Bisacridines with aromatic linking chains. Synthesis, DNA interaction, and antitumor activity

Synthesis of a series of bisacridine derivatives containing rigid aromatic linking chains is described. Their DNA interaction and in vitro cytotoxicity against HT-29 human carcinoma cells are reported.     

The Tau/A152T mutation,a risk factor for frontotemporal‐spectrum disorders,leads to NR2B receptor‐mediated excitotoxicity

We report on a novel transgenic mouse model expressing human full‐length Tau with the Tau mutation A152T (hTau^AT), a risk factor for FTD‐spectrum disorders including PSP and CBD. Brain neurons reveal pathological Tau conformation, hyperphosphorylation, mis‐sorting, aggregation, neuronal degeneration, and progressive loss, most prominently in area CA3 of the hippocampus. The mossy fiber pathway shows enhanced basal synaptic transmission without changes in short‐ or long‐term plasticity. In organotypic hippocampal slices, extracellular glutamate increases early above control levels, followed by a rise in neurotoxicity. These changes are normalized by inhibiting neurotransmitter release or by blocking voltage‐gated sodium channels. CA3 neurons show elevated intracellular calcium during rest and after activity induction which is sensitive to NR2B antagonizing drugs, demonstrating a pivotal role of extrasynaptic NMDA receptors. Slices show pronounced epileptiform activity and axonal sprouting of mossy fibers. Excitotoxic neuronal death is ameliorated by ceftriaxone, which stimulates astrocytic glutamate uptake via the transporter EAAT2/GLT1. In summary, hTau^AT causes excitotoxicity mediated by NR2B‐containing NMDA receptors due to enhanced extracellular glutamate.     

Stimulation of ALK by the growth factor midkine renders glioma cells resistant to autophagy-mediated cell death

Δ?-tetrahydrocannabinol (THC), the main active component of marijuana, promotes cancer cell death via autophagy stimulation. We find that activation of the tyrosine kinase receptor ALK by its ligand midkine interferes with the signaling mechanism by which THC promotes autophagy-mediated glioma cell death.     

Sensitive fluorescence in situ hybridization signal detection in maize using directly labeled probes produced by high concentration DNA polymerase nick translation

The signal produced by fluorescence in situ hybridization (FISH) often is inconsistent among cells and sensitivity is low. Small DNA targets on the chromatin are difficult to detect. We report here an improved nick translation procedure for Texas red and Alexa Fluor 488 direct labeling of FISH probes. Brighter probes can be obtained by adding excess DNA polymerase I. Using such probes, a 30 kb yeast transgene, and the rp1, rp3 and zein multigene clusters were clearly detected.     

Effect of antibiotic treatment on serum PSA and percent free PSA levels in patients with biochemical criteria for prostate biopsy and previous lower urinary tract infections

BACKGROUND: Controversy exists as to the influence of inflammatory foci on total and free prostate-specific antigen (PSA) concentrations. The objective was to analyze the biological variations of PSA and percent free PSA (%f-PSA) in patients with biochemical criteria for prostate biopsy (PSA higher than 4 ng/mL and normal rectal examination) and compare them with the variation induced by antibiotic treatment in a cohort of patients with a history of lower urinary tract infections and no clinical evidence of prostatitis. METHODS: Ninety patients with a history of lower urinary tract infections, non-suspicious digital rectal examination and PSA between 4 and 20 ng/mL were analyzed. PSA concentration and %f-PSA were determined. Forty-five patients were treated with three weeks of ofloxacin, following which marker determination was repeated. All patients underwent ultrasound-controlled transrectal six-core prostate biopsy. RESULTS: Sixty-seven patients presented benign prostatic hyperplasia (BPH) (30 with prostatitic foci) and 23 cancer. Significant variations in PSA (6.97 ng/mL vs. 5.82 ng/mL, p=0.001) and %f-PSA (14.84% vs. 17.53%, p=0.01) were found only in the treated patients. These differences were significant for patients with BPH-associated prostatitic foci and not for patients with BPH or cancer. The tendency was for PSA to decrease (15 treated patients with PSA <4 ng/mL vs. six non-treated patients) and for %f-PSA to increase. The median variation of %f-PSA was greater than that of PSA. When the cutoff for %f-PSA was set at 25%, 18.9% of unnecessary biopsies after the first determination and 20% after the second could be avoided. By associating the reduction in PSA, up to 46% could be avoided in treated patients. CONCLUSION: Biochemical criteria for prostate biopsy may be modified in patients with a history of lower urinary tract infections due to variations greater than those explained by intraindividual biological variations, and may be influenced by the antibiotic treatment. These results suggest that subclinical inflammatory foci may influence PSA and %f-PSA.