Role of D1 and alpha1 receptors in the enhanced locomotor response to dopamine D2-like receptor stimulation induced by repeated electroconvulsive shock

We previously reported that, in rats chronically treated with the antidepressant drug imipramine, the enhanced locomotor response to the D2-like receptor agonist quinpirole became less sensitive to the inhibitory effect of the D1 receptor antagonist SCH 23390 and more sensitive to the inhibitory effect of the alpha1 receptor antagonist prazosin. In this study, we show that in electroconvulsive shock-treated rats these antagonists behave in the opposite manner to that observed in imipramine-treated rats, with SCH 23390 being highly effective and prazosin ineffective in antagonizing the locomotor response to quinpirole. The possibility that these differences may reflect some of the clinical characteristics of these antidepressant treatments is discussed.

Clinical and EEG findings in eleven patients affected by mitochondrial encephalomyopathy with MERRF-MELAS overlap

A study of mitochondrial DNA disease was carried out on 12 members belonging to three generations of a family from northern Sardinia. On the basis of the diagnostic criteria currently used in the classification of mitochondrial diseases a typical MERRF-MELAS overlap phenotype was seen in 11 patients with the mtDNA tRNA(lys) mutation at nucleotide position 8356. Clinical and instrumental investigations (EEG in particular) were made. Patients were divided into two groups: severely and mildly affected cases. The follow-up was reported. The aim of this study was to identify, through EEG, the early signs of the disease. The EEG findings recorded during the clinical evolution allowed us to recognize four degrees of cerebral involvement, and could also suggest the prognosis.

[Anxious-excited depression: a mixed affective syndrome]

A mixed affective syndrome is described which meets the criteria for major depression but not those of the DSM III-R for a mixed state. The clinical picture is characterized by lack of motor retardation and fluent verbalization; the facial expression is animated and sometimes dramatic. Patients suffer considerably and are often tearful. They complain of inner tension and restlessness, racing thoughts and despair. Emotional lability and momentary irritability are observed. Insomnia occurs initially or with frequent early waking. Suicidal ideation occurs and makes the syndrome of concern in view of its impulsive nature. Antidepressants increase restlessness, insomnia, aggressiveness and the impulsiveness of suicidal ideation. Low-dose neuroleptics, lithium and anticonvulsivants are highly effective. A few sessions of ECT offer rapid improvement.

An AT-deletion causing a frameshift in the arylsulfatase A gene of a late infantile metachromatic leukodystrophy patient

A metachromatic leukodystrophy (MLD) patient affected with the late infantile form was found to be homozygous for an AT-deletion (2324delAT) in the arylsulfatase A gene. The mutation causes a frameshift at the beginning of exon 8 leading to an early termination codon. The parents and unaffected brother of the patient were heterozygous for the microdeletion. The mutation was not detected in another 31 MLD Italian patients. No aberrant transcript caused by the mutation was revealed by the reverse transcription-polymerase chain reaction method.

Biochemical and electrophysiological effects of 7-OH-DPAT on the mesolimbic dopaminergic system

Systemic administration of the putative selective D3 receptor agonist 7-hydroxy-2-(N,N-di-n-propylamino)tetralin (7-OH-DPAT) consistently decreased extracellular dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the nucleus accumbens and dopaminergic neuronal activity in the ventral tegmental area. 7-OH-DPAT inhibited dopamine release in the nucleus accumbens also when locally perfused through the dialysis probe. The results suggest the possibility that stimulation of dopamine D3 receptors with 7-OH-DPAT mimic biochemical and electrophysiological actions previously ascribed to D2 autoreceptor stimulation; however the lack of selective D3 antagonist precludes any firm conclusion in this sense.

Reduced serum levels of dehydroepiandrosterone sulphate in adrenal incidentalomas: a marker of adrenocortical tumour

BACKGROUND AND OBJECTIVE

Reduced serum levels of dehydroepiandrosterone sulphate (DHEAS) have been shown in patients with Cushing's syndrome resulting from adrenocortical adenoma, in contrast with normal DHEAS levels in patients with Cushing's disease. The aim of this study was to verify whether patients with incidentally discovered adrenocortical adenomas also have reduced levels of DHEAS.

DESIGN

Evaluation of serum DHEAS, serum and urinary cortisol, plasma ACTH and low dose dexamethasone suppression test in patients with adrenal incidentaloma and Cushing's syndrome.

PATIENTS

Thirty-two patients with adrenal incidentaloma and, as controls, 17 patients with overt Cushing's syndrome, were studied.

RESULTS

Serum DHEAS levels lower than normal were found in 21/24 (87.5%) patients with adrenocortical incidentaloma, but in only 1/8 patients with a mass of non-adrenocortical origin. This patient had massive bilateral metastatic infiltration of both adrenal glands and primary adrenal failure. The prevalence of low DHEAS levels in the two groups was significantly different (P = 0.0001). In patients with adrenocortical incidentaloma, the prevalence of low DHEAS levels was significantly higher (P = 0.0001) than that found for some hormonal alterations indicating pre-clinical hypercortisolism (high urinary cortisol, unsuppressed serum cortisol after low dose dexamethasone administration and low plasma ACTH). Low DHEAS levels were found in all patients with Cushing's syndrome due to adrenocortical adenoma but in none of those with Cushing's disease.

CONCLUSIONS

Our results indicate that the finding of low DHEAS levels can be considered a marker of the adrenocortical origin of an adrenal incidentaloma, provided adrenal failure has been excluded.

Antidepressant-like effect of selective dopamine D1 receptor agonists in the behavioural despair animal model of depression

We compared the effect of two selective dopamine D1 receptor agonists, SKF 38393 ((+/-)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol.HCl) and A68930 ((1R,3S)-1-aminomethyl-5,6-dihydroxy-3-phenylisochroman.HCl), and that of imipramine in the behavioural despair model of depression. The dopamine D1 receptor agonists and imipramine showed an anti-immobility effect. Moreover we found that the 'antidepressant' effect of imipramine in the behavioural despair test was antagonized by SCH 23390, a selective dopamine D1 receptor blocker. The results further support the hypothesis that dopamine D1 receptor stimulation plays an important role in the mechanism of action of antidepressants and suggest that dopamine D1 receptor agonists might be considered as potential antidepressant drugs.

Muscular weakness in the mdx mouse

mdx mice are believed to be virtually free from neuromuscular symptoms, despite the presence of a degenerative/regenerative process that involves all skeletal muscles. We analyzed both the spontaneous motility and treadmill motor activity of mdx mice aged 15 days to 6 months. Our results indicate that there is an early period, between the end of the second and up to the fifth week of life, when mdx mice experience extreme weakness. After this critical period, both spontaneous motility and endurance of mdx mice, although lower than those of controls, do not show statistically significant differences up to 6 months of age. We also carried out a detailed histological analysis of proximal and distal muscle groups in mdx mice during this early critical motility period. The occurrence of extensive necrosis followed by regeneration and involving proximal muscles before distal ones was documented in mice as young as 16-17 days of age and reached a peak at day 18. We conclude that dystrophin deficiency induces muscle degeneration and significant weakness in mdx mice, but only in an early period. Later on, during development, mdx mice adapt to the lack of this protein and do not show detectable in vivo functional muscle impairment up to 6 months of age.

[Lipiodol chemoembolization in the treatment of hepatic carcinoma. Our experience]

Of the alternative methods of treatment to surgery in the treatment of liver cancer, chemoembolization with Lipiodol appears to have obtained encouraging results. After a preoperative study to confirm the diagnosis and staging of the tumour, lipiodolisation is performed: a mix of Adriamycin, Iopamidol and Lipiodol is injected using selective catheterism of the hepatic artery; gelfoam is then added. Lipiodol selectively localises in the hepatocarcinoma and has a distal embolising effect on the vessels of the tumour, thus necrotising it, acting as a carrier for chemotherapy. Since july 1990 a total of 15 hepatocarcinoma have been observed: 6 in healthy livers and 9 in cirrhotic livers; 3 patients recovered after radical surgery, 1 patient underwent associated surgery and chemoembolization, whereas in 11 the only therapy was chemoembolization, at six monthly intervals. Lipiodolisation enabled a better diagnosis to be made and was found to be a valuable therapeutic aid both when used alone in Inoperable patients and in association with non-radical surgery.

Lack of demonstrable chromosome allele loss in hepatocellular adenoma

Several studies of loss of constitutional genetic heterozygosity in the development of hepatocellular carcinoma have been carried out with the aim of determining the location of relevant tumour suppressor genes, but there is as yet no report of a similar investigation in hepatocellular adenomas. In this study we analyzed six such patients searching for evidence of chromosome allele loss, or loss of heterozygosity, with 25 DNA probes recognising restriction fragment length polymorphisms. The 25 probes have been assigned to 21 chromosome arms. None of those probes detected allele loss in any of the 6 tumours. One of the patients had a synchronous hepatocellular carcinoma. Chromosome 17p allele loss was detected in her hepatocellular carcinoma but not in the adenoma. The study suggests that chromosome allele loss is not a frequent genetic change in the development of hepatocellular adenoma.

A MERRF/MELAS overlap syndrome associated with a new point mutation in the mitochondrial DNA tRNA(Lys) gene

Several members of a three-generation kindred from Sardinia were affected by a maternally inherited syndrome characterized by features of both myoclonus epilepsy with ragged-red fibers (MERRF) and mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). Clinically, symptoms such as myoclonus epilepsy, neural deafness and ataxia were variably associated with stroke-like episodes and/or migrainous attacks. Morphologically, numerous MELAS-associated SDH-stained vessels were observed in muscle biopsies, either alone or in combination with ragged-red fibers, the morphological hallmark of MERRF. Sequence analysis of the mtDNA tRNA genes revealed the presence of a single, heteroplasmic T-->C transition at nt 8356, in the region of the tRNA(Lys) gene corresponding to the T-psi-C stem. The T-->C(8356) transition was exclusively found in the maternal lineage of our family, and the relative amount of the mutant mtDNA species in muscle was correlated with the severity of the clinical presentation. Therefore, we propose that the T-->C(8356) transition is responsible for the mitochondrial encephalomyopathy found in our family, and must be added to the expanding list of the pathogenetically relevant mutations of human mtDNA.

A neurophysiological study on the P300 component of event-related potentials in Hakim-Adams syndrome

We have explored the variability of P300 event-related potentials in patients affected by Hakim-Adams syndrome, with raised or intermittent intracranial pressure, treated with surgical cerebrospinal fluid shunting. The clinical utility of P300 is confirmed in the light of the improvement of neurophysiological data after the surgical procedure, parallel with amelioration of neuropsychological performances.

The NMDA receptor antagonist MK-801 prevents imipramine-induced supersensitivity to quinpirole

Chronic treatment with imipramine enhanced the locomotor stimulant response to quinpirole (0.3 mg/kg s.c.), a dopamine D2/D3 receptor agonist. Chronic, but not acute, blockade of the NMDA receptor with the non-competitive antagonist MK-801 (0.3 mg/kg i.p.) prevented the imipramine-induced potentiation of the quinpirole effect. The results suggest that NMDA receptors play a role in the development of supersensitivity to dopamine receptor agonists produced by chronic antidepressant treatment.

[Fentanyl prevents the pain at the site of propofol injection]

The effect of fentanyl, administered immediately before propofol, when pain is experienced at the site of propofol injection was studied in 28 children undergoing elective surgery. The intravenous administration of fentanyl (2 micrograms/kg) significantly reduced such pain compared with a control group receiving saline. The results suggest that the administration of fentanyl may be a valid procedure in relieving pain on injection of propofol.

TRH activates mesolimbic dopamine system: behavioural evidence

The effect of TRH pretreatment on locomotor activity and stereotypy induced by d-amphetamine was examined in rats. The results show that TRH potentiates d-amphetamine-induced locomotor activity, but not d-amphetamine-induced stereotypy, suggesting that this neuropeptide selectively activates the mesolimbic dopamine system.

Biochemical diagnosis and outcome of 2 years treatment in a patient with combined methylmalonic aciduria and homocystinuria

We describe a patient with methylmalonic aciduria and homocystinuria due to a defect in cobalamin metabolism of the Cbl-C type mutant (McKusick 277400). Our case was diagnosed within the first 2 months of life by amino acid analysis (ion-exchange chromatography) and by biochemical studies in cultured fibroblasts ([14C]propionate incorporation, methionine and serine formation). We discuss the clinical course and the biochemical evolution after 2 years of hydroxycobalamin treatment that led to an improvement in general clinical condition and neurological performance.

A comparative study of protein immobilization techniques for optical immunosensors

This paper presents the results of a study of a number of antibody immobilization techniques for application to optical immunosensors. In particular, well-known methods such as covalent binding and physical adsorption have been extended to the Langmiur-Blodgett method in an attempt to improve the density and possibly the uniformity of orientation of monoclonal antibodies on an optical surface. The surface density of active immobilized antibodies was determined from enzyme immunoassay and their thickness and refractive index were deduced from ellipsometry. It is shown that, although high surface densities (500 ng/cm2) of antibody can be obtained, the major obstacle to the detection of low concentrations of antigens or haptens is the non-specific binding of foreign molecules to the sensing surface.

Role of alpha receptors in the behavioural supersensitivity to D agonists induced by chronic treatment with imipramine

Chronic treatment with imipramine increased the locomotor response to quinpirole, a selective D2 receptor agonist. This effect was blocked by minute doses of prazosin (0.1-1 mg/kg), a selective alpha 1 receptor blocker, in a dose-dependent manner. Conversely, in control rats the locomotor response to quinpirole was enhanced by the stimulation of alpha 1 receptors with the selective agonist St 587. The results suggest that alpha 1 receptor stimulation plays a permissive role in the supersensitivity of D2 receptors following chronic treatment with imipramine.

Comparative evaluation of three dosages of slow-release isosorbide dinitrate (60, 80, 100 mg) in chronic angina of the aged

In a single-blind, placebo-controlled study the acute and chronic antianginal effects of three slow-release (SR) new formulations of isosorbide dinitrate (ISDN 60, 80, 100 mg) have been comparatively evaluated in a group of aged affected by chronic stable effort-induced angina. Compared to placebo, overall the active dose paritetically improved the effort tolerance up to 24 h after the first assumption. In the time course of the trial (2 and 4 weeks) the resting hemodynamic changes induced by the first dose were partially blunted without affecting the exercise related-parameters. Also if plasma levels of ISDN and of its metabolites did not correlate to the degree of physical improvement, the peak increase in effort tolerance was observed under 100 mg treatment. Mild to moderate transient headache was experienced by 50% of actively treated and by 20% of placebo treated patients and no other serious adverse effects have been noted. One may conclude that ISDN in slow-release formulations of 60-100 mg isan effective, safe and well tolerated medication in the management of angina in the aged.

Neurophysiological study of Horner's syndrome

Sympathetic skin response from the forehead and from the hand obtained by using electric, acoustic stimuli and during deep breathing was recorded in normal subjects and in patients suffering from Horner's syndrome in order to characterize this clinical picture neurophysiologically. The reliability of the method points to its possible usefulness in the pre-postganglionic differential diagnosis also.

Chronic imipramine "reverses" B-HT 920-induced hypomotility in rats

B-HT 920, a selective DA autoreceptor agonist, reduced motor activity in rats. Chronic, but not acute, treatment with imipramine (IMI) reversed this effect. The mechanism by which chronic IMI reverses the B-HT 920 effect is discussed.