Perspektiven der Interferon-Forschung

Progress in understanding of interferon-mediated mechanisms over the past 20 years has been steady although slow. A major obstacle has always been the difficulty of obtaining sufficient quantities of highly purified interferon. Rational therapeutic applications therefore depend on a solution of problems connected with mass production and purification of interferon.     

Raised maternal serum alpha-fetoprotein in the absence of fetal abnormality-placental findings. A quantitative morphometric study

Ten placentae from pregnancies proceeding to term from mothers who on routine screening at 16–18 weeks gestation were found to have a raised serum AFP but no increase in amniotic fluid AFP and no fetal abnormality, were studied using morphometric techniques. The results were compared with 20 placentae from normal term pregnancies where the maternal serum AFP level was not elevated. The mean total placental volume, volume of parenchyma and villous surface area were increased in the placentae associated with a raised maternal serum AFP. More of these placentae were infarcted and the fetal-placental weight ratio was significantly lower. The hypothesis that elevation of maternal serum AFP level is related to the increase in placental size is addressed.     

Correct prenatal diagnosis of a hurler fetus where amniotic fluid cell cultures were of maternal origin

Contamination of amniotic fluid cell cultures by maternal cells can be expected to lead to misdiagnosis of fetal genotype in 0·1 to 0·5/100 cultures, when assays are carried out directly on cultured cells. Chemical analysis of the cell-free amniotic fluid supernatant may overcome this source of error and has the added advantages of speed and independence from amniotic cell culture failure. We describe a pregnancy at risk for Hurler's disease where amniotic cells cultured at amniocentesis had a female karyotype and an α-iduronidase activity towards both phenyl and 4-methylumbelliferyl substrates at the lower end of the normal range, suggesting a heterozygous fetus. An affected fetus was predicted, however, because of a high concentration of dermatan sulphate in the amniotic fluid. The discrepancy between these findings was shown to be due to maternal cell contamination of amniotic fluid cell cultures by the birth of a male infant with Hurler's disease.     

Synthesis and environmental degradation of polyesters based on poly (ε-caprolactone)

Poly (-caprolactone) (PCL), poly (-valerolactone) (PVL), poly (-caprolactone-co--valerolactone) [P(CL-co-VL)], and poly (-caprolactone-co-ethylene oxide-co--caprolactone) (PCL-PEO-PCL) were synthesized by ring-opening and diol-initiated polymerization of -caprolactone and -valerolactone. The degradation of the samples by chemical hydrolysis and in a soil burial test was evaluated. It was found that PCL, PVL, and P(CL-co-VL) degrade mainly enzymatically. The rate of degradation depends on their molecular weight, chemical structure, composition, and morphology. PCL-PEO-PCL block copolymers exhibit a repelling effect to the microorganisms in the soil, which depends on the molecular weight and relative amount of PEO block in the copolymer.     

Bulk carbon, oxygen, and hydrogen stable isotope composition of recent resins from amber-producing Hymenaea

Resins of Hymenaea, an angiosperm tree genus known to be a copious resin producer and a major source of amber since the Oligo-Miocene, were collected from a wide range of tropical environments from Latin America and Africa, and analyzed for their carbon, hydrogen, and oxygen stable isotope composition. The average value for ¹³C in the resins was found to be –27.0±1.3, which is very similar to the values reported for resins in other studies. ¹⁸ values for the Hymenaea resins averaged +11.2±1.6, or about 20 more depleted than normal plant cellulose. D values of the resins ranged from –196 to –319, with an average of –243±30. Rough estimates suggest a fractionation of –200 to –210 between the resins and the environmental water. This value is similar to the –200 value observed for the fractionation between other plant lipids and environmental water. The present study suggests that the stable isotope composition of fossil resins (amber) has the potential to provide information on ancient environmental waters.     

Prenatal diagnosis of mucopolysaccharidosis by two-dimensional electrophoresis of amniotic fluid glycosaminoglycans

Amniotic fluid from 72 pregnancies at risk for mucopolysaccharidosis have been analysed for glycosaminoglycans (GAG) by means of two-dimensional electrophoresis. Definite results were obtained in all cases and required only 3 days to report. Of the 66 cases for which GAG analysis was accompanied by enzyme assays on cultured amniotic fluid cells, there was agreement of results in 65. In the one case of disagreement the result of GAG analysis proved to be correct. Fourteen pregnancies were predicted to be affected and the predictions were confirmed by studies on fetal tissues and/or cultured cells, or in one case the birth of an affected infant. Of the 58 pregnancies predicted to be unaffected, 48 have so far gone to term and produced healthy infants. There have been no false negative predictions. The analytical method is simple, rapid, and, in this study, has been found completely reliable for prenatal diagnosis.     

Reconstruction of centuries-old Daphnia communities in a lake recovering from acidification and metal contamination

Paleolimnological and molecular genetic techniques were combined to reconstruct the long-term patterns in Daphnia community composition in Hannah Lake--a lake recovering from industrial acidification, metal contamination and faunal extirpation. Like many zooplankters, Daphnia produce diapausing eggs that can remain viable for decades and even over a century. Yet, the appearance of D. mendotae in Hannah Lake during the last two decades is likely the outcome of dispersal from other nearby lakes, not by colonization from the sediment egg-bank. Our genetic tests using PCR, SSCP and sequencing indicate that D. mendotae diapausing eggs are absent within the sediment record of the previous 250 years and that, prior to metal smelting operations in the region, the community was dominated by D. pulicaria. This species shift following the lake's chemical restoration is consistent with earlier historical changes in lake acidity. Environmental fluctuations may have governed community composition throughout Hannah Lake's more ancient past. Extending this molecular-paleolimnological approach to other lakes should help develop more accurate formulations of the biological recovery process.     

Full-scale evaluation of mercury control with sorbent injection and COHPAC at Alabama Power E.C. Gaston

The overall objective of this project was to determine the cost and impacts of Hg control using sorbent injection into a Compact Hybrid Particulate Collector (COHPAC) at Alabama Power's Gaston Unit 3. This test is part of a program funded by the U.S. Department of Energy's National Energy Technology Laboratory (NETL) to obtain the necessary information to assess the costs of controlling Hg from coal-fired utility plants that do not have scrubbers for SO2 control. The economics will be developed based on various levels of Hg control. Gaston Unit 3 was chosen for testing because COHPAC represents a cost-effective retrofit option for utilities with existing electrostatic precipitators (ESPs). COHPAC is an EPRI-patented concept that places a high air-to-cloth ratio baghouse downstream of an existing ESP to improve overall particulate collection efficiency. Activated carbons were injected upstream of COHPAC and downstream of the ESP to obtain performance and operational data. Results were very encouraging, with up to 90% removal of Hg for short operating periods using powdered activated carbon (PAC). During the long-term tests, an average Hg removal efficiency of 78% was measured. The PAC injection rate for the long-term tests was chosen to maintain COHPAC cleaning frequency at less than 1.5 pulses/bag/hr.     

Precipitation of swine and cattle manure phosphorous using limestone dust

The effectiveness of SPS and PULPRO, fine limestone dusts, in precipitating swine and dairy manure phosphorous (P) was determined in the laboratory. Both manures were sieved before being treated with limestone, to reproduce the treatment of mechanically separated manure and to observe the precipitation effect of limestone without that of the large manure solid particles. P precipitation was optimized by varying precipitation conditions (propeller blade speeds, mixing time and limestone levels) and limestone particle size. P precipitation was optimized using a propeller blade mixing speed of 0.3 m s(-1) for at least 5 minutes, using 3% limestone (dry limestone mass over wet manure mass). In terms of particle size, PULPRO 20 (limestone with a particle size of 0.02 mm) produced the most P precipitation and the smallest volume and mass of sludge, as compared to PULPRO 10, PULPRO 3 and SPS (limestone with a particle size of 0.01, 0.003 and 0.3 to 0.003 mm, respectively). For both 9.5% TS (total solids) dairy and 8.8% TS swine manure, mechanical separation followed by limestone precipitation concentrated 90% of manure TS and TP in a sludge volume representing 45% of the initial raw manure mass.     

Biodegradability of wheat gluten based bioplastics

A large variety of wheat gluten based bioplastics, which were plasticized with glycerol, were subjected to biodegradation. The materials covered the total range available for the biochemical control parameter Fi, which expresses the percentage of aggregated proteins. This quantity can be related to the density of covalent crosslinks in the wheat gluten network, which are induced by technological treatments. The biodegradability tests were performed in liquid medium (modified Sturm test) and in farmland soil. All gluten materials were fully degraded after 36 days in aerobic fermentation and within 50 days in farmland soil. No significant differences were observed between the samples. The mineralization half-life time of 3.8 days in the modified Sturm test situated gluten materials among fast degrading polymers. The tests of microbial inhibition experiments revealed no toxic effects of the modified gluten or of its metabolites. Thus, the protein bulk of wheat gluten materials is non-toxic and fully biodegradable, whatever the technological process applied.