Pulmonary inflammation associated with repeated, prenatal exposure to an E1, E3-deleted adenoviral vector in sheep.

Fetal gene therapy may prove useful in treating diseases that manifest in the perinatal or early postnatal period. Adenoviruses effectively transfer gene expression to a variety of tissues but also stimulate inflammatory and immune responses. The purpose of this study was to test the hypothesis that exposure of fetal sheep to a first generation adenovirus vector encoding bacterial beta-galactosidase, Av1nBg, before the development of the immune system, is safe, minimizes inflammatory and immune responses and induces tolerance. A total of 22 fetal sheep was studied; of these, two were born with respiratory distress, seven were electively killed and 13 died in utero. The incidence of mortality was higher than the < or = 10% we have experienced with other fetal sheep studies and was not likely related to complications arising from surgical or anesthetic procedures. Inflammatory and fibrotic responses were observed in the lungs and may represent untoward long-term consequences of in utero adenoviral gene therapy. Tolerance to Av1nBg was not established, and repeated exposure to Av1nBg before birth was associated with significant pathology and mortality.

Settling rate and dispersal of sealworm eggs (Nematoda) determined using a revised protocol for myxozoan spores.

Settling rates and densities of small bodies can be determined by recording settling rates in fluids of different densities, but similar viscosities, and applying Stoke's law. However, at low Reynolds numbers, drag effects reduce the object's settling rate and must be accounted for in sedimentation experiments. Using a revised protocol for spores of the myxozoan Henneguya doori that accounted for significant drag effects exerted by the experimental apparatus, we improve upon a previously described technique and apply it to eggs of the sealworm, Pseudoterranova decipiens. Sealworm eggs have a density of 1.08 x 10(3) kg/m3 and a characteristic Reynolds number of 6 x 10(-3). Fixed eggs settle in seawater at rate of 1.09 x 10(-4) m/sec, whereas fresh eggs settle at a rate of 1.01 x 10(-4) m/sec. Given reported current speeds on the Scotian Shelf off Nova Scotia, Canada, eggs would be transported approximately 50 km in 100 m of water in 12 days before sedimenting on the bottom. Eggs passed 1 m from the bottom would take about 3 hr to settle, and be transported 0.5 km. The size and density of sealworm eggs, and thus their resulting sedimentation rate, may have adaptive value in that they prevent excessive dispersion in space by strong oceanic currents.

Microfibrils provide non-linear elastic behaviour in the abdominal artery of the lobster Homarus americanus.

1. Microfibrils are becoming increasingly recognized as an important component of the extra-cellular matrix. However, almost nothing is known about their mechanical role in the diversity of tissues in which they are found. 2. Microfibrils form the principal structural component in the wall of the abdominal artery of the lobster Homarus americanus. We have used previous estimates of the mechanical properties of these microfibrils, estimates of the fraction of the aorta wall volume occupied by the microfibrils, and their angular distribution as a function of strain in a numerical model that predicts the macroscopic mechanical properties of the whole tissue. 3. Microfibrils alone, when their reorientation and deformation are accounted for, characterize the stress-strain behaviour of the vessel. Evidence of the evolutionary conservation of fibrillin between medusans, echinoderms and vertebrates implies that the mechanical properties of lobster microfibrils may apply to microfibrillar function in other taxa. This will have profound implications on the perceived roles of microfibrils in development, physiology and disease.

Effect of fetal nephrectomy on insulin-like growth factors and their binding proteins in sheep.

Bilateral nephrectomy retards fetal growth and decreases somatomedin (insulin-like growth factor-I, IGF-I) activity. To determine whether nephrectomy alters the synthesis of IGF-I or its binding proteins (IGFBPs), we studied 6 sets of twin fetuses. Kidneys were removed bilaterally from 1 twin of each set at 112-122 days of gestation (term 145 days). Plasma IGF-I concentrations were greater in nephrectomized fetuses than in the intact twins during the 1st week (261 +/- 35 vs. 153 +/- 21 ng/ml, p < 0.02; mean +/- SE) but not the 2nd week after surgery. Nephrectomy increased the abundance of the IGFBPs to levels 2-3 times greater than those in intact twins. Fetal hepatic IGFBP1 mRNA levels increased in 4 of 6 nephrectomized fetuses, while those of IGF-I, IGF-II, IGFBP2 were unchanged. Nephrectomy markedly alters the abundance of IGF-I and IGFBPs in plasma probably through mechanisms unrelated to synthesis.

The modulus of elasticity of lobster aorta microfibrils.

The presence of elastic fibres in the extracellular matrix (ECM) provides physiologically important elastic properties for many tissues. Until recently, microfibrils, one component of the ECM, were thought primarily to serve as a scaffolding on which elastin is deposited during development to form elaunin fibres [1]. The most prominent protein that forms mammalian microfibrils is fibrillin. It is known that mutations in the fibrillin gene cause a heterogenous connective tissue disease called Marfan syndrome [2], so information on mechanical properties of microfibrils or their role in tissue function would be useful. Microfibrils are also found in the ECM of some invertebrate tissues, and there is growing evidence that the protein forming the structure is homologous to mammalian fibrillin [3,4]. It has been shown that the microfibril-based arterial wall of the lobster has viscoelastic properties [5], and we have now utilized this primitive artery to measure the modulus of elasticity of microfibrils. It is similar to that of the rubber-like protein elastin.

Settling rates and density of spores of Henneguya doori (Myxosporea) in water.

Using Henneguya doori from Perca flavescens (yellow perch), the current study provides a method for examining settling rates, attitudes, and densities of myxosporean spores. Fresh and fixed spores settled similarly at 8.34 x 10(-6) m/sec and 8.53 x 10(-6) m/sec, respectively. The spores settled in the anterior end first, did not rotate, and had a specific gravity of 1.062. Comparison of settling rates proved more effective for determining spore density than direct chemical estimation. The slow rate of settling permits effective dispersal in open water.