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A Pinna

Publications and source records attributed to A Pinna.

At least 73 records · Page 4Linked to original sources

Role of vesicular dopamine in the in vivo stimulation of striatal dopamine transmission by amphetamine: evidence from microdialysis and Fos immunohistochemistry.

The role of vesicular and newly synthesized dopamine in the action of amphetamine was investigated by studying the effect of reserpine and alpha-methyl-p-tyrosine pretreatment on amphetamine-induced changes in extracellular dopamine and acetylcholine, estimated by brain microdialysis, and on c-fos expression, estimated by quantitative immunohistochemistry of the Fos antigene, in the dorsal caudate-putamen of rats. Blockade of dopamine synthesis by alpha-methyl-p-tyrosine pretreatment (1 or 2 h) only partially prevented the increase in extracellular dopamine concentrations elicited by 0.5 and 2 mg/kg s.c. of amphetamine. Inactivation of vesicular amine uptake by reserpine pretreatment (3 h) reduced the increase in extracellular dopamine by 2 mg/kg but not by 0.5 mg/kg of amphetamine. Combined pretreatment with reserpine (3 h) and alpha-methyl-p-tyrosine (1 h) drastically reduced the increase in extracellular dopamine by both doses of amphetamine (0.5 and 2 mg/kg s.c.). alpha-Methyl-p-tyrosine pretreatment reduced c-fos expression stimulated by amphetamine (2 mg/kg) in the dorsomedial and dorsolateral caudate-putamen while reserpine pretreatment reduced it only in the dorsolateral caudate-putamen. Amphetamine (2 mg/kg s.c.) stimulated acetylcholine release but this effect was not modified by reserpine or alpha-methyl-p-tyrosine pretreatment. The results indicate that blockade of dopamine synthesis, by itself, is insufficient to prevent the stimulation of dopamine transmission by amphetamine and, conversely, that inactivation of vesicular dopamine significantly reduces amphetamine effects at pre- and postsynaptic levels. Therefore, vesicular dopamine appears to contribute to the stimulation of dopamine transmission elicited by amphetamine in the dorsal caudate-putamen.

Acetylcholine↗

Adenosine A2 receptors stimulate c-fos expression in striatal neurons of 6-hydroxydopamine-lesioned rats.

The induction of the early-gene c-fos after administration of the adenosine A2a receptor agonist CGS 21680, was studied in the striatum of normal rats or in rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal neurons. CGS 21680 (2.25 mg/kg) induces c-fos expression in the 6-hydroxydopamine-lesioned striatum, while up to 40 mg/kg fails to induce c-fos in the intact striatum or in the striatum of normal rats. Blockade of muscarine receptors by scopolamine (5 mg/kg) partially prevents, and stimulation of dopamine D2 receptors by quinpirole (0.5 mg/kg) completely reverses, CGS 21680-induced c-fos expression in the 6-hydroxydopamine-lesioned striatum. In turn, CGS 21680 partially reverses c-fos expression induced by quinpirole in the lesioned globus pallidus. CGS 21680, in addition, dose-dependently reduces the turning behavior induced by quinpirole (0.5 mg/kg) in 6-hydroxydopamine-lesioned rats. The results suggest that CGS 21680 induces c-fos expression in the striatum through direct and indirect mechanisms related to the ability of A2a receptors to stimulate cyclic AMP formation or acetylcholine release which in turn would activate c-fos through muscarinic receptors.

Adenosine↗

Susceptibility of Acanthamoeba castellanii to contact lens disinfecting solutions.

A corneal isolate of Acanthamoeba castellanii was exposed to commercial contact lens disinfecting solutions containing hydrogen peroxide, benzalkonium chloride, polyaminopropyl biguanide, polyquaternium 1, and chlorhexidine-thimerosal. The minimum trophozoite amebicidal concentration and exposure times required to kill trophozoites and cysts were determined. Solutions containing hydrogen peroxide or chlorhexidine-thimerosal were active against both trophozoites and cysts. The benzalkonium chloride-based solution was effective only against trophozoites. Solutions containing polyaminopropyl biguanide or polyquaternium 1 were completely ineffective. The need for adequate exposure times must be stressed.

Acanthamoeba↗

Adenosine A2 receptors interact negatively with dopamine D1 and D2 receptors in unilaterally 6-hydroxydopamine-lesioned rats.

In rats bearing a unilateral 6-hydroxydopamine lesion of the dopaminergic nigro-striatal pathway, stimulation of adenosine A2 receptors by CGS 21680 reduced the contralateral turning behavior induced by L-3,4-dihydroxyphenylalanine (L-DOPA). Administration of CGS 21680 completely blocked the contralateral turning induced by the dopamine D1 receptor agonist, SKF 38393, and reduced the turning induced by the dopamine D2 receptor agonist, LY 171555. Quinolinic acid lesion of the striatum or 6-hydroxydopamine lesion of the dopaminergic nigro-striatal neurons demonstrated that [3H]CGS 21680 binding sites are associated to striatal intrinsic neurons. This study provides evidence for a negative postsynaptic interaction of both dopamine D1 and D2 receptors with adenosine A2 receptors.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

Differential effect of MK 801 and scopolamine on c-fos expression induced by L-dopa in the striatum of 6-hydroxydopamine lesioned rats.

In rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigro-striatal pathway, striatal D1-receptor-stimulated c-fos expression and turning behavior are positively modulated by D2 receptor stimulation and by blockade of N-methyl-D-aspartate (NMDA) or muscarinic receptors. Combined D1/D2 receptor stimulation by L-dopa activates c-fos in a manner not additive with muscarinic receptor blockade by scopolamine. On the other hand, blockade of NMDA receptors by MK 801 reduced c-fos expression induced by L-dopa while, depending on the dose of L-dopa, differentially affecting contralateral turning behavior. The results are interpreted to suggest that D2 receptor stimulation amplifies D1-receptor-mediated c-fos expression by two mechanisms differentially related to muscarinic and NMDA receptors.

Animals↗

The treatment and follow up of adult chlamydial ophthalmia.

Sixty two patients diagnosed as having adult chlamydial ophthalmia were treated with oral doxycycline and roxithromycin in association and tetracycline eye wash for 2 weeks. Chlamydial ophthalmia was diagnosed by laboratory detection of the micro-organism in ocular specimens using direct immunofluorescent monoclonal antibody staining for Chlamydia trachomatis, chlamydial culture in cycloheximide treated McCoy cells, and Giemsa staining. An immunoenzymatic method for detection of specific IgG and IgA in patients' serum was used as an additional test to confirm the diagnosis. All patients were reexamined 3 weeks after completing their course of antibiotics and in the case of persistent infection a further course of treatment was given. With this treatment regimen 48 out of 62 patients (77.4%) were cured after three courses. Because of the risks of an inadequate response to therapy, we recommend a proper post-treatment follow up in all patients with chlamydial eye infections.

Administration, Oral↗

Dissociation between in vitro cytotoxicity and in vivo cardiotoxicity of two new anthracyclines: 3'-deamino-3'-(2-methoxy-4-morpholinyl)doxorubicin and 4'-deoxy-4'-iodo-doxorubicin.

The purpose of this study was to examine the cytotoxicity and cardiotoxicity of new doxorubicin (DXR) derivatives, 3'-deamino-3'-(2-methoxy-4- morpholinyl)DXR (MRA-MT), and 4'-deoxy-4'-iodo-doxorubicin (IDXR), comparing them to doxorubicin (DXR). Both anthracycline derivatives were approximately 1.5- to 9-fold more active than DXR in inhibiting the colony-formation ability of DU145, HOS, and A2780 human cancer cell lines. Anesthetized rats given a single intravenous (i.v.) dose of DXR 10 mg/kg showed significant changes in both ECG (S alpha T segment and QRS complex widening) and hemodynamic parameters (impairment in systemic arterial dP/dtmax systolic and diastolic blood pressure), whereas animals that received MRA-MT (0.1 and 0.3 mg/kg) had no significant signs of acute cardiotoxicity. In this case the animals treated with IDXR 1.2 mg/kg showed alterations in the ECG as the animals treated with DXR. In the chronic cardiotoxicity study, some animals received MRA-MT (0.03 mg/kg i.v. once a week for 3 weeks) and others IDXR (4 mg/kg once a week for 3 weeks). They did not show any alteration in ECG and cardiac histological picture. By contrast, DXR (3 mg/kg i.v. once a week for 3 weeks) induced a severe cardiomyopathy, characterized by progressive widening of S alpha T segment, increase in T wave, and histological damage consisting of vacuolations and loss of myofibrils. These results suggest that MRA-MT and IDXR are more active in vitro and markedly less cardiotoxic in vivo than DXR.

Analysis of Variance↗

[Intermittent exotropia: evaluation of results on the basis of different treatments].

The aim of the study is to evaluate the results obtained in treatment of Intermittent Exotropia with the therapeutic programme applied at the Orthoptic Centre of Sassari Oculist Clinic. 250 patients were considered; 176 completed treatment. The patients were divided into four groups according to the kind of treatment adopted: orthoptic exercises, surgery (double recession of lateral rectus), exercises and surgery, no therapy. Results were evaluated by measuring the acquired state of orthophoria or residual exotropia: less than 10 prismatic diopters (excellent result); residual exotropia between 11 and 20 prismatic diopters (unsatisfactory result); residual exotropia > 20. The highest percentage of excellent results was found in those patients who underwent surgery but only among those who completed the therapy with cycles of orthoptic exercises. Conversely, the worst results were evident in patients who followed no therapeutic programme.

Adolescent↗

L-dopa stimulates c-fos expression in dopamine denervated striatum by combined activation of D-1 and D-2 receptors.

Administration of L-dopa to unilaterally 6-hydroxydopamine-lesioned rats, activates the early gene c-fos in the lesioned caudate-putamen. D-1 receptor blockade by SCH 23390, prevented L-dopa-induced Fos-like immunoreactivity in the whole caudate-putamen, while D-2 receptor blockade by raclopride reduced Fos-like immunoreactivity only in the dorso-lateral portion. The results suggest that L-dopa induces c-fos primarily through an activation of D-1 receptors, while D-2 receptor stimulation plays a facilitatory influence on D-1-mediated c-fos expression.

Animals↗

Percutaneous transhepatic embolization of an intrahepatic pseudoaneurysm following liver biopsy in a liver transplant patient.

A 41-year-old liver transplant patient had severe hemobilia from an intrahepatic pseudoaneurysm secondary to a liver biopsy. Selective intra-arterial embolization was not technically possible due to marked redundancy and tortuosity of the allograft hepatic artery. The pseudoaneurysm was localized by ultrasound and embolized using a direct percutaneous transhepatic approach. This is a novel way of approaching hemobilia in liver transplant patients after liver biopsy and may avoid the risks of arterial embolization.

Adult↗

Stimulation of dopamine transmission in the dorsal caudate nucleus by pargyline as demonstrated by dopamine and acetylcholine microdialysis and Fos immunohistochemistry.

The effect of pargyline on dopamine neurotransmission was investigated by trans-striatal microdialysis combined with Fos immunohistochemistry. Pargyline, 75 mg/kg i.p., increased dopamine and acetylcholine output while drastically decreased dopamine deaminated metabolites. Administration of pargyline resulted in the appearance of Fos-positive nuclei distributed along a gradient around the dialysis probe. Pretreatment with the D1 antagonist SCH 23390 potentiated the effect of pargyline on dopamine output while preventing that on acetylcholine output and on Fos formation. Similarly, lack of calcium in the perfusion medium abolished the effect of pargyline on dopamine and acetylcholine output and on Fos formation. In rats not implanted with dialysis probes pargyline administration resulted in only rare Fos-positive nuclei in the dorsal caudate. The present study indicates that pargyline stimulates dopamine transmission in the dorsal caudate in the area around the dialysis probe but not distant from the fibre or in unimplanted rats. This effect appears to reflect an interaction between the drug-induced changes and those locally elicited by the probe.

Acetylcholine↗

Blockade of muscarinic receptors potentiates D1 dependent turning behavior and c-fos expression in 6-hydroxydopamine-lesioned rats but does not influence D2 mediated responses.

In rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal pathway, blockade of muscarinic receptors by scopolamine potentiates the contralateral turning induced by selective dopaminergic D1 agonists (SKF 38393, A 68930), but does not influence the contralateral turning induced by the D2 agonist LY 171555. Studies on the expression of the early gene c-fos as reflected by the immunohistochemical demonstration of the Fos protein, show that administration of scopolamine (5 mg/kg, i.p.) potentiates c-fos expression elicited by SKF 38393 (1.5 mg/kg, s.c.) in the caudate-putamen of the lesioned side. The results indicate that cholinergic transmission is differentially involved in the behavioral expression of D1 versus D2 receptor stimulation in a denervated condition and suggest that blockade of central cholinergic transmission might be useful in improving the antiparkinsonian efficacy of D1 receptor agonists.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

Combined microdialysis and Fos immunohistochemistry for the estimation of dopamine neurotransmission in the rat caudate-putamen.

Extracellular dopamine (DA) concentrations estimated by transcerebral dialysis and D1-dependent c-fos expression, as demonstrated by Fos immunohistochemistry, were studied after blockade of DA reuptake by GBR-12909. Rats implanted with dialysis probes in the dorsal caudate-putamen did not show any Fos-positive neuronal labeling in the implanted area or in the rest of the caudate-putamen. Administration of GBR-12909 dose-dependently increased DA output in dialysates and resulted in the appearance in the caudate-putamen of Fos-positive neurons whose density was related to the dose of GBR-12909 and to the increase in extracellular concentrations of DA. The D1 antagonist SCH-23390 blocked GBR-12909-induced activation of Fos while potentiating the stimulation of DA output. The results show that following blockade of DA reuptake by GBR-12909, the induction of Fos is related to stimulation of D1 receptors by extracellular DA. Combination of brain dialysis with Fos immunohistochemistry might provide a method for estimating the functional significance of extracellular DA as measured by brain microdialysis.

Animals↗