Optrode Array for Simultaneous Optogenetic Modulation and Electrical Neural Recording.

During the last decade, optogenetics has become an essential tool for the investigation of neural signaling due to its unique capability of selective neural modulation or monitoring. As specific types of neuronal cells can be genetically modified to express opsin proteins, optogenetics enables optical stimulation or inhibition of the selected neurons. There have been several technological advances in the optical system for optogenetics. Recently, it was proposed to combine the optical waveguide for light delivery with electrophysiological recording to simultaneously monitor the neural responses to optogenetic stimulation or inhibition. In this study, an implantable optrode array (2x2 optical fibers) was developed with embedded multichannel electrodes. A light-emitting diode (LED) was employed as a light source, and a microfabricated microlens array was integrated to provide sufficient light power at the tip of the optical fibers. The optrode array system comprises the disposable part and the reusable part. The disposable part has optical fibers and electrodes, while the reusable part has the LED and electronic circuitry for light control and neural signal processing. The novel design of the implantable optrode array system is introduced in the accompanying video in addition to the procedure of the optrode implantation surgery, optogenetic light stimulation, and the electrophysiological neural recording. The results of in vivo experiments successfully showed time-locked neural spikes evoked by the light stimuli from hippocampal excitatory neurons of mice.

Anti-Melanogenic Effects of Ethanol Extracts of the Leaves and Roots of Patrinia villosa (Thunb.) Juss through Their Inhibition of CREB and Induction of ERK and Autophagy.

Patrinia villosa (Thunb.) Juss is a traditional herb commonly used in East Asia including Korea, Japan, and China. It has been administered to reduce and treat inflammation in Donguibogam, Korea. The mechanism for its anti-inflammatory effects has already been reported. In this study, we confirmed the efficacy of Patrinia villosa (Thunb.) Juss ethanol extract (Pv-EE) for inducing autophagy and investigate its anti-melanogenic properties. Melanin secretion and content were investigated using cells from the melanoma cell line B16F10. Pv-EE inhibited melanin in melanogenesis induced by α-melanocyte-stimulating hormone (α-MSH). The mechanism of inhibition of Pv-EE was confirmed by suppressing the mRNA of microphthalmia-associated transcription factor (MITF), decreasing the phosphorylation level of CREB, and increasing the phosphorylation of ERK. Finally, it was confirmed that Pv-EE induces autophagy through the autophagy markers LC3B and p62, and that the anti-melanogenic effect of Pv-EE is inhibited by the autophagy inhibitor 3-methyl adenine (3-MA). These results suggest that Pv-EE may be used as a skin protectant due to its anti-melanin properties including autophagy.

Clinical Potential of Circulating Tumor Cells in Colorectal Cancer: A Prospective Study.

OBJECTIVES: Circulating tumor cells (CTCs) in the blood have been used as diagnostic markers in patients with colorectal cancer (CRC). In this study, we evaluated a CTC detection system based on cell size to assess CTCs and their potential as early diagnostic and prognostic biomarkers for CRC. METHODS: From 2014 to 2015, 88 patients with newly diagnosed CRC, who were scheduled for surgery, and 31 healthy volunteers were enrolled and followed up in Pusan National University Hospital. CTCs were enriched using a centrifugal microfluidic system with a new fluid-assisted separation technique (FAST) and detected by cytomorphological evaluation using fluorescence microscopy. RESULTS: Two or more CTCs were detected using FAST in 74 patients and 3 healthy volunteers. The number of CTCs in the CRC group was significantly higher than that in the healthy volunteers (P < 0.001). When a receiver operating characteristic curve was created to differentiate patients with CRC from healthy volunteers, the sensitivity and specificity were almost optimized when the critical CTC value was 5/7.5 mL of blood. When this value was used, the sensitivity and specificity in differentiating patients with CRC from the healthy controls were 75% and 100%, respectively. In patients with CRC with ≥5 CTCs, vascular invasion was frequently identified (P = 0.035). All patients with stage IV were positive for CTCs. Patients with ≥5 CTCs showed a trend toward poor overall and progression-free survival. DISCUSSION: Our study demonstrated promising results with the use of FAST-based CTC detection for the early diagnosis and prognosis of CRC.

Circulating tumor cells detected by lab-on-a-disc: Role in early diagnosis of gastric cancer.

BACKGROUND: The use of circulating tumor cells (CTCs) as an early diagnostic biomarker and prognostic indicator after surgery or chemotherapy has been suggested for various cancers. This study aimed to evaluate CTCs in patients who underwent gastrectomy for gastric cancer and to explore their clinical usefulness in the early diagnosis of gastric cancer. METHODS: A total of 116 patients with gastric cancer who underwent gastrectomy and 31 healthy volunteers were prospectively included between 2014 and 2015. Peripheral blood samples were collected before gastrectomy, and CTCs were examined using a centrifugal microfluidic system with a new fluid-assisted separation technique. RESULTS: After creating a receiver operating characteristic curve to identify the discriminative CTC value needed differentiate patients with gastric cancer from healthy volunteers, sensitivity and specificity were nearly optimized at a CTC threshold of 2 per 7.5 mL of blood. Of the 102 persons with a CTC level ≥2 per 7.5 mL of blood, 99 (97.1%) had gastric cancer, and of the 45 persons with a CTC level <2 per 7.5 mL of blood, 28 (62.2%) were healthy controls. Accordingly, the sensitivity and specificity for the differentiation of patients with gastric cancer from healthy controls were 85.3% and 90.3%, respectively. However, the presence of CTCs was not associated with any clinicopathologic features such as staging, histologic type, or mucin phenotype. CONCLUSION: Although we could not prove the clinical feasibility of CTCs for gastric cancer staging, our results suggest a potential role of CTCs as an early diagnostic biomarker of gastric cancer.

Low-Affinity Zinc Sensor Showing Fluorescence Responses with Minimal Artifacts.

The study of the zinc biology requires molecular probes with proper zinc affinity. We developed a low-affinity zinc probe (HBO-ACR) based on an azacrown ether (ACR) and an 2-(2-hydroxyphenyl)benzoxazole (HBO) fluorophore. This probe design imposed positive charge in the vicinity of a zinc coordination center, which enabled fluorescence turn-on responses to high levels of zinc without being affected by the pH and the presence of other transition-metal ions. Steady-state and transient photophysical investigations suggested that such a high tolerance benefits from orchestrated actions of proton-induced nonradiative and zinc-induced radiative control. The zinc bioimaging utility of HBO-ACR has been fully demonstrated with the use of human pancreas epidermoid carcinoma, PANC-1 cells, and rodent hippocampal neurons from cultures and acute brain slices. The results obtained through our studies established the validity of incorporating positively charged ionophores for the creation of low-affinity probes for the visualization of biometals.

Expression of SPRR3 is associated with tumor cell proliferation in less advanced stages of breast cancer.

Small proline rich repeat protein 3 (SPRR3), a member of the SPRR family of cornified envelope precursor proteins, is a marker for terminal squamous cell differentiation. Previously, this laboratory showed that SPRR3 is strongly upregulated in colorectal tumors, and is involved in the tumorigenesis. The current study was performed to investigate the expression status and effect of SPRR3 in breast cancers (BCs). SPRR3 expression was examined by immunohistochemistry in 241 tumor samples from BC patients. SPRR3 was overexpressed in more than half of all BC samples. SPRR3 overexpression was significantly associated with less advanced stage (0-1 vs. II-III) and the absence of lymph node metastasis (P = 0.004 and 0.013, respectively). HER2/neu overexpression was closely correlated with SPRR3 overexpression in a multivariate analysis (OR, 3.23, P = 0.017). To assess the influence of SPRR3 on cell proliferation and related signaling pathways, SPRR3-transfected clones from the SPRR3-negative T-47D human BC cell line were generated. Among the total of six SPRR3-overexpressing clones, five showed marked proliferation compared with SPRR3-nonexpressing control cells from day 3 of culture (P < 0.001). The SPRR3-overexpressing BC clones showed increased phosphorylation of AKT and MDM2, p21 overexpression, and p53 downregulation. Furthermore, phosphorylation of MEK and MAPK was markedly increased. This study demonstrates that SPRR3 promotes BC cell proliferation by enhancing p53 degradation via the AKT and MAPK pathways and is, therefore, a potential novel therapeutic target for less advanced stages of BC.

[Prophylactic effect of Lactobacillus GG in animal colitis and its effect on cytokine secretion and mucin gene expressions].

BACKGROUND/AIMS: Lactobacillus rhamnosus GG (LGG) has been used in acute colitis treatment. However, it is unclear whether the LGG prevents chronic colitis. The aim of this study was to examine the prophylactic effect of LGG on animal colitis, cytokine secretion, and mucin gene expression. METHODS: BALB/c mice (n=64) were exposed to 5% dextran sulfate sodium (DSS) for 7 days followed by 10 days recovery period and repeatedly exposed for 4 days. Then, the mice were devided into three group; group of oral LGG adminstration throughout the recovery and repeated colitis period; PBS group of PBS administration; control group. Colon length, histologic score, tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10) levels, mucin gene expressions were determined at each period. RESULTS: In acute colitis period, the LGG group showed higher levels of disease activity index (DAI), histologic score, TNF-alpha, IL-10, but shorter colon length, lower levels of mucin gene expressions than the control group. However, in repeated colitis period, the LGG group showed markedly lower levels of DAI and IL-10 but significantly longer colon length than PBS group (p<0.05). There was no difference in the mucin gene expression. CONCLUSIONS: These results suggest that LGG prevents chronic murine colitis. It may be associated with cytokine modulation and competitive inhibition of pathogenic bacteria. However, it may not be related with gene expression.

[Measurement of telomerase activity and telomerase reverse transcriptase expression in gastric fluid and tissue for early diagnosis of stomach cancer].

BACKGROUND/AIMS: Telomerase activity and telomerase reverse transcriptase (TERT) expression have been proposed as a marker for malignancy. However, little is known about those markers in intestinal metaplasia (IM). This study was performed to evaluate the usefulness of telomerase activity in gastric washing fluid and TERT expression in tissue as a marker for early diagnosis of stomach cancer. METHODS: Gastric washing fluid and biopsies were taken endoscopically. We examined the telomerase activity by telomeric repeat amplification protocol (TRAP) and the TERT expression by semiquantitative reverse transcription-polymerase chain reaction in 26, 21 and 15 cases of cancer, IM, and normal mucosa respectively. RESULTS: The telomerase activity was positive in 65% of cancer, 44% of incomplete IM, and 33% of complete IM. The TERT was expressed in 89% of cancer, 81% of IM, but not in normal mucosa. The TERT expression level was higher in cancer and incomplete IM than in complete IM and normal mucosa (p<0.05). CONCLUSIONS: Telomerase activity in gastric washing fluid and TERT expression in tissue may have limited usefulness as a marker for the early diagnosis of stomach cancer. However, the increased levels of TERT expression in IM and cancer suggest that TERT expression may be associated with carcinogenesis in stomach cancer.