Mitochondrial transcription factor A (TFAM) has 5'-deoxyribose phosphate lyase activity in vitro.

Mitochondrial DNA (mtDNA) plays a key role in mitochondrial and cellular functions. mtDNA is maintained by active DNA turnover and base excision repair (BER). In BER, one of the toxic repair intermediates is 5'-deoxyribose phosphate (5'dRp). Human mitochondrial DNA polymerase γ has weak dRp lyase activities, and another known dRp lyase in the nucleus, human DNA polymerase ß, can also localize to mitochondria in certain cell and tissue types. Nonetheless, whether additional proteins have the ability to remove 5'dRp in mitochondria remains unknown. Our prior work on the AP lyase activity of mitochondrial transcription factor A (TFAM) has prompted us to examine its ability to remove 5'dRp residues in vitro. TFAM is the primary DNA-packaging factor in human mitochondria and interacts with mitochondrial DNA extensively. Our data demonstrate that TFAM has the dRp lyase activity with different DNA substrates. Under single-turnover conditions, TFAM removes 5'dRp residues at a rate comparable to that of DNA polymerase (pol) ß, albeit slower than that of pol λ. Among the three proteins examined, pol λ shows the highest single-turnover rates in dRp lyase reactions. The catalytic effect of TFAM is facilitated by lysine residues of TFAM via Schiff base chemistry, as evidenced by the observation of dRp-lysine adducts in mass spectrometry experiments. The catalytic effect of TFAM observed here is analogous to the AP lyase activity of TFAM reported previously. Together, these results suggest a potential role of TFAM in preventing the accumulation of toxic DNA repair intermediates.

Chemical Insights into Oxidative and Nitrative Modifications of DNA.

This review focuses on DNA damage caused by a variety of oxidizing, alkylating, and nitrating species, and it may play an important role in the pathophysiology of inflammation, cancer, and degenerative diseases. Infection and chronic inflammation have been recognized as important factors in carcinogenesis. Under inflammatory conditions, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from inflammatory and epithelial cells, and result in the formation of oxidative and nitrative DNA lesions, such as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-nitroguanine. Cellular DNA is continuously exposed to a very high level of genotoxic stress caused by physical, chemical, and biological agents, with an estimated 10,000 modifications occurring every hour in the genetic material of each of our cells. This review highlights recent developments in the chemical biology and toxicology of 2'-deoxyribose oxidation products in DNA.

Analysis of sperm chromatin packaging and reproductive biomarker to evaluate the consequence of advanced male age.

In this study, the semen parameters, sperm chromatin integrity, antioxidant enzyme levels, and reproductive hormone levels of subfertile male subjects from Pakistan were assessed in relation to their age. Data on the demographic characteristics of the 750 study participants, including their general health, body mass index (BMI), and reproductive status, were collected from subfertile men from Pakistan. Semen and blood were collected to determine standard semen parameters, sperm chromatin dispersion (Halosperm-SCD), sperm chromatin integrity using toluidine blue (TB) staining, sperm chromatin maturity using chromomycin A3 (CMA3+) staining, and reproductive hormone (FSH, LH, prolactin and testosterone levels). The patients were divided into three groups according to their age: Group 1 included male subjects aged 30 years or less (n = 90), Group 2 included male subjects between the ages of 31 and 40 years (n = 330), and Group 3 included male subjects over 40 years of age (n = 330). Conventional semen parameters, reactive oxygen species (ROS), superoxide dismutase (SOD), guaiacol peroxidase (GPX), catalase (CAT), and lipid peroxidation (MDA) did not statistically (p > 0.05) differ with increasing male age or between different age groups. When compared to younger men (<30 years), sperm SCD (23.2 ± 0.88%) was significantly (p = 0.01) lower as compared to male patients aged >40 years (26.6 ± 0.6%). The concentration of LH, FSH, and testosterone levels were comparable between the groups (p > 0.05), while a significant (p = 0.04) increase in sperm chromatin immaturity CMA3+ (30 ± 0.71%) was observed in the old age group (>40 years) compared to the <30-year group (26.6 ± 1.03%). A positive association was observed between advanced male age and sperm chromatin dispersion (SCD) (r = 0.124, p = 0.001) and decondensation (CMA3+) (r = 0.1, p = 0.009). Despite potential limitations, this study has been carried out with extensive information on the potential risk of male age on sperm integrity. The present study demonstrated the impact of male age on male reproductive health, as these patients had a higher percentage of sperm chromatin damage (SCD) in their semen. Sperm DNA damage assessment will help in the evaluation and diagnosis of the underlying cause of poor fertility and can help clinicians in selecting the right treatment options. Male age is one of the factors that have an impact on the decline in male fertility. As a result, it is preferable for patients receiving assisted reproductive technology to be younger.

An enzyme-coupled microplate assay for activity and inhibition of hmdUMP hydrolysis by DNPH1.

2'-Deoxynucleoside 5'-monophosphate N-glycosidase 1 (DNPH1) hydrolyzes the epigenetically modified nucleotide 5-hydroxymethyl 2'-deoxyuridine 5'-monophosphate (hmdUMP) derived from DNA metabolism. Published assays of DNPH1 activity are low throughput, use high concentrations of DNPH1, and have not incorporated or characterized reactivity with the natural substrate. We describe the enzymatic synthesis of hmdUMP from commercially available materials and define its steady-state kinetics with DNPH1 using a sensitive, two-pathway enzyme coupled assay. This continuous absorbance-based assay works in 96-well plate format using nearly 500-fold less DNPH1 than previous methods. With a Z prime value of 0.92, the assay is suitable for high-throughput assays, screening of DNPH1 inhibitors, or characterization of other deoxynucleotide monophosphate hydrolases.

Electronic Structure and Hole Transfer of All B-DNA Dimers and Homopolymers, via the Fishbone-Wire Model.

We employ the Tight Binding Fishbone-Wire Model to study the electronic structure and coherent transfer of a hole (the absence of an electron created by oxidation) in all possible ideal B-DNA dimers as well as in homopolymers (one base pair repeated along the whole sequence with purine on purine). The sites considered are the base pairs and the deoxyriboses, with no backbone disorder. For the time-independent problem, we calculate the eigenspectra and the density of states. For the time-dependent problem after oxidation (i.e., the creation of a hole either at a base pair or at a deoxyribose), we calculate the mean-over-time probabilities to find the hole at each site and establish the frequency content of coherent carrier transfer by computing the Weighted Mean Frequency at each site and the Total Weighted Mean Frequency of a dimer or polymer. We also evaluate the main oscillation frequencies of the dipole moment along the macromolecule axis and the relevant amplitudes. Finally, we focus on the mean transfer rates from an initial site to all others. We study the dependence of these quantities on the number of monomers that are used to construct the polymer. Since the value of the interaction integral between base pairs and deoxyriboses is not well-established, we treat it as a variable and examine its influence on the calculated quantities.

Exogenous GSH Supplementation to Raw Semen Alters Sperm Kinematic Parameters in Infertile Patients.

Glutathione is an important antioxidant found in all mammalian cells. Sperm motility is positively correlated with seminal reduced glutathione (GSH) levels, and infertile men are known to have lower GSH levels. Studies on GSH supplementation in improving sperm functions in infertility patients are limited. Here, we re-investigate the effect of exogenous GSH supplementation on human sperm motility and kinematic parameters. Residual semen samples from 71 infertility patients who came for routine semen analysis for infertility assessment were studied. Liquefied raw semen was supplemented with GSH (0-10 mM) for 1 h. The untreated sample was the blank control. Only a 5 mM concentration was tested in all 71 samples. After two washes, the sperm was incubated and then analyzed for sperm motility and kinematic parameters by computer-assisted semen analysis (CASA), followed by adenosine triphosphate (ATP), reactive oxygen species (ROS) levels, free thiols, and DNA damage analyses. At 2 hrs post-treatment, GSH supplementation significantly altered many of the kinematics, compared to the control. Straight line velocity (VSL) (p = 0.0459), curvilinear velocity (VCL) (p < 0.0001), average path velocity (VAP) (p < 0.0001), and lateral head amplitude (ALH) (p < 0.0001) were decreased, whereas straightness (STR) (p = 0.0003), linearity (LIN) (p = 0.0008), and beat cross frequency (BCF) (p = 0.0291) were increased in 5 mM group. Wobble (WOB) (p = 0.4917), motility (MOT) (p = 0.9574), and progressive motility (PROG) (p = 0.5657) were unchanged. ATP level was significantly increased in the 5 mM group (p < 0.05). It is concluded that exogenous GSH supplementation does alter sperm kinematics in humans. These altered kinematic parameters together with increased energy (ATP) may have a positive role in influencing the success rates of ART procedures.

Compounds of tucum-do-cerrado (Bactris setosa) fruit with antioxidant activity.

'Tucum-do-cerrado' (Bactris setosa) is an edible fruit from the Brazilian 'Cerrado' biome marked by a high antioxidant potential and polyphenol content when compared to other fruits from the same biome. Its antioxidant activity is higher in the peel than in the pulp. Ethanolic and aqueous peel extracts were analyzed by the ferric reducing antioxidant power (FRAP) assay. We also investigated the aqueous peel extract for its antioxidant mechanism and isolated some of its compounds using high-performance liquid chromatography. Among the extracts tested, the aqueous peel extract exhibited the highest FRAP values, with a predominant free radical scavenger activity. The isolated compounds were identified as two catechins, a cyanidin, a peonidin, and a quercetin. Testing the antioxidant potential of the isolated compounds using the 2-deoxyribose degradation assay revealed that catechin and quercetin showed the highest antioxidant activity. Thus, our results advance the identification of 'tucum-do-cerrado' compounds with antioxidant activity.

Dithioethanol (DTE)-Conjugated Deoxyribose Cyclic Dinucleotide Prodrugs (DTE-dCDNs) as STING Agonist.

To improve the chemical regulation on the activity of cyclic dinucleotides (CDNs), we here designed a reduction-responsive dithioethanol (DTE)-based dCDN prodrug 9 (DTE-dCDN). Prodrug 9 improved the cell permeability with the intracellular levels peaking in 2 h in THP-1 cells. Under the reductive substance such as GSH or DTT, prodrug 9 could be quickly decomposed in 30 min to release the parent dCDN. In THP1-Lucia cells, prodrug 9 also retained a high bioactivity with the EC50 of 0.96 µM, which was 51-, 43-, and 3-fold more than the 2',3'-cGAMP (EC50 = 48.6 µM), the parent compound 3',3'-c-di-dAMP (EC50 = 41.3 µM), and ADU-S100 (EC50 = 2.9 µM). The high bioactivity of prodrug 9 was validated to be highly correlated with the activation of the STING signaling pathway. Furthermore, prodrug 9 could also improve the transcriptional expression levels of IFN-ß, CXCL10, IL-6, and TNF-α in THP-1 cells. These results will be helpful to the development of chemically controllable CDN prodrugs with a high cellular permeability and potency.

Dynamic changes of cytokine profiles and virological markers during 48 weeks of entecavir treatment for HBeAg-positive chronic hepatitis B.

Objective: The aims of this study were to investigate the kinetic changes of serum, virological, and immunological markers during entecavir (ETV) antiviral therapy and to explore whether these indicators can predict the antiviral efficacy of ETV in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients. Methods: HBeAg-positive CHB patients were enrolled and treated with ETV 0.5 mg/day. Clinical biochemical, virological, and serological tests were performed at baseline and every 12 weeks during the 48-week treatment. Plasma levels of cytokines (Flt-3L, IFN-α2, IFN-γ, IL-10, IL-17A, IL-6, TGF-ß1, TGF-ß2, TGF-ß3, and TNF-α) were measured at baseline and at 12 and 24 weeks after treatment. Analysis of the trends of these clinical indicators in ETV antiviral therapy was performed. Results: A total of 105 HBeAg-positive CHB patients were enrolled, and 100 of them completed 48 weeks of ETV treatment and follow-up. After 48 weeks of treatment, hepatitis B s antigen (HBsAg) decline ≥ 1 log10 was found in seven patients, but no patient achieved HBsAg disappearance. serological HBeAg disappeared in 13 patients, and serological HBeAg transformed in 3 patients. The baseline HBsAg and HBeAg levels, HBV DNA load, IL-10, and TGF-ß1 levels in the complete virological response group were lower than those in the incomplete virological response group, while the ALT level in the complete virological response group was higher than that in the incomplete virological response group. Both univariate analysis and multivariate analysis showed that baseline biochemical indexes, virological indexes, and cytokine levels had no correlation with the complete virological response at 48 weeks. In multivariate analysis, low baseline HBV DNA load, and HBeAg and IL-10 levels were significantly associated with ALT normalization after 48 weeks of ETV treatment (HBeAg OR = 1.003, 95% CI 1.001-1.006, p = 0.007; HBV DNA OR = 0.184, 95% CI 0.046-0.739, p = 0.017; IL-10 OR = 0.040, 95% CI 0.972-0.999, p = 0.040). Conclusion: Cytokine levels changed dynamically during ETV antiviral therapy. Low baseline HBV DNA load, and HBeAg and IL-10 levels were significantly associated with ALT normalization after 48 weeks of ETV treatment.

S-acylthioalkyl ester (SATE)-based prodrugs of deoxyribose cyclic dinucleotides (dCDNs) as the STING agonist for antitumor immunotherapy.

Cancer immunotherapy is a powerful weapon in the fight against cancers. Cyclic dinucleotides (CDNs) have demonstrated the great potential by evoking the immune system to fight cancers. There are still a lot of unmet needs for highly active CDNs in clinical applications due to low cell permeation and serum stability. Here we reported S-acylthioalkyl ester (SATE)-based prodrugs of deoxyribose cyclic dinucleotides (dCDNs) with three different types of internucleotide linkages (3',3':11a; 2',3':11b; 2',2':11c). The parent dCDNs could be efficiently released from SATE-dCDNs by cellular esterases. Compared to 2',3'-cGAMP and ADU-S100, 11a exhibited much higher potency of activating STING pathway and higher serum stability. In a CT26-Luc tumor-bearing animal model, 11a showed the efficient antitumor activity in eliminating the established tumor and induced significant increase of mRNA expression of IFN-ß and other related inflammatory cytokines. Hence, SATE-dCDN prodrugs demonstrated their benefits in promoting cell penetration, improving serum stability, and thus enhancing bioactivity, suggesting their potential application as immunotherapy in a variety of malignancies.

Glycation of Immunoglobulin-G from Pentose Sugar: A Cause for Structural Perturbations.

BACKGROUND: Glycation of immunoglobulin-G (IgG) molecules with monosaccharides may cause significant structural disability, thus resulting in their loss of function. The accumulation of AGEs formed from glycation plays an important role in the aliments associated with metabolic diseases. Therefore, excess sugar in plasma interferes with the functioning of IgG and may contribute to a wide range of diabetes-associated complications. The long-term formation of these heterogeneous AGEs may accumulate and affect plasma proteins, especially long-lived proteins. In this study, we analyze immunoglobulin-G (IgG) glycation with 2'-deoxyribose (deoxyribose) instigated modification in IgG structure and AGEs formation. METHODS: This study aims to glycate IgG from varying concentrations of pentose sugar, 2'-deoxyribose (deoxyribose). Various physicochemical methods and techniques characterized post glycation of IgG, both the native and its glycated analogue. The glycated protein will be assessed for its stability and perturbations by UV-VIS., fluorescence and FT-IR spectroscopic techniques. Moreover, the early glycation product will be done by NBT assay, and other biochemical parameters like HMF, carbonyl content and thioflavin-T assays were also performed to see the biochemical changes induced in the glycated IgG macromolecule. RESULTS: Glycation of protein macromolecules generates stable early glycation products (Amadori products). Later, these Amadori products involved a series of chemical reactions to form more stable advanced glycation end products (AGEs). Our experimental study results could validate the modification in IgG structure and AGEs formation. CONCLUSION: The formation of IgG-AGEs from glycation of IgG with deoxyribose could exert cellular toxicity, and might initiates secondary complications of diabetes. Therefore, this study emphasized the glycation reaction of IgG from deoxyribose, which has not been reported yet.

The influence of paternal overweight on sperm chromatin integrity, fertilization rate and pregnancy outcome among males attending fertility clinic for IVF/ICSI treatment.

BACKGROUND: Low and middle-income countries are facing a rapid increase in obesity and overweight burden, particularly in urban settings. Being overweight in men is associated with infertility and a higher risk to have a low sperm count or no sperm in their ejaculate. Despite potential limitations, this is one of few studies conducted to determine the potential risk of paternal overweight on sperm standard parameters, sperm chromatin integrity and assisted conception outcome including fertilization, embryo quality, cleavage rate, reduce blastocyst development, implantation, and cumulative live birth rate (CLBR). METHODS: A cross-sectional study of 750 infertile couples undergoing assisted reproduction technique at a single reproductive medicine center of Salma Kafeel Medical Centre Islamabad. Sperm from men undergoing ART were analyzed for chromatin integrity using sperm chromatin dispersion assay (SCD), Chromomycin A3 staining (CMA3), and toluidine blue (TB) staining, while other semen parameters were assessed on same day includes; standard semen parameters, reactive oxygen species (ROS), sperm deformity index (SDI), teratozoospermic index (TZI), and hypo-osmatic swelling test (HOST). Paternal body mass index (BMI) < 24.5-20 kg/m2 served as the reference group, while the male patients with BMI > 24.5-30 kg/m2 were considered to be overweight. RESULTS: In the analysis of the percentage of spermatozoa with chromatin maturity (CMA3) and chromatin integrity (TB) was reduced significantly in overweight men (p < 0.01) compared with a reference group. Increase in paternal BMI correlate with the increase in sperm chromatin damage (SCD r = 0.282, TB r = 0.144, p < 0.05), immaturity (CMA3, r = 0.79, p < 0.05) and oxidative stress (ROS) (r = 0.282, p < 0.001). Peri-fertilization effects were increased in oocytes fertilization in couples with overweight men (FR = 67%) compared with normal-weight men (FR = 74.8%), similarly, after univariant regression paternal weight remain predictor of sperm chromatin maturity, successful fertilization and CLBR. In the embryo, developmental stage number of the embryo in cleavage was higher in normal weight men, while day 3 (D3) embryos, percent good quality embryo D3, and blastocyst formation rate were compared able between the groups. The paternal overweight group had significant (p < 0.001) increased neonatal birth weight (2952.14 ± 53.64gm; within normal range) when compared with the reference group (2577.24 ± 30.94gm) following assisted reproductive technology (ART). CLBR was higher (p < 0.05) in normal weight men compared to couples with overweight male partners. CLBR per embryo transfer and per 2PN was a statistically significant (p < 0.05) difference between the two groups. An inverse association was observed in the linear regression model between paternal BMI with fertilization rate and CLBR. CONCLUSION: The present study demonstrated the impact of paternal overweight on male reproductive health, as these patients had a higher percentage of immature sperm (CMA3) with impaired chromatin integrity (SCD, TB) in their semen and had decreased fertilization rate, CLBR following assisted reproductive treatments. The present study supports that paternal overweight should be regarded as one of the predictors for fertilization, CLBR and useful for counseling, to consider body mass index not only in women but also for men, in those couples opting for ART treatment, and warrant a poor reproductive outcome in overweight men.

Synthetic Activity of Recombinant Whole Cell Biocatalysts Containing 2-Deoxy-D-ribose-5-phosphate Aldolase from Pectobacterium atrosepticum.

In nature 2-deoxy-D-ribose-5-phosphate aldolase (DERA) catalyses the reversible formation of 2-deoxyribose 5-phosphate from D-glyceraldehyde 3-phosphate and acetaldehyde. In addition, this enzyme can use acetaldehyde as the sole substrate, resulting in a tandem aldol reaction, yielding 2,4,6-trideoxy-D-erythro-hexapyranose, which spontaneously cyclizes. This reaction is very useful for the synthesis of the side chain of statin-type drugs used to decrease cholesterol levels in blood. One of the main challenges in the use of DERA in industrial processes, where high substrate loads are needed to achieve the desired productivity, is its inactivation by high acetaldehyde concentration. In this work, the utility of different variants of Pectobacterium atrosepticum DERA (PaDERA) as whole cell biocatalysts to synthesize 2-deoxyribose 5-phosphate and 2,4,6-trideoxy-D-erythro-hexapyranose was analysed. Under optimized conditions, E. coli BL21 (PaDERA C-His AA C49M) whole cells yields 99 % of both products. Furthermore, this enzyme is able to tolerate 500 mM acetaldehyde in a whole-cell experiment which makes it suitable for industrial applications.

In Vitro One-Pot 3-Hydroxypropanal Production from Cheap C1 and C2 Compounds.

One- or two-carbon (C1 or C2) compounds have been considered attractive substrates because they are inexpensive and abundant. Methanol and ethanol are representative C1 and C2 compounds, which can be used as bio-renewable platform feedstocks for the biotechnological production of value-added natural chemicals. Methanol-derived formaldehyde and ethanol-derived acetaldehyde can be converted to 3-hydroxypropanal (3-HPA) via aldol condensation. 3-HPA is used in food preservation and as a precursor for 3-hydroxypropionic acid and 1,3-propanediol that are starting materials for manufacturing biocompatible plastic and polytrimethylene terephthalate. In this study, 3-HPA was biosynthesized from formaldehyde and acetaldehyde using deoxyribose-5-phosphate aldolase from Thermotoga maritima (DERATma) and cloned and expressed in Escherichia coli for 3-HPA production. Under optimum conditions, DERATma produced 7 mM 3-HPA from 25 mM substrate (formaldehyde and acetaldehyde) for 60 min with 520 mg/L/h productivity. To demonstrate the one-pot 3-HPA production from methanol and ethanol, we used methanol dehydrogenase from Lysinibacillus xylanilyticus (MDHLx) and DERATma. One-pot 3-HPA production via aldol condensation of formaldehyde and acetaldehyde from methanol and ethanol, respectively, was investigated under optimized reaction conditions. This is the first report on 3-HPA production from inexpensive alcohol substrates (methanol and ethanol) by cascade reaction using DERATma and MDHLx.

MYH9 binds to dNTPs via deoxyribose moiety and plays an important role in DNA synthesis.

The accepted notion of dNTP transport following cytoplasmic biosynthesis is 'facilitated diffusion'; however, whether this alone is sufficient for moving dNTPs for DNA synthesis remains an open question. The data presented here show that the MYH9 gene encoded heavy chain of non-muscle myosin IIA binds dNTPs potentially serving as a 'reservoir'. Pull-down assays showed that MYH9 present in the cytoplasmic, mitochondrial and nuclear compartments bind to DNA and this interaction is inhibited by dNTPs and 2-deoxyribose-5-phosphate (dRP) suggesting that MYH9-DNA binding is mediated via pentose sugar recognition. Direct dNTP-MYH9 binding was demonstrated by ELISA and a novel PCR-based method, which showed that all dNTPs bind to MYH9 with varying efficiencies. Cellular thermal shift assays showed that MYH9 thermal stability is enhanced by dNTPs. MYH9 siRNA transfection or treatment with myosin II selective inhibitors ML7 or blebbistatin decreased cell proliferation compared to controls. EdU labeling and cell cycle analysis by flow cytometry confirmed MYH9 siRNA and myosin II inhibitors decreased progression to S-phase with accumulation of cells in G0/G1 phase. Taken together, our data suggest a novel role for MYH9 in dNTP binding and DNA synthesis.

Synthesis of α-D-Ribose 1-Phosphate and 2-Deoxy-α-D-Ribose 1-Phosphate Via Enzymatic Phosphorolysis of 7-Methylguanosine and 7-Methyldeoxyguanosine.

A simple and efficient method for the preparation of α-D-ribose 1-phosphate and 2-deoxy-α-D-ribose 1-phosphate, key intermediates in nucleoside metabolism and important starting compounds for the enzymatic synthesis of various modified nucleosides, has been proposed. It consists in near-irreversible enzymatic phosphorolysis of readily prepared hydroiodide salts of 7-methylguanosine and 7-methyl-2'-deoxyguanosine, respectively, in the presence of purine nucleoside phosphorylase. α-D-Ribose 1-phosphate and 2-deoxy-α-D-ribose 1-phosphate are obtained in near quantitative yields (by HPLC analysis) and 74%-94% yields after their isolation and purification. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Preparation of α-D-ribose 1-phosphate barium salt (4a) Alternate Protocol 1: Preparation of 2-deoxy-α-D-ribose 1-phosphate barium salt (4b) Basic Protocol 2: Preparation of α-D-ribose 1-phosphate bis(cyclohexylammonium) salt (5a) Alternate Protocol 2: Preparation of 2-deoxy-α-D-ribose 1-phosphate bis(cyclohexylammonium) salt (5b).

Epidemiology, Genotyping, Mutational and Phylogenetic Analysis of Hepatitis B Virus Infection in North-east India.

BACKGROUND/OBJECTIVE: Hepatitis B virus (HBV) infection is a major public health problem globally. Northeast India is home to indigenous tribes with different ethnicity and high rates of drug abuse and HIV infection. The study was designed to estimate the burden of HBV infection across various spectrums of liver diseases from this region. HBV genotypes and subgenotypes play a role in the chronicity of disease, response to treatment and its progression. As very limited data are available from this region, we tried to elucidate the role of HBV genotypes, HBV mutants and their phylogenetic analysis. METHOD: We designed a prospective multicentric study, and included 7464 liver disease cases, 7432 blood donors and 650 health care workers, who were screened for HBV infection. HBV DNA positive patients were genotyped and subjected to surface protein, precore and core mutation and phylogenetic analysis. RESULTS: The prevalence of HBV infection with respect to different types of liver diseases, blood donors and health care workers was 9.9% (1550/15,546). 49.5% (768/1550) cases were found to be HBV DNA positive. The most common genotype was found to be genotype D 74.2% (570/768), followed by genotype C 6.5% (50/768), A 4.4% (34/768) and I 0.9% (7/768). CONCLUSION: This study highlights the high hepatitis B burden in Northeast India, reflecting lacunae in health care needs of the region. Also, the different genotype distribution and presence of mutations may translate into different rates of liver disease progression, prognosis and ultimately, clinical significance. However, further prospective cohort study from Northeast India is warranted, to elucidate the clinical significance of multiple genotypes and mutation in this unique population.

Prevalence of Panton Valentine Leucocidin gene containing Staphylococcus aureus in pus samples from Paediatric patients.

Staphylococcus (Staph) aureus containing Panton Valentine Leucocidin (PVL) gene are spreading in the whole world. This gene encodes PVL toxin that has lytic effect on WBCs contributing to the low immunity of the body. It also causes pus formation in various places of the body. This study was conducted to understand the effect of PVL positive Staph aureus in causing purulent infections in children between the age of one day to 15 years. Pus samples from various sites of the body from children between the age of one day to 15 years were taken. The number of pus samples containing Staph aureus was 45. These were collected over a period of one year, from October 2, 2017 to September 30, 2018, at the Shaikh Zayed Hospital, Lahore. A total of 27 (60%) PVL samples were positive Staph aureus. Prevalence of PVL gene was noted to be high in MSSA 9(64%), wound swabs 18(75%), in isolates from orthopaedic department 6(75%), indoor 21(63%), and in males 18(66%). Our study showed that most of the Staph aureus samples that were obtained from pus samples from children had PVL gene in their genome. This percentage is very high. To control its spread, we need to treat not only the patients but also their close contacts. The main objective to conduct this study was to assess the prevalence of PVL positive Staph aureus strain in our local setup. Paediatric age group was selected because it is the most vulnerable group and pus samples were chosen because this strain causes recurrent purulent infections.

Establishment of an in vitro fluorescence spectrophotometry based on end-product malondialdehyde for evaluating scavenging ability on hydroxyl radicals / 中国药理学通报

Aim To establish an in vitro fluorescence spectrophotometry based on the end-product malondialdehyde(MDA)for evaluating hydroxyl radical-scavenging ability, and compare the advantages and disadvantages of fluorescence and visible methods.Methods The reaction time, temperature, and the concentration of key reactant deoxyribose were investigated and optimized respectively.Under different solvent conditions, sensitivity and the measurement window of two methods were compared.The hydroxyl radical scavenging ability of tanshinone I was determined by these two methods.Results The optimal temperature and time was 37 °C and 60 min, and the concentration of deoxyribose was 2.8 mmol·L-1.The limit of detection for the fluorescence method(4.49 nmol·L-1)was much lower than that of the visible spectrophotometry(39.15 nmol·L-1).The ratio of model/control(the measurement window)of the fluorescence method was much larger than that of visible spectrophotometry in both the aqueous system and the organic system(containing DMSO).Within the concentrations of 62.5 mg·L-1-1 000 mg·L-1, tanshinone I showed scavenging ability on hydroxyl radicals in a concentration-dependent manner using the fluorescence method, but the visible method could not.Conclusions In contrast to visible method, fluorescence method has the advantages of higher sensitivity and stronger anti-interference ability to the color of test substance and the specificity of solvents.By virtue of large measurement window, it can be applied to evaluating the effect of fat-soluble test substances.

A Study of Prevalence of Occult Hepatitis B Virus Infection, Knowledge and Preventive Practices Against Hepatitis B Virus in Barbers Serving the Armed Forces.

OBJECTIVE: Hepatitis B virus (HBV) infection is a major health problem in the world. Barbers deal with frequent abrasions/lacerations due to sharp equipment, making them a high-risk group. Determination of HBsAg positive status excludes most reservoirs of transmission in the population. However, Occult Hepatitis B continues to be a source of transmission. The aim of this study was to study the prevalence of occult HBV infection in barbers serving the armed forces clientele and evaluate their knowledge and preventive practices against HBV transmission. METHODS: Seventy-nine HBsAg negative barbers were included in this study and interviewed for the status of immunisation and preventive practices. Anti-HBc total and HBV DNA levels were measured along with a complete haemogram, LFT, PT INR, ultrasound abdomen and Fibroscan of the liver. RESULTS: The prevalence of occult Hepatitis B status was 3.79%. Among barbers who were anti-HBc total positive, 100% were found to have replicative HBV DNA status. All barbers (100%) were unaware of the existence and modes of HBV transmission and were never screened for HBV; 98.73% of barbers followed improper disinfection practices and were never immunised. CONCLUSION: The prevalence of occult HBV infection in barbers, absence of immunisation, unawareness and improper disinfection practices are significantly at risk for transmission to the unaware clients. It is important to educate barbers, establish a universal disinfection procedure and implement a system of compulsory Hepatitis B vaccination before the commencement of their trade work.