Deoxyribonucleic Acid Content Research Articles

Meta-analysis of invitro methods on tracheal decellularization.

Tracheal decellularization is one of the main processes to provide tracheal substitutes for tracheal replacement. Recently, studies have been held for agents and combinations of processes for tracheal decellularization with different outcomes. This study aimed to evaluate the efficacy of tracheal decellularization by the immunogenic cellular elements using residual deoxyribonucleic acid (DNA) contents (ng/mg) and the preservation of biomechanical integrity by glycosaminoglycan (GAG) content (μg/mg), modulus tensile strength (MPa), ultimate tensile strength (MPa), and stress loading of 50% deformation (N). We conducted a meta-analysis based on PRISMA criteria. Data from experimental studies in MEDLINE, Scopus, and ScienceDirect from inception to August 21, 2023, were sought and computed using RevMan 5.4. The outcomes of tracheal decellularization were evaluated through effect size estimates based on pooled Standardized Mean Difference (SMD) with 95% CI. Tracheal decellularization has significantly reduced the DNA and GAG content after the process (SMD: -11.77, 95% CI [-13.92, -8.62], p < 0.00001; SMD: -6.70, 95% CI [-9.55, -3.85], p < 0.00001). No significant outcomes were observed in modulus and ultimate tensile strength result (SMD: -0.14, 95% CI [-0.64, 0.36], p = 0.58; SMD: 0.11, 95% CI [-0.57, 0.80], p = 0.75). The stress loading of 50% deformation was observed to significantly lower (SMD: -1.61, 95% CI [-2.49, -0.72], p = 0.0004). Tracheal decellularization has been proven to effectively remove immunogenic cells. However, extracellular matrix integrity and biomechanical properties vary among different decellularization techniques, indicating a need for further refinement to achieve better preservation.

A new three-dimensional modeling of fluorescence excitation-emission measurements to explore the interaction of hydroxychloroquine and DNA, and to quantify their binding constant

A new three-dimensional chemometric approach was introduced to explore the interaction of hydroxychloroquine (HCQ)-calf thymus deoxyribonucleic acid (DNA) and quantify binding constant using fluorescence excitation and emission measurements. The fluorescence excitation-emission spectra were recorded after gradual titration of HCQ with DNA. Then, the excitation and emission curves and relative concentrations of the drug and drug-DNA complex were quantitatively estimated using a three-dimensional model called Parallel Factor Analysis (PARAFAC) to a cubic fluorescence data array. The interaction of HCQ and DNA was predicted by applying newly modified Stern-Volmer equations to the relationship between the actual DNA concentration, and the HCQ concentration in the relative concentration profile of the PARAFAC model. In the PARAFAC application, the binding constants of the HCQ-DNA complex at 288, 298, and 310 K were found as 6.78 × 103, 5.07 × 103, and 3.74 × 103 L mol−1, respectively. From the temperature studies, the thermodynamic parameters (ΔS0= 3.528 J mol−1 K−1, ΔH0= −20.099 kJ mol−1 and ΔG0=-21.11, −21.12, and −21.19 kJ mol−1 at 288, 298, and 310 K, respectively) were calculated. The drug-DNA interaction is spontaneous due to negative ΔG0 values. The positive ΔS0 and negative ΔH0 values revealed the major role of the electrostatic force on the binding of HCQ to DNA. Assay results obtained from the proposed three-way modeling were compared to those provided by the traditional spectrofluorimetric method.

In vivo efficacy of date palm pit extract based chromone derivative against Aedes aegypti dengue vectors in Saudi Arabia

AbstractThis study investigated the in vivo efficacy of a chromium derivative extracted from date palms pit against Aedes aegypti the third instar larvae, the known vector of dengue fever in Saudi Arabia. Chromone 1, a flavonoid chromone component, was isolated from the alcoholic extract of date palm pits (DPP) using High‐performance liquid chromatography (HPLC). The results showed that exposure of A. aegypti larvae to whole DPP extract and chromone 1 for 24 h resulted in significant insecticidal efficacy with LC50 values of 132.82 and 54.64 ppm, respectively. The same concentrations also effectively inhibited AChE (acetylcholinesterase) activity up to −56.83 and −58.58%, respectively, compared to controls. The acetylcholine bromide test further confirmed the interaction between chromone 1 and AChE. The results also revealed that the chromone 1 treatment altered Deoxyribonucleic Acid (DNA) and protein content. It also exhibited that the extract of date palm pits DPP can effectively serve as sustainable ingredients for the control management of A. aegypti.

Advancing COVID-19 Diagnosis: Enhancement in SERS-PCR with 30-nm Au Nanoparticle-Internalized Nanodimpled Substrates.

Real-time polymerase chain reaction (RT-PCR) with fluorescence detection is the gold standard for diagnosing coronavirus disease 2019 (COVID-19) However, the fluorescence detection in RT-PCR requires multiple amplification steps when the initial deoxyribonucleic acid (DNA) concentration is low. Therefore, this study has developed a highly sensitive surface-enhanced Raman scattering-based PCR (SERS-PCR) assay platform using the gold nanoparticle (AuNP)-internalized gold nanodimpled substrate (AuNDS) plasmonic platform. By comparing different sizes of AuNPs, it is observed that using 30nm AuNPs improves the detection limit by approximately ten times compared to 70nm AuNPs. Finite-difference time-domain (FDTD) simulations show that multiple hotspots are formed between AuNPs and the cavity surface and between AuNPs when 30nm AuNPs are internalized in the cavity, generating a strong electric field. With this 30nm AuNPs-AuNDS SERS platform, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA)-dependent RNA polymerase (RdRp) can be detected in only six amplification cycles, significantly improving over the 25 cycles required for RT-PCR. These findings pave the way for an amplification-free molecular diagnostic system based on SERS.

Influence of feeding a soft diet on proteoglycan expression in rat temporomandibular joint discs

ObjectivesExtracellular matrix components play a significant role in maintaining tissue integrity and pathological processes of the temporomandibular joint (TMJ). This study aimed to evaluate the influence of a soft diet on the mRNA expression of proteoglycans and glycosaminoglycans (GAGs) linked to proteoglycan core proteins in rat TMJ discs. MethodsThirty 4-week-old male Wistar rats were assigned to one of two groups: a control group fed a regular pellet diet and a soft diet group fed a powdered diet for 4 weeks. The mRNA expression levels of 12 proteoglycans in TMJ discs were evaluated using real-time polymerase chain reaction (PCR). In addition, histomorphometric and biochemical analyses were performed to evaluate the thickness and deoxyribonucleic acid (DNA), GAG, and water content of the TMJ discs. ResultsThe TMJ disc thickness in the anterior, intermediate, and posterior bands decreased significantly in the soft diet group. The GAG content decreased significantly in the soft-diet group, whereas no significant differences in DNA content or water content ratio were observed between the groups. Real-time PCR indicated that the expression levels of aggrecan, versican, biglycan, decorin, fibromodulin, lumican, and chondroadherin decreased in the soft diet group. The expression levels of all versican isoforms decreased in the soft diet group. ConclusionsThese results indicate that the biomechanical environment of the TMJ caused by a soft diet is closely related to the expression of proteoglycans in TMJ discs, which may eventually increase the fragility of the TMJ discs.

An electrochemical DNA biosensor coupled with dual amplification strategy based on DNA-Au bio-bar codes and silver enhancement for highly sensitive and selective detection of MDR1 gene

Given the tumors might develop multidrug resistance (MDR) during chemotherapy that leading to treatment failure, rapid and sensitive determination of MDR1 gene is an effective tool to monitor the development of MDR. Herein, we established an electrochemical deoxyribonucleic acid (DNA) biosensor coupled with dual amplification strategy based on DNA-Au bio-bar codes and enhancement of silver for sensitive and selective determination of MDR1 gene. Specifically, DNA-Au bio-bar codes as signal probe were prepared by immobilizing complementary and non-complementary sequences on gold nanoparticles (AuNPs), so as to reduce the cross reaction between the target and reporter DNA. In addition, AuNPs-catalyzed reduction of silver ions greatly amplified the current signal. Under the optimal conditions, the current signal was proportional to the base-10 logarithm of target DNA concentration in a wide range from 100 fM to 1 nM with a detection limit as low as 33 fM (S/N = 3). Moreover, without the need for target amplification, the prepared biosensor exhibited superior selectivity and high sensitivity even in the presence of other sequences. Therefore, the developed electrochemical DNA biosensor is a facile and sensitive platform for MDR1 gene detection.

A review of advanced techniques for detecting the authenticity and adulteration of camellia oil

AbstractCamellia oil, one of the four major woody oils globally, possesses exceptional nutritional value due to its high contents of unsaturated fatty acids and functional compounds like tocopherols, phenolics, and chlorophyll. Unfortunately, due to high demand and cost, fraudsters deliberately mix lower‐quality vegetable oils with camellia oil for profits. This has raised concerns among stakeholders, prompting the need for robust authentication methods. This review provides a concise overview of various analytical techniques employed to assess the authenticity, quality, and potential adulteration of camellia oil. Several techniques, such as chromatography, isotope‐ratio mass spectrometry (IRMS), ion mobility spectrometry (IMS), differential scanning calorimetry (DSC), plasma‐based and deoxyribonucleic acid (DNA)‐based techniques, as well as emerging methods like electronic noses and electronic tongues, are discussed. Notably, traditional chromatographic techniques (GC and HPLC) are reported to be time‐consuming, laborious, employ toxic chemicals, and require complicated sample pretreatments. DNA techniques also face challenges in detecting adulterants due to the complex refining processes of camellia oil, including high‐temperature decolorization and deodorization, which reduce DNA content and induce degradation. In contrast, spectroscopic techniques such as fluorescence spectroscopy, nuclear magnetic resonance, and infrared (near, mid, far) spectroscopy combined with chemometric analyses, have emerged as reliable, rapid, simple, sensitive, and accurate alternative analytical tools for the quality control of camellia oil.

Inventory and quality control of biosample collection from pregnant women at different gestational ages to search for early biomarkers of pregnancy complications

Aim. To conduct an inventory and quality control of biosample collection from pregnant women at different gestational ages to search for early biomarkers of pregnancy complications.Material and methods. In this work, methods for assessing the sample preparation of biosamples were used, including the isolation of deoxyribonucleic acid (DNA)/ribonucleic acid from various biomaterials, polyacrylamide gel electrophoresis of protein, and database analysis.Results. Inventory and quality control of the collection (n=18390) was carried out, which confirmed the high safety of the biomaterial, regardless of storage period. The mean concentration of DNA was 69,96±6,56 ng/µl, extracellular DNA (ecDNA) — 0,20±0,02 ng/µl, ribonucleic acid — 38,16±5,69 ng/µl. DNA Integrity Number (DIN) &gt;9, RNA integrity number (RIN) &gt;7, A260/280 &gt;1,8 were for all studied samples. Protein electrophoresis demonstrated no degradation of protein zones after longterm storage. The number of errors detected during the inventory was 84 (0,46% of all records in the database), while there were 64 donors with incomplete clinical information (15% of all donors in the collection).Conclusion. The necessity of mandatory implementation of standard operating procedures when creating and maintaining a collection, on the one hand, and periodic inventory with biosample quality assessment, on the other, has been demonstrated.

Performance Analysis of Electrochemical Detection Platform for DNA Hybridization Using TGN-Based Nanobiosensor

Trilayer graphene nanoribbon (TGN) has great potential in related biomedical applications such as drug and gene delivery and deoxyribonucleic acid (DNA) sensing. The performance of a biosensor based on a liquid gate TGN field effect transistor (Lg-TGNFET) to different DNA cancentrations and adsorption effect on the sensing parameters are analytically investigated in this research. Also, the energy band structure, density of states, carrier concentration, electrical conductance and caused electrical response on TGN as a detection element are studied considering the spin–orbit coupling effect, in which significant current change of the TGN-based biosensor is observed after exposure to DNA different values. DNA concentration as a function of gate voltage is assumed and sensing factor is defined. The results of this research confirm that the current of the biosensor is decreased and Vg-min is obviously left-shifted by increasing value of DNA concentration, suggesting that DNA molecules n-dopes the TGN film. In order to verify the accuracy of the TGN-based biosensor, it is compared with recent analytical and experimental reports on DNA biosensors. The proposed biosensor with high specificity and sensitivity exposes higher current compared to that of monolayer graphene counterpart for analogous ambient conditions.

Interaction of Ca2+ and Fe3+ in co-precipitation process induced by Virgibacillus dokdonensis and its application

Biomineralization has garnered significant attention in the field of wastewater treatment due to its notable cost reduction compared to conventional methods. The reinjection water from oilfields containing an exceedingly high concentration of calcium and ferric ions will pose a major hazard in production. However, the utilization of biomineralization for precipitating these ions has been scarcely investigated due to limited tolerance among halophiles towards such extreme conditions. In this study, free and immobilized halophiles Virgibacillus dokdonensis were used to precipitate these ions and the effects were compared, at the same time, biomineralization mechanisms and mineral characteristics were further explored. The results show that bacterial concentration and carbonic anhydrase activity were higher when additionally adding ferric ion based on calcium ion; the content of protein, polysaccharides, deoxyribonucleic acid and humic substances in the extracellular polymers also increased compared to control. Calcium ions were biomineralized into calcite and vaterite with multiple morphology. Due to iron doping, the crystallinity and thermal stability of calcium carbonate decreased, the content of OC = O, NC = O and CO-PO3 increased, the stable carbon isotope values became much more negative, and β-sheet in minerals disappeared. Higher calcium concentrations facilitated ferric ion precipitation, while ferric ions hindered calcium precipitation. The immobilized bacteria performed better in ferric ion removal, with a precipitation ratio exceeding 90%. Free bacteria performed better in calcium removal, and the precipitation ratio reached a maximum of 56%. This research maybe provides some reference for the co-removal of calcium and ferric ions from the oilfield wastewater.

Leukocyte 8-hydroxy-2'-deoxyguanosine as an oxidative stress marker to predict cardiovascular events and death in chronic hemodialysis patients.

Hemodialysis patients have a markedly increased risk of cardiovascular (CV) morbidity and mortality. Oxidative stress plays a pathogenic role in the progression of atherosclerosis and CV disease among chronic hemodialysis patients. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) content in leukocyte deoxyribonucleic acid (DNA) has been shown as a sensitive and well-known biomarker of oxidant-induced DNA damage in chronic hemodialysis patients. We conducted a retrospective cohort study to investigate the association of leukocyte 8-OHdG and CV events and deaths in patients of chronic hemodialysis. In this study, 217 chronic hemodialysis patients were recruited from 2016 to 2021. The 8-OHdG content of leukocyte DNA was measured by a high-performance liquid chromatography electrochemical detection method. Study outcomes were CV events as well as CV and all-cause deaths. The patients were followed until May 2021. The median follow-up period was 34.8 months. At the end of May 2021, 57 first CV events and 89 all-CV events occurred. Among the first and all CV events, 17 (29.8%) and 32 (36.0%) were fatal, respectively. Multivariate Cox regression analysis showed per 1/10 5 dG increment in leukocyte 8-OHdG values increased risk of CV events (adjusted hazard ratio [aHR], 1.19; 95% CI, 1.10-1.41; p < 0.001), CV death (aHR, 1.27; 95% CI, 1.03-1.72; p = 0.034), and all-cause death (aHR, 1.11; 95% CI, 1.01-1.30; p = 0.038). This is the first study to demonstrate that oxidative stress assessed by 8-OHdG levels of leukocyte DNA predicted CV events as well as CV and all-cause deaths among chronic hemodialysis patients.

Enhanced detection sensitivity of Leptospira DNA using a post-deposition annealed carbon quantum dots integrated tapered optical fiber biosensor

Leptospirosis is an illness caused by a Leptospira bacterial infection, and it can be fatal if not correctly diagnosed and treated. This work explores the development of an optical biosensor that utilizes tapered optical fiber integrated with post-deposition annealed carbon quantum dots (CQDs) to improve Leptospira deoxyribonucleic acid (DNA) detection. A standard optical single-mode fiber was tapered before being deposited with CQDs. The surface properties of CQDs on the tapered optical fiber were then tuned using a simple, one-step annealing process. Leptospira probe DNA was covalently bonded to the annealed CQDs surface using several commercially available linkers. The detection was achieved through probe DNA fragments that were hybridized into different concentrations of complementary target DNA. The biosensor limit of detection remained at 1.0 fM, but a better sensitivity of 2.321 ± 0.048 nm/nM was obtained. The affinity towards Leptospira complementary DNA improved as the equilibrium dissociation constant value was lowered to 0.15 х 10−9 M compared to previous studies. In non-complementary DNA reactions, a minimal wavelength shift is detected, indicating the biosensor's high specificity, whereas studies using genomic DNAs from Leptospira and Clostridium difficile (as a control for genomic DNA) revealed similar observation. The integration of CQDs has achieved these remarkable biosensor traits, which hold great potential for developing a reliable leptospirosis diagnosis.

The Effect Of Streptomycin And Clindamycin On Dnase I Activity On The Quality Of Dna Of Salivary Origin

Deoxyribonucleic acid (DNA) contains genetic material with all an individual’s information. Saliva has the potential to be a good source of human DNA. When compared to blood sampling, saliva is easier to collect and the collection process is non-invasive. However, human DNA collected from saliva has the potential to be degraded due to deoxyribonuclease (DNase) activity in saliva. DNase activity can be inhibited by antibiotics, such as aminoglycoside antibiotics and lincomycin derivatives. This study aimed to determine the effect of streptomycin and clindamycin on DNAse I activity against the quality of human genomic DNA from saliva. The sampling technique was that samples were collected from 9 subjects with each subject flowing into a saliva pot. Before saliva collection, subjects were asked to rinse their mouth with a solution of chlorhexidine gargle (Listerin™) for 30 seconds, then the samples were divided into four groups. The average concentration of DNA extracted from the spin-column method was 32.91 g/mL (7.10-99.45 g/mL) while the average purity was 1.813 g/mL (1.639-2.043 g/mL). With clindamycin treatment, PCR was able to amplify the human NOTCH2 gene (~704 bp) while various concentrations of streptomycin produced multiple bands of ~100 bp. The concentration of 3.2 mM clindamycin effectively inhibits DNAse I activity and can amplify the human NOTCH2 gene while streptomycin cannot protect.

Metal-free DNA sensor based on 10-phenylphenothiazine photo-ATRP signal amplification

The development of ultrasensitive deoxyribonucleic acid (DNA) sensors related to the disease is of great significance for early diagnosis and prevention of the disease. Here, an ultrasensitive DNA sensor based on the photocatalytic atom transfer radical polymerization (photo-ATRP) strategy was prepared. In this strategy, the target DNA was specifically recognized by sulfhydryl-modified peptide nucleic acid (PNA), and α-bromophenylacetic acid (BPAA) was grafted onto the DNA via phosphate-Zr(IV)-carboxylate. In the presence of photocatalyst 10-phenylphenothiazine (PTH), α-Br was reduced under 365 nm UV light to generate active radicals, and the polymer chain containing electrochemical signaling molecule (ferrocene) was introduced to the electrode surface by mediated ATRP. Finally, the peak current value was measured by square wave voltammetry (SWV) and the concentration of DNA was evaluated. The biosensor was constructed based on a green strategy for ATRP reaction without using a heavy metal catalyst (metal-free), thus reducing the pollution of the environment. Moreover, under optimal conditions, the relationship between the DNA sensor and the target was linear in the concentration range of 0.1 fM ∼ 10 pM, and the limit of detection was 79 aM. The sensor has the advantages of high sensitivity, interference-free and good stability, which indicates that it has great practical application potential in the field of life science and medical research.

Automation and Optimization of Rat Heart Decellularization Using a Vibrating Fluid Column.

This paper presents the validation of a software application to optimize the discoloration process in simulated hearts and to automate and determine the final moment of decellularization in rat hearts using a vibrating fluid column. The implemented algorithm specifically for the automated verification of a simulated heart's discoloration process was optimized in this study. Initially, we used a latex balloon containing enough dye to reach the opacity of a heart. The complete discoloration process corresponds to complete decellularization. The developed software automatically detects the complete discoloration of a simulated heart. Finally, the process stops automatically. Another goal was to optimize the Langendorff-type experimental apparatus, which is pressure-controlled and equipped with a vibrating fluid column that shortens the decellularization time by mechanically acting directly on cell membranes. Control experiments were performed with the designed experimental device and the vibrating liquid column using different decellularization protocols for hearts taken from rats. In this work, we used a commonly utilized solution based on sodium dodecyl sulfate. Ultraviolet spectrophotometry was used to measure the evolution of the dye concentration in the simulated hearts and, similarly, to determine the concentrations of deoxyribonucleic acid (DNA) and proteins in the rat hearts.

BaoShenTongLuo formula protects against podocyte injury by regulating AMPK-mediated mitochondrial biogenesis in diabetic kidney disease

BackgroundMitochondrial dysfunction is considered to be an important contributor in podocyte injury under diabetic conditions. The BaoShenTongLuo (BSTL) formula has been shown to reduce podocyte damage and postpone the progression of diabetic kidney disease (DKD). The potential mechanisms underlying the effects of BSTL, however, have yet to be elucidated. In this study, we aimed to investigate whether the effects of BSTL are related to the regulation of mitochondrial biogenesis via the adenosine monophosphate-activated protein kinase (AMPK) pathway.MethodsHigh-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometer (HPLC–ESI–MS) analysis was performed to investigate the characteristics of pure compounds in BSTL. db/db mice and mouse podocyte clone-5 (MPC5) cells were exposed to high glucose (HG) to induce DKD and podocyte damage. Body weight, random blood glucose, urinary albumin/creatinine ratio (UACR), indicators of renal function and renal histological lesions were measured. Markers of podocyte injury, mitochondrial morphology, mitochondrial deoxyribonucleic acid (mtDNA) content, mitochondrial respiratory chain complexes activities, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) levels were assessed. Protein expressions of AMPK, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), transcription factor A (TFAM), mitochondrial fusion protein 2 (MFN2) and dynamin-related protein 1 (DRP1) were also detected. MPC5 cells were transfected with AMPKα small interfering RNA (AMPKα siRNA) to determine the underlying mechanisms of BSTL improvement of mitochondrial function under diabetic conditions.ResultsIn vivo, treatment with BSTL reduced the UACR levels, reversed the histopathological changes in renal tissues, and alleviated the podocyte injury observed in db/db mice. After BSTL treatment, the decreased mtDNA content and mitochondrial respiratory chain complex I, III, and IV activities were significantly improved, and these effects were accompanied by maintenance of the protein expression of p-AMPKαT172, PGC-1α, TFAM and MFN2. The in vitro experiments also showed that BSTL reduced podocyte apoptosis, suppressed excessive cellular ROS production, and reversed the decreased in MMP that were observed under HG conditions. More importantly, the effects of BSTL in enhancing mitochondrial biogenesis and reducing podocyte apoptosis were inhibited in AMPKα siRNA-treated podocytes.ConclusionBSTL plays a crucial role in protecting against podocyte injury by regulating the AMPK-mediated mitochondrial biogenesis in DKD.

Advancing proficiency testing for ultra in resource-limited settings using dried tube specimen: A study by SRL-Uganda.

Proficiency testing (PT) has been hard to set up due to cost limitations and technical capacity. Conventional Xpert MTB/RIF PT programs use liquid and culture spots which require stringent storage and transportation conditions with cross-contamination chances prevalent. These setbacks prompted the use of dried tube specimens (DTS) for Ultra assay PT. For continuity of PT provision, stability of DTS and compatibility with testing protocols when kept for a long period needs to be established. DTS were prepared from known isolates inactivated using a hot air oven at 85°C. 100μl of bacterial suspensions were aliquoted and dried inside a Biosafety cabinet. Panel validation was done to establish the baseline Deoxyribonucleic acid (DNA) concentration in terms of cycle threshold (Ct) value. DTS aliquots were shipped to participants to test and report within six weeks. The remaining DTS were kept at 2-8°C and room temperature for one year with testing at six months. Twenty (20) DTS samples per set remaining at one year were heated at 55°C for two weeks before testing. The means of the different samples were compared to validation data using paired t-tests. Boxplots were designed to visualize the differences in the medians of the DTS. Overall mean Ct value increased by 4.4 from the validation to testing after one year at the different storage conditions. Samples heated at 55°C showed a 6.4 Ct difference from validation data. Testing done at six months on 2-8°C stored items showed no statistical difference. At all the remaining testing times and conditions, P-values were less than 0.008 although the absolute mean Ct when compared showed slight increments and accommodated differences for the detection of MTB and rifampicin resistance. Median values for samples stored at 2-8°C were lower compared to those at room temperature. DTS stored at 2-8°C remain more stable for one year compared to higher temperatures and can be consistently used as PT materials in more than one PT round for biannual PT providers.

Deoxyribonucleic Acid, Ribonucleic Acid, and Protein in the Placentas of Normal and Selected Complicated Pregnancies

Placenta from uncomplicated term pregnancies resulting in the birth of male infants weighing between 2900 and 3800 grams were analyzed for deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein content. The mothers of the infants all had pre-pregnancy weights within +/- 15 percent expected body weight for body frame, according to the Metropolitan Life Tables. There were no significant differences, as regards the content of DNA, RNA and protein, between the placental cotyledons. Nine placenta from mothers giving birth to growth retarded infants were analyzed along with the placenta from six mothers with insulin dependent diabetes mellitus. A trend suggesting less DNA in the placenta of the severely growth retarded (symmetric) infants when compared with placenta from the normal pregnancies was not noted in the less severely growth retarded (asymmetric) infants. The placenta from the infants of diabetic pregnancies contained DNA and RNA in amounts similar to that found in normal pregnancy placenta but the protein content was greater.

Correlation of the DNA Concentration of Human Samples to Electrical Bioimpedance Measurements: A Pilot Study.

It is necessary to evaluate the total deoxyribonucleic acid (DNA) concentration in gene expression assays. The existing techniques require equipment that is expensive for many labs in developing countries. Portable and inexpensive equipment is needed for easy and economical DNA quantification. Electrical bioimpedance spectroscopy (EBiS) is a non-invasive and inexpensive technique for examining the electrical properties of biological materials. The aim of this study was to explore a potential correlation between the measurement of total DNA extracted from human samples by UV-Vis spectrophotometry and EBiS. Hence, after quantifying the total DNA extracted from each sample by UV-Vis spectroscopy, EBiS was recorded and a possible correlation between the two measurements was analyzed. Considering the bioimpedance phase parameter at 5.24 MHz, a significant correlation was found with total DNA, especially when the concentration was below 100 ng/μL (Spearman coefficient = 0.82, p<0.005). Additional experiments are warranted to confirm these findings.

Development of the DNA-based voltammetric biosensor for detection of vincristine as anticancer drug.

In the article presented herein, a deoxyribonucleic acid (DNA) biosensor is introduced for Vincristine determination in pharmaceutical preparations based on the modification of screen printed electrode (SPE) with double-stranded DNA (ds-DNA), polypyrrole (PP), peony-like CuO:Tb3+ nanostructure (P-L CuO:Tb3+ NS). The developed sensor indicated a wide linear response to Vincristine concentration ranged from 1.0 nM to 400.0μM with a limit of detection as low as .21nM. The intercalation of Vincristine with DNA guanine led to the response. The optimized parameters for the biosensor performance were ds-DNA/Vincristine interaction time, DNA concentration and type of buffer solution. The docking investigation confirm the minor groove interaction between guanine base at surface of or ds-DNA/PP/P-L CuO:Tb3+ NS/SPE and Vincristine. The proposed sensor could successfully determine Vincristine in Vincristine injections and biological fluids, with acceptable obtains.