Organ culture of urinary bladder tissue]

Bladder explants of young rats were cultivated in Carrel flasks on millipore filters, cellophane or polyvinyl chloride film. Nutritional mixture consisted of Eagles' medium, human serum and lactalbumin hydrolysate with addition of glucose, insulin and penicillin. On a millipore filter and a polyvinylchloride film the explants survived for up to 50 days, preserving a histotypical structure of the bladder mucosa. The technique described could be used for modelling various pathological conditions occurring in the urinary bladder.     

Brain MR Imaging and Proton MR Spectroscopy in Female Mice with Pyruvate Dehydrogenase Complex Deficiency

Pyruvate dehydrogenase complex (PDC) deficiency is an inborn metabolic disorder that causes neurological abnormalities. In this report, a murine model of PDC deficiency was analyzed using histology, magnetic resonance (MR) imaging and MR spectroscopy (MRS) and the results compared to PDC-deficient female patients. Histological analysis of brains from PDC-deficient mice revealed defects in neuronal cytoarchitecture in grey matter and reduced size of white matter structures. MR results were comparable to previously published clinical MR findings obtained from PDC-deficient female patients. Specifically, a 15.4% increase in relative lactate concentration, 64.4% loss of N-acetylaspartate concentration and a near complete loss of discernable glutamine plus glutamate concentration were observed in a PDC deficient mouse compared to wild-type control. Lower apparent diffusion coefficients (ADCs) were observed within the brain consistent with atrophy. These results demonstrate the usefulness of this murine model to systematically evaluate the beneficial effects of dietary and pharmacological interventions. Special issue dedicated to John P. Blass. Lioudmila Pliss and Richard Mazurchuk are two investigators who contributed equally.     

Effect of epidermal chalones on the development and growth of cheek pouch tumors in the hamster

To the cheek pouch mucosa of 118 male Syrian golden hamsters 0.5% acetone solution of 7,12-dimethylbenz (a) anthracene was applied 3 times a week during 2 months. Two months after beginning of the experiments all the hamsters developed tumors. Since that time a mixture of epidermal G1 and G2 chalones was applied to the cheek pouch mucosa of the experimental animals 5 times a week. The control hamsters received saline alone. As compared to the control, the experimental hamsters demonstrated an increase in the life-span, tumor growth retardation and regression of part of the tumors. The data obtained attest to the anti-neoplastic action of chalones.     

The Influence of Weak Geomagnetic Disturbances on the Rat Cardiovascular System under Natural and Shielded Geomagnetic Field Conditions

Biophysics - Abstract—This work was aimed at studying the effects of weak geomagnetic disturbances on systolic blood pressure, the R–R interval, the low-frequency and high-frequency...     

The role of the central nervous system imidazoline receptors in cardiovascular manifestations of emotional stress

The effect of central nervous system imidazoline receptors activation on basal blood pressure level, heart rate and arterial baroreceptor reflex in steady state and aversive emotional tension was tested in experiments on alert WKY, SHR and white bastard rats. It was found that the brain imidazoline receptors activation led to arterial baroreceptor reflex rise (both in resting and in emotional tension) and caused an emotional stress pressor effects decrease. No data proving involvement of imidazoline receptors in functioning of the systems maintaining level of blood pressure, were found.     

Neonatal neurodegeneration after N‐acetyl‐aspartylglutamate (NAAG) administration in rat hippocampus

NAAG, an agonist at Group II metabotropic glutamate receptors and at the N‐methyl‐d ‐aspartate (NMDA)‐type of ionotropic glutamate receptor, was infused at 250 nmoles in 0.25 μL of saline into each cerebral ventricle of 12‐day‐old rat pups. Proportion of pycnotic neurons was determined in 100 × 200 μm areas of medial and lateral blades of DG, and in areas CA1, CA3a, b of both dorsal and ventral hippocampus. In some sections we used Fluoro‐JADE‐B staining to visualize degenerating neuronal cell bodies. There was a marked neurodegeneration, particularly in the medial blade of DG, at 24 h after the administration of NAAG but it was lower at the 4‐day time point. No significant damage was observed in 50‐day‐old rat. The results indicate that early postnatal administration of NAAG can cause serious loss of neurons in rat hippocampus. Acknowledgement: Supported by LNOOB122 MEYS CR.     

Electron microscopy of DNA replication in 3-D: evidence for similar-sized replication foci throughout S-phase

DNA replication sites (RS) in synchronized HeLa cells have been studied at the electron microscopic level. Using an improved method for detection following the in vivo incorporation of biotin-16-deoxyuridine triphosphate, discrete RS, or foci are observed throughout the S-phase. In particular, the much larger RS or foci typically observed by fluorescence microscopic approaches in mid- and late-S-phase, are found to be composed of smaller discrete foci that are virtually identical in size to the RS observed in early-S-phase. Pulse-chase experiments demonstrate that the RS of early-S-phase are maintained when chased through S-phase and into the next cell generation. Stereologic analysis demonstrates that the relative number of smaller sized foci present at a given time remains constant from early through mid-S-phase with only a slight decrease in late-S-phase. 3-D reconstruction of serial sections reveals a network-like organization of the RS in early-S-phase and confirms that numerous smaller-sized replication foci comprise the larger RS characteristic of late-S-phase.     

Cardiovascular responses to emotional stress during activation of the brain imidazoline receptors

In alert normotensive and hypertensive (SHR) rats, effects of imidazoline receptor activating compounds of the central nervous system on the level of blood pressure, heart rate and value of arterial baroreceptor reflex at rest and in emotional tension, were investigated. It was shown, that the activation of the cerebral imidazoline receptors leads to an increase in the baroreceptor reflex value (both in resting and in emotional tension) and a decrease in the pressor reaction evoked by emotional affect. No data showing the role of imidazoline receptors in functioning of systems regulating of the initial level of blood pressure were obtained.