Exploiting the tumor immune microenvironment and immunometabolism using mitochondria-targeted drugs: Challenges and opportunities in racial disparity and cancer outcome research.

Black and Hispanic cancer patients have a higher incidence of cancer mortality. Many factors (e.g., socioeconomic differences, insufficient access to healthcare) contribute to racial disparity. Emerging research implicates biological disparity in cancer outcomes. Studies show distinct differences in the tumor immune microenvironment (TIME) in Black cancer patients. Studies also have linked altered mitochondrial metabolism to changes in immune cell activation in TIME. Recent publications revealed a novel immunomodulatory role for triphenylphosphonium-based mitochondrial-targeted drugs (MTDs). These are synthetically modified, naturally occurring molecules (e.g., honokiol, magnolol, metformin) or FDA-approved small molecule drugs (e.g., atovaquone, hydroxyurea). Modifications involve conjugating the parent molecule via an alkyl linker chain to a triphenylphosphonium moiety. These modified molecules (e.g., Mito-honokiol, Mito-magnolol, Mito-metformin, Mito-atovaquone, Mito-hydroxyurea) accumulate in tumor cell mitochondria more effectively than in normal cells and inhibit mitochondrial respiration, induce reactive oxygen species, activate AMPK and redox transcription factors, and inhibit cancer cell proliferation. Besides these intrinsic effects of MTDs in redox signaling and proliferation in tumors, MTDs induced extrinsic effects in the TIME of mouse xenografts. MTD treatment inhibited tumor-suppressive immune cells, myeloid-derived suppressor cells, and regulatory T cells, and activated T cells and antitumor immune effects. One key biological disparity in Black cancer patients was related to altered mitochondrial oxidative metabolism; MTDs targeting vulnerabilities in tumor cells and the TIME may help us understand this biological disparity. Clinical trials should include an appropriate number of Black and Hispanic cancer patients and should validate the intratumoral, antihypoxic effects of MTDs with imaging.

Chicken Combs and Wattles as Sources of Bioactive Peptides: Optimization of Hydrolysis, Identification by LC-ESI-MS2 and Bioactivity Assessment.

The production of bioactive peptides from organic by-waste materials is in line with current trends devoted to guaranteeing environmental protection and a circular economy. The objectives of this study were i) to optimize the conditions for obtaining bioactive hydrolysates from chicken combs and wattles using Alcalase, ii) to identify the resulting peptides using LC-ESI-MS2 and iii) to evaluate their chelating and antioxidant activities. The hydrolysate obtained using a ratio of enzyme to substrate of 5% (w/w) and 240 min of hydrolysis showed excellent Fe2+ chelating and antioxidant capacities, reducing Fe3+ and inhibiting 2, 2'-Azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The mapping of ion distribution showed that a high degree of hydrolysis led to the production of peptides with m/z ≤ 400, suggesting low mass peptides or peptides with multiple charge precursor ions. The peptides derived from the proteins of cartilage like Collagen alpha-2(I), Collagen alpha-1(I), Collagen alpha-1(III) and elastin contributed to generation of bioactive compounds. Hydrolysates from chicken waste materials could be regarded as candidates to be used as ingredients to design processed foods with functional properties.

Assessment of boscalid and pyraclostrobin disappearance and behavior following application of effective microorganisms on apples.

The aim of this study is to assess the disappearance of boscalid (IUPAC name: 2-chloro-N-[2-(4-chlorophenyl)phenyl]pyridine-3-carboxamide) and pyraclostrobin (IUPAC name: methyl N-[2-[[1-(4-chlorophenyl)pyrazol-3-yl]oxymethyl]phenyl]-N-methoxycarbamate) residues in apple fruit, and to verify whether an organic fertilizer enriched with strains of antagonistic microorganisms can reduce pesticide residue levels. Field trials were conducted in a commercial orchard on apples of the Gloster variety, during 21 days after the treatment with Bellis 38 WG and the subsequent application of Zumba Plant formulation containing Bacillus spp., Trichoderma spp. and Glomus spp. In control samples, the decrease rate of boscalid and pyraclostrobin residue levels followed an exponential function, described by formulae Rt = 0.2824e-0.071t and Rt = 0.1176e-0.060t, with the coefficient of determination of r2 = 0.8692 and r2 = 0.9268, respectively. These levels dropped to half (t1/2) of their initial values after 9.8 and 11.5 days, respectively. The treatment with Zumba Plant resulted in a reduction in boscalid and pyraclostrobin residue levels by 52% and 41%, respectively. The results of this study are of importance for horticulture sciences and for producers of apples using plant protection products (PPPs).

Antagonistic trait of Staphylococcus succinus strain AAS2 against uropathogens and assessment of its in vitro probiotic characteristics.

The desideratum aim of the present context was to isolate a promising antagonist probiotic bacterium from fermented food item as biocontrol agent against uropathogens. Among diversified isolates evaluated for antagonistic trait, Staphylococcus succinus strain AAS2 was found to be an auspicious candidate against urinary tract infection (UTI) causing bacterial pathogens, being the most active against Staphylococcus aureus with substantial activity of 352.5 ±â€¯5.4 AU/mL. Further, the in vitro probiotic attributes of strain AAS2 were assessed using systematic methodology. The isolate exhibited tolerance to acidic condition (up to pH 3.0) and simulated gastric juice (at pH 3.0) with fairly high survival logarithmic cell counts of 5.3 ±â€¯0.15 and 5.23 ±â€¯0.02 log cfu/mL, respectively. Additionally, strain AAS2 showed capability to resist 0.5% w/v bile salt too. It also revealed significant values of auto-aggregation (32.5 ±â€¯1.3-56.5 ±â€¯1.4%) and cell surface hydrophobicity (38.35 ±â€¯1.4%) properties. The isolate showed resistivity towards phenol (6.8 ±â€¯0.08 log cfu/mL) and lysozyme (58.6 ±â€¯1.6%). Further, the susceptibility trait of strain AAS2 to conventional antibiotics made this isolate a promising probiotic bacterium. Most importantly, the isolate depicted DPPH (2,2-Diphenyl-1-picrylhydrazyl) and hydroxyl radical scavenging activities in a concentration dependent manner, thereby exhibiting its propitious antioxidative properties. In a nutshell, the outcomes of this investigation divulge the plausible use of S. succinus strain AAS2 as biocontrol agent against uropathogens, and recommended further applications in pharmaceutics due to its pronounced probiotic traits.

Quantitative assessment of the sensitivity of dormant AML cells to the BAD mimetics ABT-199 and ABT-737.

Cells from patients with acute myeloid leukemia (AML) that remain dormant and protected by stromal cells may escape effects of chemotherapy. We modeled dormancy in vitro and investigated the ability of Bcl-2 inhibitors ABT-199 and ABT-737 to overcome chemoprotection of dormant cells. CD34-enriched primary AML cells with aberrant leukemia-associated phenotypes (LAPs) were cultured on stromal cells. The chemosensitivity of dormant (PKH26high), CD34+, LAP+ cells was ascertained by 5-colour flow cytometric counting after 12 d. The PKH26high, CD34+, LAP + subset retained clonogenic capacity. The dormant fraction was completely resistant to Ara-C (p = .007). However, ABT-199 and ABT-737 were able to reduce the dormant fraction by 84% and 80%, respectively, of their effects on proliferating counterparts. In conclusion, we have elaborated a system for quantifying chemosensitivity in LAP+ dormant leukemia cells, thought to contribute to disease relapse, and shown sensitivity of dormant LAP+ cells to ABT-199 and ABT-737 in this system.

An assessment on the role of endophytic microbes in the therapeutic potential of Fagonia indica.

BACKGROUND: Natural products of animals, plants and microbes are potential source of important chemical compounds, with diverse applications including therapeutics. Endophytic bacteria that are especially associated with medicinal plants presents a reservoir of therapeutic compounds. Fagonia indica has been recently investigated by numerous researchers because of its striking therapeutic potential especially in cancer. It is also reported that endophytes play a vital role in the biosynthesis of various metabolites; therefore we believe that endophytes associated with F. indica are of crucial importance in this regard. The present study aims successful isolation, molecular identification of endophytic bacteria and their screening for bioactive metabolites quantification and in vitro pharmacological activities. METHODS: 16S rRNA gene sequencing was used for the identification of isolated endophytic bacteria. Methanolic extracts were evaluated for total phenolic contents (TPC), total flavonoids contents (TFC), DPPH free radical scavenging activity, reducing power and total anti-oxidant assays were performed. And also screened for antibacterial and antifungal activities by disc diffusion method and their MIC were calculated by broth dilution method using microplate reader. Further, standard protocols were followed for antileishmanial activity and protein kinase inhibition. Analysis and statistics were performed using SPSS, Table curve and Origin 8.5 for graphs. RESULTS: Bacterial strains belonging to various genera (Bacillus, Enterobacter, Pantoea, Erwinia and Stenotrophomonas) were isolated and identified. Total phenolic contents and total flavonoids contents varies among all the bacterial extracts respectively in which Bacillus subtilis showed high phenolic contents 243 µg/mg of gallic acid equivalents (GAE) and Stenotrophomonas maltophilia showed high flavonoids contents 15.9 µg/mg quercitin equivalents (QA), total antioxidant capacity (TAC) 37.6 µg/mg of extract, reducing power (RP) 206 µg/mg of extract and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity with 98.7 µg/mL IC50 value. Although all the extracts tested were active to inhibit growth of selected pathogenic microbes (bacteria and fungi), but significant antibacterial activity was observed against Klebsiella pneumonia and B. subtilis. An Enterobacter cloaca was active against Leishmania tropica with IC50 value of 1.4 µg/mg extracts. B. subtilis and Bacillus tequilensis correspondingly exhibit significant protein kinase inhibition of 47 ± 0.72 and 42 ± 1.21 mm bald zones, indicating anti-infective and antitumor potential. CONCLUSIONS: Our findings revealed that crude extracts of selected endophytic bacteria from F. indica possess excellent biological activities indicating their potential as an important source of antibiotics (antifungal, antibacterial) compounds.

Antitumor activity of 4-O-Methylhonokiol in human oral cancer cells is mediated via ROS generation, disruption of mitochondrial potential, cell cycle arrest and modulation of Bcl-2/Bax proteins.

PURPOSE: The plant-derived natural product 4-O-methylhonokiol (MH) has been reported to possess tremendous pharmacological potential ranging from neuroprotection to anticancer activity. However, the anticancer activity of MH in oral squamous cell carcinoma (OSCC) cells has not been evaluated. In the present study, MH was evaluated for its anticancer activity against OSSC PE/CA-PJ41 cells and the possible underlying mechanism was determined. METHODS: Cell cytotoxicity was evaluated by colorimetrybased MTT assay while the effects on cell cycle phase distribution were assessed by flow cytometry. Effects of MH on reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) were evaluated by flow cytometry. Western blot assay was finally utilized to study the effects of MH on key cancer and apoptosis-linked proteins including Bax and Bcl-2. RESULTS: MH induced cytotoxicity in OSCC PE/CA-PJ41 cells with an observed IC50 of 1.25 µM. It also caused significant increase in the production of ROS and disrupted the MMP in a dose-dependent manner. The reduction in MMP favored mitochondrial apoptotic pathway which was further confirmed by determining the expression of Bax and Bcl-2. It was observed that MH downregulated the expression of Bax and upregulated the expression of MMP, ultimately leading to apoptosis of OSSC PE/CA-PJ41 cells. Additionally, MH also caused G2/M cell cycle arrest in a dose-dependent manner. CONCLUSION: Taken together, our results indicate that 4-Omethylhonokiol may prove a potential natural anticancer molecule against human oral carcinoma cells.

Role of transcription factor Sp1 in the 4-O-methylhonokiol-mediated apoptotic effect on oral squamous cancer cells and xenograft.

Recently, biphenolic components derived from the Magnolia family have been studied for anti-cancer, anti-stress, and anti-inflammatory pharmacological effects. However, the pharmacological mechanism of action of 4-O-methylhonokiol (MH) is not clear in oral cancer. The aim of this study was to investigate the role of MH in apoptosis and its molecular mechanism in oral squamous cell carcinoma (OSCC) cell lines, HN22 and HSC4, as well as tumor xenografts. Here, we demonstrated that MH decreased cell growth and induced apoptosis in HN22 and HSC4 cells through the regulation of specificity protein 1 (Sp1). We employed several experimental techniques such as MTS assay, DAPI staining, PI staining, Annexin-V/7-ADD staining, RT-PCR, western blot analysis, immunocytochemistry, immunohistochemistry, TUNEL assay and in vivo xenograft model analysis. MH inhibited Sp1 protein expression and reduced Sp1 protein levels via both proteasome-dependent protein degradation and inhibition of protein synthesis in HN22 and HSC4 cells; MH did not alter Sp1 mRNA levels. We found that MH directly binds Sp1 by Sepharose 4B pull-down assay and molecular modeling. In addition, treatment with MH or knocking down Sp1 expression suppressed oral cancer cell colony formation. Moreover, MH treatment effectively inhibited tumor growth and Sp1 levels in BALB/c nude mice bearing HN22 cell xenografts. These results indicated that MH inhibited cell growth, colony formation and also induced apoptosis via Sp1 suppression in OSCC cells and xenograft tumors. Thus, MH is a potent anti-cancer drug candidate for oral cancer.

In vitro assessment of antioxidant activity of tyrosol, resveratrol and their acetylated derivatives.

Consumption of phenolic compounds is associated with beneficial effects in humans even though many of them are poorly absorbed. The aim of this study was to investigate the in vitro antioxidant activity of tyrosol (T), resveratrol (R) and their acetylated derivatives (AcD), as increased lipophilicity has been reported to improve absorption. The chemically synthesized AcDs were evaluated by their ability to scavenge DPPH radicals, inhibit non-enzymatic linoleic acid peroxidation, inhibit human serum oxidation in the presence of copper ions and inhibit lipoxygenase activity. T showed an inhibitory effect only in serum oxidation, where the T-acetylated at aromatic-OH was the most active. The T-acetylated at aliphatic-OH and 3,5-diacetyl-R exhibited the most powerful effect in non-enzymatic linoleic acid peroxidation with IC50 values 2.4 mM ± 0.21 and 0.055 mM ± 0.0018, respectively. In all other tests R was the most potent among all its AcD and T. Increasing lipophilicity by acetylation improves antioxidant activity of phenolic compounds in non-enzymatic lipid peroxidation assays.

Metal-assisted synthesis of unsymmetrical magnolol and honokiol analogs and their biological assessment as GABAA receptor ligands.

We present the synthesis of new derivatives of natural products magnolol (1) and honokiol (2) and their evaluation as allosteric ligands for modulation of GABAA receptor activity. New derivatives were prepared via metal assisted cross-coupling reactions in two consecutive steps. Compounds were tested by means of two-electrode voltage clamp electrophysiology at the α1ß2γ2 receptor subtype at low GABA concentrations. We have identified several compounds enhancing GABA induced current (IGABA) in the range similar or even higher than the lead structures. At 3µM, compound 8g enhanced IGABA by factor of 443, compared to 162 and 338 of honokiol and magnolol, respectively. Furthermore, 8g at EC10-20 features a much bigger window of separation between the α1ß2γ2 and the α1ß1γ2 subtypes compared to honokiol, and thus improved subtype selectivity.

Chikungunya: un reto para los servicios de salud de la República Dominicana / Chikungunya: a challenge for the Dominican Republic's health services

Desde diciembre de 2013, la Región de las Américas se enfrenta por primera vez a una epidemia de chikungunya. Los casos iniciales se registraron en el Caribe francés y, debido al comercio y la movilización de personas, esta epidemia no tardó en llegar a la República Dominicana, cuya población es de 10 millones de habitantes y comparte con Haití la isla La Española. En este artículo se difunde información extraída de diversos artículos y documentos oficiales sobre el virus, la infección y la epidemia de chikungunya, que han sido de gran ayuda para orientar la respuesta en la República Dominicana y pueden ser útiles para mejorar tanto el conocimiento como las actuaciones frente a la epidemia de los trabajadores del sector salud de la Región. Se destaca la importancia que revisten las investigaciones realizadas en países y territorios afectados del océano Índico, como la isla de Reunión, durante la epidemia declarada entre 2005 y 2007, cuando se registró una tasa de ataque mayor de 30%, se identificaron los grupos de riesgo, las formas graves y atípicas de la infección, la transmisión vertical del virus, las formas crónicas, que pueden provocar dolores recurrentes durante tres años, y las defunciones directa o indirectamente relacionadas con el virus chikungunya. Por su alta tasa de ataque, el virus chikungunya se convierte en un reto sin precedentes para los ministerios de salud, que exige una adecuada organización de los servicios de salud, la priorización de la atención a los grupos de riesgo y a los pacientes con formas graves de la enfermedad, así como una adecuada comunicación social y respuesta intersectorial.

The Region of the Americas has been affected since December 2013 by a chikungunya epidemic for the first time. Although the first cases were recorded in the French Caribbean, the epidemic quickly spread to the Dominican Republic due to trade and people movements. The Dominican Republic, which shares the island of Hispaniola with Haiti, has a population of 10 million. This article contains information from a range of different publications and official documents about the chikungunya virus infection and epidemic. These papers were extremely helpful for guiding the response to the epidemic in the Dominican Republic and may also be useful for enhancing knowledge of the virus and responses among health workers elsewhere in the region. Particular attention is drawn to the important research undertaken in countries and territories affected by the epidemic in the Indian Ocean area. This is the case, for example, of the island of La Réunion, where the epidemic had an attack rate of more than 30% between 2005 and 2007. Researchers were able to identify risk groups, severe and atypical forms of the infection, cases of vertical transmission, chronic disease causing recurrent pain over three years, and directly- or indirectly-related deaths from the virus. Given its high attack rate, the chikungunya virus has emerged as an exceptional challenge for health ministries and calls for appropriate organized responses from the health services, prioritization of care for risk groups and patients exhibiting severe forms of the disease, and effective social communication and intersectoral actions.

Assessment of the anti-diarrhea function of compound Chinese herbal medicine Cangpo Oral Liquid.

BACKGROUND: Diarrhea is a big problem in piglets. Cangpo Oral Liquid (COL) is a compound of Chinese herbal medicine. The preparation was fed to piglets had diarrheal disease in order to determine its anti-diarrhea activity and potential applications in vivo. MATERIALS AND METHODS: The contents of Berberine hydrochloride, Magnolol and Honokiol in COL were performed on HPLC analysis. Organ bath was used to investigate the effect of COL on peristaltic reflexes and peristaltic waves in vitro. And anti-diarrhea activity of COL was evaluated in clinical. RESULTS: Thin layer chromatography (TLC) and HPLC analyses showed that the contents of Berberine hydrochloride, Magnolol and Honokiol in COL were 970µg/mL, 130µg/mL and 300µg/mL, respectively. Administration of the COL to the organ bath caused a concentration-dependent inhibition of intestinal peristalsis. When the COL concentration in the bath was cumulatively increased, the amplitude and frequency of the peristaltic waves was lowered. The result of clinical efficacy of COL was very effective to diarrheic piglets. COL can possibly inhibit the curve of peristaltic waves in vitro; and clinical trial showed a statistically significant therapeutic effect in vivo. CONCLUSION: In conclusion, COL can be used as an effective therapeutic agent. However, the ingredients, pharmacokinetics and specific signaling pathways of COL need to be further studied.

Assessment of the drug-drug interactions between fimasartan and hydrochlorothiazide in healthy volunteers.

AIM: Fimasartan is a selective angiotensin II receptor blocker. Hydrochlorothiazide (HCTZ), which is used to treat hypertension and edematous conditions, is coadministered with many antihypertensive agents. METHODS: An open-label, randomized, multiple-dosing, 2-arm, 1-sequence, 2-period study was conducted to assess the effects of fimasartan (240 mg) on HCTZ (25 mg) or vice versa in 18 and 14 healthy male volunteers, respectively. During each drug administration period, drugs were given once daily for 7 days, with a 7-day washout period between the 2 administration periods. RESULTS: The respective geometric mean ratios of fimasartan for AUC τ,ss and C max,ss with HCTZ were 1.30 [90% confidence interval (CI), 0.84-2.01] and 1.17 (90% CI, 0.93-1.47) compared with fimasartan alone. The respective geometric mean ratios of HCTZ for AUC τ,ss and C max,ss with fimasartan were 0.94 (90% CI, 0.84-1.04) and 0.88 (90% CI, 0.80-0.97) compared with HCTZ alone. Plasma renin activity indicated no significant differences between fimasartan monotherapy and coadministered treatment. CONCLUSIONS: Fimasartan administered alone or in combination with HCTZ was well tolerated at the described dosages. Coadministration of fimasartan increased the urinary excretion of HCTZ and urine volume, but these observations are unlikely to have any clinical relevance.

Molecular characterization of boscalid- and penthiopyrad-resistant isolates of Didymella bryoniae and assessment of their sensitivity to fluopyram.

BACKGROUND: Didymella bryoniae has a history of developing resistance to single-site fungicides. A recent example is with the succinate-dehydrogenase-inhibiting fungicide (SDHI) boscalid. In laboratory assays, out of 103 isolates of this fungus, 82 and seven were found to be very highly resistant (B(VHR) ) and highly resistant (B(HR) ) to boscalid respectively. Cross-resistance studies with the new SDHI penthiopyrad showed that the B(VHR) isolates were only highly resistant to penthiopyrad (B(VHR) -P(HR) ), while the B(HR) isolates appeared sensitive to penthiopyrad (B(HR) -P(S) ). In this study, the molecular mechanism of resistance in these two phenotypes (B(VHR) -P(HR) and B(HR) -P(S) ) was elucidated, and their sensitivity to the new SDHI fluopyram was assessed. RESULTS: A 456 bp cDNA amplified fragment of the succinate dehydrogenase iron sulfur gene (DbSDHB) was initially cloned and sequenced from two sensitive (B(S) -P(S) ), two B(VHR) -P(HR) and one B(HR) -P(S) isolate of D. bryoniae. Comparative analysis of the DbSDHB protein revealed that a highly conserved histidine residue involved in the binding of SDHIs and present in wild-type isolates was replaced by tyrosine (H277Y) or arginine (H277R) in the B(VHR) -P(HR) and B(HR) -P(S) variants respectively. Further examination of the role and extent of these alterations showed that the H/Y and H/R substitutions were present in the remaining B(VHR) -P(HR) and B(HR) -P(S) variants respectively. Analysis of the sensitivity to fluopyram of representative isolates showed that both SDHB mutants were sensitive to this fungicide as the wild-type isolates. CONCLUSION: The genotype-specific cross-resistance relationships between the SDHIs boscalid and penthiopyrad and the lack of cross-resistance between these fungicides and fluopyram should be taken into account when selecting SDHIs for gummy stem blight management.

Mechanisms of osteoclastogenesis inhibition by a novel class of biphenyl-type cannabinoid CB(2) receptor inverse agonists.

The cannabinoid CB(2) receptor is known to modulate osteoclast function by poorly understood mechanisms. Here, we report that the natural biphenyl neolignan 4'-O-methylhonokiol (MH) is a CB(2) receptor-selective antiosteoclastogenic lead structure (K(i) < 50 nM). Intriguingly, MH triggers a simultaneous G(i) inverse agonist response and a strong CB(2) receptor-dependent increase in intracellular calcium. The most active inverse agonists from a library of MH derivatives inhibited osteoclastogenesis in RANK ligand-stimulated RAW264.7 cells and primary human macrophages. Moreover, these ligands potently inhibited the osteoclastogenic action of endocannabinoids. Our data show that CB(2) receptor-mediated cAMP formation, but not intracellular calcium, is crucially involved in the regulation of osteoclastogenesis, primarily by inhibiting macrophage chemotaxis and TNF-α expression. MH is an easily accessible CB(2) receptor-selective scaffold that exhibits a novel type of functional heterogeneity.

Assessment of phenolic content, free-radical-scavenging capacity genotoxic and anti-genotoxic effect of aqueous extract prepared from Moricandia arvensis leaves.

The present study was undertaken to provide a set of data on the safety of an aqueous extract (AQE) from Moricandia arvensis. For this reason, Escherichia coli tested strains PQ35 and PQ37 were used to detect induction of DNA lesions by AQE. The SOS Chromotest showed that AQE induced a marginally genotoxic effect, as expressed by the induction factor (IF) value only with E. coli PQ37 tested strain (IF=1.77 at a dose of 250 microg/assay). The measurement of the anti-genotoxic activity of the AQE was also studied by inhibition of beta-galactosidase induction. A significant anti-genotoxic effect was observed with different tested doses of AQE, which suggests that M. arvensis extract has the potential to protect DNA from the action of nitrofurantoïn (NF) and free radicals generated by hydrogen peroxide (H2O2). In addition to anti-genotoxic activity, AQE showed a free-radical-scavenging capacity towards ABTS+* and DPPH*. Total phenolic content was also evaluated following Folin-Ciocalteu method and results indicated high correlation between total phenol content and anti-genotoxic and antioxidant activities for AQE, but the highest correlation was showed with its capacity to stabilize ABTS+* (R2=0.9944).

Method for assessment of viability and morphological changes of bacteria in the early stage of colony formation on a simulated natural environment.

A quantitative analysis of changes in the physiological status of bacterial cells is a fundamental type of study in microbiological research. We devised a method for measuring the viability of bacteria in the early stage of colony formation on a simulated natural environment. In this method, a solid medium containing soil extract was used, and the formation of bacterial microcolonies on a membrane filter was determined by use of a laser scanning cytometer combined with live-dead fluorescent dyes. A polychlorinated biphenyl degrader, Comamonas testosteroni TK102, was used in this study. Surprisingly, approximately 20% of the microcolonies had their growth stopped and eventually died. In the presence of biphenyl, the growth arrest was increased to 50%, and filamentous cells were observed in the colonies. Predicted intermediate metabolites of biphenyl were added to the medium to determine the relationship between the change of viability and the production of metabolites, and the addition of 2,3-dihydroxybiphenyl showed low viability. The arrest was not observed to occur on nutrient-rich medium, suggesting that the change in viability might occur in a nutrient-poor natural condition. The results of this study demonstrated that toxic metabolites of xenobiotics might change cell viability in the natural environment.

Blockade of the renin-angiotensin-aldosterone system: a key therapeutic strategy to reduce renal and cardiovascular events in patients with diabetes.

Diabetes (particularly type 2 diabetes) represents a global health problem of epidemic proportions. Individuals with diabetes are not only more likely to develop hypertension, dyslipidemia, and obesity, but are also at a significantly higher risk for coronary heart disease, peripheral vascular disease, and stroke. Angiotensin II plays a key pathophysiological role in the progression of diabetic renal disease, and blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACEi) or angiotensin II antagonists has therefore become an important therapeutic strategy to reduce renal and cardiovascular events in patients with diabetes. Several studies have demonstrated the effects of angiotensin II antagonists on the reduction of albuminuria and the progression of renal disease from microalbuminuria to macroalbuminuria. More importantly, several endpoint trials have shown that the antiproteinuric effects of losartan and irbesartan translate into cardiovascular and renoprotective benefits beyond blood pressure lowering, thereby delaying the need for dialysis or kidney transplantation by several years. These and other studies indicate that angiotensin II antagonists not only improve survival and quality of life of patients with diabetic nephropathy, but also have the potential to reduce the substantial healthcare burden associated with managing these patients. ACEi also appear to exert similar beneficial effects in diabetic patients, but whether clinically significant differences in renoprotection or mortality exist between angiotensin II antagonists and ACEi in patients with type 2 diabetes remains to be fully investigated in appropriate head-to-head studies.

An update of irbesartan and renin-angiotensin system blockade in diabetic nephropathy.

Type 2 diabetes is a chief cause of pathologies such as cardiovascular disease, nephropathy and retinopathy, and its prevalence is increasing worldwide. Development of renal disease can be slowed by tight glycaemic control and treatment of associated hypertension with angiotensin-converting enzyme inhibition, as The Diabetes Control and Complications Trial and the UK Prospective Diabetes Study have demonstrated. Recent clinical trials have supported the use of angiotensin II receptor antagonists in the treatment of diabetic nephropathy, resulting in the approval of new therapeutic indications in the US and Europe. The main goal of this review is to demonstrate how results from the Programme for Irbesartan Mortality and Morbidity Evaluation and other recent studies, based on the effects of renin-angiotensin system blockade, can be appropriate in clinical practice, thus displaying benefits of irbesartan therapy at any stage of renal disease in diabetics.

Structure-based design of selective agonists for a rickets-associated mutant of the vitamin d receptor.

The nuclear and steroid hormone receptors function as ligand-dependent transcriptional regulators of diverse sets of genes associated with development and homeostasis. Mutations to the vitamin D receptor (VDR), a member of the nuclear and steroid hormone receptor family, have been linked to human vitamin D-resistant rickets (hVDRR) and result in high serum 1,25(OH)(2)D(3) concentrations and severe bone underdevelopment. Several hVDRR-associated mutants have been localized to the ligand binding domain of VDR and cause a reduction in or loss of ligand binding and ligand-dependent transactivation function. The missense mutation Arg274 --> Leu causes a >1000-fold reduction in 1,25(OH)(2)D(3) responsiveness and is, therefore, no longer regulated by physiological concentrations of the hormone. In this study, computer-aided molecular design was used to generate a focused library of nonsteroidal analogues of the VDR agonist LG190155 that were uniquely designed to complement the Arg274 --> Leu associated with hVDRR. Half of the designed analogues exhibit substantial activity in the hVDRR-associated mutant, whereas none of the structurally similar control compounds exhibited significant activity. The seven most active designed analogues were more than 16 to 526 times more potent than 1,25(OH)(2)D(3) in the mutant receptor (EC(50) = 3.3-121 nM). Significantly, the analogues are selective for the nuclear VDR and did not stimulate cellular calcium influx, which is associated with activation of the membrane-associated vitamin D receptor.