Weak Coupling between Heterotrophic Nanoflagellates and Bacteria in a Eutrophic Freshwater Environment.

In a study on the dynamics and trophic role of the heterotrophic nanoflagellate (HNAN) assemblage in the microbial food web of a eutrophic oxbow lake abundances, biomass, and production rates of HNAN and their potential prey organisms, namely heterotrophic bacteria and autotrophic picoplankton, were monitored for a period of 2 years. No coupling between HNAN abundance and biomass and the abundance and biomass of their picoplanktonic prey was observed for the investigation period. The ratio of heterotrophic bacterial to HNAN abundance ranged from 2.2 x 103 to 8.6 x 103 (mean: 4.2 x 103 +/- 1.8 x 103). HNAN carbon consumption could account for only 10% to 40% of bacterial secondary production. The lack of coupling between HNAN and their potential prey and the low HNAN abundance relative to bacterial abundance suggested (a) that HNAN grazing was an insignificant factor in the regulation of bacterial abundance and (b) that HNAN abundance was regulated by predation rather than by prey abundance. This hypothesis was supported by the fact that HNAN growth rates were high (in the range of 0.45 d-1 to 1.00 d-1 during spring and summer, yearly mean: 0.52 d-1), and only weakly correlated with prey abundance and biomass. The results indicated strong top-down control of HNAN and consequently a weak coupling of HNAN and picoplankton in the investigated eutrophic freshwater environment.

Simultaneous identification of campylobacters and prediction of quinolone resistance by comparative sequence analysis.

Comparative sequence analysis of a 30-bp segment in the quinolone resistance-determining region of campylobacters not only allows for the detection of base changes associated with resistance but also is a powerful tool for species identification based on silent mutations.

Influence of cytokines on the density of beta 2-adrenergic receptors on peripheral blood mononuclear cells in vitro.

Previous investigations have demonstrated a decrease of the number of beta 2-adrenergic receptors (beta 2R) on peripheral blood mononuclear cells (PBMC) in patients with rheumatic diseases that correlated with the systemic inflammatory activity. However, the main factor(s) modulating the beta 2R on lymphocytes in inflammatory diseases are still unidentified. The present study aimed at evaluating the influence of interleukin 1 beta (IL-1 beta) and interleukin 2 (IL-2) on the number and on the dissociation constant (KD) of beta 2R on PBMC in vitro. PBMC from healthy volunteers were incubated with different concentrations of IL-1 beta (10-100 U/ml) or IL-2 (10-50 U/ml) for 1,6,12,24 and 72 hours (h), respectively. Cultures with medium alone served as controls. beta 2R were determined using a radioligand binding assay with 125Iodo-cyanopindolol. The results showed a significant spontaneous decline of beta 2R after 72 h (mean +/- SEM = 2674 +/- 392 binding sites/cell (bs/c) vs. 1131 +/- 149 bs/c P < 0.02). IL-2 at a concentration of 50 U/ml diminished this spontaneous reduction of beta 2R numbers significantly (control: 1439 +/- 139 bs/c vs. IL-2: 1724 +/- 107 bs/c, P < 0.05). However, beta 2R densities did not hold baseline levels and were still significantly lower as compared to preculture values. Incubation with 100 U/ml IL-1 beta for 6 h induced a significant increase of beta 2R densities (control: 1760 +/- 214 bs/c vs. IL-1: 2233 +/- 424 bs/c, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Long-term experiences with histologic control of the incision margin (3-D histology)]. / Langzeiterfahrungen mit der Technik der histologischen Schnittrandkontrolle (3-D-Histologie).

In order to make sure that malignant tumors of the skin are excised completely, excisional margin control has been performed in our department for 8 years. For this purpose, tissue is excised, fixed in formalin and embedded in paraffin. The tumor and the excisional margins are examined separately. A total of 2016 basal cell carcinomas have been followed up for up to 4 years. If histological examination of the excised margins still show evidence of the tumor, re-excision is performed until the excised margins are free of the lesion. This procedure has proven to be very successful, with a recurrence rate of only 0.35%. The tissue is processed in a routine histology laboratory according to standard procedures.

Analgesic utilization patterns in a hospice.

Many terminally ill cancer patients suffer from unnecessary pain as a result of inadequate pain management. This study analyzes analgesics and other drugs used in a hospice setting over a five-year period to control pain and improve patient care.