Sustained release choline theophyllinate in nocturnal asthma.

Nocturnal wheeze is common in patients with asthma, and slow release theophyllines may reduce symptoms. As theophyllines are stimulants of the central nervous system the effect of 10 days'' twice daily treatment with sustained release choline theophyllinate or placebo on symptoms, overnight bronchoconstriction, nocturnal oxygen saturation, and quality of sleep were studied in a double blind crossover study in nine stable patients with nocturnal asthma (five men, four women, age range 23-64 years; forced expiratory volume in one second (FEV1) 0.85-3.8 1; vital capacity 1.95-6.1 1). When treated with the active drug all patients had plasma theophylline concentrations of at least 28 mmol/l (5 micrograms/ml) (peak plasma theophylline concentrations 50-144 mmol/l (9-26 micrograms/ml]. Morning FEV1 was higher when treated with sustained release choline theophyllinate (2.7 (SEM 0.3) 1) than placebo (2.1 (0.3) 1) (p less than 0.01). Both daytime and nocturnal symptoms were reduced when the patients were treated with sustained release choline theophyllinate and subjective quality of sleep was improved (p less than 0.002). When treated with the active drug, however, quality of sleep determined by electroencephalography deteriorated with an increase in wakefulness and drowsiness (p less than 0.05) and a reduction in non-rapid eye movement sleep (p less than 0.005). Treatment with choline theophyllinate had no effect on either the occurrence or the severity of transient nocturnal hypoxaemic episodes or apnoeas or hypopnoeas. In conclusion, sustained release choline theophyllinate prevents overnight bronchoconstriction, but impairs quality of sleep defined by electroencephalography.     

Sustained release of cytokinins from natural polymers

The cytokinins 6-benzylaminopurine, 6-furfurylaminopurine and 6-(3-methyl-2-butenylamino) purine, were attached to starch and to cellulose by means of a carbamatic bond. The modified polysaccharides contained about one cytokinin molecule per 50 glucose units. The rate of release of the cytokinins was followed spectrophotometrically in aqueous solutions at different pHs. A good agreement with a first order model was found and the kinetic constants for the various systems were determined. The clear dependence on the pH of the medium supports a mechanism in which hydrolysis of the carbamatic bond is the rate determining step. The hormonal activity of the modified polymers was determined in the soybean callus bioassay and compared with the activities of non-bonded cytokinins. While high concentrations of free hormones cause inhibition of growth, such concentrations of bound hormone did not show inhibition.     

Carp experiment in space microgravity--a visual-vestibular sensory conflict model.

In the 8-d flight mission of Spacelab-J (STS-47) conducted in 1992, behavior of the dorsal light response (DLR) and EEG activity of the cerebellum were intermittently examined for two carp, normal and otolith-removed. The latter carp had immobilization trouble caused by twisting of the EEG cable on day 2 inflight. The problem continued for the remainder of the experiment. Analyses made on the normal carp provided additional evidence in fish for sensory-motor disorder and readjustment during early phase of microgravity, thus supporting the sensory conflict hypothesis for space motion sickness. In the present report, why and how this space experiment was conducted were reviewed with a brief summary of the results.     

Sustained release implants of chloroquine phosphate for possible use in chemoprophylaxis of malaria

Implants of chloroquine phosphate (CQP) using biodegradable polymer, gelatin (G) and cross-linked gelatin (CLG) were prepared and evaluated to assess their physicochemical properties and in vitro release profile. The mechanism and kinetics of release were studied to correlate the release phenomenon with the formulation parameters. Out of many batches of the implants investigated, the implant prepared with 20% gelatin at 2:1 drug polymer ratio, 10% crosslinking agent and 2% plasticizer (Batch J) was found to provide optimum release behavior conforming to the requirements of a long term implant for a week. In vivo studies conducted on albino rats showed consistent therapeutic blood level over a period of 7 days. Mean residence time (MRT) of the drug released in the body, calculated as the ratio of the area under the first moment curve (AUMC) to area under concentration time curve (AUC) was 72 hr for implant against 2.42 hr for subcutaneous injection.     

Sustained release of proteins from electrospun biodegradable fibers

Electrospinning is a simple and versatile technique of producing polymeric fibers ranging from submicron to micron in diameter. Incorporation of bioactive agents into the fibers could make a biofunctional tissue engineering scaffold. In this study, we investigated the feasibility of encapsulating human beta-nerve growth factor (NGF), which was stabilized in a carrier protein, bovine serum albumin (BSA) in a copolymer of epsilon-caprolactone and ethyl ethylene phosphate (PCLEEP) by electrospinning. Partially aligned protein encapsulated fibers were obtained and the protein was found to be randomly dispersed throughout the electrospun fibrous mesh in aggregate form. A sustained release of NGF via diffusion process was obtained for at least 3 months. PC12 neurite outgrowth assay confirmed that the bioactivity of electrospun NGF was retained, at least partially, throughout the period of sustained release, thus clearly demonstrating the feasibility of encapsulating proteins via electrospinning to produce biofunctional tissue scaffolds.     

Macrotrachela quadricornifera featured in a space experiment

Macrotrachela quadricornifera, a bdelloid rotifer, is the animal model of an experiment scheduled on the International Space Station (ISS). The focus of the experiment is the role of the cytoskeleton during oogenesis and early development. Bdelloids will fly desiccated, be rehydrated on the ISS and cultivated for five generations. We present the outline of the ISS experiment, the expectations and the state-of-the-art of ground-based research run to date on the major topics of the planned experiment: anhydrobiosis and embryogenesis. Anhydrobiosis focuses on two major aspects, storage conditions that enhance recovery rate and comparison of the resistance between dormant and active rotifers to UV radiation and other environmental injuries. Embryogenesis has been approached at the morphological level under ground conditions: developing embryos have been studied by light and confocal microscopes.     

Antarctic soil no. 726 and implications for the Viking labeled release experiment

Locomotion efficiency for a variety of animals may be improved by group movement in specific formations. A theory of formation flight developed by Lissaman & Shollenberger (1970) predicts birds may obtain energy savings through the use of a vee formation. Measurements of Canada geese (Branta canadensis) (Gould < Heppner, 1974) suggested an aerodynamic advantage was unlikely. However, further analysis of this data to obtain the critical formation parameter (wing tip spacing) suggests the theory may apply. The theory is modified to better account for the characteristics of a vee formation and adapted to the specific case of the Canada goose. The relationships between observed and optimal formations suggest that energy savings could be an important function of vee formations.     

Effect of morphine on hCG release by first trimester human trophoblast in vitro

Opiate synthesis by human placental cells and the presence of kappa-type opiate binding sites in the syncytiotrophoblast brush border membrane may indicate the possible role of morphine-like substances in the autocrine regulation of trophoblast cell metabolism. This study was undertaken to examine the in vitro effect of morphine on hCG (human chorionic gonadotrophin) and hPL (human placental lactogen) release by 1st and 3rd trimester placental tissue explants. The results have shown that morphine (100 nM) significantly stimulated hCG secretion by 6-8 weeks old trophoblast and was without effect on hPL. Hormone secretion by term placental tissue explants was unaffected by morphine treatment. Based on these results we assume that opiates may have a role in the local (autocrine and/or paracrine) regulation of hCG secretion in early gestation.     

STS-95 space experiment for plant growth and development, and auxin polar transport.

The principal objective of the space experiment, BRIC-AUX on STS-95, was the integrated analysis of the growth and development of etiolated pea and maize seedlings in space, and the effect of microgravity conditions in space on auxin polar transport in the segments. Microgravity conditions in space strongly affected the growth and development of etiolated pea and maize seedlings. Etiolated pea and maize seedlings were leaned and curved during space flight, respectively. Finally the growth inhibition of these seedlings was also observed. Roots of some pea seedlings grew toward the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles which were germinated and grown under microgravity conditions in space were significantly low. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and extremely promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.     

Photobiology in space: an experiment on Spacelab I

The joint European/US Spacelab Mission I, scheduled for October 1983 for a 9 day lasting Earth-orbiting flight, provides a laboratory system for various disciplines of science, including exobiology. On the pallet, in the experiment ES 029 "Microorganisms and Biomolecules in Space Hard Environment" 316 dry samples of Bacillus subtilis spores will be exposed to space vacuum and/or selected wavelenghs of solar UV radiation. After recovery action spectra of inactivation, mutation induction, reparability and photochemical damage in DNA and protein will be determined. The results will contribute to the understanding of the mechanism of the increased UV sensitivity of bacterial spores in vacuo and to a better assessment of the chance of survival of resistant life forms in space and of interplanetary transfer of life.     

Photobiology in space: An experiment on Spacelab I

The joint European/US Spacelab Mission I, scheduled for October 1983 for a 9 day lasting Earth-orbiting flight, provides a laboratory system for various disciplines of science, including exobiology. On the pallet, in the experiment ES 029 Microorganisms and Biomolecules in Space Hard Environment 316 dry samples ofBacillus subtilis spores will be exposed to space vacuum and/or selected wavelengths of solar UV radiation. After recovery action spectra of inactivation, mutation induction, reparability and photochemical damage in DNA and protein will be determined. The results will contribute to the understanding of the mechanism of the increased UV sensitivity of bacterial spores in vacuo and to a better assessment of the chance of survival of resistant life forms in space and of interplanetary transfer of life.