Large lowland rivers with sufficient hydrological storage capacity are capable of supporting primary production, but the dynamics of the advecting phytoplankton is poorly understood. Our study aimed at exploring how longitudinal versus lateral connectivity,
Proper diagnosis in drowning victims is often difficult due to the lack of signs specific to drowning. The diatom test is a widely used procedure for the diagnosis. Some types of water contain only minimal amounts of diatom cells which may provide false-negative results, while a negative diatom test result does not exclude drowning. In proving drowning, we used a polymerase chain reaction (PCR)-based biological method in addition to the conventional methods. DNA was extracted from postmortem spleen tissues and water of the drowning site. Samples were tested with algae (diatoms and small green algae)- and cyanobacteria (blue-green algae)-specific primers. We present here multiple drowning cases in which diatom tests of the postmortem tissue samples and the water were negative. In each case, the presence of phytoplanktonic DNA strengthened the autopsy diagnosis of drowning even in the absence of visible diatoms. In the future, the PCR method may be of consideration as a possible supplement of the diatom test in the examination of presumed drowning cases.
Marijuana is a widely used recreational drug with increasing legalization worldwide for medical purposes. Most experimental studies use either synthetic or plant-derived cannabinoids to investigate the effect of cannabinoids on anxiety and cognitive functions. The aim of this study was to mimic real life situations where young people smoke cannabis regularly to relax from everyday stress. Therefore, we exposed young adult male NMRI mice to daily stress and concomitant marijuana smoke for 2 months and investigated the consequences on physiology, behavior and adult hippocampal neurogenesis. Animals were restrained for 6-h/day for 5-days a week. During the stress, mice were exposed to cannabis smoke for 2 × 30 min/day. We burned 2 “joints” (2 × 0.8 g marijuana) per occasion in a whole body smoking chamber. Cannabinoid content of the smoke and urine samples was measured by HPLC and SFC-MS/MS. Body weight gain was recorded daily and we did unrestrained, whole body plethysmography to investigate pulmonary functions. The cognitive performance of the animals was evaluated by the novel object recognition and Y maze tests. Anxietyrelated spontaneous locomotor activity and self-grooming were assessed in the open field test (OFT). Adult neurogenesis was quantified post mortem in the hippocampal dentate gyrus. The proliferative activity of the precursor cells was detected by the use of the exogenous marker 5-bromo-20-deoxyuridine. Treatment effects on maturing neurons were studied by the examination of doublecortin-positive neurons. Both stress and cannabis exposure significantly reduced body weight gain. Cannabis smoke had no effect on pulmonary functions, but stress delayed the maturation of several lung functions. Neither stress, nor cannabis smoke affected the cognitive functioning of the animals. Results of the OFT revealed that cannabis had a mild anxiolytic effect and markedly increased self-grooming behavior. Stress blocked cell proliferation in the dentate gyrus, but cannabis had no effect on this parameter. Marijuana smoke however had a pronounced impact on doublecortin-positive neurons influencing their number, morphology and migration. In summary, we report here that long-term stress in combination with cannabis smoke exposure can alter several health-related measures, but the present experimental design could not reveal any interaction between these two treatment factors except for body weight gain.
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