Tertiary Syphilis Masquerading as Oropharyngeal Cancer

Syphilis is re-emerging in the United States. Treponema pallidum, the spirochete bacterium responsible for syphilis, has immunoevasive properties that facilitate pathogenesis and widespread tissue involvement. Host immune status, particularly the presence of HIV/AIDS, can influence the presentation and severity of the disease. Patients co-infected with HIV and syphilis may develop atypical lesions, including those involving the oropharynx. Any immunocompromised patient with tongue lesions and lymphadenopathy is presumed to have a wide differential diagnosis, and tissue sampling with histopathologic analysis is indicated. We present a patient with gumma of the tongue as the initial manifestation of tertiary syphilis

The Impact of SST and PV Interneurons on Nonlinear Synaptic Integration in the Neocortex

AbstractExcitatory synaptic inputs arriving at the dendrites of a neuron can engage active mechanisms that nonlinearly amplify the depolarizing currents. This supralinear synaptic integration is subject to modulation by inhibition. However, the specific rules by which different subtypes of interneurons affect the modulation have remained largely elusive. To examine how inhibition influences active synaptic integration, we optogenetically manipulated the activity of the following two subtypes of interneurons: dendrite-targeting somatostatin-expressing (SST) interneurons; and perisomatic-targeting parvalbumin-expressing (PV) interneurons. In acute slices of mouse primary visual cortex, electrical stimulation evoked nonlinear synaptic integration that depended on NMDA receptors. Optogenetic activation of SST interneurons in conjunction with electrical stimulation resulted in predominantly divisive inhibitory gain control, reducing the magnitude of the supralinear response without affecting its threshold. PV interneuron activation, on the other hand, had a minimal effect on the supralinear response. Together, these results delineate the roles for SST and PV neurons in active synaptic integration. Differential effects of inhibition by SST and PV interneurons likely increase the computational capacity of the pyramidal neurons in modulating the nonlinear integration of synaptic output.</jats:p

The Impact of SST and PV Interneurons on Nonlinear Synaptic Integration in the Neocortex.

Excitatory synaptic inputs arriving at the dendrites of a neuron can engage active mechanisms that nonlinearly amplify the depolarizing currents. This supralinear synaptic integration is subject to modulation by inhibition. However, the specific rules by which different subtypes of interneurons affect the modulation have remained largely elusive. To examine how inhibition influences active synaptic integration, we optogenetically manipulated the activity of the following two subtypes of interneurons: dendrite-targeting somatostatin-expressing (SST) interneurons; and perisomatic-targeting parvalbumin-expressing (PV) interneurons. In acute slices of mouse primary visual cortex, electrical stimulation evoked nonlinear synaptic integration that depended on NMDA receptors. Optogenetic activation of SST interneurons in conjunction with electrical stimulation resulted in predominantly divisive inhibitory gain control, reducing the magnitude of the supralinear response without affecting its threshold. PV interneuron activation, on the other hand, had a minimal effect on the supralinear response. Together, these results delineate the roles for SST and PV neurons in active synaptic integration. Differential effects of inhibition by SST and PV interneurons likely increase the computational capacity of the pyramidal neurons in modulating the nonlinear integration of synaptic output

The Impact of SST and PV Interneurons on Nonlinear Synaptic Integration in the Neocortex.

Excitatory synaptic inputs arriving at the dendrites of a neuron can engage active mechanisms that nonlinearly amplify the depolarizing currents. This supralinear synaptic integration is subject to modulation by inhibition. However, the specific rules by which different subtypes of interneurons affect the modulation have remained largely elusive. To examine how inhibition influences active synaptic integration, we optogenetically manipulated the activity of the following two subtypes of interneurons: dendrite-targeting somatostatin-expressing (SST) interneurons; and perisomatic-targeting parvalbumin-expressing (PV) interneurons. In acute slices of mouse primary visual cortex, electrical stimulation evoked nonlinear synaptic integration that depended on NMDA receptors. Optogenetic activation of SST interneurons in conjunction with electrical stimulation resulted in predominantly divisive inhibitory gain control, reducing the magnitude of the supralinear response without affecting its threshold. PV interneuron activation, on the other hand, had a minimal effect on the supralinear response. Together, these results delineate the roles for SST and PV neurons in active synaptic integration. Differential effects of inhibition by SST and PV interneurons likely increase the computational capacity of the pyramidal neurons in modulating the nonlinear integration of synaptic output

Tributyltin chloride (TBT) induces RXRA down-regulation and lipid accumulation in human liver cells.

A subset of environmental chemicals acts as "obesogens" as they increase adipose mass and lipid content in livers of treated rodents. One of the most studied class of obesogens are the tin-containing chemicals that have as a central moiety tributyltin (TBT), which bind and activate two nuclear hormone receptors, Peroxisome Proliferator Activated Receptor Gamma (PPARG) and Retinoid X Receptor Alpha (RXRA), at nanomolar concentrations. Here, we have tested whether TBT chloride at such concentrations may affect the neutral lipid level in two cell line models of human liver. Indeed, using high content image analysis (HCA), TBT significantly increased neutral lipid content in a time- and concentration-dependent manner. Consistent with the observed increased lipid accumulation, RNA fluorescence in situ hybridization (RNA FISH) and RT-qPCR experiments revealed that TBT enhanced the steady-state mRNA levels of two key genes for de novo lipogenesis, the transcription factor SREBF1 and its downstream enzymatic target, FASN. Importantly, pre-treatment of cells with 2-deoxy-D-glucose reduced TBT-mediated lipid accumulation, thereby suggesting a role for active glycolysis during the process of lipid accumulation. As other RXRA binding ligands can promote RXRA protein turnover via the 26S proteasome, TBT was tested for such an effect in the two liver cell lines. We found that TBT, in a time- and dose-dependent manner, significantly reduced steady-state RXRA levels in a proteasome-dependent manner. While TBT promotes both RXRA protein turnover and lipid accumulation, we found no correlation between these two events at the single cell level, thereby suggesting an additional mechanism may be involved in TBT promotion of lipid accumulation, such as glycolysis

TBT down-regulates RXRA in a fast, proteasome-dependent and PPARG-independent manner.

A) HepaRG cells were treated TBT (50 nM) or vehicle for 2–8 hours, then immunofluorescence using specific RXRA antibody was performed and single cell nuclear levels of RXRA measured. B-C) Effect of MG132 and TO070907 on TBT (50 nM, 8 h) down-regulation of RXRA represented as box-plots. *p<0.05 by ANOVA (Kruskal-Wallis test with Dunn post test).</p

TBT increase in lipid droplets is mediated through glycolysis and activation of some lipogenic genes.

A) HepaRG cells were grown in the presence of TBT (50 nM), 2-deoxyglucose (2DG, 2 mM) or vehicle for 3 days, then lipid content was analyzed as in Fig 1. Representative 40x images are shown. Scale bar: 25μm. B) quantification of images from the experiment performed in panel A, data is z-normalized based on vehicle (DMSO) treatment and shown as integrated intensity of lipid droplets/cell. *pSREBF1 and FASN was performed in HepaRG cells after 8 and 24 h (shown in the panels) of TBT or vehicle treatment. Images (60x/1.4NA) shown are max projections after deconvolution. In panel D, the number of single RNA molecules/cell was counted and represented as a box plot. Scale bar: 10 μmM. E) RT-qPCR validation of TBT induction of SREBF1 and FASN mRNAs after 24h of 50nM TBT treatment. *p<0.01 compared to Vehicle.</p