Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Apparatus for measurement of thermoelectric properties of a single leg under large temperature differences

Thermoelectric (TE) devices operate under large temperature differences, but material property measurements are typically accomplished under small temperature differences. Because of the issues associated with forming proper contact between the test sample and the electrodes and the control of heat flux, there are very few reports on large temperature difference measurements. Therefore, practically relevant performance parameters of a device, namely, power output and efficiency, are estimated by temperature averaging of material properties, whose accuracy is rarely validated by experimental investigations. To overcome these issues, we report an apparatus that has been designed and assembled to measure the TE properties-Seebeck coefficient, electrical conductivity, thermal conductivity, and power output and efficiency of a single thermoelectric material sample over large temperature gradients. The sample holder-a unique feature of this design-lowers the contact resistance between the sample and the electrodes, allowing for more accurate estimates of the sample's properties. Measurements were performed under constant temperature differences ranging from 50 to 300 K with the hot side reaching 673 K on a metallized Mg₂Si_0.3Sn_0.7 leg synthesized in the laboratory. To simulate practical operating conditions of a continuously loaded generator, continuous current flow measurements were also performed under large temperature differences. The temperature-averaged TE properties from standard low temperature difference measurements and the experimental TE properties agree with each other, indicating that the designed setup is reliable for measuring various thermoelectric generator properties of single TE legs when subjected to temperature gradients between 50 and 300 K.

Genomic insights into HSFs as candidate genes for high-temperature stress adaptation and gene editing with minimal off-target effects in flax

Flax (Linum usitatissimum) is a cool season crop commercially cultivated for seed oil and stem fibre production. A comprehensive characterization of the heat shock factor (HSF) candidate genes in flax can accelerate genetic improvement and adaptive breeding for high temperature stress tolerance. We report the genome-wide identification of 34 putative HSF genes from the flax genome, which we mapped on 14 of the 15 chromosomes. Through comparative homology analysis, we classified these genes into three broad groups, and sub-groups. The arrangement of HSF-specific protein motifs, DNA-binding domain (DBD) and hydrophobic heptad repeat (HR-A/B), and exon-intron boundaries substantiated the phylogenetic separation of these genes. Orthologous relationships and evolutionary analysis revealed that the co-evolution of the LusHSF genes was due to recent genome duplication events. Digital and RT-qPCR analyses provided significant evidence of the differential expression of the LusHSF genes in various tissues, at various developmental stages, and in response to high-temperature stress. The co-localization of diverse cis-acting elements in the promoters of the LusHSF genes further emphasized their regulatory roles in the abiotic stress response. We further confirmed DNA-binding sites on the LusHSF proteins and designed guide RNA sequences for gene editing with minimal off-target effects. These results will hasten functional investigations of LusHSFs or assist in devising genome engineering strategies to develop high-temperature stress tolerant flax cultivars.

Relationship of Parental Genetic Distance with Heterosis and Specific Combining Ability in Sesame (Sesamum indicum L.) Based on Phenotypic and Molecular Marker Analysis

The genetic distance analysis for selection of suitable parents has been established and effectively used in many crops; however, there is dearth of conclusive report of relationship of genetic distance analysis with heterosis in sesame. In the present study, an attempt was made to estimate the associations of genetic distances using SSR (GDSSR), seed-storage protein profiling (GDSDS) and agro-morphological traits (GDMOR) with hybrid performance. Seven parents were selected from 60 exotic and Indian genotypes based on genetic distance from clustering pattern based on SSR, seed-storage protein, morphological traits and per se performance. For combining ability analysis, 7 parents and 21 crosses generated from 7 × 7 half diallel evaluated at two environments in a replicated field trial during pre-kharif season of 2013. Compared with the average parents yield (12.57 g plant^-1), eight hybrids had a significant (P < 0.01) yield advantage across environments, with averages of 26.94 and 29.99% for better-parent heterosis (BPH) and mid-parent heterosis (MPH), respectively, across environments. Highly significant positive correlation was observed between specific combining ability (SCA) and per se performance (0.97), while positive non-significant correlation of BPH with GDSSR (0.048), and non-significant negative correlations with GDMOR (- 0.01) and GDSDS (- 0.256) were observed. The linear regressions of SCA on MPH, BPH and per se performance of F₁s were significant with R² value of 0.88, 0.84 and 0.95 respectively. The present findings revealed a weak association of GDSSR with F₁'s performance; however, SCA has appeared as an important factor in the determination of heterosis and per se performance of the hybrids. The present findings also indicated that parental divergence in the intermediate group would likely produce high heterotic crosses in sesame.

Assessing the genetic diversity of rice originating from Bangladesh, Assam and West Bengal

BACKGROUND

Genetic diversity among rice cultivars from Bangladesh and North East India was assessed using a custom 384-SNP microarray assay. A total of 511 cultivars were obtained from several sources, choosing landraces likely to be from the aus subpopulation and modern improved cultivars from Bangladesh. Cultivars from the OryzaSNP set and Rice Diversity Panel 1 (RDP1) were also included for reference.

RESULTS

The population analysis program STRUCTURE was used to infer putative population groups in the panel, revealing four groups: indica (76 cultivars), japonica (55) and two distinct groups within the aus subpopulation (aus-1 = 99, aus-2 = 151). Principal Component Analysis was used to confirm the four population groups identified by STRUCTURE. The analysis revealed cultivars that belonged to neither aus-1 nor aus-2 but which are clearly aus based on the combined probabilities of their membership of the two aus groups which have been termed aus-admix (96). Information obtained from the panel of 511 cultivars was used to assign rice groups to 74 additional landraces obtained from Assam and West Bengal. While both the aus-1 and aus-2 groups were represented approximately equally in India, aus-2 (which includes cultivar N 22) was more common in Bangladesh, but was not found at all in West Bengal.

CONCLUSIONS

Examining the distribution of landrace names within theaus-1 and aus-2 groups suggests that aus-1 is associated with the term "boro", a word used to describe a winter growing season in Bangladesh and Assam. The information described here has been used to select a population of 300 cultivars for Genome Wide Association studies of the aus rice subpopulation.

Morphological and genetic diversity assessment of sesame (Sesamum indicum L.) accessions differing in origin

Sesame is an important ancient oilseed crop of high medicinal value. In the present study, 37 characters including both quantitative and qualitative traits of sixty genotypes were characterized following IPGRI morphological descriptors for sesame. Multivariate analysis was computed to distinguish the varieties into different groups. Though thirty six microsatellite markers including genomic and Est-SSR markers were initially selected, but, finally, the accessions were genotyped by eight polymorphic primers. Altogether, 27 alleles were detected among the 60 genotypes, with an average of 3.37 alleles per locus. The number of alleles ranged from 2 to 6 alleles. From data of microsatellite markers, dissimilarity coefficients between varieties were computed following Jaccard's coefficient method. Principal co-ordinate analysis was used to represent the varieties in bi-directional space. Dendrogram was constructed using NJ method based on dissimilarity matrix. Cluster analysis based on morphological and molecular marker classified sesame genotypes into two major groups. Mantel test showed an insignificant correlation between phenotypic and molecular marker information. The genotypes belonging to the same geographical area did not always occupy the same cluster. The results confirmed that both genetic and phenotypic diversity in a combined way could efficiently evaluate the variation present in different sesame accessions in any breeding program.

Simultaneous measurement of all thermoelectric properties of bulk materials in the temperature range 300-600 K

Thermoelectric materials can directly convert heat into electrical energy. The characterization of different materials is an important part in thermoelectric materials research to improve their properties. Usually, different methods and setups are combined for the temperature dependent determination of all thermoelectric key quantities - Seebeck coefficient, electrical conductivity, and thermal conductivity. Here, we present a measurement system for the simultaneous determination of all of these quantities plus the direct determination of the figure of merit by means of the Harman method (zT)H in a temperature range from room temperature up to 600 K. A simultaneous measurement saves time and reduces the measurement error, and the change of all material properties can be monitored even for unstable materials. Thermal conductivity measurements are inherently affected by undesired thermal losses, in particular, through radiation at higher temperatures. We show a simple experimental approach to measure radiation losses and correct for those. Comparative measurements on traditional systems show good agreement for all measured quantities.

Lead in rice: analysis of baseline lead levels in market and field collected rice grains

In a large scale survey of rice grains from markets (13 countries) and fields (6 countries), a total of 1578 rice grain samples were analysed for lead. From the market collected samples, only 0.6% of the samples exceeded the Chinese and EU limit of 0.2 μg g(-1) lead in rice (when excluding samples collected from known contaminated/mine impacted regions). When evaluating the rice grain samples against the Food and Drug Administration's (FDA) provisional total tolerable intake (PTTI) values for children and pregnant women, it was found that only people consuming large quantities of rice were at risk of exceeding the PTTI from rice alone. Furthermore, 6 field experiments were conducted to evaluate the proportion of the variation in lead concentration in rice grains due to genetics. A total of 4 of the 6 field experiments had significant differences between genotypes, but when the genotypes common across all six field sites were assessed, only 4% of the variation was explained by genotype, with 9.5% and 11% of the variation explained by the environment and genotype by environment interaction respectively. Further work is needed to identify the sources of lead contamination in rice, with detailed information obtained on the locations and environments where the rice is sampled, so that specific risk assessments can be performed.

Variation in rice cadmium related to human exposure

Cereal grains are the dominant source of cadmium in the human diet, with rice being to the fore. Here we explore the effect of geographic, genetic, and processing (milling) factors on rice grain cadmium and rice consumption rates that lead to dietary variance in cadmium intake. From a survey of 12 countries on four continents, cadmium levels in rice grain were the highest in Bangladesh and Sri Lanka, with both these countries also having high per capita rice intakes. For Bangladesh and Sri Lanka, there was high weekly intake of cadmium from rice, leading to intakes deemed unsafe by international and national regulators. While genetic variance, and to a lesser extent milling, provide strategies for reducing cadmium in rice, caution has to be used, as there is environmental regulation as well as genetic regulation of cadmium accumulation within rice grains. For countries that import rice, grain cadmium can be controlled by where that rice is sourced, but for countries with subsistence rice economies that have high levels of cadmium in rice grain, agronomic and breeding strategies are required to lower grain cadmium.

Assessing the labile arsenic pool in contaminated paddy soils by isotopic dilution techniques and simple extractions

Arsenic (As) contamination of paddy soils threatens rice cultivation and the health of populations relying on rice as a staple crop. In the present study, isotopic dilution techniques were used to determine the chemically labile (E value) and phytoavailable (L value) pools of As in a range of paddy soils from Bangladesh, India, and China and two arable soils from the UK varying in the degree and sources of As contamination. The E value accounted for 6.2-21.4% of the total As, suggesting that a large proportion of soil As is chemically nonlabile. L values measured with rice grown under anaerobic conditions were generally larger than those under aerobic conditions, indicating increased potentially phytoavailable pool of As in flooded soils. In an incubation study, As was mobilized into soil pore water mainly as arsenite under flooded conditions, with Bangladeshi soils contaminated by irrigation of groundwater showing a greater potential of As mobilization than other soils. Arsenic mobilization was best predicted by phosphate-extractable As in the soils.

The dynamics of arsenic in four paddy fields in the Bengal delta

Irrigation with arsenic contaminated groundwater in the Bengal Delta may lead to As accumulation in the soil and rice grain. The dynamics of As concentration and speciation in paddy fields during dry season (boro) rice cultivation were investigated at 4 sites in Bangladesh and West Bengal, India. Three sites which were irrigated with high As groundwater had elevated As concentrations in the soils, showing a significant gradient from the irrigation inlet across the field. Arsenic concentration and speciation in soil pore water varied temporally and spatially; higher As concentrations were associated with an increasing percentage of arsenite, indicating a reductive mobilization. Concentrations of As in rice grain varied by 2-7 fold within individual fields and were poorly related with the soil As concentration. A field site employing alternating flooded-dry irrigation produced the lowest range of grain As concentration, suggesting a lower soil As availability caused by periodic aerobic conditions.

A comparison of the effects of physical and chemical mutagens in sesame (Sesamum indicum L.)

Three sesame genotypes (Rama, SI 1666 and IC 21706) were treated with physical (γ-rays: 200 Gy, 400 Gy or 600 Gy) or chemical (ethyl methane sulphonate, EMS: 0.5%, 1.0%, 1.5% or 2.0%) mutagens and their mutagenic effectiveness and efficiency were estimated in the M ₂ generation. The M ₃ generation was used to identify the most effective mutagen and dose for induction of mutations. The average effectiveness of EMS was much higher than γ-rays. The lowest dose of γ-rays (200 Gy) and the lowest concentration of EMS (0.5%) showed the highest mutagenic efficiency in all genotypes. Analysis of the M ₃ generation data based on parameters such as the variance ratio and the difference in residual variances derived from the model of Montalván and Ando indicated that 0.5% concentration of EMS was the most effective treatment for inducing mutations.

Arsenic influence on genetic variation in grain trace-element nutrient content in Bengal delta grown rice

It has previously been shown that across different arsenic (As) soil environments, a decrease in grain selenium (Se), zinc (Zn), and nickel (Ni) concentrations is associated with an increase in grain As. In this study we aim to determine if there is a genetic element for this observation or if it is driven by the soil As environment. To determine the genetic and environmental effect on grain element composition, multielement analysis using ICP-MS was performed on rice grain from a range of rice cultivars grown in 4 different field sites (2 in Bangladesh and 2 in West Bengal). At all four sites a negative correlation was observed between grain As and grain Ni, while at three of the four sites a negative correlation was observed between grain As and grain Se and grain copper (Cu). For manganese, Ni, Cu, and Se there was also a significant genetic interaction with grain arsenic indicating some cultivars are more strongly affected by arsenic than others.

Cystatin C and risk of vascular and nonvascular mortality: a prospective cohort study of older men

OBJECTIVE

To assess the relevance of cystatin C, as a marker of mild-to-moderate renal impairment, for vascular and nonvascular mortality in older people.

DESIGN

Prospective cohort study.

SETTING

Re-survey in 1997 to 1998 of survivors in the 1970 Whitehall study of London civil servants.

SUBJECTS

Five thousand three hundred and seventy-one men (mean age at resurvey: 77 years) who took part in the resurvey and had plasma cystatin C concentration measured.

MAIN OUTCOME MEASURES

Cause-specific mortality over subsequent 11 years (1997 to 2008).

METHODS

Cox regression was used to estimate the associations of cystatin C with vascular and nonvascular mortality, before and after adjustment for prior disease and other risk factors (including lifetime blood pressure).

RESULTS

During an 11.0-year follow-up period, there were 1171 deaths from vascular causes [26 per 1000 per year (py)] and 1615 deaths from nonvascular causes (36 per 1000 py). Compared with men with cystatin C in the bottom fifth of the distribution, men in the top 10th had about two-fold higher mortality rates from vascular and nonvascular mortality (fully adjusted P both <0.001) even after adjustment for prior disease and all measured confounders, including lifetime blood pressure. The fully adjusted relative risks per 50% higher cystatin C concentrations were 1.66 [95% CI 1.48 to 1.85] for vascular mortality, 1.92 [95% CI 1.66 to 2.22] for ischaemic heart disease mortality and 1.46 [95% CI 1.31 to 1.61] for nonvascular mortality.

CONCLUSIONS

In older men, plasma concentration of cystatin C, probably as a marker of mild renal disease, is a strong independent predictor of both vascular and nonvascular mortality.

PHF10 is required for cell proliferation in normal and SV40-immortalized human fibroblast cells

Normal human diploid fibroblasts have limited life span in culture and undergo replicative senescence after 50-60 population doublings. On the contrary, cancer cells typically divide indefinitely and are immortal. Expression of SV40 large T and small t antigens in human fibroblasts transiently extends their life span by 20-30 population doublings and facilitates immortalization. We have identified a rearrangement in chromosome 6 shared by SV40-transformed human fibroblasts. Rearrangements involving chromosome 6 are among the most frequent in human carcinogenesis. In this paper, we extend analysis of the 6q26-q27 region, a putative site for a growth suppressor gene designated SEN6 involved in immortalization of SV40-transformed cells. Detailed molecular characterization of the rearranged chromosomes (6q*, normal appearing; and 6q(t), translocated) in the SV40-immortalized cell line HALneo by isolating each of these 2 chromosomes in mouse/HAL somatic cell hybrids is presented. Analysis of these mouse/HAL somatic cell hybrids with polymorphic and nonpolymorphic markers revealed that the 6q* has undergone a chromosomal break in the MLLT4 gene (alias AF6). This result in conjunction with previous published observations leads us to conclude that SEN6 lies between MLLT4 and TBP at chromosomal region 6q27. Examination of different genes (MLLT4, DLL1, FAM120B, PHF10) located within this interval that are expressed in HS74 normal fibroblast cells reveals that overexpression of epitope-tagged truncated PHF10 cDNAs resulted in reduced cell proliferation in multiple cell lines. Paradoxically, down-regulation of PHF10 by RNAi also resulted in loss of cell proliferation in normal fibroblast cells, indicating PHF10 function is required for cell growth. Taken together, these observations suggest that decreased cell proliferation with epitope-tagged truncated PHF10 proteins may be due to dominant negative effects or due to unregulated expression of these mutant proteins. Hence we conclude that PHF10 is not SEN6 but is required for cell growth.

Environmental and genetic control of arsenic accumulation and speciation in rice grain: comparing a range of common cultivars grown in contaminated sites across Bangladesh, China, and India

The concentration of arsenic (As) in rice grains has been identified as a risk to human health. The high proportion of inorganic species of As (As(i)) is of particular concern as it is a nonthreshold, class 1 human carcinogen. To be able to breed rice with low grain As, an understanding of genetic variation and the effect of different environments on genetic variation is needed. In this study, 13 cultivars grown at two field sites each in Bangladesh, India, and China are evaluated for grain As. There was a significant site, genotype, and site by genotype interaction for total grain As. Correlations were observed only between sites in Bangladesh and India, not between countries or within the Chinese sites. For seven cultivars the As was speciated which revealed significant effects of site, genotype, and site by genotype interaction for percentage As(i). Breeding low grain As cultivars that will have consistently low grain As and low As(i), over multiple environments using traditional breeding approaches may be difficult, although CT9993-5-10-1-M, Lemont, Azucena, and Te-qing in general had low grain As across the field sites.

Environmental and genetic control of arsenic accumulation and speciation in rice grain: comparing a range of common cultivars grown in contaminated sites across Bangladesh, China, and India

The concentration of arsenic (As) in rice grains has been identified as a risk to human health. The high proportion of inorganic species of As (As(i)) is of particular concern as it is a nonthreshold, class 1 human carcinogen. To be able to breed rice with low grain As, an understanding of genetic variation and the effect of different environments on genetic variation is needed. In this study, 13 cultivars grown at two field sites each in Bangladesh, India, and China are evaluated for grain As. There was a significant site, genotype, and site by genotype interaction for total grain As. Correlations were observed only between sites in Bangladesh and India, not between countries or within the Chinese sites. For seven cultivars the As was speciated which revealed significant effects of site, genotype, and site by genotype interaction for percentage As(i). Breeding low grain As cultivars that will have consistently low grain As and low As(i), over multiple environments using traditional breeding approaches may be difficult, although CT9993-5-10-1-M, Lemont, Azucena, and Te-qing in general had low grain As across the field sites.

Study of parental handling patterns in a primary school of Kolkata

The intricate pattern of parenting in our socio-cultural context needs evaluation hence this study was done with the objective to reveal the parenting styles of school going children. 141 school children belonging to the age group 6-10 years were included in the study. The Parental Handling Questionnaire a 14-item scale consisting of 10 items of care and 4-items of control was administered to the mothers accompanying the children. Rating was done on a 3-point. The scale showed moderate internal consistency. 5 independent factors with overlapping items of care and control were deduced on factor analysis indicating multidimensional aspects of parenting in our society.

Rice-arsenate interactions in hydroponics: a three-gene model for tolerance

In this study, the genetic mapping of the tolerance of root growth to 13.3 muM arsenate [As(V)] using the BalaxAzucena population is improved, and candidate genes for further study are identified. A remarkable three-gene model of tolerance is advanced, which appears to involve epistatic interaction between three major genes, two on chromosome 6 and one on chromosome 10. Any combination of two of these genes inherited from the tolerant parent leads to the plant having tolerance. Lists of potential positional candidate genes are presented. These are then refined using whole genome transcriptomics data and bioinformatics. Physiological evidence is also provided that genes related to phosphate transport are unlikely to be behind the genetic loci conferring tolerance. These results offer testable hypotheses for genes related to As(V) tolerance that might offer strategies for mitigating arsenic (As) accumulation in consumed rice.

An arsenate tolerance gene on chromosome 6 of rice

•  The genetics of arsenic tolerance in plants has not been extensively studied and no arsenic tolerance gene has been genetically mapped. •  Screening 20 diverse genotypes of rice for reduced root growth in 13.3 m arsenate identified marked differences in tolerance. The most sensitive variety, Dawn, is known to be highly susceptible to straighthead, a condition linked to arsenic contamination of soil. •  Screening 108 recombinant inbred lines of the Bala × Azucena mapping population revealed the presence of a major gene, AsTol, which mapped between markers RZ516 and RG213 on chromosome 6. •  This gene is a good target for further characterisation. It should prove valuable for investigations into the physiological and molecular mechanism behind arsenic tolerance in plants and may lead to strategies aimed at breeding for arsenic contaminated regions.

Chemomodulatory efficacy of basil leaf (Ocimum basilicum) on drug metabolizing and antioxidant enzymes, and on carcinogen-induced skin and forestomach papillomagenesis

Basil or sweet basil (Ocimum basilicum) is cultivated throughout India and is known for its medicinal value. The effects of doses of 200 and 400 mg/kg body weight of hydroalcoholic extract (80% ethanol, 20% water) of the fresh leaves of Ocimum basilicum on xenobiotic metabolizing Phase I and Phase II enzymes, antioxidant enzymes, Glutathione content, Lactate dehydrogenase and lipid peroxidation in the liver of 8-9 weeks old Swiss albino mice were examined. Furthermore, the anticarcinogenic potential of basil leaf extract was studied, using the model of Benzo(a)pyrene-induced forestomach and 7,12 dimethyl benz(a)anthracene (DMBA)-initiated skin papillomagenesis. The hepatic glutathione S-transferase and DT-diaphorase specific activities were elevated above basal level by basil leaf treatment (from p < 0.005 to p < 0.001). Basil leaf extract was very effective in elevating antioxidant enzyme response by increasing significantly the hepatic glutathione reductase (GR) (p < 0.005), superoxide dismutase (SOD) (p < 0.05), and catalase activities (p < 0.005). Reduced glutathione (GSH), the major intracellular antioxidant, showed a significant elevation in the liver (p < 0.005) and also in all the extrahepatic organs (from p < 0.05 to p < 0.005). In the forestomach, kidney and lung, glutathione S-transferase and DT-diaphorase levels were augmented significantly, varying from p < 0.01 to p < 0.001. There were significant decreases in lipid peroxidation and lactate dehydrogenase activity. Chemopreventive response was evident from the reduced tumor burden (the average number of papillomas/mouse, p < 0.005 to p < 0.001), as well as from the reduced percentage of tumor bearing-animals. Basil leaf, as deduced from the results, augmented mainly the Phase II enzyme activity that is associated with detoxification of xenobiotics, while inhibiting the Phase I enzyme activity. There was an induction in antioxidant level that correlates with the significant reduction of lipid peroxidation and lactate dehydrogenase formation. Moreover, Basil leaf extract was highly effective in inhibiting carcinogen-induced tumor incidence in both the tumor models at peri-initiational level.

Aerobic capacity & perceived exertion after practice of Hatha yogic exercises

BACKGROUND & OBJECTIVES

Reports on the effect of yogic exercises on aerobic capacity are few. There is also no literature available on the effect of yogic exercise on perceived exertion (PE) after maximal exercise. In this study the effect of training in Hatha yogic exercises on aerobic capacity and PE after maximal exercise was observed.

METHODS

Forty men from the Indian army (aged 19-23 yr) were administered maximal exercise on a bicycle ergometer in a graded work load protocol. The oxygen consumption, carbon dioxide output, pulmonary ventilation, respiratory rate, heart rate (HR) etc., at maximal exercise and PE score immediately thereafter were recorded. The subjects were divided into two equal groups. Twelve subjects dropped out during the course of study. One group (yoga, n = 17) practiced Hatha yogic exercises for 1 h every morning (6 days in a week) for six months. The other group (PT, n = 11) underwent conventional physical exercise training during the same period. Both groups participated daily in different games for 1 h in the afternoon. In the 7th month, tests for maximal oxygen consumption (VO2Max) and PE were repeated on both groups of subjects.

RESULTS

Absolute value of VO2Max increased significantly (P < 0.05) in the yoga group after 6 months of training. The PE score after maximal exercise decreased significantly (P < 0.001) in the yoga group after 6 months but the PT group showed no change.

INTERPRETATION & CONCLUSION

The practice of Hatha yogic exercises along with games helps to improve aerobic capacity like the practice of conventional exercises (PT) along with games. The yoga group performed better than the PT group in terms of lower PE after exhaustive exercise.

Chemomodulation of carcinogen metabolising enzymes, antioxidant profiles and skin and forestomach papillomagenesis by Spirulina platensis

Numerous reports have revealed an inverse association between consumption of some selective natural products and risk of developing cancer. In the present study the effect of 250 and 500 mg/kg body wt. of Spirulina was examined on drug metabolising phase I and phase II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of 7-week-old Swiss albino mice. The implications of these biochemical alterations have been further evaluated adopting the protocol of benzo(a)pyrene induced forestomach and 7,12 dimethylbenz(a)anthracene (DMBA) initiated and croton oil promoted skin papillomagenesis. Our primary findings reveal the 'Monofunctional' nature of Spirulina as deduced from its potential to induce only the phase II enzyme activities associated mainly with carcinogen detoxification. The glutathione S-transferase and DT-diaphorase specific activities were induced in hepatic and all the extrahepatic organs examined (lung, kidney and forestomach) by Spirulina pretreatment (significance level being from p < 0.05 to p < 0.005) except for the low dose treatment in forestomach. With reference to antioxidant enzymes viz., superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and reduced glutathione were increased significantly by both the chosen doses of Spirulina from p < 0.01 to p < 0.005. Chemopreventive response was quantitated by the average number of papillomas per effective mouse (tumor burden) as well as percentage of tumor bearing animals. There was a significant inhibition of tumor burden as well as tumor incidence in both the tumor model systems studied. In the skin tumor studies tumor burden was reduced from 4.86 to 1.20 and 1.15 by the low and high dose treatment respectively. In stomach tumor studies tumor burden was 2.05 and 1.73 by the low and high doses of Spirulina treatment against 3.73 that of control.

Effects of S-nitroso-N-acetyl-penicillamine administration on glucose tolerance and plasma levels of insulin and glucagon in the dog

It has been suggested that nitric oxide (NO, nitrogen monoxide) is a regulator of carbohydrate metabolism in skeletal muscle. The present study was undertaken to investigate the acute effects of the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP) on blood glucose levels and on the gluco-regulatory hormones insulin and glucagon in healthy dogs. The acute effects of SNAP on mean arterial pressure and heart rate were also investigated. The drug was administered intravenously and the pre- and postprandial blood glucose, plasma insulin, and glucagon concentrations were determined at half-hour time intervals postadministration after a glucose challenge. The plasma nitrate and nitrite concentrations were measured and taken as the biochemical markers of in vivo NO formation. The oral glucose tolerance test revealed an impaired glucose tolerance in SNAP-treated dogs as reflected by the area under the glucose curve, 1150.50 +/- 63.00 mmol x 150 min and 1355.25 +/- 102.01 mmol/L x 150 min in dogs treated with 10 and 20 mg/kg of SNAP, respectively, compared with 860.25 +/- 60.68 mmol/L x 150 min in captopril-treated controls (P < 0.05). The 2-h blood glucose concentration in dogs treated with 20 mg/kg body wt of SNAP was 9.17 +/- 1.10 mmol/L compared with 5.59 +/- 0.26 mmol/L for captopril-treated controls (P = 0.015). The oral glucose tolerance test also confirmed an impaired insulin secretion in the SNAP-treated dogs. While the plasma insulin concentration increased gradually in the captopril-treated controls to a peak value of 39.50 +/- 2.55 microIU/ml, 1.5 h after a glucose challenge there was a decrease in the plasma insulin concentration in SNAP-treated dogs to a low value of 20.67 +/- 0.88 microIU/ml (P = 0.006). In contrast, there were no significant differences in plasma glucagon concentration in SNAP-treated dogs and captopril-treated dogs at any time points. Using the Griess reaction, we found that there was a 27-95% increase in plasma nitrate/nitrite concentration on administration of SNAP. The sustained hyperglycemic effect observed in SNAP-treated dogs was accompanied by a marginal decrease in the mean arterial blood pressure and a significant increase in heart rate (P < 0.05). We conclude that acute administration of SNAP in the oral glucose tolerance test releases NO that modulates the parameters of carbohydrate metabolism.

A gel delivery system for coccidiosis vaccine: uniformity of distribution of oocysts

A patented gel delivery system being used to deliver coccidiosis vaccine to poultry hatchlings is assessed. For effective vaccination, the coccidial oocysts must be uniformly suspended before exposure to birds. The uniformity of distribution within the gel was evaluated by incorporating a culture of chicken gut flora into gel sausages, placing sections of the sausage on culture plates, determining the appearance and distribution of bacterial colonies on culture plates after incubation, and verifying by cell counts. The uniformity of distribution of similarly prepared coccidial oocysts was verified by infecting birds with 40,000 Eimeria tenella oocysts delivered via the gel. Gel-inoculated birds were compared with control birds inoculated PO with 40,000 oocysts suspended in water by using cecal lesion scores. Both the appearance and colony counts of chicken gut flora from the gel were uniform. The standard deviation in the lesion scores for the gel-inoculated group and the water-inoculated groups were 0.51 and 0.69, respectively. The results indicate that a gel delivery system can provide uniform distribution of live organisms and vaccine agents to birds.

The hyperglycemic effect of S-nitrosoglutathione in the dog

The present study investigates the pharmacological activity of the nitric oxide (NO) donor S-nitrosoglutathione (GSNO) on the plasma glucose and insulin levels in healthy normoglycemic dogs. The plasma nitrate and nitrite concentrations were measured by a commercial autoanalyzer and taken as the biochemical markers of in vivo nitric oxide formation. Plasma glucose levels were measured by the glucose oxidase method, while the insulin levels were determined by radioimmunoassay. The possible effect of the coadministration of ascorbic acid (vitamin C) and GSNO on plasma glucose levels was also examined. In healthy normoglycemic dogs, administration of 35 and 50 mg/kg of GSNO caused a dose-dependent increase in postprandial plasma glucose levels. The plasma glucose levels were significantly elevated at the 1.5-, 2.0-, and 2.5-h time intervals of the oral glucose tolerance test at both concentrations of GSNO (P < 0.05). These values were significantly higher than those obtained using captopril (control). Furthermore, coadministration of 35 mg/kg of GSNO and 50 mg/kg ascorbic acid enhanced the postprandial hyperglycaemic effect observed for the administration of only 35 mg/kg of GSNO. There was a 35-100% increase in plasma nitrate concentration on administration of both doses of GSNO. Intravenous administration of GSNO (35 mg/kg) and captopril (20 mg/kg) significantly decreased the mean arterial blood pressure and increased the heart rate. The blood pressure-lowering effect of these drugs was more pronounced on systolic than on diastolic blood pressure (P < 0.05). These results suggests that in healthy normoglycaemic dogs: (a) nitric oxide released from GSNO increases postprandial plasma glucose levels and inhibits glucose-stimulated insulin secretion, (b) ascorbic acid enhances the postprandial hyperglycaemic effect of GSNO, probably by increasing the release of NO, and (c) GSNO decreases mean arterial blood pressure and increase heart rate in normotensive dogs.

Study of nm23 gene expression in an N-methyl-N-nitrosourea transformed human breast epithelial cell line

In the present study we pinpoint the time of nm23 down-regulation during the chemical transformation of the human breast epithelial cell line HBL100. The non-malignant HBL100 was transformed by exposing it to N-methyl-N-nitrosourea (MNU). We subsequently injected the transformed cells (HBL-T-MNU) into nude mice, resulting in tumor growth. With a second passage of these tumors in mice we observed lung and extra-regional node metastases. The expression of nm23 in the non-tumorigenic HBL100 cells was compared to the tumorigenic KBL-T-MNU cells as well as to the metastatic cell line HBL-T2(MNU) derived from the tumor induced by HBL-T-MNU cells. By using immunohistochemistry and Western blot analysis we documented the downregulation of nm23 expression in the tumorigenic HBL-T-MNU and metastatic HBL-T2(MNU) cell lines, as compared to the parental line HBL100. Once downregulated, nm23 expression in this model remains constant during the subsequent progression. These results suggest that nm23 down-regulation may indeed be associated with early neoplastic transformation and is maintained throughout neoplastic progression and metastatic stage.

SEN6, a locus for SV40-mediated immortalization of human cells, maps to 6q26-27

Normal cells show a limited lifespan in culture and the phenotype of cellular senescence. Tumors and tumor cell lines have typically overcome this form of growth suppression and grow continuously as immortal cell lines in culture. We have exploited the DNA virus SV40 to study the mechanism by which human fibroblasts overcome senescence and become immortal. Multiple steps have now been identified, including inactivation of cellular growth suppressors through direct interaction with SV40 large T antigen and through mutation of a gene on chromosome 6 (designated SEN6). In this study, we sublocalize the site of SEN6 to 6q26-27 based on molecular genetic analysis. Twelve SV40-immortalized fibroblast cell lines share a deletion in this area based on assessment for loss of heterozygostiy (LOH) for seven informative markers on 6q. Two immortal cell lines (AR5 and HALneo) appeared to have retained separate single copies of chromosome 6 despite the fact that they are both derived from the same preimmortal SV40-transformant and should share the same mutated allele of SEN6 (Hubbard-Smith et al., 1992). Detailed analysis by polymerase chain reaction, restriction fragment length polymorphism and fluorescence in situ hybridization shows, however, that although they differ for 17 markers from the centromere to 6q26, they share AR5 derived sequences (eight markers) distal to 6q26 including the minimal deletion region, further supporting the assignment of SEN6 to this region. Since human tumors including non-Hodgkins lymphoma, mammary carcinoma and ovarian carcinoma show LOH in 6q26-27, inactivation of SEN6 may be responsible for immortalization of these tumors as well.

SV40-mediated immortalization of human fibroblasts

We have identified a multistep mechanism by which the DNA virus SV40 overcomes cellular senescence. Expression of SV40 T antigen is required for both transient extension of life span and unlimited life span or immortalization. These effects are mediated through inactivation of function of growth suppressors pRB and p53 via complex formation with T antigen. However, immortalization additionally requires inactivation of a novel growth suppressor gene, which has recently been identified to be on the distal portion of the long arm of chromosome 6, designated SEN6. We propose that SEN6 is responsible for cellular senescence in fibroblasts and other cells.

Production of immunoglobulin G and G1 antibodies to cytoskeletal protein by lamina propria cells in ulcerative colitis

BACKGROUND & AIMS

Recent studies suggest an autoantigenic role for tropomyosin-related protein(s) in ulcerative colitis (UC). This study examined whether immunoglobulin G and G1 subclass antibodies against tropomyosins are produced spontaneously by the lamina propria mononuclear cells (LPMCs) that infiltrate the inflamed UC tissue.

METHODS

LPMCs were isolated from colonic biopsy specimens from 29 patients with UC, 15 with colonic Crohn's disease (CD), and 13 with non-inflammatory bowel disease (IBD). The autologous peripheral blood mononuclear cells (PBMCs) were obtained. Cells were cultured in vitro and unstimulated for 10 days. Spontaneous production of immunoglobulin G and G1 antibodies against tropomyosins was measured by enzyme-linked immunosorbent assays using highly enriched tropomyosins from skeletal muscle and colonic mucosa.

RESULTS

The total immunoglobulin G produced by LPMCs from both patients with UC and CD was comparable but higher than from patients with non-IBD (P < 0.05). However, immunoglobulin G antibodies to tropomyosins were higher in patients with UC than in patients with CD (P < 0.04) and non-IBD (P < 0.02). LPMCs from patients with symptomatic UC produced higher immunoglobulin G antibodies to tropomyosins than patients with UC in remission (P < 0.03), symptomatic CD (P < 0.04), and non-IBD (P < 0.02). Immunoglobulin G antibodies to tropomyosins predominantly belonged to immunoglobulin G1 subclass. The autologous PBMCs showed comparable results.

CONCLUSIONS

Immunoglobulin G antibodies predominantly belonging to immunoglobulin G1 subclass and reactive against tropomyosin-related protein(s) are spontaneously produced by LPMCs from the colonic mucosa in patients with UC.

Molecular cloning and characterization of the rfc gene of Pseudomonas aeruginosa (serotype O5)

Previous work from our laboratory has shown that cosmid clone pFV100, containing a 26 kb insert, is able to restore O-antigen synthesis in serotype O5 rough mutants of Pseudomonas aeruginosa. Mobilization of pFV100 into two P. aeruginosa semi-rough (SR) mutants, AK14O1 and rd7513, resulted in O-antigen expression, indicating that pFV100 may contain an O-polymerase (rfc) gene. pFV.TK6, a subclone of pFV100 that contains a 5.6 kb chromosomal insert, was able to complement O-antigen expression in these SR mutants. Mutagenesis of pFV.TK6 using Tn1000 exposed a 1.5 kb region that was essential for complementing O-antigen expression in AK14O1. A 2.0 kb XhoI-HindIII fragment, containing this region, was cloned into vector pUCP26 and the resulting plasmid called pFV.TK8. In Southern analysis of the 20 P. aeruginosa serotypes using a probe generated from the 1.5 kb XhoI fragment of pFV.TK8, the rfc probe hybridized to a common fragment of the cross-reactive O2-O5-O16-O18-O20 serogroup, suggesting that these serotypes may share a common O-polymerase gene. In functional studies of the rfc gene, the PAO1 (serotype O5) chromosomal rfc was mutated using a gene-replacement strategy. These knockout mutants expressed the SR lipopolysaccharide (LPS) phenotype, which indicated that they were no longer producing a functional O-polymerase enzyme. Nucleotide sequence analysis of the insert DNA of pFV.TK8 revealed one open reading frame (ORF), designated ORF48.9, which could code for a 48.9 kDa protein. In comparisons of the P. aeruginosa rfc nucleotide and amino acid sequences with DNA and protein databases, no significant homology was found. However, the deduced structure of the P. aeruginosa Rfc protein indicated that it is very hydrophobic and contains 11 putative membrane-spanning domains. Therefore, the predicted structure is similar to that of other reported Rfc proteins. Furthermore, comparison of the amino acid composition and codon usage of the P. aeruginosa Rfc with other Rfc proteins revealed significant similarity between them.

Identification of rfbA, involved in B-band lipopolysaccharide biosynthesis in Pseudomonas aeruginosa serotype O5

Previous work from this laboratory has shown that a 26-kb insert in cosmid clone pFV100, isolated from a Pseudomonas aeruginosa gene library, contained genes that could restore serotype-specific B-band lipopolysaccharide (LPS) expression in rough mutant ge6. In this study, subclones from pFV100 were made to identify genes responsible for B-band LPS synthesis. Transformation of Escherichia coli HB101 with cosmid clone pFV100 resulted in expression of P. aeruginosa serotype O5 B-band LPS, indicating the presence of an rfb cluster in pFV100. Expression of P. aeruginosa LPS could not be achieved in E. coli HB101 transformed with any of the subclones. Complementation studies of well-characterized rough mutants of P. aeruginosa PAO1 deficient in B-band LPS biosynthesis were performed with the various subclones. Subclone pFV110, containing a 1.4-kb XbaI-HindIII insert, restored B-band LPS biosynthesis in mutant AK44 (A+B-; complete core). Probing chromosomal DNA from the 20 International Antigenic Typing Scheme serotypes with the 1.4-kb insert from pFV110 in Southern hybridizations revealed a positive reaction to restriction fragments in serotypes O2, O5, O16, O20, and O18. LPS of serotypes O2, O5, O16, and O20 were shown earlier to have a similar backbone structure in their O antigen. The insert in pFV110 was sequenced, and the deduced amino acid sequence was compared with sequences of protein databases. No significant homology could be detected with any sequences in the database. Open reading frame analysis identified one region, ORF303, which could encode a 33-kDa protein. Using E. coli maxicells for protein expression, orf303 mediated the expression of a unique polypeptide with an apparent molecular mass of 32.5 kDa. The deficiency in the synthesis of B-band LPS biosynthesis in mutant AK44 is apparently complemented by the 33-kDa protein encoded by orf303. We have designated this ORF rfbA. This investigation is the first report on cloning and sequencing of an rfb gene involved specifically in O-antigen biosynthesis in P. aeruginosa PAO1.

Breast-carcinoma cell-lines with metastatic potential in mice

We established and characterized three human breast carcinoma cell lines (two with metastatic potential) by in vivo-in vitro propagation of tumor tissues. Tissues were processed in culture as i) direct explants (n = 185); ii) cell suspensions obtained after enzymic digestion (n = 29); or iii) explants of xenografts established in vivo (n = 18). Tissues processed as explants or cell suspensions generated no viable cell lines. However, three cell lines (MAXF-401, MAXF-583 and OHSTMAM-4) were established from xenografts. All three showed characteristic features of human breast tumor tissue. All were tumorigenic in mice and MAXF-401 and MAXF-583 showed frequent distant metastasis following s.c. transplantation. All three overexpressed EGFR, p53 and c-erbB2 proteins.