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A Yassouridis

Publications and source records attributed to A Yassouridis.

50 records · Page 3Linked to original sources
PubMed1994

Oxytocin-stimulated release of adrenocorticotropin from the rat pituitary is mediated by arginine vasopressin receptors of the V1b type.

Previous work showed the existence of receptors for arginine vasopressin (AVP) in the anterior pituitary; these receptors were classified as belonging to a distinct AVP receptor subtype, referred to as AVP-V1b receptors, and are thought to mediate the well documented ACTH-releasing activity of AVP. In the present work, high affinity receptors for another neurohypophyseal hormone, oxytocin (OT), were also shown to be present within the rat anterior pituitary; to this end, [125I]d(CH2)5[Tyr(Me)2Thr4Tyr-NH2(9)]OVT was used as a ligand in receptor binding studies. Experiments on dispersed rat anterior pituitary cells in a superfusion system confirmed earlier reports that OT acts as an additional secretagogue of ACTH, with significant effects first seen at concentrations as low as 1 nM. Further studies addressed the question of whether stimulation of ACTH release is mediated by OT receptors or whether receptors for AVP (V1b receptors) might serve this role. For this, highly selective agonist and antagonist ligands of the OT receptor and nonselective agonist and antagonist ligands of the V1b receptor were employed. Neither the OT receptor agonist Thr4Gly7OT nor the OT receptor antagonist des-Gly(NH2)9d(CH2)5-[Tyr(Me)2 Thr4]OVT displayed any influence on basal ACTH release, and des-Gly(NH2)9d(CH2)5-[Tyr(Me)2Thr4]OVT did not interfere with OT-induced ACTH release; these results indicated that OT promotes ACTH release through a receptor(s) other than the OT receptor itself. Evidence for the involvement of AVP V1b receptors was provided by the observation that the AVP receptor antagonist dP[Tyr(Me2)]AVP completely abolished OT-elicited increases in ACTH release. Thus, AVP V1b receptors mediate the actions of two structurally related peptides on ACTH secretion; the role of OT receptors in adenohypophyseal function remains to be determined.

Adrenocorticotropic Hormone↗
PubMed1993

Local analgesic effect of endogenous opioid peptides.

Opioids produce analgesia by interacting with local opioid receptors in peripheral inflamed tissue. This study investigated whether endogenous ligands of these receptors are present in synovia and whether such opioid peptides can inhibit pain by activation of intra-articular opioid receptors. Samples of synovium from 8 patients undergoing arthroscopic knee surgery were examined by immunohistochemistry for the presence of beta-endorphin, met-enkephalin, and dynorphin. All tissue samples showed synovitis. Inflammatory cells stained strongly for beta-endorphin and met-enkephalin but not for dynorphin. To find out whether blockade of intra-articular opioid receptors affected pain, we randomly assigned 22 patients undergoing arthroscopic knee surgery to receive naloxone (0.04 mg) intra-articularly (n = 10) or intravenously (n = 12); each patient received a placebo injection into the other site. Postoperative pain was assessed by visual analogue scale, a numerical rating scale, the McGill pain questionnaire, and supplementary analgesic consumption during the next 24 h. All pain scores were higher in the intra-articular naloxone group than in the intravenous naloxone group. The differences were significant (p < 0.05) during the first 4 h. Supplementary analgesic consumption was significantly higher in the intra-articular group (52.5 [14.0] vs 15.6 [8.0] mg diclofenac, p < 0.05). Opioid peptides are present in inflamed synovial tissue and can inhibit pain after knee surgery through an action specific to intra-articular opioid receptors. These findings expand the gate control theory of pain and suggest new approaches such as the development of peripherally acting opioid analgesics without central side-effects.

Adult↗
PubMed1993

Calculating paternity probabilities from DNA multilocus fingerprints in some cases of deficiency.

Paternity determination via DNA multilocus fingerprints in normal trio cases, namely when the fingerprints of the trio mother, child and putative father are available, is performed on a routine basis. But in cases of deficiency, where the DNA fingerprint of mother or putative father is missing, there exists no systematic, analytical way for paternity calculations, even in cases where DNA fingerprints of other persons related to the missing individual are available. The aim of this paper is to establish a mathematical, analytical background, that enables paternity calculations in cases of deficiency if complementary information can be obtained from the DNA fingerprints of at least one of the parents of the missing individual. Using the basic outline of our previously described procedure, the formulas for paternity calculations also allow mutations.

Chromosome Mapping↗
PubMed1991

Analgesic effect of intraarticular morphine after arthroscopic knee surgery.

BACKGROUND: Opioids can produce potent antinociceptive effects by interacting with local opioid receptors in inflamed peripheral tissue. In this study we examined the analgesic effects of the intraarticular, as compared with intravenous, administration of morphine after arthroscopic knee surgery. METHODS: In a double-blind, randomized trial, we studied 52 patients who had received one of four injections at the end of surgery. The patients in group 1 (n = 18) received 1 mg of morphine intraarticularly and saline intravenously; those in group 2 (n = 15), saline intraarticularly and 1 mg of morphine intravenously; those in group 3 (n = 10), 0.5 mg of morphine intraarticularly and saline intravenously; and those in group 4 (n = 9), 1 mg of morphine and 0.1 mg of naloxone intraarticularly and saline intravenously. The volume of the intraarticular injections was 40 ml, and that of the intravenous injections was 1 ml. After 1, 2, 3, 4, 6, and 24 hours, postoperative pain was assessed with a visual-analogue scale, a numerical-rating scale, and the McGill pain questionnaire. The need for supplemental analgesic agents, the patients' vital signs, and the occurrence of side effects were monitored. RESULTS: All pain scores were lower in group 1 than in group 2 at all times. The differences were significant (P less than 0.05) at three, four, and six hours (mean [+/- SD] visual-analogue score at six hours, 9 +/- 13 mm vs. 37 +/- 31 mm). The mean (+/- SD) consumption of supplemental analgesic medication per 24 hours was significantly lower in group 1 (36 +/- 51 mg of diclofenac and 1.2 +/- 3.4 mg of meperidine) than in group 2 (75 +/- 42 mg of diclofenac and 14 +/- 18 mg of meperidine, P less than 0.05). The visual-analogue scores in group 3 were slightly but not significantly higher than those in group 1 at all times except 6 and 24 hours after injection. The visual-analogue scores were significantly higher in group 4 than in group 1 one to four hours after injection (P less than 0.05), indicating that the analgesic effect of intraarticular morphine was reversible by naloxone. CONCLUSIONS: Low doses of intraarticular morphine can significantly reduce pain after knee surgery through an action specific to local opioid receptors that reaches its maximal effect three to six hours after injection.

Adult↗
PubMed1991

Treatment of benzodiazepine withdrawal symptoms with carbamazepine.

In 18 patients with a benzodiazepine (BZD) dependency the drug was withdrawn. The dose of BZD was gradually reduced in nine of the patients, while the others were additionally treated with carbamazepine (CBZ) for a further 15 days after BZD discontinuation. Withdrawal symptoms were assessed every third day during the study period. When comparing results in both groups, a clear trend towards less severe withdrawal symptoms could be observed in the group treated with CBZ. Some of the differences were statistically significant on days 9-12 after BZD withdrawal. Fundamental withdrawal symptoms (like hypersensitivity to sensory stimuli, abnormal perception of movement, depersonalisation or derealisation) were also less severe in the group treated with CBZ compared with the group not receiving that treatment. These findings support the results of previous reports indicating a therapeutical effect of CBZ in BZD withdrawal.

Adult↗
PubMed1990

The influence of two behavioral regimens on the distribution of sleep and wakefulness in narcoleptic patients.

Thirty-two hours (night-day-night) of polygraphic recordings were performed on 14 patients with a diagnosis of narcolepsy-cataplexy. Half of the patients stayed in bed during the day, whereas the other half were seated at a table. Patients were free to nap whenever they wanted to. Patients under continuous bedrest slept 2-3 times more during the day than patients who were sitting at the table. Rapid-eye-movement (REM) sleep and slow-wave sleep (SWS, stages 3 and 4) were nearly absent during daytime sleep in the table group, but not in the bed group. The differential behavioral regimes during the day resulted in different amounts of SWS in the consecutive night sleep. Although SWS increased from the first to the second night in the table group, it decreased in the bed group. This result suggests that the presumably homeostatic regulation of SWS is intact in narcoleptic patients.

Adult↗
PubMed1989

Presynaptic auto- and allelo-receptor regulation of hypothalamic opioid peptide release.

Recent studies have shown that inhibitory feedback mechanisms regulate the release of the endogenous opioid peptides beta-endorphin (acting predominantly at mu opioid receptors in the brain), dynorphin (a kappa opioid receptor ligand) and [Met]enkephalin (a delta opioid receptor ligand) from the rat hypothalamus. By using specific antagonists of the various opioid receptor types, it is shown that the release of these peptides from hypothalamic slices in vitro is not only controlled by homologous (auto)-receptors, but that cross-regulation between the three neuronal opioid receptor types also occurs; thus, the delta receptor antagonist N,N-diallyl-Tyr-Aib-Aib-Phe-Leu increases the release of all three peptides, the mu receptor antagonist D-tetrahydroisoquinoline-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 increases that of beta-endorphin and dynorphin, and the kappa receptor antagonist nor-binaltorphimine increases that of dynorphin; all these effects occur in the presence of tetrodotoxin, indicating a presynaptic site of action. We propose the term "allelo-receptors" to describe this particular form of neuronal regulation in which an endogenous ligand, acting via its own specific receptor, also regulates the release of related peptides which activate different classes of opioid receptors.

Animals↗
PubMed1988

Antinociceptive effects of mu- and kappa-agonists in inflammation are enhanced by a peripheral opioid receptor-specific mechanism.

Rats received an injection of Freund's complete adjuvant into the right hindpaw and developed localized inflammation. Four to six days after inoculation, the antinociceptive effect of both the mu-agonist, morphine, and the kappa-agonist U-50,488H, administered subcutaneously, was markedly enhanced in the inflamed paws. This effect was dose dependently antagonized by low dose of intraplantar, but not subcutaneous or intravenous, (-)-naloxone. (+)-Naloxone was inactive. These data indicate that the enhanced antinociceptive effects of both agonists in inflammation are mediated by a peripheral, opioid receptor-specific mechanism.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1987

Antipsychotic effect of buprenorphine in schizophrenia.

The antipsychotic potency of the partial opiate agonist buprenorphine was evaluated in 10 neuroleptic-free schizophrenic patients suffering from frequent hallucinations, delusions, and severe formal thought disorders. Buprenorphine had a pronounced antipsychotic effect, which lasted about 4 hours, in patients with schizophreniform disorders (N = 4) and paranoid schizophrenia (N = 3).

Adult↗
PubMedDate not supplied

On paternity determination from multilocus DNA profiles.

Various approaches have been worked out to calculate the probability of paternity from DNA multilocus profiles. Despite promising results, the application and practicability of these approaches are often restricted (due to, e.g., the equality assumption of the a priori probabilities by using Bayes' theorem, no allowance of mutations, etc). Here we present two methods for paternity determination, one of which is an extension of the well-known procedure of Evett et al. J. Forens. Sci. Soc. 1988, 28, 249-254. These methods depend on fewer assumptions and therefore may be applied to a wide spectrum of disputed paternity cases.

DNA↗
PubMedDate not supplied

The combined dexamethasone/CRH test: a refined laboratory test for psychiatric disorders.

This report summarizes our extensive experience with the application of the DEX/CRH test to assess hypothalamic-pituitary-adrenal-system (HPA) alteration in patients with psychiatric disorders. The application of this combined dexamethasone suppression/CRH-challenge (DEX/CRH) test requires individuals to take 1.5 mg dexamethasone (DEX) at 23:00 h orally the previous night. On the day of the test, 100 micrograms human CRH are administered to the subjects under study at 15:00 h intravenously as a bolus, and blood samples for the determination of plasma cortisol and ACTH are drawn every 15 min from 14:00 h to 18:00 h. DEX/CRH-test results from 96 patients with major depression (MDE), 11 with a manic episode (MA), 9 with panic disorder (PD), 24 with a schizophrenic psychosis (SP), and 82 healthy control subjects served as the data base for this report. Three major conclusions can be drawn from statistical analysis of these data: 1. Psychiatric patients (n = 140), regardless of diagnostic classification, release significantly more cortisol and ACTH after DEX and additional CRH in comparison with age-matched controls. This hormonal release pattern (DEX CRH-test phenomenon) supports the assumption that psychiatric patients are prone to an altered glucocorticoid feedback regulation during the acute illness episode. This supports the notion that the DEX/CRH-test phenomenon constitutes a neuroendocrine sign of these various disorders and emphasizes the usefulness of the DEX/CRH test as a laboratory test to monitor the course of these disorders. 2. The sensitivity of the DEX/CRH test for MDE (about 80%) greatly exceeds that of the standard DST (1-2 mg of DEX), which has been reported to average about 44% in a meta-analysis of the literature data; in our sample the sensitivity of the DST was about 25%. 3. The sensitivity of the DEX/CRH test can be further increased to above 90% if subjects are clustered into four different age ranges: age < 35 years, age between 35 and 50 years, age between 50 and 70 years, and age above 70 years. 4. By reducing the time points of blood sampling for ACTH and cortisol to as few as five (15:00, 15:30, 15:45, 16:00, and 16:15 h), the DEX/CRH-test procedure becomes more convenient and more easily applicable without reducing its sensitivity.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Intravenous C-type natriuretic peptide augments behavioral and endocrine effects of cholecystokinin tetrapeptide in healthy men.

Given the anxiogenic effects of the type-B natriuretic peptide receptor agonist C-type natriuretic peptide (CNP) in rodents, we investigated the influence of CNP pretreatment upon the behavioral and endocrine action of the panicogen cholecystokinin tetrapeptide (CCK-4) in healthy men. In a randomized double-blind balanced design, 20 male volunteers were given an intravenous infusion of 300 microg of CNP vs. placebo followed by 25 microg of CCK-4. The behavior was assessed using panic, anxiety, and dissociation questionaires before the infusion and after the CCK-4 stimulus. Furthermore, the stress-sensitive hormones adrenocorticotropic hormone (ACTH), cortisol, and prolactin were measured. CNP pretreatment enhanced the anxiogenic and prodissociative effects of CCK-4 and significantly augmented the ACTH surge after CCK-4. However, no effect of CNP was seen upon panic symptoms. Our preliminary data support a role of type-B natriuretic peptide receptors in anxiety modulation in normal man.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Multi-locus DNA fingerprints using oligonucleotide probe (CAC)5/(GTG)5 in the Chinese population].

In order to test the practical applicability of oligonucleotide fingerprinting in China we have investigated unrelated individuals, family members and a pair of twins from the Beijing area using the probe (CAC)5/(GTG)5. Except for the monozygotic twins highly variable banding patterns were demonstrated as expected for the randomly selected individuals but also for the relatives. On the basis of an initial survey of 50 unrelated individuals the calculated probability for obtaining by chance two identical multilocus patterns is very small (less than 1.93 x 10(-13). Therefore it seems reasonable to conclude that like in caucasians, (CAC)5/(GTG)5 fingerprints are completely individual-specific also in this population. Therefore they have already been used successfully for identification purposes and paternity tests in many actual cases.

China↗