Plasmon light scattering in biology and medicine: new sensing approaches, visions and perspectives

Surface plasmons are collective oscillations of free electrons at metallic surfaces. These oscillations can give rise to the intense colors of solutions of plasmon resonance nanoparticles and/or very intense scattering. While the use of plasmonic particle absorption based bioaffinity sensing is now widespread throughout biological research, the use of their scattering properties is relatively ill explored. We refer to the use, utility and control of surface plasmons as plasmonics. In this review and forward-looking article, we discuss the current opinions and uses of plasmonics, as well as speculate on areas of future research. These include the use of plasmon scatter for long-range immunosensing and macromolecular conformation studies, as well as the ability to Stokes shift plasmon scatter, a plasmonics phenomenon recently referred to as metal-enhanced fluorescence.     

Effects of N-acetylcystein on bleomycin-induced apoptosis in malignant testicular germ cell tumors

Oxidative stress has been shown to induce apoptosis in cancer cells. Therefore, one might suspect that antioxidants may inhibit reactive oxygen species (ROS) and prevent apoptosis of cancer cells. No study has been carried out so far to elucidate the effects of N-acetylcysteine (NAC) on bleomycin-induced apoptosis in human testicular cancer (NCCIT) cells. We investigated the molecular mechanisms of apoptosis induced by bleomycin and the effect of NAC in NCCIT cells. We compared the effects of bleomycin on apoptosis with H₂O₂ which directly produces ROS. Strong antioxidant NAC was evaluated alone and in combination with bleomycin or H₂O₂ in germ cell tumor-derived NCCIT cell line (embryonal carcinoma, being the nonseminomatous stem cell component). We determined the cytotoxic effect of bleomycin and H₂O₂ on NCCIT cells and measured apoptosis markers such as caspase-3, caspase-8, and caspase-9 activities and Bcl-2, Bax, and cytochrome c (Cyt-c) levels in NCCIT cells incubated with bleomycin, H₂O₂, and/or NAC. We found half of the lethal dose (LD₅₀) of bleomycin on NCCIT cell viability as 120???g/ml after incubation for 72?h. Incubation with bleomycin (LD₅₀) induced increases in caspase-3, caspase-8, and caspase-9 activities and Cyt-c and Bax protein levels and a decrease in Bcl-2 level. Co-incubation of NCCIT cells with bleomycin and 10?mM NAC abolished bleomycin-induced increases in caspase-3 and caspase-9 activities, Bax, and Cyt-c levels and bleomycin-induced decrease in Bcl-2 level. Our results indicate that bleomycin induces apoptosis in NICCT cells and that NAC diminishes bleomycin-induced apoptosis via inhibiting the mitochondrial pathway. We conclude that NAC has negative effects on bleomycin-induced apoptosis in NICCT cells and causes resistance to apoptosis, which is not a desirable effect in the fight against cancer.     

Mutagenic and antimutagenic properties of some lichen species grown in the Eastern Anatolia Region of Turkey

All the methanol extracts did not show mutagenic activity in Ames/Salmonella and Z. mays MI test systems. Furthermore, some extracts showed significant antimutagenic activity against 9-AA in Ames test system. Inhibition rates for 9-AA mutagenicity ranged from 25.51% (P. furfuracea??0.05 ??g/plate) to 66.14% (C. islandica??0.05 ??g/plate). In addition, all of the extracts showed significant antimutagenic activity against sodium azide (NaN₃) mutagenicity on MI values of Z. mays.     

Tomato powder impedes the development of azoxymethane-induced colorectal cancer in rats through suppression of COX-2 expression via NF-κB and regulating Nrf2/HO-1 pathway

Cancer is one of the leading causes of death worldwide. Since dietary factors have been connected to a reduced risk of a diversity of human cancers, in this study we investigated the effects of tomato powder (TP) on the development of azoxymethane (AOM)-induced colorectal cancer in Wistar rats, and possible mechanism(s) by which TP shows its chemopreventive activity. Here we show that TP added to feed at 5% rate decreases the rate of aberrant crypt foci (ACF) and reduces the development of adenocarcinoma and growth of AOM-induced colorectal cancer in rats. In addition, we demonstrate that TP supplementation shows its chemopreventive activities through inhibition of cyclooxygenase-2 (COX-2) expression via NF-κB pathway and promotion of apoptosis, as well as regulating Nrf2/HO-1 signaling pathway in colorectal tissue of AOM-treated rats. Our findings identify an intimate connection between dietary supplementation of TP and the decreased risk of colorectal cancer in rats, and suggest that consumption of TP would be a natural candidate for the prevention of colorectal cancer in men.     

Anti-inflammatory and antiulcerogenic effects of the aqueous extract of Lobaria pulmonaria (L.) Hoffm.

An aqeuous extract of Lobaria pulmonaria (L.) Hoffm., from which a tea is prepared and consumed as treatment for various diseases in northeastern Turkey, was tested for its anti-inflammatory and antiulcerogenic effects in rats. The carrageenan-induced paw edema, cotton pellet granuloma and indomethacin-induced gastric damage models were used to determine these effects. The extract exhibited moderate anti-inflammatory and strong antiulcerogenic activities.     

Lymphocyte DNA damage and oxidative stress in patients with iron deficiency anemia

Oxidant stress has been shown to play an important role in the pathogenesis of iron deficiency anemia. The aim of this study was to investigate the association between lymphocyte DNA damage, total antioxidant capacity and the degree of anemia in patients with iron deficiency anemia. Twenty-two female with iron deficiency anemia and 22 healthy females were enrolled in the study. Peripheral DNA damage was assessed using alkaline comet assay and plasma total antioxidant capacity was determined using an automated measurement method. Lymphocyte DNA damage of patients with iron deficiency anemia was significantly higher than controls (p<0.05), while total antioxidant capacity was significantly lower (p<0.001). While there was a positive correlation between total antioxidant capacity and hemoglobin levels (r=0.706, p<0.001), both total antioxidant capacity and hemoglobin levels were negatively correlated with DNA damage (r=-0.330, p<0.05 and r=-0.323, p<0.05, respectively). In conclusion, both oxidative stress and DNA damage are increased in IDA patients. Increased oxidative stress seems as an important factor that inducing DNA damage in those IDA patients. The relationships of oxidative stress and DNA damage with the severity of anemia suggest that both oxidative stress and DNA damage may, in part, have a role in the pathogenesis of IDA.     

Streptococcus pyogenes pSM19035 requires dynamic assembly of ATP-bound ParA and ParB on parS DNA during plasmid segregation

The accurate partitioning of Firmicute plasmid pSM19035 at cell division depends on ATP binding and hydrolysis by homodimeric ATPase δ₂ (ParA) and binding of ω₂ (ParB) to its cognate parS DNA. The 1.83 Å resolution crystal structure of δ₂ in a complex with non-hydrolyzable ATPγS reveals a unique ParA dimer assembly that permits nucleotide exchange without requiring dissociation into monomers. In vitro, δ₂ had minimal ATPase activity in the absence of ω₂ and parS DNA. However, stoichiometric amounts of ω₂ and parS DNA stimulated the δ₂ ATPase activity and mediated plasmid pairing, whereas at high (4:1) ω₂ : δ₂ ratios, stimulation of the ATPase activity was reduced and δ₂ polymerized onto DNA. Stimulation of the δ₂ ATPase activity and its polymerization on DNA required ability of ω₂ to bind parS DNA and its N-terminus. In vivo experiments showed that δ₂ alone associated with the nucleoid, and in the presence of ω₂ and parS DNA, δ₂ oscillated between the nucleoid and the cell poles and formed spiral-like structures. Our studies indicate that the molar ω₂ : δ₂ ratio regulates the polymerization properties of (δ•ATP•Mg²⁺)₂ on and depolymerization from parS DNA, thereby controlling the temporal and spatial segregation of pSM19035 before cell division.     

Molecular Characterization of <Emphasis Type="Italic">Cyclamen</Emphasis> Species Collected from Different Parts of Turkey by RAPD and SRAP Markers

The genus Cyclamen (family Myrsinaceae) contains about 20 species, most of which occur in the Mediterranean region. Turkey has critically important Cyclamen genetic resources. Molecular characterization of plant materials collected from different regions of Turkey in which Cyclamen species grow naturally, namely Adana, Antalya, Ayd?n, Mu?la, ?zmir, Denizli, Kahramanmara?, Osmaniye, Eski?ehir, Trabzon, and Rize provinces, was performed using RAPD and SRAP markers. DNA was successfully amplified by 30 RAPD primers and 14 SRAP primer pairs. Among the 470 bands generated by the RAPD primers, 467 were polymorphic. The number of bands detected by a single primer set ranged from 11 to 22 (average of 15.6). The percentage polymorphism was 99.3 % based on the RAPD data. In the SRAP analysis, a total of 216 bands were generated, showing 100 % polymorphism. The number of bands detected by a single primer set ranged from 9 to 22 (average of 15.4). All data were scored and UPGMA dendrograms were constructed with similar results in both marker systems, i.e., different species from nine provinces of Turkey were separated from each other in the dendrograms with the same species being clustered together.     

Development of Interleukin-2 Loaded Chitosan-Based Nanogels Using Artificial Neural Networks and Investigating the Effects on Wound Healing in Rats

The aim of this study was to develop and characterize rh- IL-2 loaded chitosan-based nanogels for the healing of wound incision in rats. Nanogels were prepared using chitosan and bovine serum albumin (BSA) by ionic gelation method and high temperature application, respectively. Particle size, zeta potential, and polydispersity index were measured for characterization of nanogels. The morphology of nanogels was examined by using SEM and AFM. The IL-2 loading capacity of nanogels was determined using ELISA method. In vitro release of IL-2 from nanogels was performed using Franz diffusion cells. Artificial neural network (ANN) models were developed using selected input parameters (stirring rate, chitosan%, BSA%, TPP%) where particle size was an output parameter for IL-2 free nanogels. Wound healing effect of IL-2 loaded chitosan-TPP nanogel was evaluated by determining the malondialdehyde (MDA) and glutathione (GSH) levels of wound tissues in rats. The particle size of IL-2 loaded chitosan-TPP nanogels was found to be larger than that of IL-2 loaded BSA-based chitosan nanogels. Drug loading capacity of nanogels was found 100%?±?0.010 for both nanogels. IL-2 was released slowly after the initial burst effect. According to SEM and AFM imaging, BSA-chitosan nanogel particles were of nanometer size and presented a swelling tendency, and chitosan-TPP nanogel particles were found to be spherical and homogenously dispersed. IL-2 loaded chitosan-TPP nanogel was found suitable for improving wound healing because it decreased the MDA levels and increased the GSH levels wound tissues comparing to control group.     

The outcome of twin pregnancies complicated by single fetal death after 20 weeks of gestation.

A retrospective study involving 972 twin births was conducted to evaluate the maternal and fetal outcomes of twin pregnancies complicated by single fetal death. The incidence of single fetal death in twin pregnancies after 20 weeks was 3.3%. Preterm birth rates for 37 and 32 gestational weeks were 81.3% and 41.6% respectively. The median interval between the diagnosis of fetal death and the delivery was 11 days (range 1-27 days). Eighteen (56%) infants were delivered by cesarean and 14 (43%) vaginally. Twin-twin transfusion syndrome (TTTS) was the cause of single fetal death in 8 of 32 twin pregnancies (25%). Ten of the surviving co-twins were lost in the neonatal period (31.3%) and half of those neonatal deaths were due to TTTS. TTTS is the major contributor for perinatal mortality in same-sex twins complicated by single fetal death. The death of one twin in utero should not be the only indication for preterm delivery, and in case of severe prematurity with a stable intrauterine environment; expectant management may be advisable until fetal lung maturation ensues.