Determination of thirty-two elements in human autopsy tissue

Inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine the concentrations of 32 elements in the human liver and kidney and 20 elements in the bone, obtained from 70 autopsied dead individuals (54 males, 16 females) between 18 and 76 yr of age from the North Bohemia territory of the Czech Republic. Geometric means, median, minimal-maximal range, as well as distribution and correlation analysis were calculated. Some significant differences among tissue concentrations of trace elements of the women and men were found. In the liver, medians of the concentrations of some elements were higher for men than that for women (Al: 770 vs 610 microg/kg; As: 42 vs 27 microg/kg; Cd: 1800 vs 1390 microg/kg; Rb: 3955 vs 3210 microg/kg; V: 160 vs 105 microg/kg). On the contrary, the content of other elements for men was lower (Bi: 0.8 vs 3.2 microg/kg; Cr: 57 vs 72 microg/kg; Hg: 228 vs 325 microg/kg; Zn: 57.1 vs 68.5 mg/kg). In the kidney of men, there were higher contents of Al (360 vs 245 microg/kg) and Hg (135 vs 75 microg/kg) and lower contents of Zn (47.7 vs 59.7 mg/kg) and I (135 vs 220 microg/kg) than those of women. In the case of bone, the concentrations of Cu and Rb were higher for men (1410 microg Cu/kg and 405 microg Rb/kg, respectively) than for women (655 microg Cu/kg and 285 microg Rb/kg, respectively). On the contrary, the content of Mn was considerably lower for men (110 microg Mn/kg) than for women (215 microg Mn/kg).     

NAS agar is more suitable than McKay agar for primary culture of <Emphasis Type="Italic">Streptococcus milleri</Emphasis> group (SMG) fastidious bacteria, <Emphasis Type="Italic">S. intermedius</Emphasis> in particular

Streptococcus milleri group (SMG) is a group of three streptococcal species (S. anginosus, intermedius and constellatus) that act as opportunist pathogens, among others in cystic fibrosis. Due to their fastidious character, they are both difficult to cultivate and to differentiate from less pathogenic streptococcal species, therefore being most probably underdiagnosed. Semi-selective McKay agar and NAS agar were developed to facilitate SMG recovery from clinical samples; however, direct comparison of recovery rates has not been published yet. We tested the performance of both media on 123 patient samples and demonstrated general superiority of NAS agar for SMG recovery during primary cultivation convincingly. This observation was also confirmed by quantitative drop tests during subculture. Despite the undisputed overall superiority of NAS agar over McKay agar, a smaller fraction of strains grew better on McKay agar. Inter-strain differences were the most probable explanation. Therefore, when economic conditions are not limiting and maximum recovery rate is desirable, both plates are advised to be used in parallel for primary cultivation of clinical samples.     

Seed bank of Littorella uniflora (L.) Asch. in the Czech Republic,Central Europe: does burial depth and sediment type influence seed germination?

Littorella uniflora (Plantaginaceae) is a scarce and declining aquatic plant in Europe. Its population has been strongly reduced by changes in fishpond management (eutrophication) in the Czech Republic since the 1950s. We studied its seed bank in both recent (n = 8) and historical localities (the last found from 1972 to 2000; n = 10) and tested the effects of sediment type and burial depth on seed germination using extracted seeds from two recent populations. The seeds were found in 60% of the historical localities, mostly in low densities (≤6 seeds per 3.75 l of sediment), and also in 100% of the recent localities in various densities (8–1390 seeds per 3.75 l of sediment); however, low germination rates (0–13.3%) were estimated. The seeds germinated best on wet filter paper, followed by nutrient-rich fishpond sediment, but poorly on sand mixed with different substrates. Burial depth significantly affected seed germination. The seeds germinated only on the soil surface and at the depth of 1 cm but no seed germinated at the depth of 3 and 5 cm. Besides low water transparency, both high rate of sediment accumulation and the absence of summer drainage may endanger L. uniflora populations in fishponds.

     

Enantioselective complexation of 1‐phenylethanol with chiral compounds bearing urea moiety

A detailed study of diastereomeric complexes of chiral ureido‐1,1′‐binaphthalene derivatives with chiral 1‐phenylethanol showed that a derivative bearing only one urea unit makes five times more stable complex with (S)‐enantiomer than with (R)‐enantiomer of the alcohol. This phenomenon could be used in chiral discrimination processes. The influence of individual parts of the structure on the complexation properties is shown. The probable structure of diastereomeric complexes based on experimental results and computational methods is proposed.