiring among 95 primate (Macaque) cortical areas could be decreased by 32%, and wiring of neuronal networks in the nematode Caenorhabditis elegans could be reduced by 48% on the global level, and by 49% for neurons within frontal ganglia. Wiring length reductions were possible due to the existence of long-distance projections in neural networks. We explored the role of these projections by comparing the original networks with minimally rewired networks of the same size, which possessed only the shortest possible connections. In the minimally rewired networks, the number of processing steps along the shortest paths between components was significantly increased compared to the original networks. Additional benchmark comparisons also indicated that neural networks are more similar to network layouts that minimize the length of processing paths, rather than wiring length. These findings suggest that neural systems are not exclusively optimized for minimal global wiring, but for a variety of factors including the minimization of processing steps.

Synthesis of new esters and oximes with 4-aminobicyclo[2.2.2]octane structure and evaluation of their antitrypanosomal and antiplasmodial activities

New 4-amino-6,7-diphenylbicyclo[2.2.2]octane derivatives, esters of bicyclo[2.2.2]octan-2-ols and O-methyl oximes of bicyclo[2.2.2]octan-2-ones were synthesised. Their activities against Trypanosoma brucei rhodesiense (STIB 900) and their activity against the K1 strain of Plasmodium falciparum (resistant to chloroquine and pyrimethamine) were determined by use of microplate assays. The cytotoxicity was assessed using L6 cells. The antiprotozoal activities of the new compounds are compared with those of former prepared derivatives and drugs in use. Structure-activity relationships are discussed.

Comparative antiplasmodial, leishmanicidal and antitrypanosomal activities of several biflavonoids

The antiplasmodial, leishmanicidal and antitrypanosomal activities of eight natural biflavonoids were estimated in vitro on a chloroquine-resistant strain of Plasmodium falciparum, axenically grown Leishmania donovani amastigotes and Trypanosoma cruzi trypomastigotes and Trypanosoma brucei rhodesiense bloodstream forms. Lanaroflavone showed the highest antiplasmodial activity (IC(50) = 0.48 microM), isoginkgetin was the most active leishmanicidal compound (IC(50) = 1.9 microM), whereas ginkgetin (IC(50) = 11 microM) and isoginkgetin (IC(50) = 13 microM) showed the best antitrypanosomal activity in our assays. The cytotoxicity and the selectivity indices for the most active compounds were also estimated. Lanaroflavone exhibited a high selectivity index value (SI = 159), indicating selective antiplasmodial activity.

The influence of interleukin-1β on γ-glutamyl transpepidase activity in rat hippocampus

Brain infections as well as peripheral challenges to the immune system lead to an increased production of interleukin-1beta (IL-1beta), a cytokine involved in leukocyte-mediated breakdown of the blood-brain barrier. The effects of IL-1beta have been reported to depend on whether the route of administration is systemic or intracerebral. Using 50-day-old male rats, we compared the effects of IL-1beta on brain gamma-glutamyl transpeptidase (GGT; an enzymatic marker of brain capillary endothelium) at 2, 24 and 96 h after either an intravenous (i.v.) injection of 5 microg IL-1beta or an intracerebroventricular (i.c.v. - lateral ventricle) infusion of 50 ng IL-1beta. When the i.v. route was used, the GGT activity underwent small but significant changes; decreasing in the hippocampus 2 h after the i.v. injection, increasing 24 h later and returning to control levels at 96 h. No significant changes in the hippocampal GGT activity were observed at 2 and 24 h following the i.c.v. infusion. The GGT activity in the hypothalamus remained unchanged regardless of the route of IL-1beta administrations. Similar changes in GGT activity were revealed histochemically. The labeling was found mainly in the capillary bed, the changes being most evident in the hippocampal stratum radiatum and stratum lacunosum-moleculare. A transient increase in GGT activity at 24 h, together with a less sharp delineation of GGT-stained vessels, may reflect IL-1beta induced increased turnover of glutathione and/or oxidative stress, that may in turn, be related to altered permeability of the blood-brain barrier in some neurological and mental disorders, including schizophrenia.

Assessing ethics and animal welfare in animal biotechnology for farm production

This paper addresses the ethical issues involved in animal biotechnology. Considerable advances in this field have been made with transgenic fish, which may be the first real test case for regulatory bodies. Intrinsic concerns about animal biotechnology are often voiced in public debate, and the paper presents and critically discusses these issues. Even though these concerns may be hard to reconcile with standards of rational argument, they might still have practical consequences for ethical policy making. Animal welfare and environmental issues are discussed as the most salient extrinsic concerns about animal biotechnology. The most serious obstacle to a good risk assessment of animal biotechnology is the extent of scientific uncertainty. Ethical assessments need to address these uncertainties upfront, and the precautionary principle provides a good criterion for responsible policies. At the end of the paper, a practical method for the ethical assessment of animal biotechnology, the so-called ethical matrix, is briefly presented and discussed.

The Number of Stratum corneum Cell Layers Correlates with the Pseudo-Absorption of the Corneocytes

The removal of the stratum corneum (SC) using adhesive tapes is a common technique in cutaneous studies. The determination of the varying amounts of the SC removed would be a helpful tool in such investigations. In the present study, the cell layers of porcine SC were counted before and after removal of several tape strips using histological techniques. In addition, the pseudo-absorption of the corneocytes reflecting the amount of these cells was determined using spectroscopy. Different amounts of SC were removed using 20 tape strips. The spectroscopically determined data correlate linearly with the number of removed cell layers. Based on these results, the pseudo-absorption of the corneocytes can be used to calculate the absolute number of cell layers removed with a standard deviation of less than 11%. In this way, the SC can be quantified using the procedure of tape stripping in combination with the spectroscopic determination of the corneocytes.

Organization, development and function of complex brain networks

Recent research has revealed general principles in the structural and functional organization of complex networks which are shared by various natural, social and technological systems. This review examines these principles as applied to the organization, development and function of complex brain networks. Specifically, we examine the structural properties of large-scale anatomical and functional brain networks and discuss how they might arise in the course of network growth and rewiring. Moreover, we examine the relationship between the structural substrate of neuroanatomy and more dynamic functional and effective connectivity patterns that underlie human cognition. We suggest that network analysis offers new fundamental insights into global and integrative aspects of brain function, including the origin of flexible and coherent cognitive states within the neural architecture.

A bioactive biflavonoid from Campnosperma panamense

Lanaroflavone (1), a biflavonoid isolated from the methanol extract of the aerial part of Campnosperma panamense by bioguided fractionation, has been assessed for in vitro antiprotozoal activity. Lanaroflavone showed both antimalarial and leishmanicidal activities, but was inactive against Chagas disease vector, Trypanosoma cruzi.

Edge vulnerability in neural and metabolic networks

Biological networks, such as cellular metabolic pathways or networks of corticocortical connections in the brain, are intricately organized, yet remarkably robust toward structural damage. Whereas many studies have investigated specific aspects of robustness, such as molecular mechanisms of repair, this article focuses more generally on how local structural features in networks may give rise to their global stability. In many networks the failure of single connections may be more likely than the extinction of entire nodes, yet no analysis of edge importance (edge vulnerability) has been provided so far for biological networks. We tested several measures for identifying vulnerable edges and compared their prediction performance in biological and artificial networks. Among the tested measures, edge frequency in all shortest paths of a network yielded a particularly high correlation with vulnerability and identified intercluster connections in biological but not in random and scale-free benchmark networks. We discuss different local and global network patterns and the edge vulnerability resulting from them.

Spatial growth of real-world networks

Many real-world networks have properties of small-world networks, with clustered local neighborhoods and low average-shortest path. They may also show a scale-free degree distribution, which can be generated by growth and preferential attachment to highly connected nodes, or hubs. However, many real-world networks consist of multiple, interconnected clusters not normally seen in systems grown by preferential attachment, and there also exist real-world networks with a scale-free degree distribution that do not contain highly connected hubs. We describe spatial-growth mechanisms, not using preferential attachment, that address both aspects.

Mutational spectrum in Usher syndrome type II

Usher syndrome type II is an autosomal recessive disorder characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa (RP). We carried out a mutation screening of the USH2A gene in 88 probands with Usher syndrome type II to determine the frequency of USH2A mutations as a cause for USH2. Six mutations, including 2299delG, 921-922insCAGC, R334W, N346H, R626X, and N357T were identified, with 2299delG mutation being the most frequent (16.5% of alleles), accounting for 77.5% of the pathologic alleles. Thirty-five percent (31/88) of the probands had a USH2A mutation. Nine of them carried two pathogenic mutations: six cases were homozygotes and three were compound heterozygotes. Twenty-two probands (25%) were found to carry only single USH2A mutations. One new missense mutation (N357T) occuring within the laminin N-terminal (type VI) domain of usherin was identified. Eight polymorphisms were found, five of which are novel. Our data support the view that the 2299delG is the most common mutation in USH2A.

Clustered Organization of Cortical Connectivity

Long-range corticocortical connectivity in mammalian brains possesses an intricate, nonrandom organization. Specifically, projections are arranged in "small-world" networks, forming clusters of cortical areas, which are closely linked among each other, but less frequently with areas in other clusters. In order to delineate the structure of cortical clusters and identify their members, we developed a computational approach based on evolutionary optimization. In different compilations of connectivity data for the cat and macaque monkey brain, the algorithm identified a small number of clusters that broadly agreed with functional cortical subdivisions. We propose a simple spatial growth model for evolving clustered connectivity, and discuss structural and functional implications of the clustered, small-world organization of cortical networks.

Perisaccadic Mislocalization Orthogonal to Saccade Direction

Saccadic eye movements transiently distort perceptual space. Visual objects flashed shortly before or during a saccade are mislocalized along the saccade direction, resembling a compression of space around the saccade target. These mislocalizations reflect transient errors of processes that construct spatial stability across eye movements. They may arise from errors of reference signals associated with saccade direction and amplitude or from visual or visuomotor remapping processes focused on the saccade target's position. The second case would predict apparent position shifts toward the target also in directions orthogonal to the saccade. We report that such orthogonal mislocalization indeed occurs. Surprisingly, however, the orthogonal mislocalization is restricted to only part of the visual field. This part comprises distant positions in saccade direction but does not depend on the target's position. Our findings can be explained by a combination of directional and positional reference signals that varies in time course across the visual field.

USH1C: a rare cause of USH1 in a non-Acadian population and a founder effect of the Acadian allele

Usher syndrome (USH) is characterized by the associated findings of hearing loss and retinitis pigmentosa (RP), leading to progressive loss of vision. Three forms of USH can be distinguished clinically. In the most severe form, USH1, profound congenital deafness is associated with vestibular dysfunction and RP. To determine the frequency of USH1C mutations as a cause for USH1, 128 probands with Usher syndrome type 1 including seven from Acadian and 121 from non-Acadian populations were systematically screened for mutations in USH1C using a combined single-strand conformational polymorphisms (SSCP)/heteroduplex and sequencing method. All seven Acadian USH1 patients were found to be homozygous for both the 216G>A mutation and the 9-repeat VNTR which characterizes the Acadian allele, confirming previous evidence for a founder effect by haplotype analysis. However, USH1C mutations were identified in only two non-Acadian USH1 probands (1.65%) including one from Pakistan who was homozygous for a 238-239insC mutation and one from Canada was also homozygous for the Acadian allele. The low prevalence of USH1C mutations in the present study suggests that the high prevalence of the 238-239insC in Germany may reflect a founder effect. Comparison of the affected haplotypes in the Canadian patient with the Acadian USH1 patients yielded evidence for a founder effect. Our data suggest that USH1C is a relatively rare form of USH1 in non-Acadian populations and that in addition to the 216G>A Acadian mutation, the 238-239insC mutation appears to be common in some populations.

Intima-media thickness and atherosclerotic plaques in familial defective apolipoprotein B-100 and familial hypercholesterolemia

Familial defective apolipoprotein B-100 (FDB) is a genetic disorder characterized by a decreased binding of low-density lipoprotein (LDL) particles to the LDL receptor due to defective apo B-100. Impaired LDL clearance could also be due to defects of the LDL receptor (familial hypercholesterolemia, FH). FDB was suggested to be clinically indistinguishable from classical FH. The measurement of the intima-media thickness (IMT) is an accepted method for the direct evaluation of early atherosclerosis. Thus, the aim of this study was to examine the IMT in patients with FDB in comparison to FH. Our data indicate that IMT in FDB does not differ from IMT in FH.

Pumpless extracorporeal lung assist using an arterio-venous shunt. Applications and limitations

We report the use of a pumpless extracorporeal lung assist (PECLA) in 70 patients with severe pulmonary failure of various causes. The device was used under rescue conditions in patients with preserved cardiac function. By establishing a shunt between femoral artery and vein using the arterio-venous pressure gradient as the driving force for the blood flow through the oxygenator, PECLA proved to be extremely effective in terms of oxygenation and carbon dioxide removal.

Migration of naive, effector and memory T cells: implications for the regulation of immune responses

T cells play an important role in protective immune responses and in the pathogenesis of many diseases. Understanding the mechanisms regulating their distribution in vivo may therefore be of therapeutic value. Reviewing studies that have followed the migration of labelled naive, effector and memory T cells in healthy animals reveals that all T-cell subsets enter all organs investigated. Within the tissue, two principally different migration patterns can be identified. First, naive and memory T cells accumulate in lymphoid organs for about 48 h after injection, as the time needed for migration through lymphoid organs is longer than through non-lymphoid organs. During this time, surface molecule expression is temporarily modified. These changes are reversed before leaving the lymphoid organs and entering the blood to start a new cycle of migration. Second, effector T cells are evenly distributed throughout the body, and most die in the tissues within 24 h. However, depending on the presence of cytokines, some are able to survive and to proliferate, and thereby accumulate in defined microenvironments of the body. Analysing the principles regulating T-cell migration and survival within the tissue may lead to the development of new options for the treatment of disease.

[N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-): a new high-nitrogen high-energetic material

The reaction of [N(2)H(5)](+)(2)[SO(4)](2-) with barium 5,5'-azotetrazolate gave new high-energy-density materials (HEDM) based on the 5,5'-azotetrazolate dianion. The dihydrazinium salt of [N(4)C-N=N-CN(4)](2-) 1, its dihydrate 2, and its dihydrazinate 3 were prepared in high yield. Synthesis in water afforded yellow needles of [N(2)H(5)](2)(+)[N(4)C-N=N-CN(4)](2-).2H(2)O (2): monoclinic, P2/c, a = 8.958(2) A, b = 3.6596(7) A, c = 16.200(3) A, beta = 96.834(3) degrees, V = 527.3(2) A(3), Z = 2; synthesis in anhydrous hydrazine gave yellow [N(2)H(5)](2)(+)[N(4)C-N=N-CN(4)](2-).2N(2)H(4) (3): triclinic, P1, a = 4.6208(6) A, b = 8.585(1) A, c = 9.271(1) A, alpha = 108.486(2) degrees, beta = 95.290(2) degrees, gamma = 102.991(2) degrees, V = 334.51(8) A(3), Z = 1. The compounds were characterized by elemental analysis and vibrational (IR, Raman) and multinuclear NMR spectroscopy ((1)H, (13)C, (14)N, (15)N). The new compounds represent new high-nitrogen HEDMs with one of the highest nitrogen contents reported to date ([N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-) 85.2%; [N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-).2H(2)O 73.3%; [N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-).2N(2)H(4) 85.7%). The standard heat of formation of the solvate-free compound 1 was computed at the MP2(FULL)/6-311+G(d,p) level of theory to be DeltaH degrees (f) = 264 kcal mol(-1), which translates to 1147 kcal kg(-1) and is one of the highest ever reported. The compounds are stable at room temperature, almost insensitive to friction and impact, but detonate violently when the explosion is initiated, e.g., by rapid heating over the decomposition temperature or by using an initiator.

Naive and memory T cells migrate in comparable numbers through the normal rat lung: only effector T cells accumulate and proliferate in the lamina propria of the bronchi

T cells reach the lung via the pulmonary and bronchial arteries that supply the alveolar and bronchial regions. Although these regions are differentially affected by T cell-mediated diseases, the migration of T-cell subsets in these two regions has not been studied. Naive, memory, and effector T cells were injected into congenic rats and traced in sections of normal lung. All three T-cell subsets were found in large numbers in the alveolar region and exited again quickly. Only effector T cells accumulated in the lamina propria of the bronchi. Further, 72 h after injection 6% of the effector T cells still proliferated in the lung, whereas apoptotic effector T cells were only observed 1 h after injection (0.2%). Thus, not only effector and memory but also naive T cells continuously migrated through the lung. The preferential accumulation of effector T cells in the bronchial lamina propria may explain why some diseases preferentially affect the bronchial region.

Phase I Clinical Trial of Alitretinoin and Tamoxifen in Breast Cancer Patients: Toxicity, Pharmacokinetic, and Biomarker Evaluations

PURPOSE: To determine the overall and dose-limiting toxicities (DLTs) of alitretinoin (9-cis-retinoic acid) in combination with tamoxifen and the pharmacokinetics of alitretinoin alone and when combined with tamoxifen in patients with metastatic breast cancer. The effect of tamoxifen and alitretinoin on MIB-1, a marker of proliferation, in unaffected breast tissue was explored.

PATIENTS AND METHODS: Eligible patients had metastatic breast cancer. Previous tamoxifen therapy was allowed. Planned dose levels for alitretinoin ranged from 50 to 140 mg/m2/d with 20 mg/d tamoxifen in all patients after 4 weeks of alitretinoin as a single agent. Plasma concentrations of alitretinoin and retinol were measured at baseline and after 1, 2, and 3 months. Breast core biopsies were obtained at baseline and after 2 months of therapy.

RESULTS: Twelve patients with metastatic breast cancer received a total of 86 cycles of therapy. At 90 mg/m2/d, three of five patients experienced a DLT: grade 3 headache, grade 3 hypercalcemia, and grade 3 noncardiogenic pulmonary edema. At 70 mg/m2/d, one of six patients experienced a DLT (headache), and this level was considered the maximal tolerated dose in this study. Three toxicities occurred that had not been reported previously with alitretinoin: an asymptomatic delay in dark adaptation, a marked decrease in high-density lipoprotein cholesterol, and the occurrence of enthesopathy. Two of the nine assessable patients had a durable clinical response: one partial response and stable disease for 18 months and one complete response in continuous remission for 48+ months. Both responding patients were estrogen receptor–positive and had had previous tamoxifen therapy. There was a high degree of interpatient variability of plasma alitretinoin concentrations, although a significant decline in alitretinoin plasma levels over time was observed. MIB-1 scores declined in four of the eight paired breast specimens obtained.

CONCLUSION: The combination of tamoxifen and alitretinoin is well tolerated and has antitumor activity in metastatic breast cancer. The recommended phase II dose is 70 mg/m2/d with 20 mg/d tamoxifen.

Life-history correlates of evolution under high and low adult mortality

Life-history theory predicts evolutionary changes in reproductive traits and intrinsic mortality rates in response to differences in extrinsic mortality rates. Trade-offs between life- history traits play a pivotal role in these predictions, and such trade-offs are mediated, at least in part, by physiological allocations. To gain insight into these trade-offs, we have been performing a long-term experiment in which we allow fruitflies, Drosophila melanogaster, to evolve in response to high (HAM) and low (LAM) adult mortality rates. Here we analyze the physiological correlates of the life-history trade-offs. In addition to changing development time and early fecundity in the direction predicted, high adult mortality affected three traits expressed early in life-body size, growth rate, and ovariole number-but had little or no effect on body composition (relative fat content), viability, metabolic rate, activity, starvation resistance, or desiccation resistance. Correlations among lines revealed trade-offs between early fecundity, late fecundity, and starvation resistance, which appear to be mediated by differential allocation of lipids.

Pumpless extracorporeal lung assist and adult respiratory distress syndrome

We report use of a pumpless extracorporeal lung assist-a safe and effective method in the management of severe acute respiratory failure that allows an extracorporal gas-exchange without the use of a pump.

Generation of complement C3 and expression of cell membrane complement inhibitory proteins by human bronchial epithelium cell line

BACKGROUND

The interrelationship between human airway epithelium and complement proteins may affect airway defence, airway function, and airway epithelial integrity. A study was undertaken to determine (1) whether unstimulated human bronchial epithelium generates complement proteins and expresses cell membrane complement inhibitory proteins (CIP) and (2) whether stimulation by proinflammatory cytokines affects the generation of complement and expression of cell membrane CIP by these cells.

METHODS

Human bronchial epithelium cell line BEAS-2B was cultured in a serum-free medium. Cells were incubated with and without proinflammatory cytokines to assess unstimulated and stimulated generation of complement C3, C1q and C5 (by ELISA), and to examine the expression of cell membrane CIP decay accelerating factor (DAF; CD55), membrane cofactor protein (MCP; CD46), and CD59 (protectin) by flow cytometry analysis.

RESULTS

Unstimulated human bronchial epithelial cell line BEAS-2B in serum-free medium generates complement C3 (mean 32 ng/10(6) cells/72 h, range 18-52) but not C1q and C5, and expresses cell membrane DAF, MCP, and CD59. Interleukin (IL)-1alpha (100 U/ml/72 h) and tumour necrosis factor (TNF-alpha; 1000 U/ml/72 h) increased generation of C3 up to a mean of 78% and 138%, respectively, above C3 generation by unstimulated cells. DAF was the only cell membrane CIP affected by cytokine stimulation. Interferon (IFN)-gamma (10 U/ml/72 h) and TNF-alpha (1000 U/ml/72 h) increased DAF expression up to a mean of 116% and 45%, respectively, above that in unstimulated cells. MCP and CD59 expression was not consistently affected by IL-1alpha, TNF-alpha, or IFN-gamma.

CONCLUSIONS

Local generation of complement C3 and expression of cell membrane CIP by human bronchial epithelium and its modulation by proinflammatory cytokines might be an additional regulatory mechanism of local airway defence and may affect airway function and epithelial integrity in health and disease.

Vitamin A deficiency results in the dose-dependent acquisition of anterior character and shortening of the caudal hindbrain of the rat embryo

The developing nervous system is particularly vulnerable to vitamin A deficiency. Retinoid has been proposed to be a posteriorizing factor during hindbrain development, although direct evidence in the mammalian embryo is lacking. In the present study, pregnant vitamin A-deficient (VAD) rats were fed purified diets containing varying levels of all-trans-retinoic acid (atRA; 0, 0.5, 1.5, 6, 12, 25, 50, 125, or 250 microg/g diet) or were supplemented with retinol. Hindbrain development was studied from embryonic day 10 to 12.5 ( approximately 6 to 40 somites). Normal morphogenesis was observed in all embryos from groups fed 250 microg atRA/g diet or retinol. The most caudal region of the hindbrain was the most sensitive to retinoid insufficiency, as evidenced by a loss of the hypoglossal nerve (cranial nerve XII) in embryos from the 125 microg atRA/g diet group. Further reduction of atRA to 50 microg/g diet led to the loss of cranial nerves IX, X, XI, and XII and associated sensory ganglia IX and X in all embryos as well as the loss of hindbrain segmentation caudal to the rhombomere (r) 3/4 border in a subset of embryos. Dysmorphic orthotopic otic vesicles or immature otic-like vesicles in both orthotopic and caudally ectopic locations were also observed. As the level of atRA was reduced, a loss of caudal hindbrain segmentation was observed in all embryos and the incidence of otic vesicle abnormalities increased. Perturbations in hindbrain segmentation, cranial nerve formation, and otic vesicle development were associated with abnormal patterning of the posterior hindbrain. Embryos from VAD dams fed between 0.5 and 50 microg atRA/g diet exhibited Hoxb-1 protein expression along the entire neural tube caudal to the r3/r4 border at a time when it should be restricted to r4. Krox-20 protein expression was expanded in r3 but absent or reduced in presumptive r5. Hoxd-4 mRNA expression was absent in the posterior hindbrain, and the rostral limit of Hoxb-5 protein expression in the neural tube was anteriorized, suggesting that the most posterior hindbrain region (r7/r8) had been deleted and/or improperly patterned. Thus, when limiting amounts of atRA are provided to VAD dams, the caudal portion of the hindbrain is shortened and possesses r4/r5-like characteristics, with this region finally exhibiting r4-like gene expression when retinoid is restricted even more severely. Thus, regions of the anterior hindbrain (i.e., r3 and r4) appear to be greatly expanded, whereas the posterior hindbrain (r5-r8) is reduced or absent. This work shows that retinoid plays a critical role in patterning, segmentation, and neurogenesis of the caudal hindbrain and serves as an essential posteriorizing signal for this region of the central nervous system in the mammal.

Experimental evolution of aging, growth, and reproduction in fruitflies

We report in this paper an evolutionary experiment on Drosophila that tested life-history theory and the evolutionary theory of aging. As theory predicts, higher extrinsic mortality rates did lead to the evolution of higher intrinsic mortality rates, to shorter lifespans, and to decreased age and size at eclosion; peak fecundity also shifted earlier in life. These results confirm the key role of extrinsic mortality rates in the evolution of growth, maturation, reproduction, and aging, and they do so with a selection regime that maintained selection on fertility throughout life while holding population densities constant.

n-Alkyl fluorenyl phases in chromatography. II. Dynamic behavior and high-performance liquid chromatography applications

The dynamic behavior of two n-hexyl fluorenyl phases (fluorene-6A [3a(Tn)(Qm)y], fluorene-6B [3b(Tn)(Qm)y]) and three n-decyl fluorenyl phases (fluorene-10A [4a(Tn)(Qm)y], fluorene-10B [4b(Tn)(Qm)y], and fluorene-10C [4c(M1)(Qm)y]) is investigated by solid-state nuclear magnetic resonance (NMR) spectroscopy using the dipolar filter technique with both 13C and 1H detection. These results are compared with those from other dynamic measurements, like the relaxation times in the rotating frame (T1pH) and the variation of the contact time (T(CH)). Additionally, another type of a fluorenyl phase [5a(Tn)(Qm)y], which has an aromatic moiety connected to the silica gel by amido couplings, was also investigated by the dipolar filter method. The solid-state NMR dynamic measurements indicate an increased mobility of the n-alkyl fluorenyl phases compared to the amido coupled fluorenyl phase. The lower the ligand density of the studied n-alkyl fluorenyl phases, the higher their mobility. The separation behavior of the respective phases in high-performance liquid chromatography was investigated with samples containing polycyclic aromatic hydrocarbons and nitro explosives. Depending on the amount of the chemically bound aromatic moiety and the length of their n-alkyl spacer groups, pi-pi interactions with the solute molecules are involved in the separation process and cause it to proceed at a different rate. Therefore, n-alkyl fluorenyl phases can be classified as mixed-mode phases.