Cytotoxic and apoptotic effects of 1,2-diborolanes with strong donor substitutes on human cancer cells.

In recent years, boron compounds have become more common as chemotherapy agents against certain types of cancers. Along with the development of boron-based therapeutic agents have come investigations into the various cancers and biochemical and molecular mechanisms affected by boron compounds and the relationships between boron compounds and chemical protection against cancer. In this preliminary study, the effects of new 1,2-N-substituted-1,2-diborolane derivatives on types of breast and liver cancers were examined for the first time. Four were found to significantly affect the cell viabilities and mitochondrial membrane potential changes in MCF-7, HepG2 and Hep3B cancer cells. Each was prepared in n-hexane at various concentrations (5, 10, 25, 50, 75 and 100 µg/mL). Human peripheral blood lymphocytes were used as control cells. Compounds 1, 2, 3a, and 3b 1,2-diborolane derivatives selectively killed cancer cells, but compound 1 was cytotoxic in a concentration-dependent manner on HepG2 and Hep3B and only at concentrations of at least 75 µg/mL on MCF-7 cells. Compound 3a exhibited cytotoxic effect on lymphocytes at 75 and 100 µgmL-1 concentrations, but compounds 1, 2 and 3b, 3c and 3d have not possessed significant cytotoxic effect on lymphocytes. Compounds 3c and 3d have not possessed significant cytotoxic effects. Mitochondrial membrane potential assay results supported these findings. Our results reveal that 1,2-diborolane derivates have high cytotoxic and apoptotic activities on human hepatocarcinoma cells and are therefore potential candidates in the development of new drugs against liver cancer.

A Novel Protein Testing Model to Assay the Efficacy of Multiple Irrigation Activation Techniques for Removal of Ex Vivo Biomolecular Film.

OBJECTIVE: This study aimed to compare the debris removal efficacies of irrigation activation techniques using ex vivo biomolecular film. MATERIALS AND METHODS: Root canals of 50 human mandibular premolars were prepared, and freshly prepared collagen solutions were applied into the root canals using a peristaltic pump. Specimens were randomly divided into the five groups and irrigated with 3 mL of 5.25% sodium hypochlorite (NaOCl): G1 (needle irrigation and control group): a 27-gauge notched-tip irrigation needle (Endo-Eze; Ultradent, South Jordan, UT); G2, Vibringe sonic irrigation system (VSS) (Vibringe B.V. Corp., Amsterdam, Netherlands); G3, EndoActivator sonic irrigation system (EA) (Dentsply Tulsa Dental Specialties, Tulsa, OK); G4, passive ultrasonic irrigation (PUI) (EMS, Nyon, Sweden); and G5, photon-induced photoacoustic streaming (PIPS) (Fotona, Ljubljana, Slovenia). Postirrigation solution was collected in beakers containing 3% sodium thiosulfate by which NaOCl solution was neutralized. Residual protein levels in NaOCl solution were evaluated by the Bradford method. Data were analyzed using ANOVA with Duncan post hoc tests (α = 0.05). RESULTS: PIPS (laser-activated irrigation) method removed more artificial collagen than other experimental groups (EA, PUI, VSS) or the control group (p ≤ 0.05). There were no statistical differences among the EA, PUI, and VSS groups. The PIPS, PUI, and EA groups were superior compared with the conventional irrigation (p ≤ 0.05); however, there were no significant differences between VSS and the conventional irrigation groups. CONCLUSIONS: Although all the methods and techniques examined in this study were suitable in extruding the ex vivo biomolecular film, the PIPS method was found significantly more effective than all the other tested groups (p ≤ 0.05).

Purification and Characterization of an Alkali-Thermostable Lipase from Thermophilic Anoxybacillus flavithermus HBB 134.

An intracellular lipase from Anoxybacillus flavithermus HBB 134 was purified to 7.4-fold. The molecular mass of the enzyme was found to be about 64 kDa. The maximum activity of the enzyme was at pH 9.0 and 50°C. The enzyme was stable between pH 6.0 and 11.0 at 25°C, 40°C, and 50°C for 24 h. The Km and Vmax of the enzyme for pNPL substrate were determined as 0.084 mM and 500 U/mg, respectively. Glycerol, sorbitol, and mannitol enhanced the enzyme thermostability. The enzyme was found to be highly stable against acetone, ethyl acetate, and diethyl ether. The presence of PMSF, NBS, DTT and ß-mercaptoethanol inhibited the enzyme activity. Hg(2+), Fe(3+), Pb(2+), Al(3+), and Zn(2+) strongly inhibited the enzyme whereas Li(+), Na(+), K(+), and NH4(+) slightly activated it. At least 60% of the enzyme activity and stability were retained against sodium deoxycholate, sodium taurocholate, n-octyl-ß-D-glucopyranoside, and CHAPS. The presence of 1% Triton X-100 caused about 34% increase in the enzyme activity. The enzyme is thought to be a true lipase since it has preferred the long-chain triacylglycerols. The lipase of HBB 134 cleaved triolein at the 1- or 3-position.

Characterization of esterase activity in Geobacillus sp. HBB-4.

A thermophilic esterase producing bacterium (Bacillus sp. 4), recently isolated from Alangüllü thermal spring in Aydin (Turkey), was analyzed using 16S rRNA and classified as Geobacillus sp. HBB-4, most closely related to Bacillus sp. BGSC W9A59 (0.70% sequence divergence) which belongs to the newly described genus Geobacillus. The effects of several chemicals on the activity of thermostable esterase from Geobacillus sp. HBB-4 were examined. Among the various metal ions tested, esterase activity was enhanced by Mn(+2) and Ni(+2), but was inhibited by Hg(+2) and Cu(+2), whereas Ca(+2), Mg(+2) and Co(+2) had no effect. In addition, other metal ions studied have caused a slight inhibition on the esterase activity. EDTA partially inhibited the HBB-4 esterase. The activator metal ions, Mn(+2) and Ni(+2) have restored partial inhibition of EDTA. The activity of HBB-4 esterase was inhibited by ionic detergents while non-ionic detergents activated the enzyme. However, a zwitterionic detergent, CHAPS, has caused a slight inhibition in the enzyme activity. HBB-4 esterase activity was inhibited at the high concentrations of all the organic solvents tested in the present study. However, 50% final concentration of DMSO increased the enzyme activity about 7%. The HBB-4 esterase has shown more than about 50% of activity in the presence of ethanol and methanol solutions. These characteristics of the enzyme along with its significant thermostability make the Geobacillus sp. HBB-4 esterase a potent candidate for future industrial applications.

Elevated expression of MMP-13 and TIMP-1 in head and neck squamous cell carcinomas may reflect increased tumor invasiveness.

BACKGROUND: Matrix metalloproteinases [MMPs], which degrade the extracellular matrix, play an important role in the invasion and metastasis of squamous cell carcinomas. One MMP, MMP-13, is thought to play a central role in MMP activation. The purpose of this study was to investigate MMP-13 and TIMP-1 expression in squamous cell carcinomas of the head and neck and to relate these levels of expression to histologic patterns of invasion. METHODS: This study included T1 lesions obtained via biopsy from the larynx, tongue, and skin/mucosa of 78 patients with head and neck squamous cell carcinomas. The relationship between expression of MMP-13 and TIMP-1 and the mode of tumor invasion [MI] was evaluated immunohistochemically, using breast carcinoma tissue as a positive control. RESULTS: Increased expression was observed in highly invasive tumors, as reflected by the significant correlation between the degree of staining for MMP-13 or TIMP-1 and MI grade [p < 0.05]. There was no significant relationship between the degree of staining for MMP-13 or TIMP-1 and patient age, sex, tumor site, or tumor histologic grade. In addition, levels of staining for MMP-13 did not correlate with levels of staining for TIMP-1. CONCLUSION: The expression of MMP-13 and TIMP-1 appears to play an important role in determining the invasive capacity of squamous cell carcinomas of the head and neck. Whereas additional studies are needed to confirm these findings, evaluating expression of these MMPs in small biopsy samples may be useful in determining the invasive capacity of these tumors at an earlier stage.

Cervicopectoral flap in head and neck cancer surgery.

BACKGROUND: Reconstruction of the head and neck after adequate resection of primary tumor and neck dissection is a challenge. It should be performed at one sitting in advanced tumors. Defects caused by the resection should be closed with flaps which match in color, texture and hair bearing characteristics with the face. Cervicopectoral flap is a one such flap from chest and neck skin mainly used to cover the cheek defects. METHODS: This study included twelve patients presenting with cancer of the head and neck to Izmir Ataturk Training Hospital and Adnan Menderes University Hospital. Tumor resection and neck dissection was performed in one session by the same surgeon. A single incision was made and a medially based cervicopectoral fascio-cutaneous flap was used for surgical exposure in neck dissection and for closure of defects after tumor resection. RESULTS: There was no major complication. Two flaps had partial superficial epidermolysis at the suture line. Good aesthetic and functional results were achieved. CONCLUSION: The cervicopectoral flap is an excellent alternative for the reconstruction of head and neck. Harvesting and application of the flap is rapid and safe. Only a single incision is sufficient for dissection and flap elevation. This flap achieves perfect surgical exposure, makes neck dissection easy and allows one to perform both tumor resection and neck dissection in one session.

The new anatomical viewpoint of the nose: the interdomal fat pad.

To the plastic surgeon, the nose is one of the most interesting and challenging facial structures and its anatomy is well defined. From the point of view of aesthetic surgery, the nasal tip area is an especially important structural unit, and the most difficult to address in rhinoplasty. The objective of this study was to demonstrate the existence of the nasal interdomal fat pad as a distinct anatomical structure that occupies the interdomal space and is apart from subcutaneous fat. In our study we proved the existence of the interdomal fat pad by histochemical studies and anatomical observations in 88 patients who underwent primary external rhinoplasty and three fresh cadavers. All specimens were examined by hemotoxylen-eosin, Sudan black, and oil red staining, as well as S100 protein immunoreactivity staining. The mass of the interdomal fat pad was greater in patients with bulbous noses and/or divergent alar cartilage than in patients with thin skin. We speculated that the interdomal fat pad may be the major anatomic structure contributing to unexpected results in difficult cases, such as those involving bulbous noses. According to our study, the existence of the interdomal fat pad should be kept in mind during the preoperative planning of rhinoplasty.