Ethanol and sucrose self-administration components: effects of drinking history.

Results of previous studies have shown that when rats consume higher concentrations of ethanol during initiation both the amount consumed and the pattern of consumption change with the return to a lower concentration. In this study, an across-sessions breakpoint procedure in the sipper-tube model was used to examine the effect that experience with drinking higher concentrations (a concentration manipulation) of both ethanol and sucrose had on appetitive and consummatory behaviors. A follow-up study was then conducted in the ethanol-consuming group with across-session breakpoint and intake examined before, during, and after a 3% sucrose/10% ethanol solution was presented in the sipper tube. As ethanol concentration increased, intake was not changed. Exposure to higher ethanol concentrations had no effect on the amount of 10% ethanol consumed when retested. The exposure tended to increase appetitive behavior (breakpoint), but this effect was not unique to ethanol, as rats self-administering 3% sucrose showed a similar increase. When the combined ethanol-sucrose solution was available, a significant increase in both intake and appetitive responding occurred; however, there was no change from prior intake or breakpoint when 10% ethanol was retested. That the addition of sucrose to the ethanol solution significantly increased appetitive and consummatory behaviors supports the suggestion that the composition of the alcoholic beverage can have a strong influence over the control of self-administration. Because most consumption of ethanol by human beings is in solutions that contain mixers that alter the taste of the solution, this taste factor needs to be considered in the regulation of ethanol drinking.     

Microinjections of dopamine agonists in the nucleus accumbens increase ethanol-reinforced responding.

Long-Evans rats (N = 3) were trained to lever press on a fixed-ratio 4 (FR 4) schedule with ethanol (10% v/v) presented as the reinforcer. Each rat received a total of six bilateral nucleus accumbens microinjections, one per week. They were tested with one physiological saline control, three 20.0-microgram/brain d-amphetamine, and two 6.0-microgram/brain quinpirole injections given 10 min prior to operant sessions. Ethanol-reinforced responding terminated after approximately 10 min during control sessions. Microinjections of the D2 agonist quinpirole and the nonspecific dopamine (DA) agonist d-amphetamine increased total responding but produced slowed response rates that continued for 45-60 min. The slowed response rate produced by d-amphetamine resulted in a peak increase in interresponse times (IRTs) between 8-10 s, whereas quinpirole increased IRTs in the 14- to 16-s range, indicating that nonspecific DA activation resulted in higher rates of ethanol-reinforced responding than specific D2 activation although both drugs decreased local response rates. These data indicate that the amount and temporal extent of ethanol-reinforced responding are increased by microinjections of DA agonists in the nucleus accumbens and support the hypothesis that DA activity in this region is involved in the regulation of ethanol-reinforced responding.     

Current possibilities for the staged rehabilitative treatment of peptic ulcer in adolescents and young adults

The authors presented the results of a follow-up of 2 groups of patients with gastroduodenal pathology diagnosed in childhood: the patients (96 persons) in the 1st group had received staged rehabilitation treatment, no staged rehabilitation measures had been used in the 2nd group (86 patients). A differentiated step-by-step complex of therapeutic and preventive measures at the onset of disease brought about positive results in 94.1% of the patients in the 1st group, whereas routine therapy without therapeutic and preventive measures at the time of remission resulted in recurrence in 72.1% (62 patients) in the 2nd group. The authors arrived at a conclusion that early detection and therapy of exacerbations of peptic ulcer and chronic ulcer-like gastroduodenitis in childhood prevented the progression of disease in young patients that was of great social importance.     

Stem cell research and cell transplantation for myocardial regeneration.

Several human organs are not capable of functional regeneration following a tissue defect and react with scar formation. In stem cell transplantation, undifferentiated or partly differentiated precursor cells are applied to defective tissue for therapeutic regeneration. After promising preclinical investigations, the transplantation of autologous stem cells for myocardial infarction treatment is being transferred to clinical use. Mesenchymal stem cells and endothelial precursor cells derived from the bone marrow or circulating blood as well as skeletal myoblasts are employed in clinical trials. Furthermore, indications for cell transplantation and delivery routes vary considerably throughout current investigations. Initial results suggest a potential for restoration of cardiac function in stem cell-treated patients; however, the mechanisms are not fully understood. This overview will focus on objectives, recent achievements, and future perspectives of diverse stem cell transplantation approaches.     

GABAergic Transmission in the Nucleus Accumbens Is Involved in the Termination of Ethanol Self-Administration in Rats

Long-Evans rats ( n = 12) were trained to lever-press on a fixed-ratio 4 schedule of reinforcement with ethanol (10% v/v) presented as the reinforcer. After implantation of bilateral stainless-steel guide cannulae aimed at the nucleus accumbens, site-specific microinjections of muscimol (1–30 ng) and bicuculline (1–10 ng) were tested for effects on ethanol-reinforced responding. Baseline response patterns were characterized by initial high rates that terminated abruptly after ∼20 min. Muscimol administration in the nucleus accumbens decreased the total number of ethanol-reinforced responses and obtained reinforcers. Bicuculline also decreased ethanol-reinforced responses and reinforcers at the highest dose tested. When a dose of bicuculline (1 ng) that was ineffective by itself was coadministered with an effective dose of muscimol (10 ng), the muscimol-induced decreases in responding were blocked. Analysis of response patterns showed that muscimol decreased ethanol self-administration by terminating responding, normally lasting 20 min, after ∼10 min with no changes in local response rate. Bicuculline decreased total responding by producing parallel, but nonsignificant, changes in time course and response rate. These data suggest that GABAergic transmission in the nucleus accumbens is involved in the termination, but not the onset or maintenance of ethanol self-administration. The specificity of this effect gives emphasis to the importance of measuring behavioral parameters, as well as products of behavior (such as intake volume) in the study of ethanol self-administration.     

Transcranial Doppler ultrasound as a guide to graded therapeutic occlusion of the carotid artery

Although gradual carotid artery occlusion is an accepted and effective treatment for some surgically inaccessible intracranial aneurysms, there are no specific guidelines to determine the optimal amount of carotid artery narrowing at each adjustment. The technique of transcranial Doppler ultrasound, however, allows continuous measurement of blood velocity in the middle cerebral artery as the carotid artery is narrowed, so that hemodynamic effects and development of collateral flow can be immediately assessed at the bedside at each adjustment of the carotid artery diameter. This case report describes the use of transcranial Doppler to guide the rate of carotid occlusion in a patient with an unclippable giant aneurysm of the carotid artery. Sudden carotid occlusion and gradual occlusion at the usual rate were not tolerated by the patient, but repeatedly tightening the clamp until the first signs of attenuation of the Doppler signal allowed an expedient occlusion without complication. Transcranial Doppler ultrasound can provide a useful dynamic guide to gradual therapeutic carotid occlusion.