A subiculum-hypothalamic pathway functions in dynamic threat detection and memory updating.

Animals need to detect threats, initiate defensive responses, and, in parallel, remember where the threat occurred to avoid the possibility of re-encountering it. By probing animals capable of detecting and avoiding a shock-related threatening location, we were able to reveal a septo-hippocampal-hypothalamic circuit that is also engaged in ethological threats, including predatory and social threats. Photometry analysis focusing on the dorsal premammillary nucleus (PMd), a critical interface of this circuit, showed that in freely tested animals, the nucleus appears ideal to work as a threat detector to sense dynamic changes under threatening conditions as the animal approaches and avoids the threatening source. We also found that PMd chemogenetic silencing impaired defensive responses by causing a failure of threat detection rather than a direct influence on any behavioral responses and, at the same time, updated fear memory to a low-threat condition. Optogenetic silencing of the main PMd targets, namely the periaqueductal gray and anterior medial thalamus, showed that the projection to the periaqueductal gray influences both defensive responses and, to a lesser degree, contextual memory, whereas the projection to the anterior medial thalamus has a stronger influence on memory processes. Our results are important for understanding how animals deal with the threat imminence continuum, revealing a circuit that is engaged in threat detection and that, at the same time, serves to update the memory process to accommodate changes under threatening conditions.

Role of the rostral dorsomedial column of the periaqueductal gray during social defeat in rats.

Previous studies showed that the dorsal premammillary nucleus of the hypothalamus (PMD) is involved in social passive defensive behaviors likely to be meditated by descending projections to the periaqueductal gray (PAG). We focused on the rostral dorsomedial PAG (rPAGdm) to reveal its putative neural mechanisms involved in mediating social defensive responses. By combining retrograde tracing and FOS expression analysis, we showed that in addition to the PMD, the rPAGdm is influenced by several brain sites active during social defeat. Next, we found that cytotoxic lesions of the rPAGdm drastically reduced passive defense and did not affect active defensive responses. We then examined the rPAGdm's projection pattern and found that the PAGdm projections are mostly restricted to midbrain sites, including the precommissural nucleus, different columns of the PAG, and the cuneiform nucleus (CUN). Also, we found decreased FOS expression in the caudal PAGdm, CUN, and PMD after the rPAGdm was lesioned. The results support that the rPAGdm mediates passive social defensive responses through ascending paths to prosencephalic circuits likely mediated by the CUN. This study provides further support for the role of the PAG in the modulation of behavioral responses by working as a unique hub for influencing prosencephalic sites during the mediation of aversive responses.

Elastose perfurante serpiginosa / Elastosis perforans serpiginosa

A elastose perfurante serpiginosa é uma dermatose perfurante rara caracterizada pela eliminação transepidérmica de fibras elásticas alteradas. A etiologia é desconhecida, mas alguns casos têm sido associados a alterações genéticas. É mais freqüente em jovens do sexo masculino na 2ª década de vida. O quadro clínico caracteriza-se por pápulas umbilicadas, com centro córneo, localizadas principalmente no pescoço e dispostas em padrão serpiginoso. Pode ser classificada em idiopática, reativa (associada a doenças do tecido conjuntivo) e induzida por penicilamina. Diferentes modalidades terapêuticas são descritas na literatura. Neste artigo descreve-se um caso de elastose perfurante serpiginosa em paciente do sexo feminino com 47 anos, com doença de Wilson, em uso prolongado de penicilamina

Elastosis perforans serpiginosa is a rare reactive perforanting dermatosis characterized by a process of transepidermal elimination of elastic fibers. The cause is unknown, but a genetically determined defect of elastic tissue has been proposed. Commonly occur in young persons in the second decade, with a higher incidence among males. Clinically, umbilicated papules with a central plug appear characteristically on the neck, creating the elevated serpiginous border. It has been characterized in idiopathic, reactive (with associated connective tissue disease) and penicillamine-induced. Different options of treatment have been described in the literature. We describe a 47-year-old female with elastosis perforans serpiginosa and Wilson?s disease who has been treated with longterm penicillamine therapy

Freqüência da hipertensäo arterial na doença de Chagas crônica: estudo clínico retrospectivo / Frequency of hypertension in chronic Chagas' disease: retrospective clinical study

OBJECTIVE: To assess the frequency of hypertension in chagasic patients, as well as its clinical behavior and cardiologic findings. METHODS: We carried out a retrospective study with 225 patients with chronic Chagas' disease and hypertension (104 males), mean age of 55.1 ± 11.8. These patients were being followed up in the outpatient care clinics from 1984 to 2000. The study assessed the clinical, electrocardiographic, and radiological viewpoints. RESULTS: Of the 225 hypertensive patients (prevalence = 33.3 percent), 78 (34.7 percent) had mild hypertension, 108 (48 percent) had moderate hypertension, and 39 (17.3 percent) had severe hypertension. The association of left anterosuperior divisional block and right bundle-branch block occurred in 39 cases (17.3 percent), and enlargement of the cardiac area on radiological examination occurred in 93 (44.9 percent) of the 207 cases studied. The undetermined form of Chagas' disease was the most prevalent, 30.2 percent of the cases, followed by the form associated with conduction disorders in 27.1 percent, and the isolated form of conduction disorders in 21.3 percent. CONCLUSION: Chagasic patients had a frequency of hypertension similar to that of the general population, and the clinical profile of the hypertensive chagasic patients seemed not to differ a lot from that of the chagasic patients

Frequency of hypertension in chronic Chagas' disease: retrospective clinical study.

OBJECTIVE: To assess the frequency of hypertension in chagasic patients, as well as its clinical behavior and cardiologic findings. METHODS: We carried out a retrospective study with 225 patients with chronic Chagas' disease and hypertension (104 males), mean age of 55.1 11.8. These patients were being followed up in the outpatient care clinics from 1984 to 2000. The study assessed the clinical, electrocardiographic, and radiological viewpoints. RESULTS: Of the 225 hypertensive patients (prevalence = 33.3%), 78 (34.7%) had mild hypertension, 108 (48%) had moderate hypertension, and 39 (17.3%) had severe hypertension. The association of left anterosuperior divisional block and right bundle-branch block occurred in 39 cases (17.3%), and enlargement of the cardiac area on radiological examination occurred in 93 (44.9%) of the 207 cases studied. The undetermined form of Chagas' disease was the most prevalent, 30.2% of the cases, followed by the form associated with conduction disorders in 27.1%, and the isolated form of conduction disorders in 21.3%. CONCLUSION: Chagasic patients had a frequency of hypertension similar to that of the general population, and the clinical profile of the hypertensive chagasic patients seemed not to differ a lot from that of the chagasic patients.