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K Leeb

Publications and source records attributed to K Leeb.

6 recordsLinked to original sources
PubMed2002

[Laparoscopic tumor nephrectomy].

Initially, laparoscopic surgery in urology was restricted to the treatment of benign diseases, whereas its role in the management of malignant disease was restricted to purely diagnostic procedures. Only recently has laparoscopy been introduced for the treatment of low stage renal cell carcinoma (RCC), and the data on both surgical efficiency and oncologic efficacy are very promising. Therefore, we present our experience with laparoscopic radical nephrectomy and data from literature. The technique of the transperitoneal approach is described in detail. Retroperitoneoscopy is a good alternative, however. Intact removal of the specimen within an organ bag to avoid tumor spillage is an important detail of our technique. Our experience amounts to radical nephrectomy in 121 patients. The indication was clinical stage T1-T2. Mean operative time and blood loss was 2.4 h and 154 ml, respectively. The rate of minor or major complications was 5% and 4%, respectively. There was no conversion to open surgery in any patient. Mean postoperative hospital stay was 6.1 days. Data on tumor control are available for 73 patients with a mean follow-up of 13.3 months. There was no recurrence within this period. Radical nephrectomy for low-stage RCC is associated with low morbidity and great surgical efficiency. The rates for local recurrences and metastases are low, tumor-specific survival is high. However, there is still a lack of long-term data on large series of patients. Despite this fact, laparoscopy is already widely accepted for this indication, and it is quite likely that it will become the standard treatment.

Carcinoma, Renal Cell↗
PubMed1995

Elevations of nucleus accumbens dopamine and DOPAC levels during intravenous heroin self-administration.

Extracellular dopamine and DOPAC (3,4-dihydroxyphenylacetic acid) levels in nucleus accumbens were sampled by microdialysis and quantified with high-performance liquid chromatography during intravenous heroin self-administration sessions in rats. Dopamine levels in 10 and 20 min samples were elevated following the first injection of each session, reaching a plateau of elevation within the first two or three injections and falling back toward baseline only when drug access was terminated. Elevations were in the range of 150-300% when unit dosages of 0.05-0.2 mg/kg were given. Increasing the work requirement from FR-1 to FR-10 did not appear to alter the degree of elevation of dopamine levels, and dopamine levels fell during extinction while lever-pressing rates increased 20-fold. While animals compensated for unit dose changes between 0.05 and 0.2 mg/kg/injection, adjusting their response rate such that the same hourly drug intake and the same asymptotic dopamine levels were maintained across these conditions, at 0.4 mg/kg/injection hourly drug intake and asymptotic dopamine levels were elevated beyond the levels sustained by the lower doses. These findings confirm that self-administered doses of intravenous heroin are sufficient to activate the mesolimbic dopamine system and suggest that significant heroin "craving" can emerge when dopamine levels are still moderately elevated, long before the development of dopamine depletion associated with opiate withdrawal.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Fluctuations in nucleus accumbens dopamine concentration during intravenous cocaine self-administration in rats.

Fluctuations in extracellular dopamine and DOPAC levels in nucleus accumbens septi (NAS) were monitored in 1-min microdialysis samples taken from rats engaged in intravenous cocaine self-administration. For four rats the dose per injection was fixed at 2.0 mg/kg; for four others the dose per injection was varied irregularly, from one response to the next, between three levels (0.5, 1.0 and 2.0 mg/kg). Regardless of the dosing regimen, extracellular dopamine levels were tonically elevated by 200-800% within the cocaine self-administration periods, fluctuating phasically within this range between responses. In the fixed dose condition, the phasic increases following each injection (and the phasic decreases preceding them) averaged approximately 50% of the mean tonic elevation. Phasic fluctuations in dopamine levels remained time-locked to lever-presses even when response rate was irregular, because of the variable dose condition. In the variable dose condition greater increases in dopamine and longer inter-response times followed injections of the higher doses; dopamine fluctuations were consistent with the multiple-infusion pharmacokinetics of cocaine. DOPAC levels showed a slow tonic depression during cocaine self-administration, but individual injections were not associated with discernible phasic fluctuations of DOPAC. These data are consistent with the hypothesis that falling dopamine levels trigger successive responses in the intravenous cocaine self-administration paradigm, but inconsistent with the notion that extracellular dopamine levels are depleted at the times within sessions when the animal initiates drug-seeking responses.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Amphetamine-induced modification of quinine palatability: analysis by the taste reactivity test.

The effects of low doses of d-amphetamine (0.25-0.5 mg/kg, IP) on taste reactions elicited by quinine solutions in a 5-10-min taste reactivity test were assessed in a series of three experiments. Amphetamine consistently suppressed aversive reactions elicited by quinine solutions. The results suggest that amphetamine, like morphine, attenuates the aversiveness of the taste of quinine solution.

Animals↗
PubMed1991

Effects of pimozide on the hedonic properties of sucrose: analysis by the taste reactivity test.

The ability of the neuroleptic agent, pimozide, to modify sucrose palatability was assessed using three 10-min taste reactivity test sessions. Pimozide was found to suppress the ingestive response of tongue protrusions, but enhance the mildly ingestive/neutral response of mouth movements elicited by an intraoral infusion of sucrose solution. Since the pattern of taste reactivity responding shifted from highly ingestive to mildly ingestive/neutral, our results suggest that pimozide pretreatment reduces the palatability of sucrose solution. The temporal pattern of the modification of these taste reactivity responses was predicted by the Anhedonia Hypothesis.

Animals↗