Left-handed DNA-PAINT for improved super-resolution imaging in the nucleus.

DNA point accumulation in nanoscale topography (DNA-PAINT) increases the resolution and multiplexing capabilities of super-resolution imaging, but cellular DNA interferes with DNA-DNA hybridization between target and probe in the nucleus. Here, we introduce left-handed DNA (L-DNA) oligomers that do not hybridize to natural right-handed DNA (R-DNA) and demonstrate that L-DNA-PAINT has the same specificity and multiplexing capability as R-DNA-PAINT, but improves the imaging of nuclear targets by substantially reducing background signal.

Ashbya gossypii as a model system to study septin organization by single-molecule localization microscopy.

Heteromeric complexes of GTP-binding proteins from the septin family assemble into higher order structures that are essential for cell division in many organisms. The correct organization of the subunits into filaments, gauzes, and rings is the basis of septin function in this process. Electron microscopy and polarization fluorescence microscopy contributed greatly to the understanding of the dynamics and organization of such structures. However, both methods show technical limitations in resolution and specificity that do not allow the identification of individual septin complexes in assemblies in intact cells. Single-molecule localization-based fluorescence superresolution microscopy methods combine the resolution of cellular structures at the nanometer level with highest molecular specificity and excellent contrast. Here, we provide a protocol that enables the investigation of the organization of septin complexes in higher order structures in cells by combining advantageous features of the model organism Ashbya gossypii with single-molecule localization microscopy. Our assay is designed to investigate the general assembly mechanism of septin complexes in cells and is applicable to many cell types.

Even illumination in total internal reflection fluorescence microscopy using laser light.

In modern fluorescence microscopy, lasers are a widely used source of light, both for imaging in total internal reflection and epi-illumination modes. In wide-field imaging, scattering of highly coherent laser light due to imperfections in the light path typically leads to nonuniform illumination of the specimen, compromising image analysis. We report the design and construction of an objective-launch total internal reflection fluorescence microscopy system with excellent evenness of specimen illumination achieved by azimuthal rotation of the incoming illuminating laser beam. The system allows quick and precise changes of the incidence angle of the laser beam and thus can also be used in an epifluorescence mode.

[Interactions between nitrous oxide and central depressants]. / Wechselwirkungen zwischen Stickoxydul und zentral dämpfend wirkenden Pharmaka.

The combined effects on mice of N2O and various central depressants were investigated. A loss of the righting reflex was taken as the criterion for the drug effects. Essential differences could be demonstrated in the type of interaction: diazepam, flunitrazepam, and medazepam have a supra-additive effect in combination with N2O; the solvent of diazepam and an experimental product, Ro 21-3981 (8-Chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo [1,5-a] [1,4]-benzodiazepine maleate) a simply additive one. However, the interactions between N2O and barbiturates (pentobarbitone and phenobarbitone), and N2O and ethanol were found to be infra-additive. The results of this and previous investigations indicate that additive or supra-additive interactions can only be expected in those cases in which at most one of the two active ingredients in addition to its depressive effect also exhibits an excitatory component.

[Clinical experiences with a disposable biopsy set according to Menghini for percutaneous liver biopsy (author's transl)]. / Klinische Erfahrungen mit einem Einmal-Punktionsbestect zur perkutanen Leberbiopsie nach Menghini.

The handling and reliability of a new disposable biopsy set (Hepafix) have been evaluated in 170 percutaneous liver biopsies according to the technique of Menghini. In comparison with the conventional multiple biopsy set the new set provides several advantages discussed in the paper. The wider use of the disposable liver biopsy set may contribute to the prevention of transmission of hepatitis.

[Serum gastrin levels in patients with changes of gastric or duodenal mucosa (author's transl)]. / Serumgastrinspiegel bei Patienten mit Magen- und Duodenalschleimhautveränderungen

The mean concentration of gastrin in serum was determined in healthy fasting persons (n = 27), it amounted to 56.8 pg/ml (SD = 19.8 PG/ML). The values of gastrin in serum of patients, who were grouped by endoscopicbioptic criteria of antral mucosa and who exceptionally showed diffuse inflammation of gastric mucosa, amounted to 73.2 pg/ml in patients with mild superficial gastritis (n = 24), to 73.4 pg/ml in those with severe superficial gastritis (n = 55), to 82.3 pg/ml in patients with chronic atrophic gastritis (n = 11) and to 70.7 pg/ml in those with chronic atrophic gastritis and intestinal metaplasia (n = 17). The concentration of serum gastrin in patients with additional pathological processes of gastric or duodenal mucosa was also determined. Patients with gastric resection according to Billroth II (n = 15) revealed gastrin values of 47.8 pg/ml, those with duodenal ulcer (n = 5) of 58.5 pg/ml, with gastric ulcer (n = 50) of 61.3 pg/ml, with polyps in stomach (n = 10) of 109.6 pg/ml and with neoplasms of the stomach (n = 27) of 77.7 pg/ml. Gastrin values were not correlated to age or sex. The difference between the mean gastrin concentrations of the mentioned groups of patients however is not marked enough and the range of values is too wide to characterize those groups by specific gastrin levels. The determination of gastrin in serum of fasting patients is not helpful for diagnosis of gastritis without antibodies to intrinsic factor or for diagnosis of certain localized pathological conditions in stomach or duodenum obviously.

[Side effects after stimulation of gastric secretion with pentagastrin (author's transl)]. / Nebenwirkungen nach Stimulation der Magensekretion mit Pentagastrin

Application of pentagastrin (by infusion, by intramuscular and subcutaneous injection) in the usual dose of 6 mug/kg/hr revealed a short lasting enhancement in frequency of pulse-rate and a slight rise in blood-pressure (5 to 10 mmHg), which exceeded the alteration of pulserate, in 30 healthy volunteers with normal blood-pressure. The enhancement of pulse-rate is considered as a psychogenic reaction to injection. The reason of the rise in blood-pressure, which immediately occured and was of long standing duration, is a pharmacodynamic effect obviously. An extensive increase in blood-pressure, collaps, bradycardia or tachycardia was not observed during 120 investigations. We were not able to detect any significant changes in a number of components of serum or blood. The influence on the values of SGOT, LAP, urea, the red and white blood cell count as well as on hemoglobin concentration and hematocrit cannot be excluded however.