Cytostatic, cytotoxic and mutagenic effects of voacristine, an indole alkaloid in wild-type and repair-deficient yeasts

Voacristine, an indole alkaloid isolated from the leaves of Ervatamia coronaria (Stapf.) (Apocynaceae) has dose-dependent cytostatic and cytotoxic effects on cultures of Saccharomyces cerevisiae. These inhibitory effects take place only in growing cells. Among the different repair-deficient mutants examined, a mutant defective in excision-resynthesis repair pathway (rad3-e5) was found to be the most sensitive to such a toxic effect. The mutant rad52-1 blocked in the DNA strand break repair pathway showed an intermediary sensitivity to the lethal effect induced by this indole alkaloid, whereas the mutant defective in the mutagenic repair pathway (rad6-1) demonstrated practically the same sensitivity as the wild-type strain. The nuclear reversion mutation for the locus lysl-1 was induced by voacristine, whereas the mitochondrial "petite" mutation was not induced by this alkaloid. These results indicate that the lesions induced by voacristine in vivo are likely to be of the adducts type; such damage is repairable in the wild-type; the DNA strand break repair pathway plays a minor role in the repair of voacristine-induced lesions.     

Primary cutaneous cryptococcosis

Cottonseed protein agar and a modified Tween-albumin casein hydrolysate (TAC) medium were compared for the yeast phase conversion of Blastomyces dermatitidis strains including fresh isolates as well as strains maintained in long-term storage. It was found that both media converted all the B. dermatitidis (mycelial phase) strains studied to yeast phase in three days. The TAC medium has the added advantage that it is clear and the growth can be recognized earlier than in the opaque cottonseed agar medium. The conversion in most cases was more than 95% and the morphology of the yeast cells was uniformly typical with broad base budding. There was a striking difference between the sensitivity of the yeast and mycelial phases of B. dermatitidis strains. The yeast phase was usually more sensitive to Amphotericin B than the mycelial phase of B. dermatitidis. Similarly, the yeast phases of four out of six strains were more sensitive to ketoconazole than their respective mycelial phases, while two strains showed identical sensitivity in cottonseed agar. The yeast phase organism was more susceptible to Amphotericin B when cottonseed medium was used whereas the yeast phase showed more susceptibility to ketoconazole in TAC medium. Since the sensitivity among the various strains differed, it is necessary to determine the antifungal susceptibility of the pathogenic phase of the organism for initiating proper therapy and monitoring effectiveness.Dr. Rose actively participated in this research; expired February 2, 1984.     

Inactivation of beef heart mitochondrial F1-ATPase by the 2',3'-dialdehyde derivatives of adenine nucleotides

Beef heart mitochondrial F1-ATPase was inactivated by the 2',3'-dialdehyde derivatives of ATP, ADP and AMP (oATP, oADP, oAMP). In the absence of Mg2+, inactivation resulted from the binding of 1 mol nucleotide analog per active unit of F1. The most efficient analog was oADP, followed by oAMP and oATP. Complete inactivation was correlated with the binding of about 11 mol [14C]oADP/mol F1. After correction for non-specific labeling, the number of specifically bound [14C]oADP was 2-3 mol per mol F1. By SDS-polyacrylamide gel electrophoresis, [14C]oADP was found to bind covalently mainly to the alpha and beta subunits. In the presence of Mg2+, oATP behaved as a substrate and was slowly hydrolyzed.     

Absolute dependence of phenylalanine and tyrosine biosynthetic enzyme on tryptophan in Candida maltosa

Candida maltosa synthesizes phenylalanine and tyrosine only via phenylpyruvate and p-hydroxyphenylpyruvate. Tryptophan is absolutely necessary for the enzymatic reaction of chorismate mutase and prephenate dehydrogenase; activity of prephenate dehydratase can be increased 2.5-fold in the presence of tryptophan. Activation of the chorismate mutase, prephenate dehydratase and prephenate dehydrogenase by tryptophan is competitive with respect to chorismate and prephenate with Ka 0.06mM, 0.56mM and 1.7mM. In addition tyrosine is a competitive inhibitor of chorismate mutase (Ki = 0.55mM) and prephenate dehydrogenase (Ki = 5.5mM).     

Phenolic composition and antiparasitic activity of plants from the Brazilian Northeast “Cerrado”

This work describes the antiparasitic and cytotoxic activities of three plant species from the Cerrado biome, Northeastern Brazil. Significant antiparasitic inhibition was observed against Trypanosoma cruzi (63.86%), Leishmania brasiliensis (92.20%) and Leishmania infantum (95.23%) when using ethanol extract from leaves of Guazuma ulmifolia Lam. (Malvaceae), at a concentration of 500 μg/mL. However, low levels of inhibition were observed when assessing leishmanicidal and trypanocidal (Clone CL-B5) activities of crude ethanol extracts from leaves and bast tissue of Luehea paniculata (Malvaceae) and leaves and bark of Prockia crucis (Salicaceae) at a concentration of 500 μg/mL. The extracts revealed the presence of phenolic acids such as gallic acid, chlorogenic acid, caffeic acid and rosmarinic acid, as well as flavonoids such as rutin, luteolin, apigenin and quercetin – the latter detected only in G. ulmifolia. G. ulmifolia extract displayed higher leishmanicidal activity probably due to the presence of quercetin, a potent known leishmanicidal compound. A cytotoxicity test indicated values over 50% at the highest concentration (1000 μg/mL) for all natural products, which were considered cytotoxic. This points out the need for further tests to enable future in vivo trials, including antineoplastic activity on human tumor cells.     

Investigating Sources of Heterogeneity in Randomized Controlled Trials of the Effects of Pharmacist Interventions on Glycemic Control in Type 2 Diabetic Patients: A Systematic Review and Meta-Analysis

Objective

To assess the effect of pharmacist interventions on glycemic control in type 2 diabetic patients and to examine factors that could explain the variation across studies.

Methods

A comprehensive literature search was performed in PubMed, Scopus, and LILACS databases for randomized controlled trials (RCTs) published up to July 2015. The search strategy included the use of MeSH terms or text words related to pharmacist interventions, type 2 diabetes, and randomized controlled trials. RCTs published in English, Portuguese, or Spanish that evaluated the effect of pharmacist intervention on glycemic control in type 2 diabetic outpatients were included. Two independent authors executed study selection, data extraction, and risk of bias assessment. Mean differences in glycosylated hemoglobin (HbA1c) were estimated using random-effect models, and heterogeneity was evaluated by subgroup and meta-regression analyses.

Results

The literature search yielded 963 records of potential interest, of which 30 were included in the systematic review and 22 in the meta-analysis. Most of these RCTs were conducted in the United States in patients in outpatient clinics using face-to-face contact only. All RCTs performed patient education, and most executed the medication review. The appraised sample showed uncertain or high risk of bias in most of the items evaluated, resulting in low-quality studies. In comparison with usual care, pharmacist interventions were associated with significant reductions in HbA1c levels (-8.5% [95% CI: -1.06, -0.65]; P < 0.0001; I² = 67.3%). Subgroup analysis indicated differences of heterogeneity by country, baseline HbA1c levels, setting, intervention frequency, and random allocation. Age and HbA1c levels partly explained the variability across studies by meta-regression.

Conclusions

Our findings confirmed that pharmacist interventions improve glycemic control in patients with type 2 diabetes compared with usual care and suggest that younger patients or with higher baseline HbA1c levels may be the main beneficiaries of pharmacist care.

Protocol PROSPERO Registration Number

CRD42014007457     

Micronutrient Deficiencies and Plasmodium vivax Malaria among Children in the Brazilian Amazon

Background

There is a growing body of evidence linking micronutrient deficiencies and malaria incidence arising mostly from P. falciparum endemic areas. We assessed the impact of micronutrient deficiencies on malaria incidence and vice versa in the Brazilian state of Amazonas.

Methodology/Principal Findings

We evaluated children <10 years old living in rural communities in the state of Amazonas, Brazil, from May 2010 to May 2011. All children were assessed for sociodemographic, anthropometric and laboratory parameters, including vitamin A, beta-carotene, zinc and iron serum levels at the beginning of the study (May 2010) and one year later (May 2011). Children were followed in between using passive surveillance for detection of symptomatic malaria. Those living in the study area at the completion of the observation period were reassessed for micronutrient levels. Univariate Cox-proportional Hazards models were used to assess whether micronutrient deficiencies had an impact on time to first P. vivax malaria episode. We included 95 children median age 4.8 years (interquartile range [IQR]: 2.3–6.6), mostly males (60.0%) and with high maternal illiteracy (72.6%). Vitamin A deficiencies were found in 36% of children, beta-carotene deficiency in 63%, zinc deficiency in 61% and iron deficiency in 51%. Most children (80%) had at least one intestinal parasite. During follow-up, 16 cases of vivax malaria were diagnosed amongst 13 individuals. Micronutrient deficiencies were not associated with increased malaria incidence: vitamin A deficiency [Hazard ratio (HR): 1.51; P-value: 0.45]; beta-carotene [HR: 0.47; P-value: 0.19]; zinc [HR: 1.41; P-value: 0.57] and iron [HR: 2.31; P-value: 0.16]). Upon reevaluation, children with al least one episode of malaria did not present significant changes in micronutrient levels.

Conclusion

Micronutrient serum levels were not associated with a higher malaria incidence nor the malaria episode influenced micronutrient levels. Future studies targeting larger populations to assess micronutrients levels in P. vivax endemic areas are warranted in order to validate these results.     

Genotoxic and Cytotoxic Effects of Antiretroviral Combinations in Mice Bone Marrow

Commonly used guidelines for the management of human immunodeficiency virus (HIV) infection (highly active antiretroviral therapy, HAART) include drug combinations such as tenofovir disoproxil fumarate (TDF) + lamivudine (3TC) and combivir [zidovudine (AZT) + 3TC] + efavirenz (EFV). These combinations may enhance the genotoxic effects induced by such drugs individually, since the therapy requires lifelong adherence and the drugs have unknown effects during treatment. Thus, the evaluation of the benefits and risks of HAART is of great importance. In order to assess the cytotoxic and genotoxic potential of three concentrations of each of the antiretroviral combinations TDF + 3TC (800 + 400, 1600 + 800, and 3200 + 1600 mg/kg body weight, BW) and combivir + EFV (200 + 100 + 400, 400 + 200 + 800, and 800 + 400 + 1600 mg/kg BW) after two exposure periods (24 h and 48 h), in the present study the in vivo comet assay (single-cell gel electrophoresis) and the mouse bone marrow micronucleus test were used. Neither TDF + 3TC nor combivir + EFV induced DNA damage at any concentrations tested after 24 h or 48 h using the comet assay. After 24 h, both combinations increased the micronucleus frequency at all concentrations tested. After 48 h, combivir + EFV increased the micronucleated polychromatic erythrocyte (MNPCE) frequency at the two highest concentrations tested. Polychromatic erythrocytes (PCE)/normochromatic erythrocytes (NCE) ratio was high for both combinations, suggesting that they can be mitogenic. Since genotoxicity may be related to carcinogenesis, it is necessary to conduct further studies to verify the long-term mutagenic effects of these drugs.     

Colonization by Macroinvertebrates of Experimentally Disturbed Stones in Three Tropical Streams Differing in Size

We experimentally disturbed stones in three streams of different sizes and followed the macroinvertebrate colonization process in terms of abundance, species richness and similarity over 64 days. We hypothesized that colonization in the smallest and in the largest streams would be slower than in the medium‐sized stream. The small upstream pool of colonists available in the smallest stream could restrict colonization, while in the largest stream predation by the diverse fish assemblage could restrict drifting colonists. The medium‐sized stream did not have these two constraints. We found similar colonization patterns in all three streams, leading to the rejection of the stated hypotheses. Lack of support of the original hypothesis might be due to the weakness of the two hypothesized restrictions on colonization. In addition, colonization by crawling species from undisturbed nearby patches might be of significant importance. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)