Boron as Boric Acid Induces mRNA Expression of the Differentiation Factor Tuftelin in Pre-Osteoblastic MC3T3-E1 Cells

The effects of boron on the formation and maintenance of mineralized structures at the molecular level are still not clearly defined. Thus, a study was conducted using MC3T3-E1 cells to determine whether boron affected mRNA expressions of genes associated with bone/alveolar bone formation around the teethMC3T3-E1 (clone 4) cells were cultured in media treated with boric acid at concentrations of 0, 0.1, 10, 100, or 1000 ng/ml. Total RNAs of each group were isolated on day 3. Gene expression profiles were determined by using RT² Profiler PCR micro-array that included 84 genes associated with osteogenic differentiation. Tuftelin1 mRNA expression was upregulated by all boron treatments. The upregulation was confirmed by quantitative RT-PCR using the tuftelin probe. While 100 ng/ml had no effect on the integrin-α2 (Itga2) transcript and 1 ng/ml boric acid induced Itga2 mRNA expression (2.1-fold), 0.1, 10, and 1000 ng/ml boric acid downregulated the integrin-α2 gene transcript 2.2-, 1.5-, and 2.1-fold respectively. While 0.1 ng/ml boric acid induced BMP6, increased BMP1r mRNA expression (1.5 fold) was observed in 1000 ng/ml boric acid treatment. The findings suggest that boron affects the regulation of the tuftelin1 gene in osteoblastic cells. Further studies are needed to establish that the beneficial actions of boron on alveolar bone and tooth formation and maintenance include an effect on the expression of the tuftelin1 gene.

Discovery of novel pyrimidine molecules containing boronic acid as VCP/p97 Inhibitors

Valine-containing protein (VCP) is a member of the adenosine triphosphate family involved in a variety of cellular activities. VCP/p97 is capable of maintaining protein homeostasis and mediating the degradation of misfolded polypeptides by the ubiquitin-proteasome system (UPS). In this manuscript, a series of novel p97 inhibitors with pyrimidine as core structure were designed, synthesized and biologically evaluated. Based on the enzymatic results, a detailed structure-activity relationship discussion of the synthesized compounds was carried out. Furthermore, cellular activities of the compounds with enzymatic potency of less than 200 nM were investigated by using A549 and RPMI8226 cell lines. Among the screened inhibitors, compound 17 (IC₅₀, 54.7 nM) showed good enzymatic activity. Investigation of cellular activities with non-small cell lung cancer A549 and multiple myeloma (MM) RPMI8226 further confirmed the potency of 17 with the IC₅₀ values of 2.80 μM and 0.86 μM, respectively. Compound 17 is now being developed as a candidate. Finally, docking studies were carried out to explore the possible binding mode between the active inhibitor 17 and p97.

Boron concentration by industrial anion exchanger resins from model solutions in a dynamic mode

Kamchatka geothermal fields should be considered not only as heat and energy resources but also as possible sources of chemical compounds. Boron is one of such chemical elements. The Pauzhetskaya, Nalychevskoe, Pushchinskoe, Kireunskoe steam-hydrothermal fields are the most promising for boron recovery. Data obtained from experimental studies on boric acid sorption using the industrial ion exchangers KU-2-8, AV-17-8, EDE-10P, and AN-31 are presented in this article. The experiments are conducted in a dynamic mode, and the results showed that the method of sequential/consecutive two-stage sorption is most effective for: 1 – removal of the main part of cations using KU-2-8 cation exchanger; 2 – boric acid recovery using weakly basic AN-31 anion exchanger. The sorption capacity of the studied anion exchangers increases in the order as follows: AV-17-8 <EDE-10P < AN-31.

Evaluation of Boron's Adjuvant Activity in Inactive Bacterin Vaccines Using the Mice Model

Vaccination is the most effective, reliable, and economical way of preventing or reducing the effect of infectious diseases. When preparing inactive vaccines, a range of additives called adjuvants are necessary to enhance the magnitude of the immune response. Boron has a wide range of industrial and medical applications, and its positive effects on distinct functions have been described in plants, humans, and animals. However, no studies exist about the possible adjuvant activities of boron compounds in vaccines. Hence, in this study, the potential adjuvant effect of boric acid was explored and compared with common veterinary adjuvants in a mice model. Staphylococcus aureus (S. aureus) used as vaccine antigen was isolated from dairy cows with bovine mastitis. Vaccines adjuvanted with boric acid, aluminum hydroxide, Montanide ISA 50 and ISA 206, and Montanide + boric acid combinations were prepared. The efficacy of vaccines was evaluated according to local reactions at the injection site, C-reactive protein, total Ig G, total Ig M, and anti-S. aureus antibody levels in mice. Boric acid reduced local inflammatory reactions induced by the Montanide adjuvants. Moreover, mice vaccinated with boric acid-adjuvanted vaccine had higher levels of anti-S. aureus antibody than those in the controls (P < 0.05) and were similar to the levels found in mice sensitized with aluminum hydroxide. Total Ig G and Ig M results were, however, unsuitable for the assessment of adjuvant activity for this study. In conclusion, this study revealed that boric acid has an adjuvant potential in inactive bacterin vaccines, but further target animal studies are needed.

Boric acid was orally toxic to different instars of Blattella germanica (L.) (Blattodea: Blattellidae) and caused dysbiosis of the, gut microbiota

Boric acid, a well-established chemical insecticide, has a good control effect on various types of cockroaches. In this study, we investigated the oral virulence effect of boric acid on German cockroach (Blattella germanica) of various instars and characterized its effect on the gut microbiota by high-throughput sequencing technology. The results of an oral toxicity test showed that the toxicity of boric acid was positively correlated with its concentration and negatively correlated with the instar of cockroach nymphs. The 1-3 instar nymphs showed the strongest sensitivity to boric acid, which exhibited a median lethal time of only 3.16 d, while the 6-7 instar nymphs showed the weakest sensitivity, and exhibited a median lethal time of 10.15 d. There was no significant difference between male and female insects regarding their sensitivity to boric acid. Oral treatment of boric acid resulted in severe dysbiosis in cockroaches, the relative abundances of Bacteroides, which can degrade a variety of complex macromolecules, and Enterococcus, which can inhibit pathogenic microorganisms, were significantly reduced, while the relative abundance of the opportunistic pathogenic bacterium Weissella was significantly increased. It was speculated that dysbiosis of gut microbiota might accelerate the toxicity of boric acid on German cockroaches.

Boric acid inhibits alveolar bone loss in rat experimental periodontitis through diminished bone resorption and enhanced osteoblast formation

Background/purpose

Inhibition of bone resorption is essential for periodontal treatment. Recently, it has been suggested that boric acid suppresses periodontitis, but the mechanism of this inhibition is still not well understood. Therefore, to analyze the cellular response to boric acid administration, we histologically evaluated alveolar bone in experimental periodontitis of rats administered boric acid.

Materials and methods

5-0 silk ligatures were placed around the cervix of the second maxillary molars of 4 week-old rats treated with or without boric acid. Five and 14 days after ligature placement, the periodontal tissues between first and second molars were investigated histologically and immunohistochemically using antibodies to CD68, cathepsin K, and α-smooth muscle actin (SMA).

Results

Five days after the beginning of the experiment, many CD68-positive cells appeared in the periodontal tissues with ligature placement without boric acid administration. Also, the number of cathepsin K-positive osteoclasts had increased on the surface of alveolar bone. However, boric acid administration prevented severe bone resorption and reduced the number of cells positive for CD68 and cathepsin K. At day 14 post treatment, cells positive for α-SMA were seen in the periodontal tissues after boric acid administration, whereas no such cells were found around the alveolar bone without the administration of boric acid.

Conclusion

Boric acid inhibited the inflammation of ligature-induced periodontitis. This agent might reduce bone resorption by inhibiting osteoclastogenesis and also could accelerate osteoblastogenesis.

Boric acid modified S and N co-doped graphene quantum dots as simple and inexpensive turn-on fluorescent nanosensor for quantification of glucose

A new fluorescent nanosensor based on S and N co-doped graphene quantum dots (S,N-GQDs) modified by boric acid was designed for glucose detection. First, the S,N-GQDs was prepared via one pot hydrothermal process utilizing citric acid and thiourea as precursors. Then, S,N-GQDs was modified by boric acid to fabricate (B)/S,N-GQDs. The excitation dependent photoluminescence spectra of (B)/S,N-GQDs confirmed the heteroatom (S,N) dopant effect on GQDs emission. FT-IR and energy dispersive X-ray (EDX) spectroscopies confirmed the modification of S,N-GQDs with boric acid. The optical and electrochemical band gaps of the obtained (B)/S,N-GQDs were found to be 2.7 and 2.5 eV, respectively. The boric acid functionalized S,N-GQDs exhibited fluorescent enhancement at 455 nm upon addition of glucose. Such fluorescence response was used for glucose quantification with a detection limit of 5.5 μM which is comparable with previous boronic acid based fluorescent sensing systems. However, compared with earlier reported expensive boronic acid based glucose sensors, this modified system is simpler, more economical, and efficient. A mechanism was proposed for fluorescence enhancement based on the reaction of cis-diol units of glucose with the boric acid groups of (B)/S,N-GQDs which creates rigid (B)/S,N-GQDs-glucose structures, restricting the non-radiative intramolecular motions and results in the fluorescent enhancement.

Effects of boric acid supplementation on bone health in crossbred calves under tropical condition

INTRODUCTION

Boron (B) is thought to play key role in proper bone growth and development as well as have some role in regulation of minerals such as calcium (Ca), phosphorus (P) and magnesium (Mg) which act synergistically with vitamin D.

OBJECTIVE

Present study was planned in two phases to assess the effect of optimum and supranutritional levels of (B) in the form of boric acid (BA) supplementation on bone health of growing cross bred calves.

METHOD

During Phase-1, twenty four male crossbred calves were blocked into four groups (n = 6) on the basis of their body weight (154.83 ± 8.5 kg), age (7-9 months) and were supplemented with 0 (C), 2.6 (T-1), 5.4 (T-2) and 10.7 (T-3) g BA for appropriate B (0.175 adjustment factor to calculate B form BA) consumption i.e. 0, 100, 200 and 400 ppm in each group respectively, for 90 days. During phase 2, twenty-one male crossbred calves were divided into 3 groups (n = 7) on the basis of their body weight (103.76 ± 4.34 kg) and age (5-8 months). All the groups were on similar dietary regimen with additional supplementation of boric acid as 0 g (control); 3.6 g (200 ppm B; T-1) and 10.8 g (600 ppm B; T-2), respectively for a period of 120 d.

RESULTS

From the first experiment it is reported that plasma levels of bovine alkaline phosphatase (BALP), type I collagen cross-linked N-telopeptide (NTx) and Ca were significantly (P < 0.05) affected in T-2 and T-3 groups as compared to T-1 and control groups. Whereas, plasma osteocalcin (OCN) concentration was found to be higher in T-2 and T-3 groups as compared to control group. However, plasma concentrations (ng/mL) of tartrate resistant acid phosphatase (TRAP) remained unaltered due to dietary treatments. Based on the results, another experiment was conducted to validate the above findings and further to determine the effect of still higher i.e supranutritional levels of BA supplementation on bone health of calves. Results revealed that supplementation of BA in T-2 group had no beneficial effect on bone health as the plasma concentration of BALP, OCN, NTx, 25 (OH) vitamin D and Ca as compared to T-1 group in phase 2. Other possible attributes of bone health i.e. plasma concentration of Mg, P, parathyroid hormone (PTH), and calcitonin were not affected by BA supplementation at any levels.

CONCLUSION

Overall from present study it can be concluded that supplementation of boric acid 3.6 g/d (equivalent to 200 ppm B) in the diet of growing animals has positive effect on bone health related biomarkers (OCN, NTx and BALP) and supplementation of supranutritional level of BA i.e. 10.8 g (equivalent to 600 ppm B) level had neither additional beneficial nor harmful effect on bone health of calves.

In vitro effects of boric acid on human liver hepatoma cell line (HepG2) at the half-maximal inhibitory concentration

BACKGROUND

Boron is a prominent part of the human diet and one of the essential trace elements for humans. Dietary boron is mostly transformed into boric acid within the body and has been associated with desirable health outcomes. Non-dietary resources of boron, such as boron-based drugs and occupational exposure, might lead to excessive boron levels in the blood and provoke health adversities. The liver might be particularly sensitive to boron intake with ample evidence suggesting a relation between boron and liver function, although the underlying molecular processes remain largely unknown.

METHODS

In order to better understand boron-related metabolism and molecular mechanisms associated with a cytotoxic level of boric acid, the half-maximal inhibitory concentration (IC₅₀) of boric acid for the hepatoma cell line (HepG2) was determined using the XTT assay. Cellular responses followed by boric acid treatment at this concentration were investigated using genotoxicity assays and microarray hybridizations. Enrichment analyses were carried out to find out over-represented biological processes using the list of differentially expressed genes identified within the gene expression analysis.

RESULTS

DNA breaks were detected in HepG2 cells treated with 24 mM boric acid, the estimated IC₅₀-level of boric acid. On the other hand, pleiotropic transcriptomic effects, including cell cycle arrest, DNA repair, and apoptosis as well as altered expression of Phase I and Phase II enzymes, amino acid metabolism, and lipid metabolism were discerned in microarray analyses.

CONCLUSION

HepG2 cells treated with a growth-inhibitory concentration of boric acid for 24 h exhibited a senescence-like transcriptomic profile along with DNA damage. Further studies might help in understanding the concentration-dependent effects and mechanisms of boric acid.

Histopathology changes in the rainbow trout (Onchorhyncus mykiss) consuming boric acid supplemented fish fodder

OBJECTIVE

Even though boron (B), as a trace micronutrient, occurs in natural waters and organisms, its high concentration could cause harmful and even toxic for organisms. The aim of present study was to investigate the effects of boric acid (BA) added to feed (0.01%, 0.05%, 0.10%, and 0.20% of B in feed) on Rainbow Trout (Oncorhynchus mykiss) by histopathological methods and compared to the control feed as without B.

METHODOLOGY

At the end of the feeding, after weighing the live weight of 9 rainbow trout from each group, tissue fragments were taken from the liver, gill, kidney, skeletal muscle, spleen and brains of fish, which systemic necropsies was done, and were fixed in 10 % buffered formalin solution.

RESULTS

Histopathological examinations revealed degenerative and necrotic changes in the liver, gill, kidney, skeletal muscle, spleen and brain. Hydropic and vacuolar degenerations in liver parenchyma, lamellar edema in the gills, hyaline accumulation in the kidneys, degenerations in the muscles, necrosis in the spleen and hyperemia in the brain were observed in all groups except control group. It was observed that the destruction of boric acid on fish increased depending on the amount of boron supplemented to the feed, and the most effect was in the group fed with 0.20 % boron supplemented feed.

CONCLUSIONS

The findings aside from causing pathological changes in all organs in terms of histopathological findings of Boric Acid (BA), the most severe lesions were observed in the liver.

Chronic suppurative otomastoiditis due to nontuberculous mycobacteria: A case series

INTRODUCTION

Eight new cases of chronic otomastoiditis due to nontuberculous mycobacteria were reported at Center Hospitalier Universitaire Sainte-Justine (CHUSJ) between 2008 and 2018. In the literature, only 89 cases have been described since 1972. This case series aims to define the clinical presentation, infectious pathogens, as well as diagnostic and therapeutic means employed in cases of nontuberculous mycobacteria otitis media encountered in our tertiary pediatric reference center.

METHODS

All cases of otitis media caused by nontuberculous mycobacteria diagnosed at Sainte-Justine between 2008 and 2018 were reviewed. Species identification was retrieved from the Laboratoire de Santé Publique du Québec, Quebec's provincial public health and reference laboratory.

RESULTS

All 8 cases occurred in immunocompetent children. Clinical features on presentation were chronic tympanostomy tube otorrhea with abundant granulation tissue in 7 cases. CT scan demonstrated coalescent mastoiditis in 3 cases. The median delay between initial presentation and identification of nontuberculous mycobacteria was 81 days. Seven patients had a Mycobacterium (M.) abscessus complex infection. Treatment consisted of weekly microscopic granulation debridement, a combined systemic antibiotic therapy for an average duration of 21 weeks, as well as instillation of boric acid into the middle ear. While 3 cases required at least one mastoidectomy, 2 cases were treated only medically.

CONCLUSION

Nontuberculous mycobacteria otitis media is a rare clinical entity, for which high clinical suspicion and specific microbiological analyses could minimize diagnostic delay. The use of boric acid as a desiccating agent may allow for a better local control.

Boric-acid-modified Fe3O4@PDA@UiO-66 for enrichment and detection of glucose by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Herein, boric-acid-modified multifunctional Zr-based metal-organic frameworks (denoted as Fe₃O₄@PDA@B-UiO-66) were synthesized by hydrothermal reaction and surface modification. Compared to traditional matrix, Fe₃O₄@PDA@B-UiO-66 has the advantages of high ionization efficiency, high surface area, low matrix background, porous structure, and numerous boric-acid-active sites. By combining matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), Fe₃O₄@PDA@B-UiO-66 was used as an adsorbent and matrix for enrichment and detection of glucose, based on a specific reaction between boric acid and glucose. The limit of detection was 58.5 nM. The proposed method provides a simple and efficient approach for the sensitive and quantitative detection of glucose in complex samples based on MALDI-TOF MS. Design and synthesis of boric-acid-modified multifunctional magnetic metal-organic frameworks (designated as Fe₃O₄@PDA@B-UiO-66) applied as adsorbent and matrix for the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis of glucose in complex biosamples.

Conversion of lignocellulose into biochar and furfural through boron complexation and esterification reactions

The aim of this work was to study the conversion of lignocellulose into biochar and furfural through boron complexation and esterification reaction. Boric acid was used to modify lignocellulose to obtain a high biochar yield boron-lignocellulosic material through complexation and esterification reactions. Furthermore, clean furfural was obtained as the gas products of boron-lignocellulosic materials pyrolysis. The structures of the boron-lignocellulosic materials were characterized, and their compound principle was revealed. Boric acid treatments increased the initial thermal degradation temperature of lignocellulose and promoted the formation of biochar and furfural. The biochar yield rate increased by 135.7% from 18.6 to 42.9% at 600 ℃ after 5% boric acid solution treatment. Compared with pure lignocellulose, cleaner and higher quantities of furfural were obtained from boron-lignocellulose pyrolysis. Finally, the possible chemical decomposition pathways of boron-lignocellulosic materials were identified. This study provides a new perspective on the thermochemical conversion of lignocellulose to furfural and biochar.

Suitability of boric acid as a boron drug for boron neutron capture therapy for hepatoma

Hepatoma is the second leading cause of cancer death worldwide. Due to the poor outcomes of patients with late diagnosis, newer treatments for hepatoma are still needed. As an emerging therapy, boron neutron capture therapy (BNCT) may be an effective solution in hepatoma management. In this study, boric acid (BA) was used as the boron drug for in vivo analysis of action mechanism. The N1S1 single liver tumor-bearing rat and the VX2 multifocal liver tumor-bearing rabbit models were used to investigate the retention status of BA in the tumor regions during BNCT. The autoradiographic examination showed BA can localize specifically not only in the hepatoma cells but also in tumor blood vessels. Our findings indicate that superior hepatoma targeting could be achieved in BA-mediated BNCT, which supports BA to be a suitable boron drug for BNCT for hepatoma.

Theoretical Study on Ionization of Boric Acid in Aqueous Solution by Ab Initio and DFT Methods at T=298.15 K

Objectives

The aim of this research work was to theoretically calculate the pK_a value of boric acid in aqueous solution by theoretical methods at T=298.15 K.

Materials and Methods

Boric acid has antifungal and antiviral properties. It is used in various prescription pharmaceutical products. The ab initio and density functional theory (DFT) methods were used in this research work.

Results

To explain the determined acidic dissociation constant, the various molecular conformations and solute-solvent interactions of the species of boric acid were considered. The basis set at the B3LYP/6-31+G (d) level of theory was selected for DFT calculations. We analyzed the formation of intermolecular hydrogen bonds between several species of boric acid and water molecules through Tomasi's method.

Conclusion

The result showed that there was comparable agreement between the experimentally and theoretically determined pK_a values for boric acid.

The Role of Oxidative Stress, Renal Inflammation, and Apoptosis in Post Ischemic Reperfusion Injury of Kidney Tissue: the Protective Effect of Dose-Dependent Boric Acid Administration

Ischemia/reperfusion (I/R) injury is associated with a strong inflammatory and oxidative stress response to hypoxia and reperfusion that impair organ function. We aimed to investigate the role of oxidative stress, renal inflammation, and apoptosis in the injury of the kidney tissue after ischemic reperfusion, and the protective effect of dose-dependent boric acid administration. For this purpose, 35 Sprague Dawley albino rats were divided into five groups of seven animals in each group: Sham, I/R and I/R + boric acid (BA) (i.p at doses of 50, 100, and 200 mg/kg). All animals underwent nephrectomy (the right kidney was removed) and were expected to recover for 15 days. After recovery, each animal received 45 min of ischemia. BA was injected intraperitoneally 10 min before reperfusion and a 24-h reperfusion procedure was performed. Sham group only underwent surgical stress procedure. In order to investigate the oxidative stress induced by I/R injury and antioxidant effects of different BA doses in the kidney tissue, TAS, TOS, MDA, SOD, CAT, and GSH levels were measured. DNA fragmentation, cytochrome C levels, caspase 3 activity were measured to determine apoptotic index in tissue. IL-6 and TNF-α levels were measured in the evaluation of inflammation. Hematoxylin-eosin and TUNEL staining was performed for histopathological examinations. As a result, increased oxidative stress, inflammation, and apoptosis after I/R were decreased with different doses of BA treatment. The application of high-dose BA was found to be lower in anti-apoptotic, anti-inflammatory, and antioxidant effects than in the low-dose groups.

Comparative Evaluation of Boric Acid Gel versus Chlorhexidine Gel in the Treatment of Chronic Periodontitis: Randomized, Placebo-Controlled Clinical Study

Background:

Over the years, various antimicrobials have been tried and tested in the treatment of periodontitis. Chlorhexidine (CHX) has emerged as the gold standard. In recent years, trend has shifted toward the use of agents with antibacterial, anti-inflammatory, and osteoblastic activity. Boric acid (BA) is one such agent which possess all such properties and thus been evaluated in the treatment of periodontitis.

Aim and Objective:

The aim of the study is to compare and evaluate the efficacy of 0.75% BA gel versus 1% CHX gel as an adjunct to scaling and root planing in patients with chronic periodontitis both clinically and microbiologically.

Materials and Methods:

The present study was a randomized, placebo-controlled clinical trial where 45 systemically healthy patients with chronic periodontitis were included in the study. About 15 patients each were divided into three groups, that is, Group I received BA gel, Group II received CHX gel, and Group III received placebo gel as a local drug delivery agent. Clinical parameters such as gingival index, plaque index, modified sulcus bleeding index, probing pocket depth, and clinical attachment level were evaluated at baseline and 6-month follow-up. Microbiological analysis to check for mixed anaerobic flora was done using subgingival plaque samples at baseline and 3 months after treatment.

Results:

Significant reduction was seen in all clinical parameters in both BA and CHX gel groups as compared to control group (P < 0.05). However, on comparing BA gel group with CHX gel, the results were statistically insignificant (P > 0.05).

Conclusion:

BA gel and CHX gel both were equally effective in improving the clinical and microbiologic parameters in patients with chronic periodontitis when used as a local drug delivery agent.

Effects of boric acid on cell death and oxidative stress of mouse TM3 Leydig cells in vitro

BACKGROUND

Boron (B) is an abundant element on earth and presents at physiological pH in the form of boric acid (BA). It has both positive and negative effects on biological systems. BA and sodium borates have been considered as being toxic to the reproduction system in animal experiments. Unfortunately, the molecular mechanism underlying the toxic effects of BA is not fully understood.

METHODS

Here, we demonstrate the influence of BA on mouse TM3 Leydig cells which are male reproductive system cells targeted by BA exposure. The cytotoxicity was evaluated by MTT and NRU assays. Annexin V-FITC/PI double staining kit, mitochondria membrane potential (ΔΨm) assay kit with JC-1 and caspase-3 colorimetric assay kit were used to indicate the cell death pathway. To estimate the role of oxidative stress in BA induced toxicity, glutathione (GSH) level, catalase (CAT) and superoxide dismutase (SOD) activities were measured manually.

RESULTS

The cell viability assays showed that BA was not cytotoxic within the tested concentrations up to 1000 μM. Sub-toxic concentrations were used for detecting oxidative stress status. BA exposure was significantly reduced GSH level at 1000 μM and CAT activity in a concentration-dependent manner. However, SOD activity was increased at the tested concentrations (100-1000 μM). Moreover, ΔΨm was significantly decreased at 500 and 1000 μM of BA, while caspase-3 activity was not changed apparently.

CONCLUSION

These findings demonstrated that BA is not cytotoxic and apoptotic but may slightly induces oxidative stress in TM3 Leydig cells at higher concentrations.

Effects of boron compounds on human reproduction

Because of the high pK_a of boric acid, inorganic borates, when taken up by the human or animal organism, exist in the body almost exclusively in the form of non-dissociated boric acid. Therefore, the variety of inorganic boron compounds is commonly addressed in the toxicological literature as "boron" (B). There is a discussion concerning categorisation of inorganic boron compounds as reproductive toxins. Boron treatment of rats, mice and dogs was dose-dependently associated with testicular toxicity, characterised by inhibited spermiation at lower dose levels and by reduction of epididymal sperm counts at higher dose levels. The NOAEL for such fertility effects of boric acid in male rats (oral feeding, Sprague Dawley strain) was evaluated to be 17.5 mg B/kg bw per day. As far as developmental toxicity is concerned, oral dosing of 9.6 mg B/kg bw daily to female pregnant Sprague Dawley rats remained without effects, with foetal skeletal effects observed at higher doses. Therefore, 9.6 mg B/kg bw (oral dosing) was evaluated as NOAEL for developmental effects of boric acid. The blood level in rats, equivalent to this NOAEL, is 1270 ng B/g. As far as B-exposed humans are concerned, field studies on the effect of boron on human reproduction are possible only in a few boron-rich geographical areas. Published field studies were conducted in China's Liaoning province, the Argentinian Andes and Western Anatolia/Turkey. Particularly relevant are studies on occupationally B-exposed groups, because the potential exposure to boron is much higher in occupational compared to environmental settings. Comparison of estimated daily B exposure levels in humans and actually measured B blood levels confirms the preference of biomonitoring for exposure assessment in environmental and occupational studies. A boron blood level scaling shows that the levels of high occupational B exposures reported in China and in Turkey are compatible. Compared to the experimental B blood levels at boron-related NOAELs for male fertility and for developmental toxicity in rats, the human blood level means of the highest occupational exposure groups in China and in Turkey are lower by factors of > 4 and > 2, respectively. Basically, concentrations of B within the body that exert reproductive toxicity in humans are not reached under the conditions of human normal handling and use, including conditions of extreme occupational exposures. In consequence, all relevant results of studies into human reproductive toxicity of B are basically negative. Considering the effective doses, there is no scientific contradiction between experimental and human results of B reproductive toxicity.

Effects of boric acid feeding on the oxidative stress parameters in testes, sperm parameters and DNA damage in mice

This study was aimed to determine the effects of boric acid on oxidative stress, testicular tissue and spermatozoon DNA. Experiments were performed with Swiss Albino mice divided equally into two groups based on the tratment period: one for 4 and the other for 6-week duration. These groups were further divided into subgroups as Control and those administered daily at oral doses of 115 mg/kg, 250 mg/kg and 450 mg/kg of boric acid. Then, testicular tissue were examined postmortem and analyzed using ex-vivo biochemical tools for oxidative stress, spermatozoon membrane integrity, sperm motility and live cell rate (%). In both 4 and 6-week groups, v. seminalis weight, membrane integrity, motility, live cells and GSH levels exhibited a decreasing trent compared to the controls. In addition, 6-week group had a decrease in SOD level. MDA level was higher in controls in both 4 and 6-week groups. Spermatozoon DNA was intact in the 4-week group, but damaged in the 6-week group, and the degree of the damage dependent on the administered dose. Boric acid induces oxidative stress in testicular tissue, and its long-term application (only 6 weeks) caused damage in spermatozoon DNA.

Boron incorporation into precipitated calcium carbonates affected by aqueous pH and boron concentration

The objectives of this study were to investigate the amount of B incorporation into precipitated calcium carbonate (PCC) in the coprecipitation process, and to determine specific mineral phases (calcite or vaterite) and the mode of B coordination (trigonal or tetrahedral) in PCC under different pH and B concentrations. The amount of B incorporation into PCC increased in general with increasing aqueous B (B_aq) concentrations in the pH range from 8 to 12. The B removal by PCC reached maximum (∼200 mmol kg^-1) at pH 10 with B_aq concentrations between 30 and 50 mM. The transformation of vaterite to calcite was promoted with increasing B_aq at pH 8 and 10, whereas an excess concentration of aqueous (poly)borate anions (100 mM) inhibited crystal growth of calcite. As determined by B K-edge X-ray absorption fine structure spectroscopy, the coordination of B incorporated in PCC was preferentially tetrahedral (^IVB, 55-70%) over trigonal (^IIIB, 30-45%) at B_aq <75 mM. In contrast, the preferential incorporation of ^IVB into PCC was not observed in the solution with a high B concentration (i.e., 100 mM). The amount of B incorporation, the morphology of PCC and B coordination in PCC were remarkably changed in high B_aq concentrations.

Ameliorative effect of boric acid against formaldehyde-induced oxidative stress in A549 cell lines

Formaldehyde (HCHO) is a reactive agent and the most essential common carcinogenic environmental pollutant. The present study investigated the protective and ameliorative effects of boric acid (BA) against formaldehyde-induced oxidative stress in A549 cell lines. The first group served as a control, the second group was treated with only 100 μM formaldehyde, and the third, fourth, and fifth groups were treated with 2.5, 5, and 10 mM BA, respectively. The sixth, seventh, and eighth groups were treated with 2.5, 5, and 10 mM BA plus 100 μM formaldehyde, respectively. In A549 cell lines, formaldehyde treatment significantly decreased cell viability, glutathione level, and enzyme activities of superoxide dismutase and catalase; however, malondialdehyde levels of the cell lysate were found to increase compared with the control group. In addition, formaldehyde treatment did not significantly alter nitric oxide levels. Meanwhile, mRNA expression levels of Tnf-α, NFĸB, and caspase-3 significantly increased but the Bcl-XL level did not show significant alteration by formaldehyde treatment. In contrast, the BA treatment reversed the formaldehyde-induced alteration in A549 cell lines. Consequently, BA exhibited a protective effect in A549 cell line against formaldehyde-induced lipid peroxidation. Furthermore, it ameliorated the antioxidant status and mRNA expression levels of proinflammatory cytokines.

High Concentrations of Boric Acid Trigger Concentration-Dependent Oxidative Stress, Apoptotic Pathways and Morphological Alterations in DU-145 Human Prostate Cancer Cell Line

Boric acid is known to regulate the proliferation of cancer cells. Prostate cancer is among the types of cancer with high mortality in men. There are a few numbers of studies investigating the effects of boric acid on prostate cancer cells. The objective of the present study was to assess the effects of boric acid at concentrations higher than that can be achieved in blood by dietary intake on DU-145 human prostate cancer cells for 24 h. Firstly, we determined the cytotoxic activity of boric acid (0 to 12.5 mM) on DU-145 human prostate cancer cells by using 3-(4, 5-dimethylthiazol, 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and defined the IC50 concentration of boric acid. Then, by employing the doses found in MTT, the levels of antioxidant-oxidant molecules and apoptotic proteins were measured and morphological changes were evaluated. We have concluded that boric acid caused oxidative stress, inhibition of cell growth, apoptosis, and morphological alterations in a concentration-dependent manner in DU-145 cells. Furthermore, treatments with increasing boric acid concentrations decreased the antioxidant levels in cells. We actually revealed that boric acid, known as an antioxidant, may prevent cell proliferation by acting as an oxidant in certain doses. Although the high IC50 concentration of boric acid is perceived to be negative, we think it provides important background for subsequent studies.

Fluconazole Prophylaxis in Prevention of Symptomatic Candida Vaginitis

Due to broad spectrum susceptibility of Candida species to fluconazole, its convenience as an oral agent, and predictable patient tolerance and safety, current practice guidelines recommend the use of long-term suppression regimens of fluconazole as prophylaxis for recurrent vulvovaginal candidiasis (RVVC), as well as in abbreviated doses when known trigger factors emerge and inevitable symptomatic episodes are predictable. However, recent concerns of fluconazole-resistant Candida albicans strains may impact fluconazole use, particularly, concerns of overuse. This literature review discusses current recommendations for prophylaxis of vulvovaginal candidiasis with fluconazole.

Propolis and Its Combination with Boric Acid Protect Against Ischemia/Reperfusion-Induced Acute Kidney Injury by Inhibiting Oxidative Stress, Inflammation, DNA Damage, and Apoptosis in Rats

Ischemia reperfusion (I/R) injury which causes kidney dysfunction is one of the most studied diseases directly linked to oxidative stress. In this regard, it is important to protect cells against damage by inducing antioxidant response. Herein, we aimed to evaluate the therapeutic roles and possible mechanisms of propolis and boric acid in kidney I/R injury based on relevant basic research and clinical studies. Sprague-Dawley rats were subjected to 50 min of ischemia followed by 3 h of reperfusion. Animals were randomly divided into a control group (the abdominal wall was just opened and closed), an I/R injury group, the propolis intervention group (200 mg/kg, intragastric administration, 1 h before ischemia), boric acid intervention group (14 mg/kg, intragastric administration 1 h before ischemia), and the propolis + boric acid intervention group (intragastric administration 1 h before ischemia). Kidney function, the antioxidant defensive system, and renal damage were assessed. In addition, the oxidative stress and inflammatory status were estimated in renal tissue. Furthermore, DNA damageand apoptosis were detected by immunohistochemistry. When compared with I/R group, propolis alone and especially propolis + boric acid groups significantly improved functional parameters. While the antioxidant response was increased, renal injury size and apoptosis were significantly decreased in both groups. Also, the MDA and TNF-α levels besides the 8-OHdG formation were downregulated. According to these outcomes, it can be said that especially propolis together with boric acid ameliorates kidney injury caused by I/R through acting as an antioxidant, anti-inflammatory, and antiapoptotic agent. In conclusion, propolis alone and its combination with boric acid could be developed as therapeutic agents against serious renal I/R injuries.