Opposing modifications in intrinsic currents and synaptic inputs in post-traumatic mossy cells: evidence for single-cell homeostasis in a hyperexcitable network

Recent experimental and modeling results demonstrated that surviving mossy cells in the dentate gyrus play key roles in the generation of network hyperexcitability. Here we examined if mossy cells exhibit long-term plasticity in the posttraumatic, hyperexcitable dentate gyrus. Mossy cells 1 wk after fluid percussion head injury did not show alterations in their current-firing frequency (I-F) and current-membrane voltage (I-V) relationships. In spite of the unchanged I-F and I-V curves, mossy cells showed extensive modifications in Na(+), K(+) and h-currents, indicating the coordinated nature of these opposing modifications. Computational experiments in a realistic large-scale model of the dentate gyrus demonstrated that individually, these perturbations could significantly affect network activity. Synaptic inputs also displayed systematic, opposing modifications. Miniature excitatory postsynaptic current (EPSC) amplitudes were decreased, whereas miniature inhibitory postsynaptic current (IPSC) amplitudes were increased as expected from a homeostatic response to network hyperexcitability. In addition, opposing alterations in miniature and spontaneous synaptic event frequencies and amplitudes were observed for both EPSCs and IPSCs. Despite extensive changes in synaptic inputs, cannabinoid-mediated depolarization-induced suppression of inhibition was not altered in posttraumatic mossy cells. These data demonstrate that many intrinsic and synaptic properties of mossy cells undergo highly specific, long-term alterations after traumatic brain injury. The systematic nature of such extensive and opposing alterations suggests that single-cell properties are significantly influenced by homeostatic mechanisms in hyperexcitable circuits.     

On the use of denaturing gradient gel electrophoresis approach for bacterial identification in endodontic infections

Bacteria in infected root canals of teeth evincing chronic apical periodontitis lesions were identified by a polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) approach. DNA was extracted from root canal samples, and part of the 16S rRNA gene of all bacteria was amplified by PCR and separated by DGGE, generating banding patterns representative of the community structure. Twenty visible bands were cut out of the gel, re-amplified, and sequenced to provide identification. Sequencing analysis revealed the presence of both cultivable and as-yet-uncultivated species in the samples analyzed, including representatives of the genera Fusobacterium, Bacteroides, Dialister, Synergistes, Prevotella, Eubacterium and Peptostreptococcus. Unambiguous identification was not always possible and the method’s limitations are discussed. In general, the findings showed that PCR-DGGE can be useful for the identification of both cultivable and as-yet-uncultivated bacteria in endodontic infections.     

Replacement of a fixed partial denture secondary to abutment fracture

BACKGROUND: The authors present a case that demonstrates the efficient replacement of a fixed prosthesis after a patient's abutment tooth fractured and required extraction. The fractured tooth had a local infection, and the maxillary bone was low-density and limited in height. CASE DESCRIPTION: The authors removed the tooth and grafted the site with particulate bone, while concurrently placing two implants in the edentulous region. After four months, they placed one additional implant and secured a fixed provisional prosthesis within one week. CLINICAL IMPLICATIONS: The patient wanted to minimize the time that she would have to be without a fixed prosthesis. The authors met her expectations by using an accelerated treatment plan.     

Leishmaniasis in cat shelters: A serological,molecular and entomological study

An epidemiological Leishmania spp. and entomological Phlebotomine sandflies survey was performed in cat shelters at leishmaniasis endemic area of Brazil. Blood and conjunctival swab (CS) samples were collected from 94 cats in two animal protection shelters. These samples were subjected to serological tests using the indirect immunofluorescence antibody test (IFAT) and indirect enzyme‐linked immunosorbent assay (ELISA) and to molecular test by polymerase chain reaction (PCR). In addition, a Phlebotomine sandflies survey was performed in the same shelters. The analyses revealed a positivity of 31.91% (30/94) through ELISA and 29.79% (28/94) through IFAT. The two serological tests showed a positive association with perfect agreement (k = 0.925). None of the cats were positive by Leishmania spp. DNA. One Lutzomyia (Lutzomyia) longipalpis male was found in one of the cat shelters. The results and the implications of our findings are discussed below.     

The soluble catalytic ectodomain of ACE2 a biomarker of cardiac remodelling: new insights for heart failure and COVID19

The angiotensin-converting enzyme 2 (ACE2) is a type I integral membrane that was discovered two decades ago. The ACE2 exists as a transmembrane protein and as a soluble catalytic ectodomain of ACE2, also known as the soluble ACE2 that can be found in plasma and other body fluids. ACE2 regulates the local actions of the renin-angiotensin system in cardiovascular tissues, and the ACE2/Angiotensin 1–7 axis exerts protective actions in cardiovascular disease. Increasing soluble ACE2 has been associated with heart failure, cardiovascular disease, and cardiac remodelling. This is a review of the molecular structure and biochemical functions of the ACE2, as well we provided an updated on the evidence, clinical applications, and emerging potential therapies with the ACE2 in heart failure, cardiovascular disease, lung injury, and COVID-19 infection.

     

Case report: peritoneal sarcoidosis in an unusual location

A 48-year-old woman underwent surgery for a lesion seen on ultrasound and interpreted as a uterine myoma. The surgery revealed multiple nodules that had seeded on the omentum, peritoneum, and ovaries. The macroscopic interpretation was either metastasis or tuberculosis. The biopsy showed noncaseating granulomas, and a diagnosis of peritoneal sarcoidosis was reported. The AFB (acid fast bacillus) and L?wenstein-Jensen culture were negative. She was treated with methylprednisolone for 1 year for pulmonary sarcoidosis progression, with a resulting decrease in her DLCO (diffusing lung capacity for carbon monoxide). Computed tomography showed only a slight decrease in the multiple nodules and cysts. She is currently symptom-free.