Aberrant intrinsic functional connectivity in thalamo-cortical networks in major depressive disorder.

OBJECTIVE: Growing evidence has implicated dysfunction of the thalamus and its projection cortical targets in depression. However, the anatomical specificity of thalamo-cortical connectivity in major depressive disorder (MDD) remains unknown due to the regional heterogeneity of the thalamus and limited methods to examine this. METHODS: Resting-state fMRI was collected on 70 MDD patients and 70 healthy controls. The thalamus was parcellated based on connectivity with six predefined cortical regions of interest (ROIs). The segmented thalamic nuclei were used as seeds to map connectivity with the rest of the whole brain. The cortical-to-thalamus connectivity values and thalamus-based connectivity maps were compared between groups. RESULTS: The cortical ROIs demonstrated correlations with spatially distinct zones within the thalamus. We found a trend toward reduced parietal ROI-to-thalamus connectivity in MDD. Importantly, MDD patients demonstrated reduced connectivity between prefrontal and parietal thalamus ROIs and bilateral middle frontal gyrus (MFG) and the right posterior default mode network (DMN) and between the prefrontal and motor thalamus ROIs and lateral temporal regions. Conversely, increased connectivity emerged between the motor thalamus ROI and right MFG and right medial frontal gyrus/anterior cingulate; between motor/somatosensory thalamus ROIs and right posterior DMN; between prefrontal/somatosensory thalamus ROIs and cerebellum; and between the parietal thalamus ROI and left insula. CONCLUSIONS: This study is the first to examine the anatomical specificity of thalamo-cortical connectivity disturbances in MDD. Subjects with MDD demonstrated altered thalamo-cortical connectivity characterized by a complex pattern of region-dependent hypo- or hyperconnectivity. We therefore speculate that selectively modulating the connectivity of thalamo-cortical circuitry may be a potential novel therapeutic mechanism for MDD.

[Silymarin Protects Umbilical Cord-Derived Mesenchymal Stem Cells against Apoptosis Induced by Serum-Deprivation].

OBJECTIVE: To investigate the protection of silymarin against the human mesenchymal stem cell (MSC) apoptosis induced by serum deprivation and its underlying mechanism. METHODS: Human umbilical cord MSCs were cultured in the absence of serum, and the silymain of different concentration (1-10 µg/ml) was added into the medium. MTT test was performed to observe the cell proliferation status. After being cultured for 72 hours, the cells were collected, and flow cytometry with Annexin-V-PI double-staining was used to detect the apoptotic cells from the control and silymarin-treated groups. Furthermore, the intracellular contents of BAX and BCL-2 were detected by Western blot for exploring the potential mechanism. RESULTS: The silymarin promoted the proliferation of human UC-MSCs in a dose-dependent manner, reaching its maximal at a dose of 5 µg/ml. Moreover, silymarin could inhibit the serum deprivation-induced apoptosis of MSCs and, the inhibitory rate reached up to 30% when it was added at a concentration of 5 µg/ml. The content of intracellular BAX was obviously elevated after serum-deprivation treatment, and this increase could be blunted by the addition of silymarin. Meanwhile, the content of BCL-2 was not obviously changed. CONCLUSION: The silymarin can stimulate MSC growth and inhibit the apoptosis of MSCs probably by the mitochondria pathway.

[Investigation on the internalization pathway of microparticles into human umbilical cord endothelial cells].

OBJECTIVE: To investigate the mechanisms underlying the incorporation of microparticles(MP) derived from human bone marrow mesenchymal stem cells (MSCs) into human umbilical cord endothelial cells (HUVECs). METHODS: MPs were isolated from the supernatants of MSCs which had exposed to a hypoxia/serum-deprivation condition. Electron microscope was used to identify the MPs. The surface molecule profile was evaluated with the bead-based flow cytometry technique. The expression level of the phosphatidylserine receptor (PSR) was detected by immunofluorescence cytochemistry. MPs were co-cultured with HUVECs in the presence or absence PSR-antibody, and the internalization of MPs was observed with laser scanning microscopy. RESULTS: The MPs derived from MSCs expressed highly PS, while PSR expressed on the surface of HUVECs. The confocal result revealed that MPs could quickly be uptaken by the endothelial cells, and mainly distributed in the cytoplasm surrounding of the nuclei. The internalization of MPs reduced significantly after PSR specific blockage. CONCLUSION: The reaction between PS on the MP and the PSR of HUVECs plays an important role in the internalization of MSC-MPs.

Modification of atrioventricular node in a special condition treating paroxysmal supraventricular tachycardia.

Modification of atrioventricular node is a usual and necessary operation to cure atrioventricular nodal reentrant tachycardia (AVNRT). In this operation, atrioventricular block is the most severe complication and its prevention is of our great concern. This complication always occurs under some special circumstances with potential risk. So, it is very important to realize such conditions, as in this paper. A patient with paroxysmal palpitation for 10 years, aggravating to shortness of breath with chest distress for 1 year; cardiac electrophysiological examination found slow conduction in both antegrade and retrograde paths of reentrant loop, and typical AVNRT could be induced. During effective ablation there was no junctional rhythm. In some special cases, modification of atrioventricular node should not only rely on the junctional rhythm to determine the ablation effect, but also on the time of cardiac electrophysiological examination, as such to avoid the severe complication of atrioventricular block caused by excessive ablation.

[Brain natriuretic peptide and left ventricular remodeling after emergency percutaneous coronary intervention in acute myocardial infarction patients].

OBJECTIVE: To investigate the effect of emergency percutaneous coronary interventional (PCI) treatment on plasma brain natriuretic peptide (BNP) levels and left ventricular remodeling in patients with acute myocardial infarction (AMI). METHODS: This study included 118 patients with AMI and 20 healthy volunteers (their results were regarded as normal reference). Fifty-two patients who underwent successful emergency PCI 6-12 hours after onset were named as PCI group, and 66 patients rejected or in whom emergency PCI failed served as the control group. Plasma BNP levels were determined with Triage rapid assay at admission,at 12, 24, 48, 72 hours and 7, 14, 28 days after admission for both groups. Left ventricular ejection function (LVEF) was assessed by echocardiography with the modified Simpson's equation on 3-5 days and 28 days. Same assay was performed for 20 healthy volunteers. RESULTS: Plasma BNP levels of both groups were significantly higher at admission than those of volunteers. There was significant difference in BNP levels between two groups at corresponding time points (all P<0.01). In PCI group, BNP level peaked during 12-24 hours after admission, whereas two peaks of elevation of BNP levels were detected in control group, the first peak appeared during 12-24 hours and the second peak on 7 days after admission. Plasma BNP levels in PCI group were significantly lower than those of control group at corresponding time points (all P<0.01). There was no difference in LVEF level between two groups on 3-5 days after admission. LVEF level after emergency PCI was significantly higher than that of control group on 28 days after admission (P<0.01). CONCLUSION: Emergency PCI lowers plasma BNP level and improve LVEF level in patients with AMI, and it may reverse ventricular remodeling.