A method for the approximation of the relative humidity in the upper human airways

In order to determine the growth of inhaled aerosol particles in the human respiratory tract the relative humidity in a lung model has been calculated using a numerical method. The computations take into account different types of airflows, enhanced transport mechanisms and an optimized wall temperature profile in the upper airways. These parameters are varied to fit experimental temperature data. Under certain conditions the corresponding relative humidity shows a maximum near the first bifurcation, which exceeds the final humidity in the alveoli. This high humidity forces dry NaC1 particles with diameters less than 0.5 μm to grow to their maximum size in the first bronchi. Thereafter the droplets loose water and reach their final size in the terminal bronchioles.     

Interactions between Nile tilapia (Oreochromis niloticus) and cladocerans in ponds (Khartoum,Sudan)

Juvenile Nile tilapia (Oreochromis niloticus) are omnivorous, and the question asked in this study is how they affect on their environment? Do they mainly act as predators on the cladoceran zooplankton or do they compete with the cladocerans for phytoplankton? This problem was studied in three ponds with and three ponds without small tilapia (3–5 cm). The fish growth rate, the succession of plankton species and the changes in abiotic conditions, were monitored over a period of 67 days. The fish biomass was kept low and the mean was approximately constant (12.6 g m^?2) during the experiment. Phosphate was added to avoid phytoplankton nutrient limitation. Although the diet of Nile tilapia contained both phytoplankton and zooplankton, the fish affected the ecosystem in a similar way as zooplanktivorous fish. The fish ponds got more phytoplankton due to increase of Chlorophyta. Effects on the other phytoplankton groups Euglenophyta, Bacillariophyta, Cryptophyta and Cyanophyta could not be registered. The ponds without fish had higher densities of Daphnia lumholtzi and D. barbata. The other Cladocerans seemed less influenced by fish presence. The relative fish growth rate was most positively correlated with the density of Daphnia lumholtzi, Diaphanosmoa excisum and Bosmina longirostris. Tilapia seemes to have two feeding modes: (1) preying on large zooplankton and (2) unselective filtration of small planktonic organisms such as phytoplankton. In our experiment the first feeding mode affected the ecosystem more than the second.     

Abbau und Umsetzung von lignifiziertem Pflanzenmaterial durch mikroskopische Bodenpilze

Zusammenfassung Es wird über eine Methode berichtet, an extrem dünnen Holzfolien die Abbauleistungen von Bodenpilzen zu messen.Aus einer Gesamtzahl von 280 geprüften Pilzarten wurden bei 27 mikroskopischen Pilzen mit hoher Aktivität Gewichtsabnahme und Reißfestigkeit von Ahornholz bestimmt.An Weizenstroh wurde mit einer Auswahl leistungsfähiger Pilze die Verminderung des Lignin- und Cellulosegehalts untersucht.Nach 120 Bebrütungstagen lag die Abnahme für Lignin zwischen 31 und 52%, für Cellulose zwischen 33 und 66%.Von den untersuchten Pilzen zeichneten sich Mammaria echinobotryoides, Hormiactis candida und Chaetomium piluliferum durch eine besonders starke Phenolproduktion aus.Die für alle geprüften Pilze mehr oder weniger typische Phenolproduktion stand in enger Beziehung zur Bildung von Huminstoffen, die bei der Rotte des Strohes auftraten.

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Decomposition and transformation of lignified plant material by microscopic soil fungi

Summary The use of ultra-thin foils prepared from maple wood for measuring the wood-destroying capacity of soil fungi is described.Data are given on the reduction of dry-weight and tensile strength by the action of 27 highly active species from a total number of 280 microfungi.The decrease in lignin and cellulose content of wheat straw was studied with a selected number of fungi.The percentage reduction after an incubation period of 120 days was found to be between 31 and 52% for lignin, 33 and 66% for cellulose content respectively.A remarkable production of phenols was found in liquid cultures of Mammaria echinobotryoides, Hormiactis candida and Chaetomium piluliferum.The phenol production was more or less typical for all the examined fungi. There was a close relationship between the phenol metabolism and dark humic acid-like substances occurring during the decomposition of straw.

     

Decomposition of 14C-labelled lignin and phenols by a Nocardia sp.

A Gram-positive bacterium which was isolated from a Finnish soil and identified as a Nocardia sp., was able to decompose lignin and to assimilate lignin degradation products as a carbon source. It could release ¹⁴CO₂ from ¹⁴C-labelled methoxyl groups, side chains or ring carbons of coniferyl alcohol dehydropolymers (DHP) and from specifically ¹⁴C-labelled lignin of plant material. Furthermore, it could release ¹⁴CO₂ from phenolcarboxylic and cinnamic acids and alcohols labelled in the OCH₃, COOH groups, side chain or aromatic ring carbons.Non-Common Abbreviations Used DHP dehydropolymers of coniferyl alcohol     

Anaerobic dechlorination and degradation of hexachlorocyclohexane isomers by anaerobic and facultative anaerobic bacteria

Screening studies with strict and facultative anaerobic bacteria showed that Clostridium app. and several other representatives of Bacillaceae and Enterobacteriaceae actively degraded -hexachlorocyclohexane (-HCH) under anaerobic conditions. Representatives of Lactobacillaceae and Propronibacterium were inactive. With ³⁶Cl-labelled -HCH a nearly complete dechlorination was shown to occur in 4–6 days by Clostridium butyricum, C. pasteurianum and Citrobacter freundii, while other facultative anaerobic species were less active.Aerobically grown facultative anaerobes also dechlorinated actively -HCH during subsequent anaerobic incubation with glucose, pyruvate or formate as substrates. The -, - and -HCH isomers were also, but more slowly, dechlorinated (>>-HCH). All species active in anaerobic degradation of -HCH formed -tetrachlorocyclohexene (TCH) as the main intermediate metabolite and no -pentachlorocyclohexene (PCH) or other isomers of TCH or PCH have been found. Small amounts of tri- and tetrachlorinated benzenes have been found too. The mechanism of dechlorination is discussed.Non-Common Abbreviations Used -HCH -hexachlorocyclohexane - -TCH -2,3,4,5-tetrachlorocyclohexene - -PCH -1,2,3,4,5-pentachlorocyclohexene - GLC gas liquid chromatography     

Pituitary cytology of radiothyroidectomised teleost Heteropneustes fossilis (Bloch.).

The pituitary of Heteropneustes fossilis is divisible into rostral (RPD) and proximal (PPD) pars distalis, and pars intermedia (PI). Neurohypophysis extensively ramifies in the PI. The RPD is formed of acidophilic prolactin cells and lead hematoxylin (H. Pb) positive ACTH cells. The latter is arranged around the neurohypophysial extensions. The PPD is comprised of thyrotrophs (TSH) and gonadotrophs which are stainable with PAS, AF, and aniline blue. Acidophilic somatotrophs (STH) and chromophobes are scattered throughout the PPD. In the pars intermedia PAS positive and H. Pb positive cells are present. The latter is believed to secrete MSH whereas the function of the former is yet to be confirmed. In the partly and completely thyroidectomised H. fossilis the TSH cells exhibited marked hypertrophy. They are located in the middle of the PPD flanked by the gonadotrophs on either side. Hypertrophy of the ACTH cells were also evident. But the other cell types did not show any marked changes as compared to the controls.     

Enzymhistochemical Localization of Alkaline Phosphatases in Germinal Cysts of the Testis of the Frog Rana temporaria (Anura)

Alkaline phosphatases have been demonstrated enzymhistochemically in the testis of the common frog Rana temporaria, caught in the month of January. The follicle cells in the cyst walls and the lamina propria of the seminiferous tubules showed strong enzymatic activity; also a weak activity was observed in the peripheral region of some of the germinal cells lying within the cysts. The possible interaction of alkaline phosphatases in the transport processes across the cyst walls has been discussed.     

Heterologous expression, purification, and kinetic comparison of the cytoplasmic and mitochondrial glyoxalase II enzymes, Glo2p and Glo4p, from Saccharomyces cerevisiae

The aims of the present study are (i) to purify a mitochondrial glyoxalase II to homogeneity for the first time from any organism and (ii) to compare its kinetic properties with those of the cytoplasmic enzyme. Both the cytoplasmic and the mitochondrial glyoxalases II from Saccharomyces cerevisiae, which are the products of two distinct genes, GLO2 and GLO4, were purified from yeast and in recombinant form from Escherichia coli. To obtain a higher protein yield (compared to wild-type expression) in yeast, the genes were placed under the control of the strong GAL1 promoter on a multicopy plasmid. Amino-terminal sequencing and molecular mass determination by MALDI-TOF mass spectrometry of the mitochondrial Glo4 protein revealed Met-11 of the primary translation product of the gene as the N-terminal amino acid. Judged by enzyme kinetic properties the recombinant and natural proteins were equivalent. The cytoplasmic and the mitochondrial enzyme differed in the pH dependence of the kinetic parameters for the main substrate, S-d-lactoylglutathione. Whereas the cytoplasmic protein showed a pronounced peak of enzyme activity between pH 7-8 and a continuous up to fivefold increase of the K(M) value with increasing pH (from 5. 5-9.0), the mitochondrial protein had a nearly constant K(M) value and an activity maximum over a broad pH range (6.5-9.0). The kinetic parameters (at pH 7.5) of both the cytoplasmic and the mitochondrial enzyme for S-D-lactoylglutathione were of the same order of magnitude as reported recently for the human and Arabidopsis thaliana enzymes which are presumably of cytoplasmic origin. However, both yeast enzymes showed a severalfold lower preference for the more hydrophobic substrate, S-d-mandeloylglutathione.     

Elevation of neutrophil-derived factors in patients after multiple trauma

Trauma represents one of the leading causes of death worldwide. Traumatic injuries elicit a dynamic inflammatory response with systemic release of inflammatory cytokines. Disbalance of this response can lead to systemic inflammatory response syndrome or compensatory anti-inflammatory response syndrome. As neutrophils play a major role in innate immune defence and are crucial in the injury-induced immunological response, we aimed to investigate systemic neutrophil-derived immunomodulators in trauma patients. Therefore, serum levels of neutrophil elastase (NE), myeloperoxidase (MPO) and citrullinated histone H3 (CitH3) were quantified in patients with injury severity scores above 15. Additionally, leukocyte, platelet, fibrinogen and CRP levels were assessed. Lastly, we analysed the association of neutrophil-derived factors with clinical severity scoring systems. Although the release of MPO, NE and CitH3 was not predictive of mortality, we found a remarkable increase in MPO and NE in trauma patients as compared with healthy controls. We also found significantly increased levels of MPO and NE on Days 1 and 5 after initial trauma in critically injured patients. Taken together, our data suggest a role for neutrophil activation in trauma. Targeting exacerbated neutrophil activation might represent a new therapeutic option for critically injured patients.     

Genetically engineered neural stem cells (NSCs) therapy for neurological diseases; state-of-the-art

Neural stem cells (NSCs) are multipotent stem cells with remarkable self-renewal potential and also unique competencies to differentiate into neurons, astrocytes, and oligodendrocytes (ODCs) and improve the cellular microenvironment. In addition, NSCs secret diversity of mediators, including neurotrophic factors (e.g., BDNF, NGF, GDNF, CNTF, and NT-3), pro-angiogenic mediators (e.g., FGF-2 and VEGF), and anti-inflammatory biomolecules. Thereby, NSCs transplantation has become a reasonable and effective treatment for various neurodegenerative disorders by their capacity to induce neurogenesis and vasculogenesis and dampen neuroinflammation and oxidative stress. Nonetheless, various drawbacks such as lower migration and survival and less differential capacity to a particular cell lineage concerning the disease pathogenesis hinder their application. Thus, genetic engineering of NSCs before transplantation is recently regarded as an innovative strategy to bypass these hurdles. Indeed, genetically modified NSCs could bring about more favored therapeutic influences post-transplantation in vivo, making them an excellent option for neurological disease therapy. This review for the first time offers a comprehensive review of the therapeutic capability of genetically modified NSCs rather than naïve NSCs in neurological disease beyond brain tumors and sheds light on the recent progress and prospect in this context.