The covariation of common psychosomatic symptoms among children from socio-economically differing residential areas. An epidemiological study

Psychosomatic symptoms among children are believed to be commonplace. In this investigation by questionnaire, 47% of 1333 schoolchildren reported one or several symptoms, such as recurrent abdominal pain, headache, chest pains, loss of appetite and disturbances in bowel function. Coexistence of such symptoms was considerable and if a child had one of these, the probability that it would have one or more other symptoms was significantly increased. This correlation may strengthen both the suspicion that these symptoms are often psychosomatic and the idea that they have common CNS origin. There were appreciable differences in the frequency of the symptoms, between children at the more socially stable schools and schools with social problems. In the latter, the frequencies of symptoms differed between Swedish and immigrant children, which was not the case in the more socially stable schools.     

Adjuvant arthritis: influence of the adjuvant volume and composition on the non-specific inflammation

Adjuvant-induced arthritis is an animal model of chronic inflammatory disease widely used in anti-inflammatory and immunosuppressive drugs testing. When the development and the inhibition of the induced arthritis are measured by the injected paw oedema, it is difficult to delineate the immunological contribution from the persistent non-specific primary section. To study the influence of volume and composition of the injected adjuvant upon the primary non-specific inflammation, we devised a 3X4 factorial experiment on a strain of inbred rats with a low susceptibility to adjuvant-induced arthritis. The injection of mineral oil alone produces a persistent oedema. The injection of mycobacteriae in suspension in saline induces a rapid inflammatory response followed by a fast decrease of the oedema. When complete adjuvant is used, there is always a very strong interaction between the effects of the two components of the adjuvant, i.e. the measured oedemas are much greater than the calculated values, For a given injected volume, the inflammation is maximum when the concentration of mycobacteriae is 2.5 mg/ml. All the rats injected with complete adjuvant present a transient oedema of the non-injected hind paw. This oedema is very small and proportional to the amount of mycobacteria injected.     

Agricola und die Geologie

This paper on the occasion of the 500th birthday of the great Saxon humanistic scholar Georgius Agricola deals with his contributions to geology in the narrow sense. These, contrary to his voluminous works on mining, metallurgy and mineralogy (De re metallica and De natura fossilium, resp.) are parts of the booksDe ortu et causis subterraneorum andDe natura eorum, quae effluunt ex terra. In those we find statements on the causes of earthquakes, on volcanos and the subterranean fire as well as the effects of the running water in mountain-building. Agricola's ideas on geological time and his statements on dynamics of the Earth's crust are remarkable.     

Apatite as an interesting seed to remove phosphorus from wastewater in constructed wetlands.

Intensive use of phosphates has resulted in high P levels in surface waters and therefore eutrophication problems. Over the last decade many studies have revealed the advantage of using specific materials with efficient phosphorus retention capacities. Recent studies state that Ca materials are of particular interest for long-term retention of P, but can induce negative effects. To improve P retention and avoid negative counter-effects we tested the potential of natural apatites. Apatite sorption was evaluated using batch and open reactor experiments. Batch experiments identify sorption mechanisms and the influence of the ionic characteristics of the solution; open reactor experiments evaluate sorption capacities in relation to the ionic composition of the solution and biomass development. In parallel, observation of the material by electron microscopy was used to give more precision information about the mechanisms involved. This work reveals the strong chemical affinity between apatites and phosphorus. Compared to other calcareous materials apatite is better able to maintain low outlet P levels. After more than 550 days feeding, sorption was still present and low P outlet levels were still being obtained when sufficient contact time and calcium content in the solution were ensured. This work demonstrates the advantages of using apatites for phosphorus removal in constructed wetlands. The behaviour of apatite in phosphorus retention is explained and its suitability for use in such extensive systems defined.     

Karyotype description of Pomacea patula catemacensis (Caenogastropoda, Ampullariidae), with an assessment of the taxonomic status of Pomacea patula.

Mitotic chromosomes of the freshwater snail Pomacea patula catemacensis (Baker 1922) were analyzed on gill tissue of specimens from the type locality (Lake Catemaco, Mexico). The diploid number of chromosomes is 2n = 26, including nine metacentric and four submetacentric pairs; therefore, the fundamental number is FN = 52, No sex chromosomes could be identified. The same chromosome number and morphology were already reported for P. flagellata, i.e., the other species of the genus living in Mexico. The basic haploid number for family Ampullariidae was reported to be n = 14 in the literature; so, its reduction to n = 13 is probably an apomorphy of the Mexican Pomacea snails. Lanistes bolteni, from Egypt, also shows n = 13, but its karyotype is much more asymmetrical, and seems to have evolved independently from P. flagellata and P. patula catemacensis. The nominotypical subspecies, P. patula patula (Reeve 1856), is a poorly known taxon, whose original locality is unknown. A taxonomical account is presented here, and a Mexican origin postulated as the most parsimonious hypothesis.