Activation-induced changes in evoked and slow brain potentials: effect of cocaine in rabbits previously subchronically treated by cocaine

To study the type of adaptive modification (tolerance vs. sensitization) in different organism's indices following intermittent cocaine (COC) administrations, acute COC (2 mg/kg, SC)-induced changes in heart and breathing rate, response to increasing noxious stimulation, spontaneous EEG and event-related evoked and slow brain potentials (ERP) registered from the occipital cortex and hippocampal CA1 region were investigated in naive rabbits and one subchronically treated with COC (6 injections at a same dose). Tolerance developed for bradycardia, depression of noxious responsiveness, cortical desynchronization and increase of main components of cortical ERP, typical to acute COC, while the changes in breathing and hippocampal ERP were stable. These changes as well as a significant increase due to COC administrations of the basal values of an animal's noxious responsiveness and increase in relative changes in main component of cortical ERP (N205) are considered as a consequence of adaptive changes in neurophysiological/neurochemical substrate accepting COC action and mediating phenomena tolerance-sensitization and dependence typical to the drug.     

Saponins from Thinouia coriacea]

The investigation of the stems of Thinouia coriacea Britton (Sapindaceae), an ichthyotoxic plant from South Brazil, afforded eight glycosides of oleanolic acid. Structures were assigned based on data from partial hydrolysis. 13C-NMR and mass spectral procedures as 3-O-alpha-L-arabinopyranoside (1), 3-O-alpha-L-rhamnopyranosyl-(1----2)-alpha-L-arabinopyranoside+ ++ (2), 3-O-beta-D-glucopyranosyl-(1----4)-alpha-L-arabinopyranoside (3), 3-O-beta-D-glucopyranosyl-(1----3)-alpha-L-rhamnopyranosyl-(1----2 )-alpha-L-arabinopyranoside (4), 3-O-alpha-L-rhamnopyranosyl-(1----2)[beta-D-glucopyranosyl-(1----4 )]-alpha-L-arabinopyranoside (5), 3-O-beta-D-xylopyranosyl-(1----3)-alpha-L-rhamnopyranosyl-(1----2) [beta-D-glucopyranosyl-(1----4)[alpha-L-arabinopyranoside (6), 3-O-beta-D-glucopyranosyl-(1----3)-alpha-L-rhamnopyranosyl-(1----2 )[beta-D-glucopyranosyl-(1----4)]-alpha-L-arabinopyranoside (8). Saponin 7 showed the same sugars as 8, but the attachment between the sugars could not be elucidated. The same saponins were present in the roots, but not in the leaves.     

Improved haemorheology associated with a reduction in plasma fibrinogen and LDL in patients being treated by heparin-induced extracorporeal LDL precipitation (HELP)

Heparin-induced Extracorporeal LDL-Precipitation (HELP) is an effective procedure for the elimination of both plasma LDL and fibrinogen. In 10 adult patients with severe type II hyperlipoproteinemia, a single HELP treatment of 3 1 plasma led to an acute decrease in the average plasma viscosity (PV) from 1.30 to 1.1 mPas. At the same time, an even more marked decrease in the mean erythrocyte aggregation rate from a pathological value of 7.9% to a value of 3.7% (normal range less than 5%) was observed. Long-term studies on five patients demonstrated a lasting improvement in these two haemorheological variables. The acute rheological changes were also accompanied by an improvement in polarographically determined muscle oxygen tension. Mean oxygen tension values measured in both the m.biceps brachii and the m.tibialis anterior in five patients before and after a single HELP treatment increased from 30 +/- 4 to 37 +/- 7 mmHg and from 27 +/- 2 to 31 +/- 3 mmHg respectively. These results may provide an explanation for the rapid improvement in patients' clinical symptoms such as angina pectoris and in stress electrocardiogram which have been observed during HELP therapy.     

Three different pathogenic mechanisms for paraparesis in association with bacterial infections

Three different pathogenic mechanisms are apparent for paraparesis in association with a bacterial infection: a spinal cord compression caused by either an epidural abscess or a vertebral collapse due to spondylitis, an ischaemic spinal cord lesion as a result of septic thromboembolus in abdominal aorta, and a nonspecific, probably immunological, cause in association with reactive polyarthritis. An example of each of these mechanisms is described by means of case histories.     

Adjustment and adaptation

As in many other scientific disciplines, in gerontology adaptation is a central term. Yet it is not being used in a standardized way. This article describes the concepts and theoretical approaches which can be identified in Social Gerontology, together with their functions and the results of research.     

A comparative study of the tissue-destroying effect of the laser and electrocoagulation

The effect of the laser on compact, glandular tissue at the dosage employed for the local palliative treatment of tumors, can largely be mimicked with the aid of high-frequency current (HF-current), applied with the aid of an electro-hydro-thermo-probe: The experiments described in the present study were performed on the livers of 70 male Wistar rats. The laser was applied for 2 seconds at an output of 80 J at a distance to the tissue of 0.5 cm. In the first stage, in the acute experiment, the effect of the HF-current was matched to that of the laser by varying the modulated and unmodulated current components. It was found that the depths of penetration into the tissue at the given laser settings could be achieved with modulated HF-current (so-called coagulation current) at an output of more than 72 watts (equipment setting K 10) coagulation being performed for 10 seconds. The admixture of modulated HF-current (so-called cutting current) reduces the depth of penetration into the tissue. In the first 5 days, the depth of penetration increases after both laser irradiation and HF-coagulation, by a factor of 2 to 3. With respect to the depths of penetration (DP), the scatter ranges, and the histological changes, no difference is to be seen between laser and HF lesions: Laser DP = 5.7 mm (confidence range: 4.4-7.0 mm); HF DP (equipment setting K 10) = 4.8 mm (confidence range: 3.6-5.4 mm).(ABSTRACT TRUNCATED AT 250 WORDS)     

Histology of port wine stains after copper vapour laser treatment

We report histological changes in four patients with port wine stains treated with 578 nm yellow light from a high power copper vapour laser. Histology showed that selective damage occurred to the ectatic blood-vessels in the dermis, without haemorrhage and damage to non-vascular structures, and without scarring. The initial damage to the overlying epidermis was not permanent, and the damaged ectatic vessels returned to normal size or were completely necrosed and replaced by collagen.     

Reserpine enhances amphetamine stereotypies without increasing amphetamine-induced changes in striatal dialysate dopamine

Indirect evidence suggests that amphetamine (AMPH) releases dopamine (DA) from an extravesicular, cytoplasmic pool. Disruption of vesicular DA storage by reserpine has been hypothesized to increase the concentration of extravesicular DA available for release by AMPH, which is consistent with the observation that reserpine does not prevent but augments the behavioral response to AMPH. In order to more directly test this hypothesis, the in vivo microdialysis technique was used to concurrently examine the behavioral and striatal dopaminergic response to AMPH (1.25 or 2.5 mg/kg) 24 h following reserpine pretreatment (2.5 mg/kg). Reserpine decreased tissue levels of DA by approximately 90% and reduced baseline dialysate DA concentrations by approximately 80%. Reserpine augmented the behavioural effects of AMPH, particularly increasing the occurrence and intensity of stereotypies. In contrast, reserpine did not alter the amount or duration of AMPH-induced DA release. This observation confirms that DA release by AMPH does not depend on vesicular stores but is inconsistent with the hypothesis that augmentation or behaviour by reserpine results from increased striatal DA release.