Anastomotic leak after transanal total mesorectal excision: grading of severity and management aimed at preservation of the anastomosis

AIM

The transanal approach to total mesorectal excision (TaTME) as an alternative to conventional anterior resection offers an improved view to otherwise restricted anatomical regions in obese and narrow male pelves and unfavourable tumour locations. Guidelines for the management of anastomotic leakage (AL) following low rectal resections are scarce.

PATIENTS AND METHODS

Prospectively collected data of all consecutive patients undergoing TaTME between December 2014 and April 2017 in our centre were analysed retrospectively. Existing classification systems for AL were modified with regard to transanal anastomotic-preserving management.

RESULTS

TaTME was performed in 66 patients with a median age of 56.2 years. The overall incidence of AL was 12.1% (n = 8). AL grading was differentiated in Grades I to V according to the severity of necrosis and abscess development. Two patients suffered from AL Grade II, one patient from Grade III, three patients from Grade IV and two patients from Grade V. Preservation of the anastomosis following AL was achieved by the damage control concept in six of eight patients (75%) with a median duration of hospital stay of 36 days. Two patients received a Hartmann procedure (Grades IV and V).

CONCLUSION

Our study demonstrates that management of AL following TaTME is challenging but definitely amenable to strategies aimed at preserving the anastomosis by appropriate damage control. The modified classification system might serve as guidance for anastomosis-preserving management.

Pseudo-Leptomeningeal Contrast Enhancement at 3T in Pediatric Patients Sedated by Propofol

BACKGROUND AND PURPOSE

Propofol is a cerebral vasoconstrictor that modulates cerebral perfusion by decreasing the metabolic rate of oxygen. Because younger children often undergo intravenous sedation for MR imaging, this study set out to evaluate the degree of leptomeningeal contrast enhancement on 3T postcontrast brain MR imaging and to determine whether this phenomenon relates to sequence, sedation dosage, or patient age or weight.

MATERIALS AND METHODS

During a 2-year period, of 152 children 1-5 years of age who underwent MR imaging, 43 were included for MRI review. Of these, 37 underwent postcontrast imaging with either solely gradient-echo T1WI (n = 20) or spin-echo T1WI (n = 17); notably, 6 patients underwent both sequences. Three neuroradiologists separately graded the degree of leptomeningeal contrast enhancement (grades 0-3) that was correlated with various factors and calculated the interobserver reliability.

RESULTS

For the 43 patients, the mean patient age was 3.1 ± 1.4 years. The leptomeningeal contrast-enhancement grade was significantly greater (P < .0001) on spin-echo T1WI (1.9-2.1) versus gradient-echo TIWI (1.2-1.4). Patient weight (r = -0.366 to -.418, P = .003-.01) and age (r = -0.315 to -0.418, P = .004-.032) moderately and inversely correlated with the leptomeningeal contrast-enhancement grade, while the propofol dosage, sedation duration, and time to T1WI post-contrast administration did not (each, P > .05). The interobserver κ was strong regarding the leptomeningeal contrast-enhancement grade on both spin-echo T1WI (κ = 0.609-0.693, P < .0001) and gradient-echo TIWI (κ = 0.567-0.698, P < .0001).

CONCLUSIONS

Leptomeningeal contrast enhancement (or "pseudo"-leptomeningeal contrast enhancement) occurs with a greater frequency and degree on 3T postcontrast spin-echo T1WI relative to gradient-echo TIWI in younger children sedated with propofol and should not be mistaken for disease. This phenomenon may be more prominent with lower age or size and may arise from propofol-induced vascular smooth-muscle dilation.

Robotic low anterior resection versus transanal total mesorectal excision in rectal cancer: A comparison of 115 cases

BACKGROUND

Robotic low anterior resection (RLAR) and transanal total mesorectal excision (TaTME) are novel surgical techniques for resection of rectal cancer. To our knowledge, no data exist on direct comparison of these procedures in terms of oncological or functional parameters.

METHODS

60 RLAR and 55 TaTME for rectal cancer were compared in respect to patient characteristics, clinicopathological parameters, intraoperative and perioperative results and anatomopathological outcome.

RESULTS

62 surgeries addressed tumors of the lower third (53.9%). No intergroup differences in terms of patient characteristics and clinicopathological parameters were observed. Operating time did not differ between groups (p = 0.312), nor did the perioperative complication rate (p = 0.176). Circumferential resection margin was wider in the RLAR than in the TaTME group (p < 0.001), while no differences were found in the remaining oncological parameters.

CONCLUSION

Our study shows comparable results for RLAR and TaTME in rectal cancer treatment. Both procedures should be considered equally feasible for low rectal cancer cases and as an alternative to conventional anterior resections (open or laparoscopic). Furthermore, both techniques allow excellent oncological outcome especially in patients with anatomical limitations.

Reversible left hemispheric ischemia secondary to carotid compression in Eagle syndrome: surgical and CT angiographic correlation

Symptoms of ipsilateral carotid artery compression secondary to an elongated styloid process or calcified stylohyoid ligament may be seen in Eagle syndrome. The patient will typically experience cervicofacial pain due to stimulation of the arterial nervous plexus. In addition, symptoms directly attributable to compression of the carotid artery may be seen, including visual symptoms and syncope. We report here the case of a patient who developed symptoms consistent with left hemispheric ischemia within 15 seconds of turning his head to the left. These symptoms were completely reversible on returning the head to the neutral position. No long-term sequelae were detected clinically or radiographically.

An HPLC tracing of the enhancer regulation in selected discrete brain areas of food-deprived rats

The recent discovery of the enhancer regulation in the mammalian brain brought a different perspective to the brain-organized realization of goal-oriented behavior, which is the quintessence of plastic behavioral descriptions such as drive or motivation. According to this new approach, 'drive' means that special endogenous enhancer substances enhance the impulse-propagation-mediated release of transmitters in a proper population of enhancer-sensitive neurons, and keep these neurons in the state of enhanced excitability until the goal is reached. However, to reach any goal needs the participation of the catecholaminergic machinery, the engine of the brain. We developed a method to detect the specific enhancer effect of synthetic enhancer substances [(-)-deprenyl, (-)-PPAP, (-)-BPAP] by measuring the release of transmitters from freshly isolated selected discrete brain areas (striatum, substantia nigra, tuberculum olfactorium, locus coeruleus, raphe) by the aid of HPLC with electrochemical detection. To test the validity of the working hypothesis that in any form of goal-seeking behavior the catecholaminergic and serotonergic neurons work on a higher activity level, we compared the amount of norepinephrine, dopamine, and serotonin released from selected discrete brain areas isolated from the brain of sated and food-deprived rats. Rats were deprived of food for 48 and 72 hours, respectively, and the state of excitability of their catecholaminergic and serotonergic neurons in comparison to that of sated rats was measured. We tested the orienting-searching reflex activity of the rats in a special open field, isolated thereafter selected discrete brain areas and measured the release of norepinephrine, dopamine, and serotonin from the proper tissue samples into the organ bath. The orienting-searching reflex activity of the rats increased proportionally to the time elapsed from the last feed and the amount of dopamine released from the striatum, substantia nigra and tuberculum olfactorium, that of norepinephrine released from the locus coeruleus and that of serotonin released from the raphe increased significantly in the hungry rats proportionally to the time of fasting. For example: the amount of dopamine released from the substantia nigra of sated rats (4.62 +/- 0.20 nmoles/g wet weight) increased to 5.95 +/- 0.37 (P < 0.05) and 10.67 +/- 0.44 (P < 0.01) in rats deprived of food for 48 and 72 hours, respectively.

A pharmacological analysis elucidating why, in contrast to (-)-deprenyl (selegiline), alpha-tocopherol was ineffective in the DATATOP study

The Parkinson Study Group who conducted the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) trial designed their study in the belief that the MAO inhibitor (-)-deprenyl (selegiline), the antioxidant alpha-tocopherol, and the combination of the two compounds will slow the clinical progression of the disease to the extent that MAO activity and the formation of oxygen radicals contribute to the pathogenesis of nigral degeneration. In fact, (-)-deprenyl only delayed the onset of disability associated with early, otherwise untreated Parkinson's disease, however, in contrast to the expectation of the authors, alpha-tocopherol proved to be ineffective in the DATATOP study. Enhancer substances, (-)-deprenyl, (-)-1-phenyl-2-propylaminopentane [(-)-PPAP] the (-)-deprenyl analogue free of MAO inhibitory potency, and R-(-)1-(benzofuran-2-yl)-2-propylaminopentane [(-)-BPAP] the presently known most potent enhancer substance, are peculiar stimulants. They enhance the impulse propagation mediated release of the catecholamines in the brain. Due to their enhancer effect, the amount of catecholamines released from selected discrete brain areas (striatum, substantia nigra, tuberculum olfactorium, locus coeruleus) is significantly higher in rats treated with an enhancer substance than in saline treated rats. We compared the effect of (-)-deprenyl 0.025 and 0.25 mg/kg, (-)-PPAP 0.1 mg/kg, (-)-BPAP 0.0001 mg/kg, and alpha-tocopherol 25 and 50 mg/kg, in this test. The doses of (-)-deprenyl and alpha-tocopherol were selected to be in compliance with the dose given in the DATATOP study. Compared to saline treated rats, the enhancer substances significantly increased the amount of dopamine released from the striatum, substantia nigra and tuberculum olfactorium and the amount of norepinephrine released from the locus coeruleus; alpha-tocopherol was ineffective. The results indicate that alpha-tocopherol was ineffective, because, unlike (-)-deprenyl it dose not enhance the activity of the nigrostriatal dopaminergic neurons.

Combined occurrence of a heterozygous missense mutation in the protein C gene and allelic exclusion of one protein S allele leading to severe venous thrombosis

Individuals with more than one defect in the natural anticoagulant system exhibit an increased risk for thrombosis. We report on a family with two cases of combined protein C (PROC) and protein S (PROS) deficiency, five cases of isolated PROC deficiency Type I, and two cases of isolated PROS deficiency Type I. PROC and PROS deficiency were documented by functional and immunologic tests. The sequencing of all exons and splice junctions of the PROC gene led to the identification of a new, unpublished G-->A transition at nt 8490, leading to an exchange of alanine 259 by threonine. The mutation was present in all family members with PROC deficiency. The carriers of the isolated PROC mutation were asymptomatic at ages of 4, 7, 10, 11, and 80 years. The combination of the PROC mutation with a PROS deficiency in two family members triggered venous thromboembolism at age 31 and 6 years, respectively. The PROS deficiency was associated with complete exclusion of one PROS allele. Two family members with isolated PROS deficiency are still asymptomatic at age 21 and 9 years, respectively. Our findings in this family suggest that the heterozygous mutation at codon 259 of the PROC gene represents a mild thrombotic risk factor and only confers a high thrombotic risk in combination with a second defect, such as the complete exclusion of one PROS allele.

Structure–activity studies leading to (−)1-(Benzofuran-2-yl)-2-propylaminopentane, ((−)BPAP), a highly potent, selective enhancer of the impulse propagation mediated release of Catecholamines and Serotonin in the brain

The catecholaminergic and serotoninergic neurons in the brain change their performance according to the physiological need via a catecholaminergic/serotoninergic activity enhancer (CAE/SAE) mechanism. Phenylethylamine (PEA), tyramine and tryptamine are the presently known endogenous CAE/SAE substances which enhance the impulse propagation mediated release of catecholamines and serotonin in the brain. A PEA derivative, (-)deprenyl (selegiline), known as a selective inhibitor of MAO-B, is for the time being the only CAE/SAE substance in clinical use. Aiming to develop a selective CAE/SAE substance much more potent than (-)deprenyl, a series of new 1-aryl-2-alkylaminoalkanes, structurally unrelated to PEA and the amphetamines, was designed and prepared. Among them, (-)1-(benzofuran-2-yl)-2-propylaminopentane ((-)BPAP) was selected as a promising candidate substance for further studies. (-)BPAP significantly enhanced in rats the impulse propagation mediated release of catecholamines and serotonin in the brain 30min after acute injection of 0.36nmol/kg sc. In the shuttle box, (-)BPAP was in rats about 130 times more potent than (-)deprenyl in antagonizing tetrabenazine induced inhibition of performance. (+/-)BPAP protected cultured hippocampal neurons from the neurotoxic effect of beta-amyloid in 10(-14)-10(-15)M concentration.

Pure optical contrast in scattering-type scanning near-field microscopy

We have enhanced the apertureless scattering-type scanning near-field optical microscope by two improvements which together achieve a recording of the true near field without any height-induced artefact. These are the use of interferometric detection of the scattered light on one hand, and the use of higher-harmonic dither demodulation of the scattered signal on the other. Here we present the basic rationale for these techniques, and give examples measured with two different experiments, one in the infrared (10 microm wavelength), the other in the visible (633 nm). The latter operates in a fully heterodyne mode and displays simultaneous images of optical near-field phase and amplitude, at below 10 nm resolution.

Improvement of the specificity of enzyme immunoassays for the detection of rotavirus and adenovirus in fecal specimens

A variable rate of false-positive results may be observed with commercial enzyme immunoassays (EIAs) for the detection of rotavirus and adenovirus antigen in stool specimens, depending on the quality of the reagents and the presence of potentially interfering substances in stool samples. The present study was performed in an attempt to improve the specificity of current commercial rotavirus and adenovirus EIAs without significant loss of sensitivity by optimizing the cut-off value. A collective of 174 stool samples obtained from children suffering from acute gastroenteritis was tested. Electron microscopy (EM) and PAGE were used as reference methods for rotavirus detection. For the evaluation of the adenovirus kits, virus isolation in cell culture and the polymerase chain reaction served as reference standards. The highest sensitivity for rotavirus and adenovirus detection was achieved by the Ridascreen(R) Rotavirus and Ridascreen Adenovirus. However, the Ridascreen(R) Rotavirus and Ridascreen Adenovirus produced the highest number of false-positive results (n = 9) for each rotavirus and adenovirus detection. Cross-reactivities to coronaviruses and reoviruses were observed with the rotavirus antigen EIAs. For Rotazyme II, Ridascreen Rotavirus and Ridascreen Adenovirus, the specificity could be markedly increased without loss of sensitivity by doubling the cut-off value. For the alternative immunoassays, which were overall more specific, it was not possible to significantly decrease the rate of false-positive results without impairment of sensitivity by raising the cut-off value. In conclusion, at least for some rotavirus and adenovirus antigen EIAs, the cut-off value set by the manufacturer may not permit an optimal differentiation between true-positive and -negative samples. By raising the cut-off value from 50 to 100%, the specificity of two rotavirus antigen and one adenovirus antigen EIA can be improved markedly without significant loss of sensitivity.

Sexual hormones terminate in the rat: the significantly enhanced catecholaminergic/serotoninergic tone in the brain characteristic to the post-weaning period

The amount of dopamine released from the striatum, substantia nigra and tuberculum olfactorium, noradrenaline from locus coeruleus and serotonin from the raphe, was significantly higher in four and five weeks old rats than in three month old ones, proving that the catecholaminergic/serotoninergic activity enhancer (CAE/SAE) regulation works unrestrained during developmental longevity and is restricted thereafter. As the dampening of the CAE/SAE regulation (end to the second month of age) coincided temporally with the appearance of sexual hormones, we castrated three weeks old male and female rats and measured at the end of the third month of their life the release of catecholamines and serotonin from selected discrete brain regions. The amount of catecholamines and serotonin released from the neurons was significantly higher in castrated than in untreated or sham operated rats, signalting that sexual hormones inhibit the CAE/SAE regulation in the brain. We therefore treated male and female rats s.c. with oil (0.1 ml/rat), testosterone, (0.1 mg/rat), estrone (0.01 mg/rat) and progesterone (0.5 mg/rat), respectively, and measured their effect on the CAE/SAE regulation. Twenty-four hours after a single injection with the hormones, the release of noradrenaline, dopamine and serotonin was significantly inhibited in the testosterone or estrone treated rats, but remained unchanged after progesteron treatment. In rats treated with a single hormone injection, testosterone in the male and estrone in the female was the significantly more effective inhibitor. Remarkably, the reverse order of potency was found in rats treated with daily hormone injections for 7 or 14 days. After two-week treatment with the hormones estrone was in the male and testosterone in the female the significantly more potent inhibitor of the CAE/SAE regulation. The data indicate that sexual hormones terminate the hyperactive phase of adolescence by dampening the impulse propagation mediated release of catecholamines and serotonin in the brain.

Complete congenital bony syngnathia in a case of oromandibular limb hypogenesis syndrome

Congenital fusion of the maxilla and mandible (syngnathia) is rare and can present in a wide range of severity from single mucosal bands (synechiae) to complete bony fusion (synostosis). Congenital synostosis of the mandible and maxilla is even less common than synechiae, with only 19 cases reported in the literature. Most of them have presented as an incomplete, unilateral fusion. Only three of the reported cases showed more extensive but still incomplete, intermaxillary bony fusion. We present a case of complete bony fusion of the maxilla and mandible associated with a cleft palate, hypoglossia, micrognathia, unilateral choanal atresia, and limb abnormalities as a feature of oromandibular limb hypogenesis syndrome. Details of operative management are presented.

(-)1-(Benzofuran-2-yl)-2-propylaminopentane, [(-)BPAP], a selective enhancer of the impulse propagation mediated release of catecholamines and serotonin in the brain

1. The brain constituents beta-phenylethylamine (PEA) and tryptamine enhance the impulse propagation mediated transmitter release (exocytosis) from the catecholaminergic and serotoninergic neurons in the brain ('catecholaminergic/serotoninergic activity enhancer, CAE/SAE, effect'). (-)Deprenyl (Selegiline) and (-)1-phenyl-2-propylaminopentane [(-)PPAP] are amphetamine derived CAE substances devoid of the catecholamine releasing property. 2. By changing the aromatic ring in PPAP we developed highly potent and selective CAE/SAE substances, structurally unrelated to the amphetamines. Out of 65 newly synthetized compounds, a tryptamine derived structure, (-)1-(benzofuran-2-yl)-2-propylaminopentane [(-)BPAP] was selected as a potential follower of (-)deprenyl in the clinic and as a reference compound for further analysis of the CAE/SAE mechanism in the mammalian brain. 3. (-)BPAP significantly enhanced in 0.18 micromol 1(-1) concentration the impulse propagation mediated release of [(3)H]-noradrenaline and [(3)H]-dopamine and in 36 nmol 1(-1) concentration the release of [(3)H]-serotonin from the isolated brain stem of rats. The amount of catecholamines and serotonin released from isolated discrete rat brain regions (dopamine from the striatum, substantia nigra and tuberculum olfactorium, noradrenaline from the locus coeruleus and serotonin from the raphe) enhanced significantly in the presence of 10(-12) - 10(-14) M (-)BPAP. BPAP protected cultured hippocampal neurons from the neurotoxic effect of beta-amyloid in 10(-14) M concentration. In rats (-)BPAP significantly enhanced the activity of the catecholaminergic and serotoninergic neurons in the brain 30 min after acute injection of 0.1 microg kg(-1) s.c. In the shuttle box, (-)BPAP in rats was about 130 times more potent than (-)deprenyl in antagonizing tetrabenazine induced inhibition of performance.

Mid-infrared scanning near-field optical microscope resolves 30 nm

We explore the performance of a scanning near-field infrared microscope, which works by scattering tightly focused CO2 laser radiation (lambda = 10 microm) from the apex of a metallized atomic force microscope tip. The infrared images of test samples prove a spatial resolution of 30 nm and are free of topographical and inertial artefacts, thus they should be of great interest for practical applications. We also observe that the infrared contrast vanishes when the input beam polarization is orthogonal to the tip axis, in accordance with theoretical expectations for a mechanism of longitudinal field interaction.

[Initial results with withdrawal treatments of male and female participants in the diversified Janus opiate prescription project in Basel]

Since the beginning of the 'Janus' opiate project in Basel in which severely opiate-dependent persons are treated intravenously with heroin, morphine or methadone 11 from 160 participants (to november 1995) were treated in the withdrawal and intervention unit at the psychiatry clinic of the university of Basel. 7 patients sought a total, 4 a partial withdrawal. Whereas the 4 patients wanting withdrawal from consumption of drugs in addition to study drugs all reached their goal 4 of the 7 persons aiming at total withdrawal interrupted treatment prematurely. The 3 patients who were successful are-as far as the authors know-still off opiates. Substitution of intravenous opiates provided by 'Janus' with oral methadone and slow tapering off of the latter over days to weeks occurred mostly without problems. Participants of the 'Janus' project thus desired a withdrawal oriented treatment with equal frequency and had not less success than persons substituted with oral methadone in achieving this goal.

Differences in some behavioural effects of deprenyl and amphetamine enantiomers in rats

Effects of deprenyl and amphetamine enantiomers on different behavioural patterns were compared. Whereas (+)-amphetamine in doses of 1-3 mg/kg SC, (-)-amphetamine, and (+)-deprenyl in doses of 5-20 mg/kg SC increased the locomotor activity and the time the animals displayed stereotyped head movement, enhanced the acquisition of conditioned avoidance responses, and developed positive place preference conditioning, (-)-deprenyl, even in as high a dose as 20 mg/kg SC, failed to show any amphetamine-type behavioural effect. The results provide further proof why (-)-deprenyl, in contrast to other members of the amphetamine family, can be considered as a safe drug.

Phenylethylamine and tyramine are mixed-acting sympathomimetic amines in the brain

On the helical strip of a capacitance vessel, the pulmonary artery of the rabbit, phenylethylamine (PEA) and tyramine act solely via displacement of noradrenaline from their storage sites and this effect is inhibited by desmethylimipramine (DMI). In contrast, on a resistance vessel, the perfused central ear artery of the rabbit, PEA enhances stimulation induced contractions in 0.2-0.8 microgram/ml concentration [catecholaminergic activity enhancer (CAE) effect], and increases smooth muscle tone (noradrenaline displacing effect) in 4-6 micrograms/ml concentration. This latter effect only is blocked by DMI. Tyramine acts similarly and is more potent than PEA. On the isolated brain stem PEA, tyramine and (-)methamphetamine are, in the presence of cocaine and DMI, highly potent enhancers of stimulation induced release of 3H-noradrenaline, 3H-dopamine and 3H-serotonin. Compounds with specific CAE effect in the brain, (-)deprenyl and 1-phenyl-2-propylaminopentane [(-)PPAP], antagonize tetrabenazine-induced depression of performance of rats in the shuttle box. PEA and tyramine, which are rapidly metabolized in vivo, are ineffective in this test up to 40 mg/kg, whereas (-)methamphetamine, the stable PEA derivative, is highly effective. Compounds with CAE effect enhance at low concentrations the slow inward Ca2+ current in the sino-auricular fibers of the frog heart and inhibit it in high concentration. PEA and tyramine enhance Ca2+ influx from 0.05 to 4 micrograms/ml and inhibit it in 8 micrograms/ml. In conclusion, PEA and tyramine stimulate primarily coupling of action potential to transmitter release in the catecholaminergic neurons in the brain and displace catecholamines in higher concentration only.

(-)Deprenyl and (-)1-phenyl-2-propylaminopentane, [(-)PPAP], act primarily as potent stimulants of action potential-transmitter release coupling in the catecholaminergic neurons

The activity of the catecholaminergic neurons in the rat brain is enhanced significantly 30 min after the subcutaneous injection of very small doses of (-)deprenyl (threshold doses: 0.01 mg/kg for noradrenergic neurons and 0.025 mg/kg for dopaminergic neurons). As a catecholaminergic activity enhancer (CAE) substance (-)deprenyl is about ten times more potent than its parent compound, (-)methamphetamine. While the (+)methamphetamine is 3-5 times more potent than (-)methamphetammine in releasing catecholamines, the (-)methamphetamine is the more potent CAE substance. The mechanism of the CAE effect of (-)deprenyl and (-)PPAP, a deprenyl-derived substance devoid of MAO inhibitory potency, was studied in rats by measuring: a) the release of catecholamines from striatum, substantia nigra, tuberculum olfactorium and locus coeruleus; b) the stimulation induced release of 3H-noradrenaline from the isolated brain stem; and c) the antagonistic effect against tetrabenazine-induced depression of learning in the shuttle box. The CAE effect was found to be unrelated: a) to the inhibition of MAO activity; b) to the inhibition of presynaptic catecholamine receptors; c) to the inhibition of the uptake of catecholamines; and d) to the release of catecholamines. It was concluded that (-)deprenyl and (-)PPAP act primarily as potent stimulants of action potential-transmitter release coupling in the catecholaminergic neurons of the brain. We show that both (-)deprenyl and (-)PPAP enhance the inward Ca2+ current in sino-auricular fibers of the frog heart. (-)PPAP was much more potent than either (+)PPAP or (-)deprenyl in this test.

High performing rats are more sensitive toward catecholaminergic activity enhancer (CAE) compounds than their low performing peers

Two breeds of rats, Charles River Wistar [Crl(Wi)Br.] and HSD Wistar [Wistar per LATI (Budapest) Br.], with remarkable difference in learning performance were selected. The rats were trained in the shuttle box with 100 trials per day and the number of conditioned avoidance responses (CARs), the escape failures (EFs) to the unconditioned stimulus and the intersignal reactions (IRs) were counted and evaluated by multi-way analysis of variance (ANOVA). Rats of the Crl (Wi) breed proved to be the 'low performing' (LP) animals and rats of the Wistar per LATI (Budapest) breed the 'high performing' (HP) ones. The HP rats produced higher number of CARs (p<0.001), lower number of EFs (P<0.05) and higher number of IRs (P<0.01) than their LP peers. Significantly higher amounts of noradrenaline from the locus coeruleus and serotonin from the raphe were released in the HP than in the LP rats (p<0.01). There was no difference between HP and LP rats in the amount of dopamine released from the striatum, the substantia nigra and the tuberculum olfactorium. The catecholaminergic activity enhancer (CAE) substance, 1-phenyl-2-propylaminopentane HCl, [(-)PPAP], which enhances action potential-transmitter release coupling in the catecholaminergic neurons, fully antagonized in a dose of 1 mg/kg, tetrabenazine-induced learning depression in HP rats and this dose was ineffective in LP rats. The findings were regarded as further support for the view that endogenous CAE substances regulate catecholaminergic activity in the brain and (-)PPAP acts via this regulation.

The pharmacology of 1-phenyl-2-propylamino-pentane (PPAP), a deprenyl-derived new spectrum psychostimulant

The peculiar tyramine uptake inhibitory effect of (-)deprenyl prompted structure-activity relationship studies aiming to develop new spectrum central nervous system stimulants which are devoid of MAO inhibitory potency and operate de facto as indirectly acting, nonreleasing sympathomimetics. Of the derivatives synthesized for this purpose, 1-phenyl-2-propylaminopentane (PPAP) was selected as the reference substance and its pharmacological spectrum is presented. PPAP is taken up by the catecholamine axon terminal membrane and the vesicular membrane but it is devoid of catecholamine-releasing property. As a result, PPAP is, by interference, a potent inhibitor of the uptake of indirectly acting sympathomimetic releasers and of the catecholamine transmitters. This was proved, on the one hand, by measuring the uptake of [14C]PPAP into the catecholaminergic axon terminals and the inhibition of the uptake of [3H]noradrenaline and [3H]dopamine by PPAP in the rat brain, and, on the other hand, on the pulmonary artery strip of the rabbit and, in vivo, using the rat nictitating membrane as a detector. PPAP increases motility at 2 mg/kg and, in contrast to amphetamine, inhibits it at very high doses (50 mg/kg) only. A two-sided antagonism in the motility-increasing effect between PPAP and amphetamine and, more pronounced, between PPAP and mazindol was detected. PPAP is substantially less effective in inducing stereotyped behavior than either amphetamine or methamphetamine. PPAP facilitates learning and retention, is highly potent in antagonizing the tetrabenazine-induced depression in behavioral tests and is very effective in the forced swimming test. Whereas amphetamines facilitate performance in a very narrow range of low doses, which turns, at a modest elevation of the dose, into the opposite effect, PPAP improves performance within a reasonably broad dose range. Based on the peculiar pharmacological profile of PPAP, its potential usefulness in depression, in Alzheimer's disease and in attention-deficit-hyperkinetic disorder seems to be plausible.

(-)Deprenyl (selegiline) is devoid of amphetamine-like behavioural effects in rats

Central effects of high dose (-)deprenyl (50-100 mg/kg sc) was compared to that of (+)deprenyl and (+/-)amphetamine (AM). (+)Deprenyl and AM induced stereotyped behaviour, increased spontaneous motility in smaller and decreased it in higher doses, inhibited escape behaviour and shuttle-box avoidance. (-)Deprenyl failed to possess any of these effects, providing further evidence that AM-type metabolites have no share in the action of (-)deprenyl.

The effect of (-) deprenyl (selegiline) on different behavioral changes induced by dopamine agonists in the rat

The effect of (-) deprenyl was investigated both on the stereotyped behavior and on other types of activities induced by various dopamine (DA) agonists. (-) Deprenyl was given in a single dose, 1 h prior to the DA agonists. 1-2 mg/kg sc (-) deprenyl decreased the stereotypy induced by amphetamine (AMPH, 2.5 mg/kg sc), but 20 mg/kg was needed to reduce the stereotypy-inducing effect of apomorphine (APO, 0.3 mg/kg sc). The stereotypy-inducing effect of phenyl-ethyl-amine (PEA, 40 mg/kg sc) was significantly enhanced by 0.25 mg/kg sc (-) deprenyl pretreatment. The PEA or AMPH-induced increase in the horizontal activity (locomotion) and the vertical activity (rearing) remained unchanged after a single dose of (-) deprenyl, showing that this drug acts primarily on the nigro-striatal dopaminergic system.

Serotonin-mediated behavior in rats chronically treated with (-) deprenyl

(-) Deprenyl given in small (0.25 mg/kg) daily doses for 30 days to rats left the serotonin (5-HT) and the 5-hydroxyindoleacetic acid (5-HIAA) levels in the striatum unchanged. The postsynaptic 5-HT receptor responsiveness, as measured with 5-methoxy-N,N-dimethyl-tryptamine (5-MeODMT), remained also unaltered. In (-) deprenyl-treated rats the p-chloroamphetamine (PCA)-induced 5-HT syndrome was significantly increased and this enhancement of the PCA effect was not abolished by the reserpine-induced depletion of the 5-HT stores.

Long-term administration of (-)deprenyl (selegiline), a compound which facilitates dopaminergic tone in the brain, leaves the sensitivity of dopamine receptors to apomorphine unchanged

The effect of repeated administration of the MAO-B enzyme blocker (-)deprenyl on the apomorphine (APO) sensitivity of dopamine (DA) receptors was investigated in rats, and compared to the effect of other drugs influencing the dopaminergic system. APO was given either in a high dose (0.1-0.6 mg/kg), which induces stereotyped behaviour or in a smaller one (0.02 mg/kg) causing sedation. Repeated administration of all the other drugs investigated (except (-)deprenyl), i.e. haloperidol, d-amphetamine, (1 mg/kg s.c., respectively) and the MAO-A blocker clorgyline (0.25 mg/kg s.c.) altered the efficiency of APO on the stereotypy. Haloperidol, clorgyline (0.5 mg/kg s.c.) and imipramine (10 mg/kg i.p.) attenuated the APO-sedation. The long-lasting administration of (-)deprenyl (0.25 mg/kg s.c., daily for 42 days) however, left the effects of APO unchanged, demonstrating that (-)deprenyl facilitates the dopaminergic tone in the rat brain without altering the sensitivity of DA receptors.

The effect of repeated administration of (-) deprenyl on the phenylethylamine-induced stereotypy in rats

Phenylethylamine (PEA) in a dose of 40 mg/kg induces a moderate and short-lasting stereotype behaviour. The intensity and duration of PEA-induced stereotypy was strongly potentiated in rats with single selective doses of (-) deprenyl and J-508 (0.25 and 0.1 mg/kg s.c., respectively), which inhibit selectively the B form of MAO. Neither the increase of the single dose nor the daily administration of the selective doses of (-) deprenyl and J-508 for eight weeks caused a more intense or longer lasting potentiation of the PEA effect than single small dose of these drugs. Stopping administration of MAO-B inhibitors, normal sensitivity towards PEA returned after 3-4 weeks, in a parallel way with the recovery of MAO-B activity in the brain. Clorgyline, the selective inhibitor of MAO-A failed to influence the effect of PEA (0.25-2 mg/kg s.c.). The data support the view that the strong potentiation of the stimulatory effects of endogenous PEA via inhibition of its metabolism by (-) deprenyl may play a role in the antidepressant effect of this drug in man.

The anorectic effect of satietin is unrelated to carbohydrate metabolism

The effect of satietin and amphetamine on the carbohydrate metabolism of free fed and food deprived rats was studied. Rats deprived of food for 96 hours maintained normal glucose and glucagon blood levels but the blood concentration of insulin dropped from 232.02 +/- 23.93 to 12.48 +/- 0.71 pmol/l. Amphetamine (500 micrograms/animal, intracerebroventricularly) left in normally fed rats the blood concentration of glucose, insulin and glucagon unchanged. The same treatment, however, increased the insulin concentration in the blood of food deprived rats from 11.37 +/- 4.43 to 73.47 +/- 8.29 pmol/l. Glucose and glucagon, as well as insulin levels remained unchanged in both normally fed and food deprived rats when treated with satietin (20 micrograms/rat, intracerebroventricularly). It was concluded that the anorectic effect of satietin is unrelated to carbohydrate metabolism.

Comparative study of intravenous, nasal, oral and buccal TRH administration among healthy subjects

Four different modes of TRH application (400 micrograms iv, 1 mg nasal, 10 mg buccal and 40 mg oral) were investigated in young healthy subjects for evaluation of thyrotropin (TSH) and prolactin (PRL) stimulation. Plasma TSH, PRL, T4, T3, thyroxine-binding-globulin (TBG) were measured by radioimmunoassay. There were significant increases of TSH and PRL following TRH stimulation by all test forms. Bolus injection of TRH led to maximal TSH and PRL plasma levels within 20 min to 30 min, compared with 30 min to 45 min following nasal administration. Buccal and oral application produced more prolonged TSH and PRL increases, achieving plateau levels after 120 min to 180 min. Stimulated PRL levels were higher in women than in men. Uniformity of PRL response was better after iv or nasal than buccal and oral TRH stimulation. Known side effects were lower after nasal than iv TRH application. Buccal and oral administration provoked no side effects. Nasal TRH application seems to be a well suited test form for TSH and PRL stimulation.

Synthetic tripeptides with anorexogenic effect

Thirty two synthetic tripeptides structurally related both to thyrotropin releasing hormone (TRH) and anorexogenic tripeptide (Glp-His-Gly-OH) were investigated for anorexogenic effect in rats. While the two endogenous peptides, TRH and Glp-His-Gly-OH, were ineffective in rats deprived of food for 96 hours when they were administered intracerebroventricularly, some of the synthetic analogues showed significant food intake reducing effect under the same conditions. This anorexogenic effect of the tripeptides is similar--though much weaker--to that of satietin, a highly potent anorexogenic glycopeptide in human and mammalian serum. These tripeptides were ineffective when they were administered intravenously.

Effects of selective monoamine oxidase (MAO) inhibitors on conditioned avoidance responses (CAR) of rats

Dopamine (DA) insufficiency in the ipsilateral corpus striatum produced by unilateral electrolytic lesion of the substantia nigra (SN) resulted in an impairment in rats' behavior as tested by one-way and two-way avoidance techniques. Selective MAO-A inhibitor, clorgyline (1 mg/kg sc daily for 7 days), improved the reduced learning capacity of SN lesioned animals, restored the decreased DA content in the corpus striatum, and caused significant hyperactivity as tested in the open field. At the same time the selective MAO-B inhibitor (-)deprenyl (injected the same way) proved to be ineffective. J-508, a selective MAO-B inhibitor, used in a non-selective dose (1 mg/kg), acted like clorgyline. The results support the hypothesis that in the rat nigrostriated system (but not in human beings) DA is preferentially deaminated by the A form of MAO.

The effect of selective MAO inhibitors on the conditioned avoidance response of Wistar rats

Behavioral and biochemical effects of 1-deprenyl and clorgyline were studied in Wistar rats. Behavioral performances was tested in a one-way and in a two-way avoidance system. The two MAO inhibitors were given acutely (1 and 10 mg/kg sc) anc chronically (1 mg/kg sc/daily, for 7 days), and their influences on learning and retention performance was tested 24 hr after the last injection. Behavioral reactions remained unchanged after acute administration of the inhibitors, while they were significantly improved following the chronic treatments, either in the one-way or in the two-way experimental situation. Biochemical analysis indicated dissociation between the influence on striatal dopamine content and the behavioral effects of 1-deprenyl and clorgyline.