Quantum key distribution over multicore fiber.

We present the first quantum key distribution (QKD) experiment over multicore fiber. With space division multiplexing, we demonstrate that weak QKD signals can coexist with classical data signals launched at full power in a 53 km 7-core fiber, while showing negligible degradation in performance. Based on a characterization of intercore crosstalk, we perform additional simulations highlighting that classical data bandwidths beyond 1Tb/s can be supported with high speed QKD on the same fiber.

Increased proteasome-dependent degradation of the cyclin-dependent kinase inhibitor p27 in aggressive colorectal carcinomas.

The cell-cycle inhibitor p27 is a potential tumor suppressor, but its gene has never been found inactivated in human tumors. Because cell-cycle regulation of p27 cellular abundance occurs at the post-transcriptional level, we analyzed p27 protein expression and degradation in human colorectal carcinomas. Proteasome-mediated degradation activity of p27 was compared with its protein levels in a subset of tumor samples. We found that carcinomas with low or absent p27 protein displayed enhanced proteolytic activity specific for p27, suggesting that low p27 expression can result from increased proteasome-mediated degradation rather than altered gene expression. Patients whose tumors expressed p27 had a median survival of 151 months, whereas patients who lacked p27 (10%) had a median survival of 69 months. By multivariate analysis, p27 was found to be an independent prognostic marker. Lack of p27 was associated with poor prognosis (2.9 risk ratio for death; P = 0.003). The absence of p27 protein expression is thus a powerful negative prognostic marker in colorectal carcinomas, particularly in stage II tumors, and thereby may help in the selection of patients who will benefit from adjuvant therapy. These data suggest that aggressive tumors may result from the selection of a clone or clones that lack p27 due to increased proteasome-mediated degradation.

Role of the ubiquitin-proteasome pathway in regulating abundance of the cyclin-dependent kinase inhibitor p27.

The p27 mammalian cell cycle protein is an inhibitor of cyclin-dependent kinases. Both in vivo and in vitro, p27 was found to be degraded by the ubiquitin-proteasome pathway. The human ubiquitin-conjugating enzymes Ubc2 and Ubc3 were specifically involved in the ubiquitination of p27. Compared with proliferating cells, quiescent cells exhibited a smaller amount of p27 ubiquitinating activity, which accounted for the marked increase of p27 half-life measured in these cells. Thus, the abundance of p27 in cells is regulated by degradation. The specific proteolysis of p27 may represent a mechanism for regulating the activity of cyclin-dependent kinases.

The Space Physics Environment Data Analysis System (SPEDAS).

With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (www.spedas.org), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have "crib-sheets," user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer's Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its "modes of use" with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11214-018-0576-4) contains supplementary material, which is available to authorized users.

Differential expression and cell cycle regulation of the cyclin-dependent kinase 4 inhibitor p16Ink4.

p16Ink4 (inhibitor of cyclin-dependent kinase 4) is a cell cycle regulator that specifically binds to and inhibits Cdk4. Recently, the human mts1 (multiple tumor suppressor 1) gene, deleted or mutated in various primary tumors and in a large number of transformed cell lines, was found to be identical to ink4. In this study we have surveyed by immunoblotting the protein levels of p16Ink4 in normal and transformed human cells. We determined that p16Ink4 was differentially expressed in diploid cells derived from different tissues, in contrast to another cell cycle inhibitor, p21Waf1, which is ubiquitously expressed. In some tumor cell lines p16Ink4 protein was not detected, presumably because of a homozygous deletion of its gene. By contrast, it was found to be overexpressed in other cell lines when compared to levels in their normal counterparts. Interestingly, high levels of p16Ink4 protein correlated with functional inactivation of the retinoblastoma gene product. We also found that p16Ink4 protein expression varies during the cell cycle peaking during S phase. These results show a functional relationship between p16Ink4 and the retinoblastoma gene product and indicate that p16Ink4 is required for Cdk4 inhibition only at the G1-S transition at the time when Cdk4 kinase activity is no longer necessary.

Differential expression and regulation of Cyclin D1 protein in normal and tumor human cells: association with Cdk4 is required for Cyclin D1 function in G1 progression.

In this study we have surveyed by immunoblotting the protein levels of Cyclin D1, D2, D3 and their catalytic partners, Cdk4 and Cdk6 in normal and transformed human cells. We found that all these proteins were differentially expressed in diploid cells derived from different tissues, in contrast to Cyclin E, Cyclin A and Cdk2 which are ubiquitously expressed. D-type Cyclins were never dramatically overexpressed and often very poorly expressed in tumor cell lines when compared to the levels in their normal counterparts. In contrast, Cdk4 was expressed at high levels in several tumor cell lines and Cdk6 was ectopically expressed in two sarcoma lines, suggesting a possible involvement of these two Cdks in oncogenesis. Interestingly, low levels of Cyclin D1 and D3 proteins always correlated with functional inactivation of the retinoblastoma gene product (pRb). In cells displaying active pRb, Cyclin D1 was found associated with Cdk4 regardless of whether the p53 gene was wild-type or mutant. Microinjection during G1 of Cyclin D1 anti-sense cDNA or anti-Cyclin D1 antibody in these cells arrested the cell cycle in G1. In cells lacking pRb function, Cyclin D1 was dissociated from Cdk4. Microinjection during G1 of Cyclin D1 antisense cDNA or anti-Cyclin D1 antibody in these cells did not affect G1 progression. These results show that (i) in the absence of pRb, Cyclin D1 is expressed at low levels, is dissociated from Cdk4 and becomes dispensable in G1; (ii) Cyclin D1 needs to be associated with its catalytic subunit, Cdk4, to function as a positive regulator of G1 progression.

Binding of thrombin to human platelet plasma membranes.

Binding of 125I-labeled thrombin to isolated human platelet plasma membranes was studied. Two classes of sites, one with high and one with low affinity for thrombin, were demonstrated. The apparent dissociation constants for the high and low affinity sites were 3.2 and 600 nM, respectively, similar to values obtained with intact platelets. Maximum binding was within 10 s, the shortest time measured, and then decreased with time to a constant level of binding within 45 s. When the equilibrium was perturbed by dilution, the system re-equilibrated with less thrombin bound than in a control that was dilute before mixing thrombin and membranes. Neither the time-dependent decrease nor the dilution effect were observed with phenylmethylsulfonyl-125I-labelled thrombin, an irreversibly inhibited thrombin, suggesting that these phenomena may involve a thrombin-catalyzed modification of the membranes leading decreased binding.

Differential effects of anesthetics on phosphatidylethanolamine biosynthesis in hamster tissue.

The anesthetic effects of diethyl ether and sodium pentobarbital on phosphatidylethanolamine biosynthesis in hamster organs were investigated. No significant difference was observed in the livers and hearts between control and anesthesized animals. However, a 30% reduction in phosphatidylethanolamine labelling was detected in the kidney of the diethyl ether-anesthesized hamsters. Such reduction appears to be caused by an inhibition of phosphoethanolamine cytidylyltransferase, a rate-limiting enzyme in the major pathway for the biosynthesis of phosphatidylethanolamine. The uptake of ethanolamine by the organs was not affected during anesthesia.

Yohimbine: a clinical review.

Although yohimbine (YOH) has been available for the treatment of male erectile dysfunction (ED) for longer than Viagra, there is a perception that little is known about the clinical performance of the drug. This review attempts, by comprehensive analysis of the literature, to cover the clinical, pharmacological, and therapeutic profiles of YOH, relevant to its potential utility in the management of patients with ED. Relatively few well-designed studies have been completed. From these, however, it can be concluded that YOH as monotherapy possesses only modest efficacy in ED patients. In acute and chronic (long-term) studies, YOH has been found to be relatively free of side effects over the dose range predicted to be effective in ED. At much higher doses, the most frequently observed effects, consistent with the primary pharmacological action of the drug, are elevation of blood pressure, a slight anxiogenic action, and increased frequency of urination. These side effects are all easily reversible on termination of YOH therapy. There is increasing evidence that the erectogenic action of YOH can be augmented by concomitant administration of agents that augment the release and/or action of nitric oxide in the corpus cavernosum. YOH has yet to be studied in female sexual dysfunction. Overall, the benefit risk profile of YOH would indicate that it has potential, more probably as part of a combination strategy, e.g., with a drug that enhances the nitric oxide pathway, in the treatment of ED.

Kip1 degradation via the ubiquitin-proteasome pathway.

The cell cycle has been the object of extensive studies for the past years. A complex network of molecular interactions has been identified. In particular, a class of cell cycle inhibitory proteins has been identified but details of the molecular mechanism of their action have yet to be resolved. These inhibitors regulate the progression through G1 and the G1/S transition via the inhibition of the cyclin-dependent kinase (Cdk) activity. The potential function of these negative regulators as tumor suppressors provides new insights into the link between the cell cycle and oncogenesis. Kip1 is a potent inhibitor of Cdks. In quiescent cells Kip1 accumulates without an increase in mRNA or protein synthesis. We demonstrated that cell cycle regulation of Kip1 levels, both in normal and transformed human cells, occurs via the ubiquitin-proteasome pathway. In a crude in vitro system, Kip1 is ubiquitinated and degraded in an ATP dependent manner and inhibition or depletion of the proteasome blocks Kip1 degradation. Human Ubc2 and Ubc3, the homologs of yeast Rad6 and Cdc34 gene products respectively, are specifically involved in the ubiquitination of Kip1. Compared to proliferating cells, quiescent cells contain a far lower amount of Kip1 ubiquitinating activity. These results represent the first demonstration that the ubiquitin-proteasome pathway plays a role in the regulation of a cell cycle protein in human cells, namely the Cdk inhibitor Kip1. The specific proteolysis of Kip1 may be involved in the pathway of inactivation of Cdks.

The role of adenosine 3',5'-monophosphate in dopaminergic inhibition of prolactin release in anterior pituitary cells.

The relationship between cAMP stimulation and dopaminergic inhibition of PRL release was studied in primary cultures of rat anterior pituitary cells. Bromocriptine, a dopaminergic agonist, and cholera enterotoxin, isobutylmethylxanthine, theophylline, and 8-bromo-cAMP, agents which mimic cAMP action or cause increases in cAMP, were used. Short term PRL release (that which occurs within 1 or 2 h) was stimulated 1.5- to 2-fold by all of the cAMP agents. Bromocriptine (5 nM) decreased basal release and completely abolished any short term stimulation above basal caused by cholera enterotoxin and 8-bromo-cAMP. Isobutylmethylxanthine and theophylline did cause some stimulation of PRL release above basal, but the magnitude of the increase was half that in the absence of bromocriptine. The short term release stimulated by 8-bromo-cAMP was dependent on extracellular calcium. PRL accumulation in the medium for 1-3 days was increased by all of the cAMP agents. A long term increase caused by these agents was also observed in the presence of bromocriptine. The magnitude of the increase in release above basal was the same with and without bromocriptine, but the total PRL in the medium was always less in the presence of bromocriptine, since basal release was reduced. These results show that the short term inhibition of PRL release by bromocriptine cannot be completely reversed by agents which increase cAMP.

Human cathepsin B-encoding cDNAs: sequence variations in the 3'-untranslated region.

We have isolated two cathepsin B (CTSB)-encoding cDNAs, hCBF1 and hCBF2, from a normal human embryonic fibroblast library. These clones demonstrate 98% identity to overlapping regions of published human hepatoma and kidney CTSB cDNAs, but show some interesting differences from the published sequences in the 3'-untranslated region (3'-UTR). Both hCBF1 and hCBF2 contain a 10-bp insertion in the 3'-UTR that may permit formation of a highly stable stem-loop structure not present in mRNAs without this insertion. Our hCBF1 cDNA also contains a 1019-bp extension of the 3'-UTR sequence that resembles the long 3'-UTR reported for murine CTSB cDNAs. Probes unique to this 3'-UTR extension hybridize to 4.0- and 1.7-kb CTSB RNAs on Northern blots, but not to the major 2.2-kb mRNA transcript. Our data reveal variations in normal human CTSB transcripts that result from differences in the length of the 3'-UTR, as well as the presence or absence of a stem-loop stabilizing sequence.

Electrophysiological effects of selective sigma-receptor agonists, antagonists, and the selective phencyclidine receptor agonist MK-801 on midbrain dopamine neurons.

Extracellular single unit recording techniques were used to study the effects of selective sigma-receptor agonist [(+)-3-PPP, (+)-pentazocine, and DTG] and selective sigma-receptor antagonists (BMY 14802 and Rimcazole) on dopamine neurons of the substantia nigra. Intravenous (IV) administration of sigma agonists decreased, whereas IV administration of the sigma antagonist BMY-14802 increased the firing rate of dopamine neurons. The other sigma antagonist Rimcazole produced inconsistent changes in dopamine unit activity. These data, in conjunction with anatomic data suggesting sigma receptor localization on dopamine neurons in the substantia nigra (Gundlach et al: J Neurosci 6:1757-1770, 1986; Graybiel et al: Soc Neurosci Abstr 13:28, 1987) demonstrate a relationship of the sigma receptor with the dopamine system and further suggest a model system to study agonist-antagonist interactions of sigma ligands. The selective phencyclidine (PCP) agonist MK-801 was equipotent to PCP in regard to stimulatory properties on dopamine neurons. However, the relative potencies do not correspond to their relative binding affinities, suggesting that non-PCP-receptor properties may mediate this effect.

Biochemical, behavioral, and electrophysiologic actions of the selective sigma receptor ligand (+)-pentazocine.

Research on the sigma receptor, a binding site associated with drug-induced psychotomimetic behaviors, has been hampered because most sigma agonists also interact with the phencyclidine (PCP) receptor. (+)-Pentazocine, a human psychotogen, is a selective sigma receptor ligand. To demonstrate sigma receptor activities, we studied the behavioral and electrophysiologic actions for (+)-pentazocine. In the behavioral drug discrimination procedure in which rats were trained to discriminate between 2.0 mg/kg (5.59 mumol/kg) (+)-pentazocine and saline, (+)-pentazocine produced dose-related increases in the percentage of trials completed on the (+)-pentazocine lever. At a dose of 1.0 mg/kg (3.29 mumol/kg) (+)-N-allylnormetazocine generalized completely to (+)-pentazocine. By contrast, PCP only partially generalized. In the visual evoked potential test, these compounds produced a significant dose-dependent slowing of the N2 latency. This response was prevented by haloperidol pretreatment. These results demonstrate pharmacologic actions for the selective sigma receptor ligand (+)-pentazocine and suggest some overlapping pharmacologic properties of the sigma and PCP receptor sites despite differences in central nervous system distribution.

3-Substituted, 3-(4-pyridinylmethyl)-1,3-dihydro-1-phenyl-2H-indol-2-ones as acetylcholine release enhancers: synthesis and SAR.

A series of 3-substituted, 3-(4-pyridinylmethyl)-1,3-dihydro-1-phenyl-2H-indol-2-ones was synthesized and found to enhance the stimulus-induced release of neurotransmitter acetylcholine (AcCh), and by doing so, might be useful in treating cognitive disorders where the level of this neurotransmitter may be diminished in the brain, as in Alzheimer's disease. An attempt has been made to correlate the structure of the 3-substitution with the ability of the compounds to enhance the release of AcCh from the striatum region of rat brain preparations.

Modification of the enkephalin "message" with an artificial polycationic C-terminus.

The C-terminal "address" sequences of prodynorphin-derived opioid peptides contain an unusually high proportion of basic residues, which are known to be crucial for conferring high activity and selectivity for kappa-opioid receptors. In an effort to investigate the possibility that the polycationic "tails" may be involved in a coulombic interaction with a complementary polyanionic receptor domain, we attached a series of achiral peptide-like cationic fragments to the C-terminus of the opioid peptide "message", Tyr-Gly-Gly-Phe. Binding of the various compounds to opioid receptor types in guinea pig brain membranes was weak, and the pharmacologic activities in the guinea pig ileum were marginal. These results indicate either that the chosen ligand design does not satisfy the structural requirements of the hypothesized coulombic interaction or that the latter is a minor criterion governing receptor recognition.

Peptides as receptor selectivity modulators of opiate pharmacophores.

In an effort to investigate whether "address" segments of endogenous opioid peptides, which are responsible for modulating receptor selectivity, also could modulate the selectivity of opioid alkaloid pharmacophores, we have synthesized analogues of leucine-enkephalin and dynorphin in which the N-terminal dipeptide "message" sequence has been replaced by oxymorphone or naltrexone. A hydrazone group was employed as a linkage between the alkaloids and peptides. The binding data for mu, kappa, and delta receptors indicate that peptide portions of the analogues can modulate the receptor selectivity of the attached alkaloid pharmacophores. The selectivity for different opioid receptor types depends on a balance between the affinities of the message and address components. In cases where these components have comparable receptor affinities, the address can significantly shift selectivity by increasing affinity to one receptor type while reducing affinity to other types. When the message component has high affinity for a particular receptor type, the modulatory role of the address is expressed mainly by reducing the affinity of the ligand for other opioid receptor types.

Selective reversible and irreversible ligands for the kappa opioid receptor.

(+-)-(5 beta,7 alpha,8 beta)-3,4-Dichloro-N-methyl-N-[3-methylene-2- oxo-8-(1-pyrrolidinyl)-1-oxaspiro[4,5]dec-7-yl]benzeneacetamide (14) and its (5 alpha,7 alpha,8 beta) diastereomer 15 have been synthesized from 1,4-cyclohexanedione monoethylene ketal (1) in 10 steps. Compound 14, which we have designated SMBU-1, was found to bind with moderate affinity (Ki = 109 nM) and good selectivity (mu/kappa = 29) to the kappa opioid receptor, while 15 was only 1/10 as potent as a kappa ligand. Preincubation of brain membranes with 14 resulted in wash-resistant inhibition of kappa-receptor binding (69 +/- 6% of control at 10(-6) M). The ketone precursor trans-N-methyl-N-[5-oxo-2-(1- pyrrolidinyl)cyclohexyl]benzeneacetamide (12) showed a higher kappa-affinity (Ki = 78 nM) and a much higher kappa-selectivity (mu/kappa = 166) than 14. Compound 10, the ethylene ketal precursor of 12, exhibited a similar receptor binding profile to 14, with increased kappa-selectivity (mu/kappa = 55), while ketal 11, being a regioisomer of 10 and an oxygen isostere of the kappa-selective analgesic spiradoline (U-62,066), demonstrated the highest kappa-affinity (Ki = 1.5 nM) and kappa-selectivity (mu/kappa = 468) observed in this series.

Synthesis and opioid activity of 7-oxygenated 2,3,4,4a,5,6,7,7a-octahydro-1H-benzofuro[3,2-e]isoquinolin-9-ols.

3-(Cyclopropylmethyl)-9-hydroxy-7-oxo-2,3,4,4a alpha,5,6,7,7a alpha- octahydro-1H-benzofuro[3,2-e]isoquinoline (4b) containing the ACNO ring system of morphine and a 7-keto function on ring C has been synthesized and found to possess potent PQW (ED50 = 0.15 mg/kg sc) and anti-Straub tail (ED50 = 0.02 mg/kg sc) activity. As compared to its 7-deoxy analog 1b, introduction of the 7-keto group did not significantly affect binding to any of the three opioid receptors (mu, kappa, and delta), but caused a 34-fold reduction in sigma-binding, suggesting reduced propensity to induce psychotomimetic effects. The C/D cis isomer of 4b (4c) was much less potent at the three opioid receptors, while displaying a slight increase in sigma affinity. Both 7-hydroxy derivatives 4e and 4f were active in anti-Straub tail assay (ED50 < or = 0.8 mg/kg sc), but only the alpha-isomer 4e demonstrated analgesic activity (PQW ED50 = 0.37 mg/kg sc) in the dose range tested. In guinea pig ileum preparations, 4e was characterized as a selective full agonist at the kappa opioid receptor (IC50 = 2.8 nM); while its beta-isomer 4f was a partial agonist (78% at 1 microM), with antagonist activity observed at both mu- and kappa-opioid receptors.

Opioid agonist and antagonist bivalent ligands. The relationship between spacer length and selectivity at multiple opioid receptors.

Bivalent ligands containing the oxymorphamine or naltrexamine pharmacophores connected to spacers of varying length were synthesized and evaluated for their selectivity at mu, kappa, and delta opioid receptors. The oxymorphamine bivalent ligands (1-8) behaved as mu agonists on the electrically stimulated guinea pig ileum longitudinal muscle preparation (GPI). The spacer that conferred peak agonist activity in these series contains a total of four glycyl units (n = 2). Binding studies with guinea pig brain membranes showed a qualitatively similar profile at mu receptors as a function of spacer length. Also, delta receptor selectivity increased as the spacer was lengthened. The naltrexamine bivalent ligands (9-13) effectively antagonized the mu receptor agonist morphine in the GPI at the same optimal spacer length (n = 2) as in the agonist series. However, the peak antagonism of ethylketazocine, a kappa receptor agonist, occurred with the bivalent ligand 9 containing the shortest spacer (n = 0), and it was found that 9 is the most selective kappa antagonist in the series. While receptor binding roughly parallels that of kappa antagonist activity in the GPI, no correlation between binding and antagonist activity was observed at mu opioid receptors. The possible significance of these results is discussed.