Intraperitoneal alginate-encapsulated neonatal porcine islets in a placebo-controlled study with 16 diabetic cynomolgus primates

BACKGROUND

A nonhuman primate model of diabetes is valuable for assessing porcine pancreatic islet transplants that might have clinical benefits in humans.

METHODS

Neonatal porcine islets, microencapsulated in alginate-polyornithine-alginate, were injected intraperitoneally (10,000 IEQs/kg islets) into eight adult male cynomolgus monkeys rendered diabetic with streptozotocin. Eight diabetic controls were given an equivalent dose of empty placebo capsules. All subjects received a repeat transplant 3 months after the first.

RESULTS

The transplant was well tolerated and no adverse or hypoglycemic events occurred. There were two deaths from nontransplant treatment or diabetic complications unrelated to the transplants. After transplantation, the average insulin dose was reduced in the islet-treated group and increased in the control group. At 12 weeks after the first transplant there was a mean 36% (95% CI: 6% to 65%, P = .02) drop in daily insulin dose compared with the control group. After 24 weeks the difference increased to a mean of 43% (95% CI: 12% to 75%, P = .01) without significant differences in blood glucose values between the two groups. Individual responses after islet transplant varied and one monkey was weaned off insulin by 36 weeks. At terminal autopsy, organs appeared normal and there was no visible peritoneal reaction. No animal had polymerase chain reaction (PCR)-amplified signals of porcine endogenous retrovirus or exogenous virus infections in blood or tissues.

CONCLUSION

Repeated intraperitoneal transplantation of microencapsulated neonatal porcine islets is a safe procedure in diabetic primates. It was shown to result in a significant reduction in insulin dose requirement in the majority of animals studied, whereas insulin requirement increased in controls.

Characterization of soluble, salt-loaded, degradable PLGA films and their release of tetracycline

A local drug delivery system has been designed to release tetracycline over a period of 30 days from poly (lactide-co-glycolide) films. Incorporation of either soluble salt excipients or low molecular weight polymeric species has been found to modulate the release kinetics of the system. The following research describes the fabrication of the delivery system, monitors tetracycline release from the system, and fully characterizes the degradation of the polymer films via scanning electron microscopy, gel permeation chromatography, differential scanning calorimetry, Fourier-transform infrared spectroscopy, and X-ray diffraction techniques. Results show that the modulation via use of salts occurs without changing the inherent degradation rate of the system. We suggest that this phenomenon may be due to the increased amount of swelling and uptake of buffer by the films loaded with soluble salt. Uptake, therefore, may be creating microscopic pores that permit further diffusion of tetracycline from the polymer matrix as well as allow the free monomers to leave the system, thereby preventing autocatalysis within the system.

Increased encapsulated cell biodelivery of nerve growth factor in the brain by transposon-mediated gene transfer

Nerve growth factor (NGF) is a potential therapeutic agent for Alzheimer's disease (AD) as it has positive effects on the basal forebrain cholinergic neurons whose degeneration correlates with the cognitive decline in AD. We have previously described an encapsulated cell biodelivery device, NsG0202, capable of local delivery of NGF by a genetically modified human cell line, NGC-0295. The NsG0202 devices have shown promising safety and therapeutic results in a small phase 1b clinical study. However, results also show that the NGF dose could advantageously be increased. We have used the sleeping beauty transposon expression technology to establish a new clinical grade cell line, NGC0211, with at least 10 times higher NGF production than that of NGC-0295. To test whether encapsulation of this cell line provides a relevant dose escalation step in delivering NGF for treatment of the cognitive decline in AD patients, we have validated the bioactivity of devices with NGC0211 and NGC-0295 cells in normal rat striatum as well as in the quinolinic acid striatal lesion model. These preclinical animal studies show that implantation of devices with NGC0211 cells lead to significantly higher NGF output, which in both cases correlate with highly improved potency.

Campanulaceae: a family with small seeds that require light for germination

BACKGROUND AND AIMS

The Campanulaceae is a large cosmopolitan family, but is understudied in terms of germination, and seed biology in general. Small seed mass (usually in the range 10-200 µg) is a noteworthy trait of the family, and having small seeds is commonly associated with a light requirement. Thus, the purpose of this study was to investigate the effect of light on germination in 131 taxa of the Campanulaceae family, from all five continents of its distribution.

METHODS

For all taxa, seed germination was tested in light (8 or 12 h photoperiod) and continuous darkness under constant and alternating temperatures. For four taxa, the effect of light on germination was examined over a wide range of temperatures on a thermogradient plate, and the possible substitution of the light requirement by gibberellic acid and nitrate was examined in ten taxa.

KEY RESULTS

For all 131 taxa, seed germination was higher in light than in darkness for every temperature tested. Across species, the light requirement decreased significantly with increasing seed mass. For larger seeded species, germination in the dark reached higher levels under alternating than under constant temperatures. Gibberellic acid promoted germination in darkness whereas nitrates partially substituted for a light requirement only in species showing some dark germination.

CONCLUSIONS

A light requirement for germination, observed in virtually all taxa examined, constitutes a collective characteristic of the family. It is postulated that smaller seeded taxa might germinate only on the soil surface or at shallow depths, while larger seeded species might additionally germinate when buried in the soil if cued to do so by fluctuating temperatures.

Variable desiccation tolerance in Acer pseudoplatanus seeds in relation to developmental conditions: a case of phenotypic recalcitrance?

Nine seedlots of the widely planted southern and central European native tree species Acer pseudoplatanus L. were collected along a north-south gradient spanning 21° of latitude in Europe. We investigated how the heat sum during seed development influences seed maturity as assessed by physical, physiological and biochemical traits. Using principal component analysis we found predictable and consistent patterns in all traits, which correlated with heat sum. For example, compared with fruits from their native range (Italy and France, heat sum >3000°C d), fruits from the coldest location (Scotland; heat sum of 1873°C d) were shorter (c. 30 v. 42 mm), germinated over a narrower temperature range (5-20 v. 5-35°C) and had smaller embryos (28 v. > 70 mg) with a higher water content (c. 63 v. 48%), less negative solute potentials (c. -2.4 v. -4.1 MPa) and were more desiccation sensitive (critical water potential of -20.2 v. -55.4 to -60.7 MPa). The observed level of desiccation-tolerance for the French and Italian seedlots is more consistent with the intermediate category than the previous classification of A. pseudoplatanus as recalcitrant. Our results demonstrate that a lower heat sum causes fruits from northern Europe to be dispersed before maximum potential seed quality is achieved.

Effect of phosphorus concentration of the nutrient solution on the volatile constituents of leaves and bracts of Origanum dictamnus

The chemical composition of the essential oils obtained from the leaves and bracts of hydroponically cultivated Origanum dictamnus were analyzed by GC-MS techniques. Three different concentrations of phosphorus (5, 30, and 60 mg/L) in the nutrient solution were used for the cultivation, using the nutrient film technique (NFT). A total of 46 different compounds were identified and significant differences (qualitative and quantitative) were observed between the samples. Carvacrol and p-cymene were identified as the main compounds in all samples analyzed, whereas thymoquinone was found in higher percentage in the leaves than in bracts. The essential oils were tested for their antibacterial activity against Gram-positive and Gram-negative bacteria. The oils obtained from the bracts were found to be more active. The results obtained from GC-MS analyses were submitted to chemometric analysis.

Transfection of HEK cells via DNA-loaded PLGA and P(FASA) nanospheres

HEK cells were transfected with the GFP gene using various vectors: naked DNA, lipofectamine, and both PLGA and P(FASA) plasmid-loaded nanospheres. All methods were assessed alone and with the use of chloroquine, a lysosomal enzyme inhibitor. Transfection efficiencies were determined and compared at various times post-incubation using a fluorescence standard curve. Neither naked DNA alone nor naked DNA and chloroquine were capable of transfecting cells. No differences were evident between lipofectamine with chloroquine and lipofectamine alone which transfected cells with a constant increase in efficiency up to 2 weeks. While transfection was not feasible with polymeric nanospheres alone, the addition of chloroquine allowed DNA released from nanospheres within cells to escape endosomal degradation and transfect the cells. The increase in transfection efficiency via nanospheres over time was exponential up to 1 week, as compared to the constant rate seen for the bolus-type administration of lipofectamine, indicating that nanospheres delivered DNA to the cells by a controlled release mechanism. Additionally, the effective dose delivered to cells via nanospheres was approximately 25% that of lipofectamine, indicating that transfection via PLGA and P(FASA) nanospheres might actually be more efficient.

Volatile constituents of bracts and leaves of wild and cultivated Origanum dictamnus

The chemical composition of the volatile constituents from bracts and leaves of wild and hydroponically cultivated ORIGANUM DICTOMNUS were analysed by GC and GC-MS. Three different levels of nitrogen (100,150, 200 mg/l), were used in the nutrient solution for the cultivation, using the Nutrient Film Technique (N.F.T). Carvacrol was the predominant compound in all cases. The essential oils were investigated for their antimicrobial activity against STAPHYLOCOCCUS AUREUS, STAPHYLOCOCCUS EPIDERMIDIS, STAPHYLOCOCCUS HOMINIS, ESCHEIRICHIA COLI, and PSEUDOMONOS AERUGINOSA.

Phytochrome-mediated germination control of maize caryopses

Maize caryopses sown in water germinate equally well either in darkness or under any light regime. However, when they are imbibed in mannitol solutions, continuous far-red light proves to be strongly inhibitory on the final germination as compared to darkness. Similar but less pronounced inhibition is also exhibited by continuous red or blue light. Intermittent far-red light can partially substitute for continuous far-red light in inhibiting maize caryopsis germination, and its effect is reversed to the intermittent red light level when red light is given immediately after each far-red illumination. These results are interpreted as a proof of existence and involvement of phytochrome in the germination control of maize caryopses, though its manifestation is realized only under osmotic stress.

Integrated conservation of important plant taxa through the improvement of the original plant micro-reserve (PMR) approach: The intensive PMR monitoring case of Ophrys kotschyi

Developing a monitoring system and a conservation strategy against the negative impact of global change on threatened plant species, is nowadays the challenge for conservation experts. The Plant Micro-Reserve (PMR) approach became a highly effective approach in protecting plant species, since mild active management of vegetation plots and protection of plant populations takes place. The PMR has greatly evolved since its initial concept of managing a large network of PMRs, to having fewer protected areas subject to intensive scientific monitoring (e.g. Intensive Monitoring PMR; IM-PMR). This study further improved the IM-PMR approach by focusing on the threatened plant species of Ophrys kotschyi in Cyprus. The proposed IM-PMR enhances the available knowledge on the biology, physiology and ecology of the targeted plant species, through implementing an intensive monitoring system and assessing its genetic diversity. Within the framework of IM-PMR, the population size of O. kotschyi recorded statistically significant differentiation during the monitoring period, most likely due to the vegetative dormancy of the species. The subpopulation size and dormancy in O. kotschyi was correlated with precipitation and air temperature for specific months. In addition, the different local climatic conditions and the species dormancy between years seem to influence the flowers production among individuals, in the four monitoring years. Nevertheless, the low natural fecundity compared to the artificially pollinated plants and the absent correlation with any of the climatic parameters, might be closely related to the lack of pollinators at this site. The genetic diversity (H_T = 0.456) is higher compared to other endemic and short-lived perennial species, while the genetic differentiation among the subpopulations of O. kotschyi showed significant substructure (F_ST^FIS=0.5 = 0.097*). The subpopulation within IM-PMR showed relatively lower genetic diversity among the largest subpopulations of O. kotschyi, and the highest percentage of linked loci. Such observations support the non-random association of different loci in this subpopulation, and the ineffective pollen flow within this single subpopulation. The improvement of the original PMR approach in the current IM-PMR proposal denotes that different ecological aspects are taken into account towards gaining a holistic knowledge on a target species. The IM-PMR approach as implemented for O. kotschyi, could lead to the development of an integrated conservation approach for rare, threatened, or endangered species.

The seed morphospace, a new contribution towards the multidimensional study of angiosperm sexual reproductive biology

BACKGROUND

The evolutionary success of flowering plants is associated with the vast diversity of their reproductive structures. Despite recent progress in understanding angiosperm-wide trends in floral structure and evolution, a synthetic view of the diversity in seed form and function across angiosperms is lacking.

SCOPE

Here we present a roadmap to synthesize the diversity of seed forms in extant angiosperms, relying on the morphospace concept, i.e. a mathematical representation which relates multiple traits and describes the realized morphologies. We provide recommendations on how to broaden the range of measurable traits beyond mass, by using key morphological traits representative of the embryo, endosperm and seed coat but also fruit attributes (e.g. dehiscence, fleshiness). These key traits were used to construct and analyse a morphospace to detect evolutionary trends and gain insight into how morphological traits relate to seed functions. Finally, we outline challenges and future research directions, combining the morphospace with macroevolutionary comparative methods to underline the drivers that gave rise to the diversity of observed seed forms.

CONCLUSIONS

We conclude that this multidimensional approach has the potential, although still untapped, to improve our understanding of covariation among reproductive traits, and further elucidate angiosperm reproductive biology as a whole.