Evidence for the involvement of extinction-associated inhibitory learning in the forced swimming test.

The forced swimming test (FST) remains one of the most used tools for screening antidepressants in rodent models. Nonetheless, the nature of immobility, its main behavioral measure, is still a matter of debate. The present study took advantage of our recent finding that mice of the inbred DBA/2J strain require a functioning left dorsolateral striatum (DLS) to consolidate long-term memory of FST to test whether immobility is the outcome of stress-related learning. Infusion of the GABA-A agonist muscimol in the left DLS immediately after a single experience of FST prevented and infusion in the left or the right amygdala impaired recall of the acquired levels of immobility in a probe test performed 24h later. Post-training left DLS infusion of muscimol, at a dose capable of preventing retention of FST-induced immobility, did not influence 24h retention of inhibitory avoidance training or of the escape response acquired in a water T-maze. However, this same treatment prevented 24h retention of the extinction training of the consolidated escape response. These results indicate that a left DLS-centered memory system selectively mediates memory consolidation of FST and of escape extinction and support the hypothesis that immobility is the result of extinction-like inhibitory learning involving all available escape responses due to the inescapable/unavoidable nature of FST experience.

Peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE in individuals with neck or mediastinal paraganglioma (PGL).

Paragangliomas (PGLs) are neuroendocrine tum-ors that arise embryologically from the neural crest. Sympathetic PGLs can be located in the thoracic-abdominal region while parasympathetic PGLs are mainly situated in the head and neck region. Most PGLs are sporadic, but in 30% of cases they are hereditary (associated with mutations of SDHB, SDHC, SDHD, SDHAF2, SDHA, TMEM, MAX, and VHL); they can be classified into 4 different paraganglioma syndromes: PGL1, PGL2, PGL3, and PGL4. Surgery is the treatment of choice for both sympathetic and parasympathetic PGLs. Other types of treatment include medical agents (such as gemcitabine, cisplatin, or sunitinib) and radiotherapy (external-beam radiotherapy or stereotactic surgery). Surgery and radiotherapy, however, can cause important side effects such as vascular complications and peripheral nerve damage (hypoglossal, recurrent laryngeal, glossopharyngeal, and vagus). Another possible treatment option is the use of peptide receptor radionuclide therapy (PRRT), including PRRT with 177Lu-DOTATATE. We studied 4 patients with hereditary nonmetastatic paraganglioma syndrome type 1 (PGL1), with progressive disease, in whom surgical excision was not possible. They were treated with 177Lu-DOTATATE (3-5 cycles) and all had a partial response (PR) or a stable disease (SD) to the treatment. In conclusion, a good alternative treatment when surgical or radiation therapy are contraindicated could be radiometabolic therapy with 177Lu-DOTATATE.

Role of ultrasound and color Doppler imaging in the detection of carotid paragangliomas.

INTRODUCTION: Carotid body paragangliomas (PGLs) are highly vascularized lesions that arise from the paraganglia located at the carotid bifurcation. PURPOSE: To evaluate the usefulness of gray-scale ultrasound (US) and color Doppler ultrasound (CDUS) in the detection and follow-up of carotid PGLs of the neck. MATERIALS AND METHODS: The authors retrospectively reviewed US and CDUS examinations of the neck performed in 40 patients with PGL syndrome type 1 and single or bilateral neck PGLs confirmed by CT or MRI; the patients had a total of 60 PGLs of the neck. US and CDUS outcome was compared to the outcome of second-line imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT). The following findings were considered: presence/absence of focal lesions at US imaging and difference in maximum diameter of the lesion measured at US and MRI/CT. Results were compared using the Student's t-test. RESULTS: Of the 60 PGLs of the neck only 5 (8.3%) were not visualized at US or CDUS examination. The difference in maximum diameter of these lesions measured at CT/MRI and US/CDUS ranged between -5 mm and +16 mm (mean difference 2.2 ± 6.0). This difference was statistically significant (p = 0.008). CONCLUSIONS: US and CDUS are useful methods for identifying carotid PGLs also measuring less than 10 mm in diameter. However, diagnostic accuracy of US and CDUS is reduced in the measurement of the exact dimensions of the lesions.

Polyglandular autoimmune endocrine insufficiency complicated by severe osteoporosis.

In literature different cases of polyglandular autoimmune type II syndrome (PGA II) are reported, where Addison's disease is associated with gonadal insufficiency. The lack in the production of sexual steroids causes a severe postmenopausal osteoporosis. The case we report is related to a 38-year-old woman we met in 1988 and who was suffering from deep asthenia, cramps, cutaneous hyperpigmentation, nausea, vomiting, abdominal pain, weight loss and hypotension. The biochemical data were indicative for autoimmune adrenal failure. Between 1988 and 1997 the patient developed a progressive insufficiency of other endocrine glands, leading to the classic feature of PGA II. In 1998, this clinical status was complicated by a severe osteoporosis. We thought that the sudden decrease in the bony mineral density was due to the lack of the protective role played by adrenal gland androgens in postmenopausal osteoporosis. They would directly act on the bony tissue, independently from oestrogens peripheral conversion, thus producing a stimulant effect on the bone formation. A new therapeutical approach, in case of osteoporosis, is today represented by DHEA replacement therapy in women showing low hormone levels.