Effectiveness of GenoType MTBDRsl in excluding TB drug resistance in a clinical trial

OBJECTIVES: To assess the performance of the GenoType MTBDRsl v1, a line-probe assay (LPA), to exclude baseline resistance to fluoroquinolones (FQs) and second-line injectables (SLIs) in the Standard Treatment Regimen of Anti-tuberculosis Drugs for Patients With MDR-TB 1 (STREAM 1) trial.METHODS: Direct sputum MTBDRsl results in the site laboratories were compared to indirect phenotypic drug susceptibility testing (pDST) results in the central laboratory, with DNA sequencing as a reference standard.RESULTS: Of 413 multidrug-resistant TB (MDR-TB) patients tested using MTBDRsl and pDST, 389 (94.2%) were FQ-susceptible and 7 (1.7%) FQ-resistant, while 17 (4.1%) had an inconclusive MTBDRsl result. For SLI, 372 (90.1%) were susceptible, 5 (1.2%) resistant and 36 (8.7%) inconclusive. There were 9 (2.3%) FQ discordant pDST/MTBDRsl results, of which 3 revealed a mutation and 5 (1.3%) SLI discordant pDST/MTBDRsl results, none of which were mutants on sequencing. Among the 17 FQ- and SLI MTBDRsl-inconclusive samples, sequencing showed 1 FQ- and zero SLI-resistant results, similar to frequencies among the conclusive MTBDRsl. The majority of inconclusive MTBDRsl results were associated with low bacillary load samples (acid-fast bacilli smear-negative or scantily positive) compared to conclusive results (P < 0.001).CONCLUSION: MTBDRsl can facilitate the rapid exclusion of FQ and SLI resistances for enrolment in clinical trials.

Predictors and Barriers to Condom Use in the African Cohort Study

Consistent condom use is an inexpensive and efficacious HIV prevention strategy. Understanding factors associated with condom use and barriers to use can inform strategies to increase condom uptake. The ongoing African Cohort Study prospectively enrolls adults at 12 clinical sites in Uganda, Kenya, Tanzania, and Nigeria. At enrollment, participants are asked about condom use at last sex with a regular partner. Robust Poisson regression models were used to evaluate predictors of self-reported condom use. Participants who reported not using condoms were asked to provide reasons. From January 2013 to September 2019, 2482 participants reported having at least one regular sexual partner in the preceding 6 months. Of those, 1577 (63.5%) reported using a condom at last sex. Condom use was more common among older participants, males, HIV-infected participants, and those with an HIV-infected partner. Married participants, those with a partner of unknown HIV status, and those reporting alcohol use were less likely to report condom use at last sex. Condom use at last sex also varied significantly by clinical site. Partner disapproval or refusal to use a condom was a consistent driver of disparities in condom use among participants who were HIV infected, female, and aged 18-24 years. Effective HIV prevention programs should integrate condom education with the tools necessary to negotiate condom use with regular partners.

Anti-tuberculosis drug resistance in Ethiopia: systematic review

BACKGROUND

Resistance to anti-tuberculosis drugs threatens to undermine effective control of tuberculosis (TB). In areas with weak TB control and misuse of anti-tuberculosis drugs, hotspots of multidrug-resistant TB (MDR-TB) have appeared. The aim of this review is to determine the prevalence rate of any anti-tuberculosis drug resistance, monoresistance and MDR-TB in Ethiopia.

METHODS

A systematic review of the literature on any resistance, monoresistance and MDR-TB was conducted.

RESULTS

Of the total 468 articles found using electronic search, 14 met the eligibility criteria and were included in the review. The prevalence rate of any drug resistance, polyresistance and MDR-TB was respectively 6.7-72.9%, 0-54% and 0-46%. A higher rate of streptomycin monoresistance (1.5-20.4%) was observed.

CONCLUSION

The prevalence and distribution of drug-resistant TB remains a serious public health problem in Ethiopia. Rapid, advanced diagnostic tools should be introduced, along with strong treatment and follow-up strategies.

The delivery of ivermectin (Mectizan)

Over a comparatively short period of time, the development and distribution of ivermectin (Mectizan) has radically altered the consequences of infection with Onchocerca volvulus. To achieve this required the fostering of many partnerships and the development of new tools and methods. The long-term commitment of Merck, the World Bank and other sponsors, as well as governments and non-governmental organizations, has been crucial. Yet the enthusiasm with which communities have taken up the delivery of ivermectin among themselves is perhaps the greatest reason for the success of this programme. The present challenge is sustaining the methods that have brought success so far, and making them part of health services and disease control programmes in some of the world's most impoverished and unstable areas. A major part of this challenge is continuing the commitment to controlling onchocerciasis as memory of the disease is fading, and while the hope of elimination or eradication for most endemic countries remains distant.

Analysis of isoflavone contents in vegetable soybeans

In addition to oil and soyfoods, soybean is also produced for vegetable use. The importance of consuming vegetable soybean for the prevention of chronic diseases is well documented. The objectives of this study were to determine the magnitude of genotype x year interactions for isoflavone concentration and pattern, estimate heritabilities, and identify genotypes with a stable isoflavone concentration and pattern. Thirty-one soybean genotypes from maturity groups (MGs) III to VI were grown at Randolph Research Farm of Virginia State University, Petersburg, Virginia, during 3 years. The genotypes were harvested at immature green pod stage (R6-R7) and analyzed for isoflavone contents. Significant (P < 0.05) differences among the genotypes were found for genistein, daidzein, glycitein, and total isoflavones. The genotype x year interactions were also significant (P < 0.05) for the seed traits analyzed, indicating that the performance of the genotype changes from year to year. However, genotypes Pella and Aoda consistently showed with higher means than the overall means for all the seed traits throughout the 3 years. MG differences were also observed for genistein, daidzein, and total isoflavone content. Low- to moderate-heritability estimates of 54, 45, 58, and 64% were observed for genistein, daidzein, glycitein, and total isoflavone content, respectively, suggesting that the seed traits are equally influenced by environments and genetic variations. In general, for all seed traits with the exception of daidzein, the percentage contribution of genotype to the total sum of square was higher than the genotype x year interaction. The seed traits were interdependent and the associations among them were positive and significant suggesting that simultaneous selection and improvements are possible.

Acceptability of green soybeans as a vegetable entity

A profile of the sensory characteristics of green soybean and consumer intent of purchasing the product were determined. Thirty-one green soybean genotypes from maturity groups III to VI harvested between R6 and R7 were frozen, boiled, shelled, and evaluated for color, texture, sweetness, nuttiness, beaniness, oiliness, aftertaste and overall eating quality by three sensory panels. Results showed highly significant (p <0.01) variabilities among the genotypes in all sensory parameters and highly significant correlations among several parameters. The green soybeans, when boiled, ranged from lightly green to green, were slightly resistant to chewing, slightly nutty, slightly beany, not oily, imparted a pleasant aftertaste and had a fairly good overall eating quality. The green soybeans would be potentially acceptable as a vegetable in the frozen state and for use in recipes. When selecting genotypes for production, consideration should be given to the sensory attributes of the genotypes, because there was significant variability among the characteristics of the green soybeans, and several characteristics together enhanced the overall acceptability of the vegetable soybeans. To further increase the acceptability of green soybeans as a vegetable, geneticists need to consider breeding a vegetable soybean that has as many desirable sensory attributes as possible.

Accumulation of phytate in vegetable-type soybean genotypes harvested at four developmental stages

A total of 17 vegetable-type soybean (Glycine max [L.] Merr) genotypes were planted in four-row plots arranged in a randomized complete block design in 1988 and 1989 at Petersburg, Virginia. Each genotype was harvested at four developmental stages and evaluated for phytate content. Highly significant differences for phytate content were observed among the stages of harvest and genotypes, and there was an interaction between genotype x stage of harvest. The significant differences observed for phytate content among genotypes indicated that genetic variation exists among the tested genotypes for selection and improvement through hybridization. Among the genotypes, 'Kingston' and PI 423852 had the highest phytate content in most stages of harvest while PI 416771, 'Emperor', and PI 416982 had the lowest phytate values. A heritability estimate of 81 percent was observed for phytate content. This high heritability value indicates that selecting genotypes for lower phytate content would be effective. Significant correlations were observed for phytate content among genotypes harvested at R6, R7, R8, and overall. The magnitude of association of R6 with the overall phytate mean was especially high. These results illustrate that determining the phytate content of genotypes at the R6 growth stage would be a good predictor of the overall genotypic performance.

Improved radiolabeled substrates for soluble epoxide hydrolase

Two rapid assays for the soluble epoxide hydrolase (sEH) are described. First, a sensitive radiometric assay based on thin-layer chromatography of [(14)C]-cis-9,10-epoxystearic acid and its corresponding diol ((14)C]-9,10-dihydroxystearic acid) is described. The cis fatty acid oxide exhibits higher specific activity of hydration with sEH from mouse, rat, human, and potato compared to trans-stilbene oxide (TSO). The K(m) and V(max) obtained for [(14)C]-cis-9,10-epoxystearic acid with mouse sEH are 11.0 microM and 3460 nmol/min/mg protein, respectively. [(14)C]-cis-9,10- Epoxystearic acid might more closely mimic the structures of natural substrates for sEH. Second, [2-(3)H]-trans-1,3-diphenyl-propene oxide ([(3)H]-tDPPO) and [2-(3)H]-cis-1,3-diphenylpropene oxide ([(3)H]-cDPPO) were synthesized and rapid radiometric assays for epoxide hydrolases (EHs) were developed by differential partitioning of the epoxide into iso-octane and its corresponding diol into aqueous phase containing methanol. It was shown that sEHs from mouse, rat, human, and potato rapidly hydrolyze [(3)H]-tDPPO and in comparison to TSO have 20-,49-,28-, and 7-fold higher rates, respectively. Mouse sEH hydrates [(3)H]-tDPPO at 26,200 nmol/min/mg protein, and a K(m)p4 of 2.80 microM is observed.

Family variation in gas exchange, growth and leaf traits of black locust half-sib families

Variations in several growth, gas exchange and leaf traits among greenhouse-grown black locust (Robinia pseudoacacia L.) seedlings from 11 half-sib families were investigated. Three weeks after germination, early growth rates ranged from a minimum of 1 cm d(-1) in the slowest growing family, to a maximum of 3 cm d(-1) in the fastest growing family. Significant family variation in net photosynthetic rate per unit leaf area (P(N)), stomatal conductance, chlorophyll content, height, diameter, stem dry weight and total dry weight was observed. Net photosynthetic rate declined with seedling age. Net photosynthetic rate per unit leaf area was significantly correlated (r < 0.4) with specific leaf area, total chlorophyll, root dry weight, foliage dry weight and total dry weight. The correlation coefficients were higher (r >/= 0.55) between P(N) x total leaf area and growth traits (height, stem dry weight, foliage dry weight and total dry weight). The study indicated that variation in leaf area among the families was one reason for the lack of a strong relationship between P(N) and growth.

Nutrient composition and anti-nutritional factors in selected vegetable soybean (Glycine max [L.] Merr.)

The genetic variation in the nutrient composition and anti-nutritional factors of 17 vegetable soybean genotypes were determined and a wide variation in protein %, total phosphorus (TPi) and available phosphorus (AP) was found among these genotypes. Variations in Ca, K, Fe, Mn, and Cu were also documented. Variation was also found for trypsin inhibitor (TI) activity and Phytate (PA) content. A highly significant and negative correlation (r = -0.533, P less than 0.01) was observed between TI and total protein. Strong positive correlation (r = 0.90) was also found between TPi and AP. Several genotypes (Sooty, Emperor, Wilson-5, PI 416771, PI 417322) showed good nutritional potential and can be used in the breeding program. High protein %, TPi, and minerals are desirable qualities for vegetable-type soybeans that make it as food with high nutrient density. Studies on the nutritional evaluation of immature vegetable type soybean seeds at different reproductive stages are also underway.

Inheritance of ambient ozone insensitivity in common bean (Phaseolus vulgaris L.)

The inheritance of ozone (O(3)) insensitivity in common bean (Phaseolus vulgaris L.) was evaluated using F(2) and F(3) populations under ambient conditions. This study was conducted over two growing seasons (1987, 1988) at Virginia State University, Randolph Research Farm, Petersburg, Virginia. Two populations were obtained by crossing insensitive plant introductions with sensitive commercial cultivars. Ratings on the scale of 1 to 5 (1 = 0 to 20% leaf injury, 2 = 21 to 40%, 3 = 41 to 60%, 4 = 61 to 80%, and 5 > 80%) were made on 160 F(2), F(3) progenies, and parental lines. Population mean injury ratings were recorded and estimates of genotypic, environmental, and phenotypic variances were computed. Estimates of heritability in the broadsense and of genetic advance were calculated for each population using F(2) and family component variance methods. Population means of the F(2) and F(3) progenies were not significantly different from their mid-parent values, suggesting that genetic variance was primarily additive. Broad-sense heritability estimates using F(2) variance method ranged from 51.4 to 70.5% and using family component variance method ranged from 62.1 to 75.6%. In this study, the computed genetic advance values closely parallel those of heritability estimated values. The high heritable nature of insensitivity would indicate that effective levels of insensitivity could be transferred to agronomically superior cultivars in a relatively short time.