Deconstructing cytisine: The syntheses of (+/-)-cyfusine and (+/-)-cyclopropylcyfusine, fused ring analogs of cytisine

A novel fused tricyclic analog (11) of cytisine has been prepared (coined 'cyfusine') and determined to have high affinity at neuronal nicotinic acetylcholine receptors. A [3+2] cycloaddition protocol permitted entry into a 3,4-differentially difunctionalized dihydropyrrole (7). The penultimate cyclization was accomplished using the modified Van Tamelen conditions developed in our earlier synthesis of (+/-)-cytisine. Sequential ring-forming reactions ([3+2] cycloaddition/cyclopropanation/pyridone cyclization) gives a unique cyclopropyl analog (16) possessing a skeleton isoatomic with that of cytisine.     

Discovery of novel 1,2,3,4-tetrahydroisoquinolines and 3,4-dihydroisoquinoline-1(2H)-ones as potent and selective inhibitors of KDR: synthesis, SAR, and pharmacokinetic properties

1,2,3,4-Tetrahydroisoquinolines and 3,4-dihydroisoquinoline-1(2H)-ones were identified as potent and selective inhibitors of KDR. The discovery, synthesis, and structure–activity relationships of these novel inhibitors are reported. In vitro metabolism and pharmacokinetic profiles of the most interesting compounds are discussed.     

Amidines as amide bond replacements in VLA-4 antagonists

VLA-4 (alpha(4)beta(1), very late activating antigen-4), a key cell surface integrin plays an important role in inflammation by promoting leukocyte attachment and extravasation from the vasculature into the peripheral tissues. As such, VLA-4 antagonists may be useful in the treatment, prevention, and suppression of diseases where cell adhesion and migration are important such as asthma, rheumatoid arthritis, and multiple sclerosis. Herein, we report on the discovery, synthesis, and biological evaluation of amidines as small molecule antagonists of VLA-4.     

Polyamine stress at high pH in <Emphasis Type="Italic">Escherichia coli</Emphasis> K-12

Background  

Polyamines such as spermine and spermidine are required for growth ofEscherichia coli; they interact with nucleic acids, and they bind to ribosomes. Polyamines block porins and decrease membrane permeability, activities that may protect cells in acid. At high concentrations, however, polyamines impair growth. They impair growth more severely at high pH, probably due to their increased uptake as membrane-permeant weak bases. The role of pH is critical in understanding polyamine stress.     

Murine renal organic anion transporters mOAT1 and mOAT3 facilitate the transport of neuroactive tryptophan metabolites

Tryptophan metabolites such as kynurenate (KYNA), xanthurenate (XA), and quinolinate are considered to have an important impact on many physiological processes, especially brain function. Many of these metabolites are secreted with the urine. Because organic anion transporters (OATs) facilitate the renal secretion of weak organic acids, we investigated whether the secretion of bioactive tryptophan metabolites is mediated by OAT1 and OAT3, two prominent members of the OAT family. Immunohistochemical analyses of the mouse kidneys revealed the expression of OAT1 to be restricted to the proximal convoluted tubule (representing S1 and S2 segments), whereas OAT3 was detected in almost all parts of the nephron, including macula densa cells. In the mouse brain, OAT1 was found to be expressed in neurons of the cortex cerebri and hippocampus as well as in the ependymal cell layer of the choroid plexus. Six tryptophan metabolites, including the bioactive substances KYNA, XA, and the serotonin metabolite 5-hydroxyindol acetate inhibited [³H]p-aminohippurate (PAH) or 6-carboxyfluorescein (6-CF) uptake by 50–85%, demonstrating that these compounds interact with OAT1 as well as with OAT3. Half-maximal inhibition of mOAT1 occurred at 34 µM KYNA and 15 µM XA, and it occurred at 8 µM KYNA and 11.5 µM XA for mOAT3. Quinolinate showed a slight but significant inhibition of [³H]PAH uptake by mOAT1 and no alteration of 6-CF uptake by mOAT3. [¹⁴C]-Glutarate (GA) uptake was examined for both transporters and demonstrated differences in the transport rate for this substrate by a factor of 4. Trans-stimulation experiments with GA revealed that KYNA and XA are substrates for mOAT1. Our results support the idea that OAT1 and OAT3 are involved in the secretion of bioactive tryptophan metabolites from the body. Consequently, they are crucial for the regulation of central nervous system tryptophan metabolite concentration. kidneys; brain; macula densa; transforming growth factor; N-methyl-D-aspartate receptor     

Spatial and temporal woodland patterns along the lower Turkwel River, Kenya

Spatial and temporal patterns of riverine woodlands in arid regions of Africa are poorly documented despite their considerable conservation value. We studied 1540 ha of riverine woodland in the lower Turkwel River floodplain, Kenya, between 1990 and 1998. Forty‐one woodland patches were mapped and their soil physical and chemical characteristics, tree species diversity, woody cover, tree density, wood volume and woodland regeneration were determined. The riverine woodland comprised nine vegetation types and a total of 14 woody species. Woodland patch mosaics were associated with microtopographical features and selected soil attributes. The most important woody species were Hyphaene compressa H. Wendl., Acacia tortilis (Forssk.) Hayne and Cadaba rotundifolia Forssk. The exotic Prosopis chilensis (Mol.) St. was invading parts of the riverine woodland. Overall, woody species diversity was low compared to similar riverine woodlands in East Africa. Tree density, wood volume and woody plant regeneration declined over the 8‐year study period, while woody cover was unchanged. Reduced tree density, wood volume and regeneration of woody species might be linked to changes in river flood patterns following the impoundment of the Turkwel Gorge Dam. It is suggested that spatially heterogeneous and temporally stochastic regeneration events, together with occasional tree mortality caused by channel abandonment, create the complex pattern of woodland patches in the lower Turkwel River floodplain. The mapped woodland patches may serve as monitoring units, which in future could reveal the interplay between changes in flooding patterns as a result of dam impoundment, anthropogenic disturbance and the well‐being of the riverine woodlands.     

Institutional Delivery Service Utilization among Women from Rural Districts of Wolaita and Dawro Zones,Southern Ethiopia; a Community Based Cross-Sectional Study

Introduction

The highest number of maternal deaths occur during labour, delivery and the first day after delivery highlighting the critical need for good quality care during this period. Therefore, for the strategies of institutional delivery to be effective, it is essential to understand the factors that influence individual and household factors to utilize skilled birth attendance and institutions for delivery. This study was aimed to assess factors affecting the utilization of institutional delivery service of women in rural districts of Wolaita and Dawro Zones.

Methods

A community based cross-sectional study was done among mothers who gave birth within the past one year preceding the survey in Wolaita and Dawro Zones, from February 01 –April 30, 2015 by using a three stage sampling technique. Initially, 6 districts were selected randomly from the total of 17 eligible districts. Then, 2 kebele from each district was selected randomly cumulating a total of 12 clusters. Finally, study participants were selected from each cluster by using systematic sampling technique. Accordingly, 957 mothers were included in the survey. Data was collected by using a pretested interviewer administered structured questionnaire. The questionnaire was prepared by including socio-demographic variables and variables of maternal health service utilization factors. Data was entered using Epi-data version 1.4.4.0 and exported to SPSS version 20 for analysis. Bivariate and multiple logistic regressions were applied to identify candidate and predictor variables respectively.

Result

Only 38% of study participants delivered the index child at health facility. Husband’s educational status, wealth index, average distance from nearest health facility, wanted pregnancy, agreement to follow post-natal care, problem faced during delivery, birth order, preference of health professional for ante-natal care and maternity care were predictors of institutional delivery.

Conclusion

The use of institutional delivery service is low in the study community. Eventhough antenatal care service is high; nearly two in every three mothers delivered their index child out of health facility. Improving socio-economic status of mothers as well as availing modern health facilities to the nearest locality will have a good impact to improve institutional delivery service utilization. Similarly, education is also a tool to improve awareness of mothers and their husbands for the improvement of health care service utilization.     

Lack of O-GlcNAcylation enhances exercise-dependent glucose utilization potentially through AMP-activated protein kinase activation in skeletal muscle

O-GlcNAcylation is a post-translational modification that is characterized by the addition of N-acetylglucosamine (GlcNAc) to proteins by O-GlcNAc transferase (Ogt). The degree of O-GlcNAcylation is thought to be associated with glucotoxicity and diabetic complications, because GlcNAc is produced by a branch of the glycolytic pathway. However, its role in skeletal muscle has not been fully elucidated. In this study, we created skeletal muscle-specific Ogt knockout (Ogt-MKO) mice and analyzed their glucose metabolism. During an intraperitoneal glucose tolerance test, blood glucose was slightly lower in Ogt-MKO mice than in control Ogt-flox mice. High fat diet-induced obesity and insulin resistance were reversed in Ogt-MKO mice. In addition, 12-month-old Ogt-MKO mice had lower adipose and body mass. A single bout of exercise significantly reduced blood glucose in Ogt-MKO mice, probably because of higher AMP-activated protein kinase α (AMPKα) protein expression. Furthermore, intraperitoneal injection of 5-aminoimidazole-4-carboxamide ribonucleotide, an AMPK activator, resulted in a more marked decrease in blood glucose levels in Ogt-MKO mice than in controls. Finally, Ogt knockdown by siRNA in C2C12 myotubes significantly increased protein expression of AMPKα, glucose uptake and oxidation. In conclusion, loss of O-GlcNAcylation facilitates glucose utilization in skeletal muscle, potentially through AMPK activation. The inhibition of O-GlcNAcylation in skeletal muscle may have an anti-diabetic effect, through an enhancement of glucose utilization during exercise.     

STAT1 activation causes translocation of Bax to the endoplasmic reticulum during the resolution of airway mucous cell hyperplasia by IFN-gamma

Disruption of the normal resolution process of inflammation-induced mucous cell hyperplasia may lead to sustained mucous hypersecretion in chronic diseases. During prolonged exposure of mice to allergen, IFN-gamma reduces mucous cell hyperplasia, but the signaling responsible for the cell death is largely unknown. A brief phosphorylation of STAT1 by IFN-gamma was required for cell death in airway epithelial cells (AEC), and during prolonged exposure to allergen, mucous cell hyperplasia remained elevated in STAT1(-/-) but was resolved in STAT1(+/+) mice. Although IFN-gamma treatment of primary human AECs and other airway cell lines left Bax protein levels unchanged, it caused translocation of Bax from the cytosol to the endoplasmic reticulum (ER) but not to the mitochondria. Localization of Bax to the ER was observed in IFN-gamma-treated primary AECs isolated from STAT1(+/+) mice but not in cells from STAT1(-/-) mice. In addition, ER Bax was detected in mucous cells of STAT1(+/+) but not STAT1(-/-) airways of mice exposed to allergen for prolonged periods. IFN-gamma did not release cytochrome c from mitochondria but reduced ER calcium stores and dilated the ER, confirming that the IFN-gamma-induced cell death is mediated through changes localized in the ER. Collectively, these observations suggest that STAT1-dependent translocation of Bax to the ER is crucial for IFN-gamma-induced cell death of AECs and the resolution of allergen-induced mucous cell hyperplasia.     

Cholesterol-depleting statin drugs protect postmitotically differentiated human neurons against ethanol- and human immunodeficiency virus type 1-induced oxidative stress in vitro

The majority of human immunodeficiency virus type 1 (HIV-1)-infected individuals are either alcoholics or prone to alcoholism. Upon ingestion, alcohol is easily distributed into the various compartments of the body, particularly the brain, by crossing through the blood-brain barrier. Both HIV-1 and alcohol induce oxidative stress, which is considered a precursor for cytotoxic responses. Several reports have suggested that statins exert antioxidant as well as anti-inflammatory pleiotropic effects, besides their inherent cholesterol-depleting potentials. In our studies, postmitotically differentiated neurons were cocultured with HIV-1-infected monocytes, T cells, or their cellular supernatants in the presence of physiological concentrations of alcohol for 72 h. Parallel cultures were pretreated with statins (atorvastatin and simvastatin) with the appropriate controls, i.e., postmitotically differentiated neurons cocultured with uninfected cells and similar cultures treated with alcohol. The oxidative stress responses in the presence/absence of alcohol in these cultures were determined by the production of the well-characterized oxidative stress markers, 8-isoprostane-F2-alpha, total nitrates as an indicator for various isoforms of nitric oxide synthase activity, and heat shock protein 70 (Hsp70). An in vitro culture of postmitotically differentiated neurons with HIV-1-infected monocytes or T cells as well as supernatants from these cells enhanced the release of 8-isoprostane-F2-alpha in the conditioned medium six- to sevenfold (monocytes) and four- to fivefold (T cells). It was also observed that coculturing of HIV-1-infected primary monocytes over a time period of 72 h significantly elevated the release of Hsp70 compared with that of uninfected controls. Cellular supernatants of HIV-1-infected monocytes or T cells slightly increased Hsp70 levels compared to neurons cultured with uninfected monocytes or T-cell supernatants (controls). Ethanol (EtOH) presence further elevated Hsp70 in both infected and uninfected cultures. The amount of total nitrates was significantly elevated in the coculture system when both infected cells and EtOH were present. Surprisingly, pretreatment of postmitotic neurons with clinically available inhibitors of HMG-coenzyme A reductase (statins) inhibited HIV-1-induced release of stress/toxicity-associated parameters, i.e., Hsp70, isoprostanes, and total nitrates from HIV-1-infected cells. The results of this study provide new insights into HIV-1 neuropathogenesis aimed at the development of future HIV-1 therapeutics to eradicate viral reservoirs from the brain.