Energy state and vasomotor tone in hypoxic pig lungs

To evaluate the role of energy state in pulmonary vascular responses to hypoxia, we exposed isolated pig lungs to decreases in inspired PO2 or increases in perfusate NaCN concentration. Lung energy state was assessed by 31P nuclear magnetic resonance spectroscopy or measurement of adenine nucleotides by high-pressure liquid chromatography in freeze-clamped biopsies. In ventilated lungs, inspired PO2 of 200 (normoxia), 50 (hypoxia), and 0 Torr (anoxia) did not change adenine nucleotides but resulted in steady-state pulmonary arterial pressure (Ppa) values of 15.5 +/- 1.4, 30.3 +/- 1.8, and 17.2 +/- 1.9 mmHg, respectively, indicating vasoconstriction during hypoxia and reversal of vasoconstriction during anoxia. In degassed lungs, similar changes in Ppa were observed; however, energy state deteriorated during anoxia. An increase in perfusate NaCN concentration from 0 to 0.1 mM progressively increased Ppa and did not alter adenine nucleotides, whereas 1 mM reversed this vasoconstriction and caused deterioration of energy state. These results suggest that 1) pulmonary vasoconstrictor responses to hypoxia or cyanide occurred independently of whole lung energy state, 2) the inability of the pulmonary vasculature to sustain hypoxic vasoconstriction during anoxia might be associated with decreased energy state in some lung compartment, and 3) atelectasis was detrimental to whole lung energy state.     

Optimisation of a series of potent,selective and orally bioavailable GlyT1 inhibitors

A series of heterocyclic sulfonamides have been developed which are potent and selective inhibitors of hGlyT1. SAR studies to optimise the in vitro and in vivo properties are described. Optimisation of the central scaffold resulted in cyclohexane sulfones 28 and 29, which have good PK properties and show promise for further development.     

Oral Administration of Electron-Beam Inactivated Rhodococcus equi Failed to Protect Foals against Intrabronchial Infection with Live,Virulent R. equi

There is currently no licensed vaccine that protects foals against Rhodococcus equi–induced pneumonia. Oral administration of live, virulent R. equi to neonatal foals has been demonstrated to protect against subsequent intrabronchial challenge with virulent R. equi. Electron beam (eBeam)-inactivated R. equi are structurally intact and have been demonstrated to be immunogenic when administered orally to neonatal foals. Thus, we investigated whether eBeam inactivated R. equi could protect foals against developing pneumonia after experimental infection with live, virulent R. equi. Foals (n = 8) were vaccinated by gavaging with eBeam-inactivated R. equi at ages 2, 7, and 14 days, or gavaged with equal volume of saline solution (n = 4), and subsequently infected intrabronchially with live, virulent R. equi at age 21 days. The proportion of vaccinated foals that developed pneumonia following challenge was similar among the vaccinated (7/8; 88%) and unvaccinated foals (3/4; 75%). This vaccination regimen did not appear to be strongly immunogenic in foals. Alternative dosing regimens or routes of administration need further investigation and may prove to be immunogenic and protective.     

Malaria parasites tolerate a broad range of ionic environments and do not require host cation remodelling

Malaria parasites grow within erythrocytes, but are also free in host plasma between cycles of asexual replication. As a result, the parasite is exposed to fluctuating levels of Na⁺ and K⁺, ions assumed to serve important roles for the human pathogen, Plasmodium falciparum. We examined these assumptions and the parasite's ionic requirements by establishing continuous culture in novel sucrose‐based media. With sucrose as the primary osmoticant and K⁺ and Cl^? as the main extracellular ions, we obtained parasite growth and propagation at rates indistinguishable from those in physiological media. These conditions abolish long‐known increases in intracellular Na⁺ via parasite‐induced channels, excluding a requirement for erythrocyte cation remodelling. We also dissected Na⁺, K⁺ and Cl^? requirements and found that unexpectedly low concentrations of each ion meet the parasite's demands. Surprisingly, growth was not adversely affected by up to 148 mM K⁺, suggesting that low extracellular K⁺ is not an essential trigger for erythrocyte invasion. At the same time, merozoite egress and invasion required a threshold ionic strength, suggesting critical electrostatic interactions between macromolecules at these stages. These findings provide insights into transmembrane signalling in malaria and reveal fundamental differences between host and parasite ionic requirements.     

Splice site m6A methylation prevents binding of U2AF35 to inhibit RNA splicing

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Tetra substituted thiophenes as anti-inflammatory agents: exploitation of analogue-based drug design

A series of 17 novel tetra substituted thiophenes was designed, synthesized, and screened for anti-inflammatory activity in carrageenin induced rat paw edema model, an acute in vivo model. The lead molecule selected was Tenidap, a dual COX/LOX inhibitor. Compounds I (43%), III (60%), IV (60%), and VIII (64%) showed moderate to good anti-inflammatory activity. The best candidate among the whole series was VIII, which gave 64% protection to the inflamed paw. The side chain of candidate VIII had resemblance to that of Romazarit, a DMARD, which was withdrawn due to its toxicity profile. A probable reason for the metabolic stability of the proposed side chain not having the possibility of generating peroxy type radicals or acrylic acid moieties, unlike Romazarit, is discussed. The biological activity exhibited by the three designed series was in the order of methyl amino series > ethyl amino series > carbethoxy amino series. The –(CO)–CH₂–COOR side chain at the fifth position as in candidate VIII, the methyl amino group at the second position, and the ester at the third position of the thiophene can be considered as a three-point pharmacophore for designing better anti-inflammatory agents. The present study is a classical example of the exploitation of an analogue based drug design, which culminated in the development of good anti-inflammatory agents that have the potential of becoming dual inhibitors.     

Tolypocladium cylindrosporum (Deuteromycotina: Moniliales), a fungal pathogen of the mosquito Aedes australis

A blastoconidial preparation of the New Zealand isolate of T. cylindrosporum was tested in two field trials against larvae of the freshwater mosquito Aedes subalbirostris and the brackish water species Ae. australis. There was some reduction in the population of the Ae. subalbirostris larvae and larvae collected from the test pools exhibited signs of fungal infection when reared in the laboratory. In the brackish pools there was no observable decrease in the larval populations even though Ae. australis is the natural host of T. cylindrosporum [NZ]. Water volume fluctuations in the test pools were a major difficulty experienced when monitoring the results.Tests against field-collected non-target fauna indicated that T. cylindrosporum is non-specific in action. Species of daphnid, dixid larvae and copepods were all susceptible to infection at varying degrees.     

INDUCED DIFFERENTIATION OF GERANIUM PLANTS FROM UNDIFFERENTIATED CALLUS IN VITRO

Geranium callus produced from explants of stem tip, internode pith with vascular tissue on synthetic media with or without coconut milk and 2,4-dichlorophenoxyacetic acid grew well for many generations, but only tracheids were induced in them. If callus produced on these media was subcultured immediately on Murashige and Skoog medium with 0.1 mg/liter/α-naphthalene acetic acid (NAA) and 10.0 mg/liter kinetin (K) and incubated at 16/8-hr light/dark cycle, shoots were induced in 8-10 weeks and roots in another 8-10 weeks. Callus produced on the MS medium with the same supplements of NAA and K, subcultured on the same medium and incubated in 16/8-hr light/dark cycle, produced shoots in 6-8 weeks. However, on callus subcultured more than three times, shoots differentiated with greater difficulty and none differentiated after six subcultures. Some abnormal shoot-like structures were also produced, the cells of which showed virus-like inclusion bodies. Requirements of the different varieties for differentiating organs differed. Among 12/12-, 15/9-, 16/8-, and 20/4-hr light/dark photoperiods that induced differentiation, 15/9- and 16/8-hr were more effective than the others. Continuous illumination did not induce differentiation. Differentiated shoots formed roots more readily on a medium with reversed proportions of auxin and kinetin. On agar roots were devoid of root hairs. Root hairs were formed when the shoots and plantlets were cultured on filter-paper bridges. Many “mother” stock plants were produced. These are being studied for their growth qualities and for possible viruses and other pathogens.