A novel orthotopic mouse model of head and neck cancer and lymph node metastasis.

Prognosis of head and neck squamous cell carcinoma (HNSCC) is largely determined by the extent of lymph node (LN) metastasis at diagnosis, and this appears to be controlled by cancer cell genetics. To examine the role of these genes in LN metastasis, we created a human-in-mouse orthotopic model of HNSCC and performed comparative microarray analysis of gene expression between populations of HNSCC cell lines derived before and after serial transplantation and in vivo metastasis in mice. Microarray analysis comparing the USC-HN3-GFP, USC-HN3-GFP-G1 and USC-HN3-GFP-G2 cell lines identified overexpression of genes implicated in epithelial-to- mesenchymal transition and the formation of cancer stem cells, including CAV-1, TLR-4 (Toll-like receptor 4), MMP-7 (matrix metalloproteinase 7), ALDH1A3, OCT-4 and TRIM-29. Ingenuity Pathway Analysis confirmed upregulation of respective gene signaling pathways in the USC-HN1-GFP-G2 cell line. Patient HNSCC samples from advanced stages overexpressed ALDH1A3, CAV-1 and MMP-7. Our results show that CAV-1, TLR-4, MMP-7, ALDH1A3, OCT-4 and TRIM-29 have increased expression in HNSCC cells selected for an enhanced metastatic phenotype and suggest that these genes may have an important role in the metastatic potential of HNSCC cells. Inhibition of these genes may therefore have prognostic and therapeutic utility in HNSCC.

Runx2 promotes both osteoblastogenesis and novel osteoclastogenic signals in ST2 mesenchymal progenitor cells.

UNLABELLED: We profiled the global gene expression of a bone marrow-derived mesenchymal pluripotent cell line in response to Runx2 expression. Besides osteoblast differentiation, Runx2 promoted the osteoclastogenesis of co-cultured splenocytes. This was attributable to the upregulation of many novel osteoclastogenic genes and the downregulation of anti-osteoclastogenic genes. INTRODUCTION: In addition to being a master regulator for osteoblast differentiation, Runx2 controls osteoblast-driven osteoclastogenesis. Previous studies profiling gene expression during osteoblast differentiation had limited focus on Runx2 or paid little attention to its role in mediating osteoblast-driven osteoclastogenesis. METHODS: ST2/Rx2(dox), a bone marrow-derived mesenchymal pluripotent cell line that expresses Runx2 in response to Doxycycline (Dox), was used to profile Runx2-induced gene expression changes. Runx2-induced osteoblast differentiation was assessed based on alkaline phosphatase staining and expression of classical marker genes. Osteoclastogenic potential was evaluated by TRAP staining of osteoclasts that differentiated from primary murine splenocytes co-cultured with the ST2/Rx2(dox) cells. The BeadChip™ platform (Illumina) was used to interrogate genome-wide expression changes in ST2/Rx2(dox) cultures after treatment with Dox or vehicle for 24 or 48 h. Expression of selected genes was also measured by RT-qPCR. RESULTS: Dox-mediated Runx2 induction in ST2 cells stimulated their own differentiation along the osteoblast lineage and the differentiation of co-cultured splenocytes into osteoclasts. The latter was attributable to the stimulation of osteoclastogenic genes such as Sema7a, Ltc4s, Efnb1, Apcdd1, and Tnc as well as the inhibition of anti-osteoclastogenic genes such as Tnfrsf11b (OPG), Sema3a, Slco2b1, Ogn, Clec2d (Ocil), Il1rn, and Rspo2. CONCLUSION: Direct control of osteoblast differentiation and concomitant indirect control of osteoclast differentiation, both through the activity of Runx2 in pre-osteoblasts, constitute a novel mechanism of coordination with a potential crucial role in coupling bone formation and resorption.

Prevalence of complications of simple tooth extractions and its comparison between a tertiary center and peripheral centers: a study conducted over 8,455 tooth extractions.

This study was conducted to investigate and compare the prevalence of complications of simple tooth extractions in a tertiary centre (BP Koirala Institute of Health Sciences, Dharan) and the peripheral centers (Mechi and Koshi zonal hospitals). This is a prospective descriptive study. Tooth extractions were carried out under local anesthesia in the tertiary and the peripheral centers during one year period (March 15"th 2004 to March H"111 2005). Intraoperative and postoperative complications were recorded and analyzed. Out of 8,455 tooth extractions in 6,639 [male-2,465 (37.12%) and females - 4,174 (62.88%)] patients aged between 5yrs- 65 yrs, 7,152 extractions were done in tertiary center and 1,393 extractions were done in peripheral centers.90 complications (1.06%) were observed. 53(58.89%) complications were intraoperative and 37(41.12%) complications were postoperative. 60(0.84%) complications were observed in the tertiary center and 30 (2.3%) complications were observed in the peripheral centers and the difference was highly significant (P<0.000001). The most frequent complication in the tertiary centre was fracture of tuberosity (0.15%) and in the peripheral centers it was 'roots left' (0.77%). Prevalence of 'roots left', injury to adjacent tooth and postoperative hemorrhage was significantly high (P<0.05) in peripheral centers. The higher prevalence rate of complications of tooth extractions in the peripheral centers should not be overlooked and well equipped and organized extraction procedure with qualified dental practitioner is strongly suggested to minimize the complications.

Fluoroscope-aided retrograde placement of guide wire for tracheal intubation in patients with limited mouth opening.

Passing a retrograde catheter/wire into the pharynx through a cricothyroid puncture can facilitate tracheal intubation in difficult situations where either a flexible fibre-optic bronchoscope or an expert user of such a device is not available. Some mouth opening is essential for the oral and/or nasal retrieval of the catheter/wire from the pharynx. Two patients with temporo-mandibular joint (TMJ) ankylosis and extremely limited mouth opening required gap arthroplasty of the TMJ under general anaesthesia. Because we did not have a flexible fibre-optic bronchoscope, we performed fluoroscopy-assisted nasal retrieval of the guide wire passed up through a cricothyroid puncture and subsequently accomplished wire-guided naso-tracheal intubation. In the absence of a flexible fibre-optic bronchoscope, this technique is a very useful aid to intubation in patients with limited mouth opening.

Retrieval of a retrograde catheter using suction, in patients who cannot open their mouths.

In difficulty, tracheal intubation can be facilitated by passing a retrograde catheter, but the mouth has to be opened for the retrieval of the catheter from the pharynx. Two patients with ankylosis of a temporomandibular joint were unable to open their mouth, and required general anaesthesia for gap arthroplasty. Because we did not have a flexible fibreoptic laryngoscope, we used a suction catheter to retrieve an epidural catheter from the pharyngeal cavity, which had been passed retrogradely from a cricothyroid puncture. Catheter-guided tracheal intubation was done without complication. A suction catheter can assist retrograde retrieval of a catheter to aid intubation in patients who cannot open the mouth.

A polystyrene based membrane electrode for cadmium(II) ions.

A polystyrene based membrane of 3,4:12,13-dibenzo-2,5,11,14-tetraoxo- 1,6,10,15-tetraazacyclooctade-cane shows a Nernstian response to Cd(II) ions over a wide concentration range (3.16 x 10(-6) - 1.00 x 10(-1) mol L(-1) with a Nernstian slope of 29.8 mV/decade of concentration, between pH 2.0 and 6.0. This electrode has been found to be chemically inert and of adequate stability with a response time of 20s. The electrode gives reproducible results with a lifetime of 130 days. The membrane works satisfactorily in a partially non-aqueous medium up to a maximum 35% (v/v) content of methanol and ethanol. The practical utility of the proposed chemical sensor has been observed by using it as end-point indicator in the titration of Cd(II) ions with EDTA. The potentiometric selectivity coefficient values indicate that the membrane sensor is highly selective for Cd(II) ions over a number of cations. Small amounts of surfactants do not disturb the functioning of the sensor. This electrode has also been used to estimate cadmium ions in real samples.

Poly(vinyl chloride)-based macrocyclic membrane sensors for magnesium.

Poly(vinyl chloride)-based membranes of macrocycles 4,11-dimethyl-2,4,9,11-tetraethyl-1,5,8,12-tetraaza cyclotetradeca-1,8-diene (I) and 4,11-dioxa-2,9-dimethyl-1,5,8,12-tetraaza cyclotetradeca-1,8-diene (II) with sodium tetraphenyl borate (STB) as an anion excluder and dibutyl phthalate (DBP), dioctyl phthalate (DOP), dibutylbutyl phosphonate (DBBP) and 1-chloronaphthalene (CN) as plasticizing solvent mediators were prepared and investigated as magnesium selective electrodes. The best performance was observed having the composition (II)-PVC-STB-DBP in the ratio 2:10:1:7, which works well over a wide concentration range (1.9x10(-6) to 1.0x10(-1) M) with a Nernstian slope of 29 mV per decade of activity between pH 2.5 and 6.5. These electrodes have been found to be chemically inert showing a fast response time of 15 s and were used over a period of 3 months with good reproducibility (S=+/-0.2 mV). The selectivity coefficient values for mono-, di- and trivalent cations indicate excellent selectivity for Mg(2+) over a large number of cations. The electrodes have also been used successfully in partially non-aqueous medium and as an indicator electrode in the potentiometric titration of Mg(2+) with EDTA. Anions such as Cl(-) and SO(4)(2-) do not interfere in the working of the electrode. The practical utility of the membrane sensor has also been observed in solutions contaminated with detergents (cetyltrimethyl ammonium bromide and sodium dodecyl sulphate). Above all, the membrane sensor has been very successfully used to analyse some babyfood products and soft drinks for the determination of Mg(2+).