Is the Use of a GnRH Antagonist Effective in Patients with Polycystic Ovarian Syndrome? A South African Perspective

Introduction. Polycystic ovarian disease (PCOS) can account for up to 35 - 40 of the female factor causes of infertility. These patients present as medically complex cases and are challenging to manage and treat successfully. They are resistant to treatment and are often offered controlled ovarian stimulation (COS) and in vitro fertilisation (IVF) technology. Aim. The aim of this study was to assess whether there was a difference in the pregnancy outcomes of women with PCOS when a standard gonadotrophin-releasing hormone (GnRH) antagonist (cetrorelix) protocol was used for ovarian stimulation; compared with non-PCOS patients undergoing IVF. Methods. A retrospective patient record audit was performed on 142 patients with PCOS and 501 non-PCOS patients undergoing a similar cetrorelix-based COS treatment protocol during a specified time period. Results. The main primary outcome was an ongoing pregnancy at 12 weeks; achieved in 34 of patients in the PCOS group and 27 in the non-PCOS group. This was not significantly different (p=0.07). No patient in the PCOS group experienced severe hyperstimulation syndrome. Conclusion. There was no significant difference in pregnancy rates in patients with PCOS undergoing GnRH-antagonist ovarian stimulation compared with non-PCOS patients. The fact that no hyperstimulation syndrome occurred makes this an attractive option for women with PCOS

Influence of fumigants on soil microbial diversity and survival of E. coli O157:H7.

The aim of this study was to assess the effects of soil fumigation with methyl bromide (MeBr; CH(3)Br) and methyl iodide (MeI, iodomethane; CH(3)I) on the microbial community structure and diversity in two soils and determine the effects of microbial diversity on the survival of Escherichia coli O157:H7 from contaminated irrigation water. Polymerase chain reaction (PCR) was used to amplify 16S rRNA from total bacterial community composition and the products were subjected to denaturing gradient gel electrophoresis (DGGE). The Shannon-Weaver index of diversity (H') was used to determine the effects of both fumigants on soil microbial diversity. The effect was more severe in sandy soil than in clay soil at the normal application rate of MeBr and MeI. Our results showed that MeBr and MeI have about the same effects on soil microbial diversity. The two fumigants had greater impact on microbial diversity in sandy soil than in clay soil and this resulted in higher survival of E. coli O157:H7 in sandy soil than in clay soil during the 50 days that the study was conducted. MeBr has been used as soil fumigant for >40 years with no serious detrimental effects on agricultural production and our research also suggests that the use of MeI may also produce no long-term detrimental effects on agricultural production since both fumigants had about the same effects on soil microbial communities. Therefore, soil systems with reduced microbial diversity may offer greater opportunities for the survival of pathogenic bacteria such as E. coli O157:H7.

Persistence of Escherichia coli O157:H7 on the rhizosphere and phyllosphere of lettuce.

AIMS: The major objective of this study was to determine the effects of low levels of Escherichia coli O157:H7 contamination on plant by monitoring the survival of the pathogen on the rhizosphere and leaf surfaces of lettuce during the growth process. METHODS AND RESULTS: Real-time PCR and plate counts were used to quantify the survival of E. coli O157:H7 in the rhizosphere and leaf surfaces after planting. Real-time PCR assays were designed to amplify the stx1, stx2 and the eae genes of E. coli O157:H7. The detection limit for E. coli O157:H7 quantification by real-time PCR was 2.4 x 10(3) CFU g(-1) of starting DNA in rhizosphere and phyllosphere samples and about 10(2) CFU g(-1) by plate count. The time for pathogens to reach detection limits on the leaf surface by plate counts was 7 days after planting in comparison with 21 days in the rhizosphere. However, real-time PCR continued to detect stx1, stx2 and the eae genes throughout the experimental period. CONCLUSION: Escherichia coli O157:H7 survived throughout the growth period as was determined by real-time PCR and by subsequent enrichment and immunomagnetic separation of edible part of plants. SIGNIFICANCE AND IMPACT OF THE STUDY: The potential presence of human pathogens in vegetables grown in soils contaminated with E. coli O157:H7 is a serious problem to our national food supply as the pathogen may survive on the leaf surface as they come in contact with contaminated soil during germination.

Estimating yields of salt- and water-stressed forages with remote sensing in the visible and near infrared.

In arid irrigated regions, the proportion of crop production under deficit irrigation with poorer quality water is increasing as demand for fresh water soars and efforts to prevent saline water table development occur. Remote sensing technology to quantify salinity and water stress effects on forage yield can be an important tool to address yield loss potential when deficit irrigating with poor water quality. Two important forages, alfalfa (Medicago sativa L.) and tall wheatgrass (Agropyron elongatum L.), were grown in a volumetric lysimeter facility where rootzone salinity and water content were varied and monitored. Ground-based hyperspectral canopy reflectance in the visible and near infrared (NIR) were related to forage yields from a broad range of salinity and water stress conditions. Canopy reflectance spectra were obtained in the 350- to 1000-nm region from two viewing angles (nadir view, 45 degrees from nadir). Nadir view vegetation indices (VI) were not as strongly correlated with leaf area index changes attributed to water and salinity stress treatments for both alfalfa and wheatgrass. From a list of 71 VIs, two were selected for a multiple linear-regression model that estimated yield under varying salinity and water stress conditions. With data obtained during the second harvest of a three-harvest 100-d growing period, regression coefficients for each crop were developed and then used with the model to estimate fresh weights for preceding and succeeding harvests during the same 100-d interval. The model accounted for 72% of the variation in yields in wheatgrass and 94% in yields of alfalfa within the same salinity and water stress treatment period. The model successfully predicted yield in three out of four cases when applied to the first and third harvest yields. Correlations between indices and yield increased as canopy development progressed. Growth reductions attributed to simultaneous salinity and water stress were well characterized, but the corrections for effects of varying tissue nitrogen (N) and very low leaf area index (LAI) are necessary.

Changes in developing plant microbial community structure as affected by contaminated water.

The effects of sand and clay soils and water contaminated by Escherichia coli O157:H7 on the development of rhizosphere and phyllosphere microbial communities were analyzed to determine the influence of plant age on microbial community structure and composition. Community bacterial nucleic acids were extracted from lettuce rhizosphere and phyllosphere samples at different stages of plant development after the soils were irrigated with water contaminated with E. coli O157:H7 at planting and 15 days after planting. PCR was used to amplify 16S ribosomal RNA (rRNA) for total bacterial community composition and the products were subjected to denaturing gradient gel electrophoresis (DGGE). Prominent DGGE bands were excised and sequenced to gain insight into the identities of predominant bacterial populations. The majority of DGGE band sequences were related to bacterial genera previously associated with the rhizosphere and phyllosphere, such as Pseudomonas, Acidobacterium, Bacillus and Agrobacterium. The PCR-DGGE patterns observed for rhizosphere samples were more complex than those obtained from the bulk soil and the phyllosphere. The Shannon index of diversity (H) was used to determine the complexity of the DGGE bands from the phyllosphere, rhizosphere and the bulk soils at different growth stages. A higher diversity was observed in the clay soil than sandy soil during the first week. Few changes in diversity were observed after the first week. The results show that microbial community development in lettuce may take about 7-12 days and this may be the most likely period for maximum pathogen contamination in plants.

Detection and quantification of Escherichia coli O157:H7 in environmental samples by real-time PCR.

AIMS: To apply the real-time Polymerase chain reaction (PCR) method to detect and quantify Escherichia coli O157:H7 in soil, manure, faeces and dairy waste washwater. METHODS AND RESULTS: Soil samples were spiked with E. coli O157:H7 and subjected to a single enrichment step prior to multiplex PCR. Other environmental samples suspected of harbouring E.coli O157:H7 were also analysed. The sensitivity of the primers was confirmed with DNA from E.coli O157:H7 strain 3081 spiked into soil by multiplex PCR assay. A linear relationship was measured between the fluorescence threshold cycle (C T ) value and colony counts (CFU ml(-1)) in spiked soil and other environmental samples. The detection limit for E.coli O157:H7 in the real-time PCR assay was 3.5 x 10(3) CFU ml(-1) in pure culture and 2.6 x 10(4) CFU g(-1) in the environmental samples. Use of a 16-h enrichment step for spiked samples enabled detection of <10 CFU g(-1) soil. E. coli colony counts as determined by the real-time PCR assay, were in the range of 2.0 x 10(2) to 6.0 x 10(5) CFU PCR (-1) in manure, faeces and waste washwater. CONCLUSIONS: The real-time PCR-based assay enabled sensitive and rapid quantification of E. coli O157:H7 in soil and other environmental samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability to quantitatively determine cell counts of E.coli O157:H7 in large numbers of environmental samples, represents considerable advancement in the area of pathogen quantification for risk assessment and transport studies.

Evaluation of Atriplex lines for selenium accumulation, salt tolerance and suitability for a key agricultural insect pest.

Thirty Atriplex lines were examined for potential habitat improvement and phytoremediation of selenium (Se) contaminated sites. Studies were conducted to determine the biomass production, Se accumulation, and resistance of each line to the beet armyworm, Spodoptera exigua, an agriculturally important insect. Plants were tested using three salinity treatments: (1) control, no Se; (2) NaCl and CaCl2 salts and 1 mg l(-1) Se (12.7 microM) added as sodium selenate; and (3) iso-osmotic to treatment 2 containing high concentrations of sulfate and I mg l(-1) Se added as sodium selenate. Insect bioassays measured survival, growth, and development. Atriplex patula. A. spongiosa 415862, A. hortensis, A. hortensis 379088 and A. hortensis 379092 were among the top biomass producers and Se accumulators, yet they exhibited significantly reduced insect growth, development, and survival. High background sulfate strongly reduced Se accumulation, suggesting that phytoremediation potential is greatest in saline areas having low to moderate sulfate levels. However, these lines grew well in high salinity soils, indicating possible use as a self-seeding cover crop to improve habitat. All plant lines grown in control and high sulfate salinity treatments are acceptable oviposition sites for S. exigua, indicating that these plants would help reduce populations of this key agricultural pest.

Ion partitioning among soil and plant components under drip, furrow, and sprinkler irrigation regimes: field and modeling assessments.

Soil and water resources can be severely degraded by salinity when total salt input exceeds output in irrigated agriculture. This study was conducted to examine partitioning of Ca2+, Na+, and Cl- between soil and soybean [Glycine max (L.) Merr.] plants under different irrigation regimes with both field and modeling assessments. In drip and sprinkler treatments, the irrigation water was salinized with NaCl and CaCl2 salts to simulate a Cl- and Na+ dominant saline drainage water. In the furrow irrigation treatment, the soil was salinized, prior to planting, with NaCl and CaCl2 salts to simulate a Cl- and Na+ dominant saline soil. A total of 756 soil and 864 plant samples were collected and analyzed for the salt ions to obtain ion partitioning and mass balance assessments. Modeling of salt ion uptake by plants and distribution in the soil profile was performed with a two-dimensional solute transport model for the three irrigation regimes. Results indicated that about 20% of the applied Ca2+ was recovered in harvested soybean biomass in all treatments. Plant uptake of either Na+ or Cl- was less than 0.5% in the drip and furrow, and about 2% in the sprinkler irrigation treatment. Significant increases in soil salinity were found in the sprinkler plot that received the highest cumulative amount of salts. Simulated ion distributions in the soil were comparable with the measurements. Compared with the total seasonal salt input, mass balances between 65 and 108% were obtained. Most salt inputs accumulate in the soil, and need to be removed periodically to prevent soil salinization.

Validity of test meals for determining binge eating.

Assessment of binge eating has been criticized because of serious doubts concerning the accuracy of self-report. This experiment tested the validity of a laboratory test meal as an indicator of binge eating. Eight individuals diagnosed with binge-eating disorder (BED), eight obese non-binge-eaters, and eight normal-weight non-binge-eaters ate a test meal under conditions designed to increase the likelihood of inducing a binge episode. Non-binge-eaters, regardless of weight, felt in control of their eating and ate a relatively small amount of the test meal, while participants with BED ate significantly more food and felt significantly more out of control. Eating behavior during test meals can be a useful indicator of BED diagnostic status and may be a useful method for objectively defining binge eating.

Stable carbon isotope discrimination: an indicator of cumulative salinity and boron stress in Eucalyptus camaldulensis.

Saplings of Eucalyptus camaldulensis Dehn. Clone 4544, irrigated with water of differing salinities (2 to 28 dS m-1) and boron concentrations (1 to 30 mg l-1), integrated the history of these stresses through the discrimination of stable isotopes of carbon in leaf and woody tissues. Carbon isotope discrimination (delta) was reduced primarily by salinity. Decreases in discrimination in response to boron stress were detected in the absence of salinity stress, but the decreases were significant only in leaf tissues with visible boron injury. Sapwood core samples indicated that salinity- and boron-induced reductions in delta increased with increasing tree age. Absolute values of delta varied with location of leaf or wood tissue, but relative effects of salinity on the relationship between delta and transpiration efficiency (W) were similar. In response to increasing salinity stress, relative decreases in delta paralleled relative decreases in biomass and both indices yielded similar salt tolerance model parameters. The strong correlations between delta, tree fresh weight, leaf area and W suggest that delta is a useful parameter for evaluating salt tolerance of eucalyptus

Estimation of food intake: effects of the unit of estimation.

While many studies have shown that individuals under-estimate caloric intake, few studies have examined how individuals estimate intake when using other units of measurement (e.g. cups, ounces). Forty-one women (21 obese, 20 normal weight) ate a test meal of Häagen-Dazs chocolate ice cream and were asked to estimate the amount they ate in both calories and cups. As expected, participants under-estimated intake when asked to estimate how much they ate in calories, but considerably over-estimated their intake when measured in cups. Thus, individuals can both under- and over-estimate how much of the same food they have eaten, depending on the unit they are asked to use for estimation. Obesity and eating disorders treatment programs should take into account the tendency to over-estimate volumetric portions as well as under-estimate caloric intake.

Secondary sexual development in rural and urban South African black children.

The timing and duration of secondary sexual development in two samples of rural and urban South African black children were investigated using the Tanner staging techniques and compared to similar data from Switzerland and England. In general rural black children were consistently delayed in the age at which they entered the events of puberty, and took longer to pass through each of the stages. Urban black children, from good socioeconomic backgrounds, were advanced in relation to their rural peers and slightly ahead of the European samples. There were no significant differences in the sequence of events. Estimates of testicular volume on the well-off urban boys demonstrated that they exhibited similar volumes to European boys at similar ages. It is suggested that the British clinical longitudinal growth standards could be effectively used to sensitively monitor the growth and maturation of black urban children from good socioeconomic backgrounds.

The effect of ethnic group on appendicular bone mass in children.

The prevalence of senile and postmenopausal osteoporotic fractures is considerably higher in white than black women. Although the reasons for the genetic difference have not been elucidated, it has been suggested that ethnic differences in peak bone mass may be partially responsible. The present study examined appendicular bone mass (single-photon absorptiometry, SPA) in black and white children between the ages of 6 and 20 years. The sample was stratified for ethnic group, age, and sex. The effect of weight, height, puberty, and skinfold thickness on bone mass was also assessed. The bone width (BW) and bone mineral content (BMC) of males were significantly higher than those of females (p less than 0.0001). There were no statistically significant differences in bone mineral content normalized for bone width (BMC/BW) between the sexes (p = 0.1743 for whites and p = 0.5456 for blacks). The bone mass parameters of black girls were generally lower than those of white girls. After adjusting for height, BMC and BMC/BW of black girls tended to be greater than those of white girls (unadjusted p = 0.0258 for BMC and p = 0.0340 for BMC/BW). White boys tended to have greater bone mass parameters than black boys. After adjusting for height the trends disappeared. Thus, unlike the studies of bone mass in adults from the United States, we were unable to show that age-matched black children have higher bone mass than whites. After adjusting for height, however, the bone mass of black children (especially black girls) was marginally, but not significantly, greater than that of white girls.

Knowledge increment assessed for three methodologies of teaching physiology.

A study was conducted on a group of forty-six students of physiology, to compare the knowledge increment following three different teaching methods. The assessment of knowledge increase was done by a pre-test preceding each teaching method, followed by a post-test for each method. The three methods assessed were: (1) a lecture with audio-visual aids; (2) a formal didactic lecture; and (3) a self-study tutorial. The pre-test/post-test method of assessment was found to be valid and reliable. The results indicated a favourable increment for the audio-visually aided lecture and for the self-study tutorial. There was no significant increment for the didactic lecture. A questionnaire completed by the students indicated an overall preference for the audio-visually aided method and a lesser preference for the self-study tutorial. The formal didactic lecture found no favour with the students.

Immunoblot analysis of the humoral immune response to Leishmania donovani infantum polypeptides in human visceral leishmaniasis.

Using the immunoblot technique, we have compared the reactions of Leishmania donovani infantum polypeptides with the immunoglobulin G of human sera from patients with parasitologically proven L. d. infantum infection, with suspected visceral leishmaniasis, and with other leishmaniases, protozoiases, helminthiases, and fungal or bacterial diseases. A 94-kDa component reacted with all L. d. infantum-infected sera and with 75% of sera from patients with clinical and serological but no parasitological diagnoses. No reaction was observed with sera from patients in the other disease groups or with control sera. Studies of eight different isolates, subspecies, and species of the genus Leishmania demonstrated that the 94-kDa component was expressed in all strains examined.

crnA encodes a nitrate transporter in Aspergillus nidulans.

The nucleotide sequence of the Aspergillus nidulans crnA gene for the transport of the anion nitrate has been determined. The crnA gene specifies a predicted polypeptide of 483 amino acids (molecular weight 51,769). A hydropathy plot suggests that this polypeptide has 10 membrane-spanning helices with an extensive hydrophilic region between helices six and seven. No striking homology was observed between the crnA protein and other reported membrane proteins of either prokaryotic or eukaryotic organisms, indicating that the crnA transporter may represent another class of membrane protein. Northern blotting results with wild-type cells show that (i) control of crnA expression is subject to nitrate (and nitrite) induction as well as nitrogen metabolite repression and (ii) regulation of the crnA gene is exerted at the level of mRNA accumulation, most likely at transcription, in response to the nitrogen source in the growth medium. Furthermore, similar studies with mutants of nirA and areA control genes and the niaD nitrate reductase structural gene show that crnA expression is mediated by the products of nirA (nitrate induction control gene), areA (nitrogen metabolite repression control gene), and niaD (involved in autoregulation of nitrate reductase).

Homologous transformation of Cephalosporium acremonium with the nitrate reductase-encoding gene (niaD).

We report the development of a homologous transformation system for Cephalosporium acremonium using the niaD gene of the nitrate assimilation (NA) pathway. Mutants in the NA pathway were selected on the basis of chlorate resistance by conventional means. Screening procedures were developed to differentiate between nitrate reductase apoprotein structural gene mutants (niaD) and molybdenum cofactor gene mutants (cnx) as wt C. acremonium, unlike most filamentous fungi, fails to grow on minimal medium with hypoxanthine as a sole source of nitrogen. Phage clones carrying the niaD gene were isolated from a C. acremonium library constructed in lambda EMBL3 using the A. nidulans niaD gene as a heterologous probe. An 8.6-kb EcoRI fragment was subcloned into pUC18, and designated pSTA700. pSTA700 was able to transform stable niaD mutants to NA at a frequency of up to 40 transformants per microgram DNA. Transformants were easily visible since the background growth was low and no abortives were observed. Gene replacements, single copy homologous integration and complex multiple integrations were observed. The niaD system was used to introduce unselected markers for hygromycin B resistance and benomyl resistance into C. acremonium by cotransformation.