Genotypic and phenotypic characteristics of tunisian isoniazid-resistant <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> strains

Forty three isoniazid (INH)-resistant Mycobacterium tuberculosis isolates were characterized on the basis of the most common INH associated mutations, katG315 and mabA −15C→T, and phenotypic properties (i.e. MIC of INH, resistance associated pattern, and catalase activity). Typing for resistance mutations was performed by Multiplex Allele-Specific PCR and sequencing reaction. Mutations at either codon were detected in 67.5% of isolates: katG315 in 37.2, mabA −15C→T in 27.9 and both of them in 2.4%, respectively. katG sequencing showed a G insertion at codon 325 detected in 2 strains and leading to amino acid change T326D which has not been previously reported. Distribution of each mutation, among the investigated strains, showed that katG S315T was associated with multiple-drug profile, high-level INH resistance and loss or decreased catalase activity; whereas the mabA −15C→T was more prevalent in mono-INH resistant isolates, but it was not only associated with a low-level INH resistance. It seems that determination of catalase activity aids in the detection of isolates for which MICs are high and could, in conjunction with molecular methods, provide rapid detection of most clinical INH-resistant strains.     

Formulation and Evaluation of a Salted-out Isoniazid-loaded Nanosystem

The purpose of this study was to develop a drug-loaded nanosystem that has the ability to achieve flexible yet rate-controlled release of model drug isoniazid (INH) employing either an aqueous or emulsion-based salting-out approach. Formulation conditions were aimed at reducing the polymeric size with subsequent rate-modulated INH release patterns from the polymeric nanosystem. The emulsion-based salted-out nanosystems had particle sizes ranging from 77–414 nm and a zeta potential of −24 mV. The dispersant dielectric constant was set at 78.5 and a conductivity of 3.99 mS/cm achieved. The reduced nanosystem size of the aqueous-based approach has demonstrated an intrinsically enhanced exposure of methacrylic acid-ethyl acrylate to zinc sulphate which was employed as a crosslinking reagent. This resulted in robustly interconnected polymeric supports in which INH was efficiently embedded and subsequently released. The multi-layer perceptron data obtained showed that the aqueous and emulsion-based salting out approaches had Power (law) (MSE = 0.020) and Linear (MSE = 0.038) relationships, respectively. Drug release from the nanosystems occurred in two phases with an initial burst-release in aqueous-based nanosystems (30–100%) and significantly lower bursts observed in emulsion-based nanosystems (20–65%) within the first 2 h. This was followed by a gradual exponential release phase over the remaining 12 h. The nanosystems developed demonstrated the ability to control the release of INH depending on the formulation approach adopted.     

Herbivory and novel weapons: no evidence for enhanced competitive ability or allelopathy induction of <Emphasis Type="Italic">Centaurea diffusa</Emphasis> by biological controls

Biological control of weeds by arthropod herbivores is thought to work by reducing the competitive ability of the weed relative to the surrounding vegetation. However, the assumption that herbivory reduces plant competitive ability has not been tested in most biological control systems, and counter to expectation, recent research on the impact of biological control agents on invasive Centaurea species suggests that this genus may respond to herbivory by increased competitive ability through enhanced plant re-growth and/or by inducing increased production of phytotoxic allelochemicals. We examined the impact of two biological control agents of the invasive plant diffuse knapweed (C. diffusa) to see if feeding by either of these insects would enhance the plant’s competitive ability or allelochemical output. Sub-lethal herbivory by either of the biological control agents significantly reduced knapweed performance when the plant was grown in competition with either of two native species. Competition with knapweed significantly reduced the performance of both native species (Artemisia frigida and Bouteloua gracilis), and herbivory by one of the biocontrol agents resulted in a small but significant increase in both native species’ performance. Diffuse knapweed’s putative allelochemical 8-hydroxyquinoline was not detected in experimental or field collected soils from knapweed-infested sites. In contrast to other studies on the impacts of biological control on other Centaurea species, these data support the premise that biological control agents may reduce invading plant competitive ability. We find no evidence for diffuse knapweed allelopathy mediated by 8-hydroxyquinoline or enhanced allelopathy in response to herbivory by biological control agents.     

Sexual coercion and forced in-pair copulation as sperm competition tactics in humans

Rape of women by men might be generated either by a specialized rape adaptation or as a by-product of other psychological adaptations. Although increasing number of sexual partners is a proposed benefit of rape according to the “rape as an adaptation” and the “rape as a by-product” hypotheses, neither hypothesis addresses directly why some men rape their long-term partners, to whom they already have sexual access. In two studies we tested specific hypotheses derived from the general hypothesis that sexual coercion in the context of an intimate relationship may function as a sperm competition tactic. We hypothesized that men’s sexual coercion in the context of an intimate relationship is related positively to his partner’s perceived infidelities and that men’s sexual coercion is related positively to their mate retention behaviors (behaviors designed to prevent a partner’s infidelity). The results from Study 1 (self-reports from 246 men) and Study 2 (partner-reports from 276 women) supported the hypotheses. The Discussion section addresses limitations of this research and highlights future directions for research on sexual coercion in intimate relationships.     

A collaborative study of a test for carcinoembryonic antigen (CEA) in the sera of patients with carcinoma of the colon and rectum

Five university centres in Canada and the United States have collaborated in a study of a test for carcinoembryonic antigen, with the Montreal General Hospital laboratory acting as the reference laboratory, examining duplicate halves of specimens from patients examined in local laboratories.Between June 1971 and April 1972, 503 patients were admitted to the study, 146 with cancer of the colon or rectum. Discrimination between colo-rectal cancer and “other” diagnoses was good at 2.5 ng./ml. or more, such a result being obtained in 66% of the patients with colo-rectal cancer in the local laboratories and 62% in the reference laboratory compared with 39% and 33% respectively of patients with “other” diagnoses. Patients with Duke''s C lesions of the colon or rectum were more likely to have raised CEA levels than patients with more localized lesions. CEA was also more commonly found in patients with other cancers and in patients with liver disease than in patients with other (benign) diagnoses.It is concluded that the test can be reproduced in other laboratories and that it or another simplified technique could become an important diagnostic aid for colo-rectal cancer.     

Geographic Access to High Capability Severe Acute Respiratory Failure Centers in the United States

Objective

Optimal care of adults with severe acute respiratory failure requires specific resources and expertise. We sought to measure geographic access to these centers in the United States.

Design

Cross-sectional analysis of geographic access to high capability severe acute respiratory failure centers in the United States. We defined high capability centers using two criteria: (1) provision of adult extracorporeal membrane oxygenation (ECMO), based on either 2008–2013 Extracorporeal Life Support Organization reporting or provision of ECMO to 2010 Medicare beneficiaries; or (2) high annual hospital mechanical ventilation volume, based 2010 Medicare claims.

Setting

Nonfederal acute care hospitals in the United States.

Measurements and Main Results

We defined geographic access as the percentage of the state, region and national population with either direct or hospital-transferred access within one or two hours by air or ground transport. Of 4,822 acute care hospitals, 148 hospitals met our ECMO criteria and 447 hospitals met our mechanical ventilation criteria. Geographic access varied substantially across states and regions in the United States, depending on center criteria. Without interhospital transfer, an estimated 58.5% of the national adult population had geographic access to hospitals performing ECMO and 79.0% had geographic access to hospitals performing a high annual volume of mechanical ventilation. With interhospital transfer and under ideal circumstances, an estimated 96.4% of the national adult population had geographic access to hospitals performing ECMO and 98.6% had geographic access to hospitals performing a high annual volume of mechanical ventilation. However, this degree of geographic access required substantial interhospital transfer of patients, including up to two hours by air.

Conclusions

Geographic access to high capability severe acute respiratory failure centers varies widely across states and regions in the United States. Adequate referral center access in the case of disasters and pandemics will depend highly on local and regional care coordination across political boundaries.     

Comparative blood levels and metabolism of INH and an INH-matrix preparation in fast and slow inactivators

Two groups of tuberculosis patients, phenotyped as either slow or fast inactivators of isoniazid, participated in a preliminary bioavailability study of a new INH-matrix preparation with sustained action. The absorption, excretion and metabolic patterns of the new form were compared with those of standard INH tablets in both sets of patients, using a crossover technique.The INH-matrix was more slowly absorbed by both slow and fast inctivators. When the latter were treated with 30 mg./kg. of the matrix formulation the blood levels attained were comparable with those observed in slow acetylators treated with 10 mg./kg. normal INH. Although this dose is three times that normally recommended with standard INH, blood levels remained within safe limits owing to the drug''s slow release from the matrix.     

Effect of isoniazid on glutathione biosynthesis and degradation inMycobacterium smegmatis

The mechanism of glutathione (GSH) depletion by isoniazid (INH) was studied inM. smegmatis. INH increased the activity of γ-glutamyl transferase (GGT) whether added before medium inoculation or to actively growing cells. The activity of GGT in cells grown from the beginning in INH-containing medium increased significantly on growth days 2–6. Three-day oldM. smegmatis cells treated with INH exhibited a 30–65 % increase in the activity of GGT. The activities of γ-glutamyl-cysteine synthase (GGCS) and GSH synthase (GS) were lowered by 50 and 56 % respectively on the second day of growth whenM. smegmatis was grown in a medium supplemented with 1.5 mg INH per L. In 3-day oldM. smegmatis, INH significantly inhibited the activities of GSH biosynthetic enzymes. The results demonstrate that the increased activity of GGT and decreased activities of GSH biosynthetic enzymes are responsible for GSH depletion by INH inM. smegmatis.     

Women,resources, and dispersal in nineteenth-century Sweden

In a recent study, female dispersal in nineteenth-century Sweden has been found to correlate negatively with access to resources: women with limited access to local resources tended to migrate more frequently. In this paper I review the literature to explore whether this observed correlation was derived from a relationship in which a woman’s limited access to resources worsened her position in the marriage market and led to migration, as a strategy to improve resources and this position. Many studies within a variety of disciplines indicate that a woman’s propensity to disperse from her parish of birth variedinversely with her propensity to inherit resources. My review of the literature suggests that the less likely a woman was to inherit resources, the lower her probability of marriage, the later her expected age at marriage, and the earlier she left home, presumably to improve her resource base for marriage. This work was funded in part by the Population and Environment Dynamics Program and by the Evolution and Human Behavior Program, University of Michigan. Alice L. Clarke is a doctoral candidate in the School of Natural Resources and Environment, University of Michigan, Ann Arbor. Her dissertation research examines the ecology of human dispersal in nineteenth-century Sweden. Her broader research interests include the ecological basis of human demography and resource use.     

The combined action of p-aminosalicylic acid and streptomycin with isonicotinic acid hydrazide in vitro

Summary A method is described of investigating and representing graphically the simultaneous action of two antibacterial agents. The results are reported of the investigation with the H₃₇R_v strain and the PAS and INH resistant forms obtained from this strain on mixtures of PAS and INH, and the results of the investigation with the H₃₇R_v strain and the streptomycin and INH resistant forms obtained on mixtures of streptomycin and INH. It appears that there is a definite synergism in mixtures containing about 99% PAS and 1% INH. Additivity, to slight antagonism, is found in mixtures consisting of streoptomycin and INH. This research was supported in part by Riker Laboratories Inc., Los Angelos, California.     

Amazon Forestry Tranformed: Integrating Knowledge for Smallholder Timber Managemet in Eastern Brazil

Recent discussions of local knowledge emphasize its dynamic nature invoking local peoples’ ability to effectively integrate traditional or local with science-based or “modern” knowledges. The smallholder timber industry of the Amazon’s estuarine floodplain provides an outstanding example of local patterns of resource management and economic activities transformed from within by smallholder farmers who participated in the industrial timber boom of the 1970s and 1980s. These farmers of eastern Amazonia have developed a vertically integrated local industry based on expertise reflecting profound locally developed knowledge of specific forests and management of ecological processes, individual observation and experimentation, as well as concepts and practices derived from temporary employment by large-scale industrial timber firms. At each stage of the smallholder forestry process—from managing natural regeneration to running small sawmills and marketing lumber—local managers apply an innovative set of practices reflecting their diverse experiences. This combination of technical, market, and ecological knowledge results in forests, timber markets, and economic patterns that do not correspond to many of the widely-held generalizations concerning either local or industrial tropical timber exploitation. This article uses data from 7 years of research in the Amazon floodplain.

Influence of diversity and road access on palm extraction at landscape scale in SE Ecuador

The relationship between biodiversity and the activities of small-scale farmers remains poorly understood despite its importance for conservation. In tropical forest areas farmers often include extraction of forest products in their subsistence strategies, and it has been suggested that factors such as market access and diversity levels influence people’s use of forest products. To investigate these relationships, we studied the use of palms in five villages inhabited by colonists and indigenous Shuar in the lower montane forest in south-eastern Ecuador by means of interviews and line transects around the villages. We found that use of palms was not driven by the diversity of palms available in the forest surrounding each village. Instead, the most important factor seemed to be lack of market access so in villages furthest away from the nearest road people used more palm products for their subsistence life compared to villages closer to the road. Forests around more remote villages had higher utility levels when evaluated on the basis of the villagers’ use of palms, despite lower levels of palm diversity and richness in these forests. The lower diversity levels may reflect past human activity or ecological factors, or a combination of both. In either case, our results show that forests with higher diversity levels are not necessarily more valuable to local people compared to less diverse forests. Instead, socio-economic factors such as market access may be more important in shaping people’s relationship with the natural environment.     

University Evolution Education: The Effect of Evolution Instruction on Biology Majors�� Content Knowledge, Attitude Toward Evolution, and Theistic Position

Issues regarding understanding of evolution and resistance to evolution education in the United States are of key importance to biology educators at all levels. While research has measured student views toward evolution at single points in time, few studies have been published investigating whether views of college seniors are any different than first-year students in the same degree program. Additionally, students choosing to major in biological sciences have largely been overlooked, as if their acceptance of evolution is assumed. This study investigated the understanding of evolution and attitude toward evolution held by students majoring in biological science during their first and fourth years in a public research university. Participants included students in a first-year introductory biology course intended for biological science majors and graduating seniors earning degrees in either biology or genetics. The portion of the survey reported here consisted of quantitative measures of students’ understanding of core concepts of evolution and their attitude toward evolution. The results indicate that students’ understanding of particular evolutionary concepts is significantly higher among seniors, but their attitude toward evolution is only slightly improved compared to their first-year student peers. When comparing first-year students and seniors, students’ theistic position was not significantly different.     

Induction of cytotoxic T cells and their antitumor activity in mice transgenic for carcinoembryonic antigen

In order to develop immunotherapy strategies that are based on eliciting immune responsiveness to the self-antigen, human carcinoembryonic antigen (CEA), we examined whether cytotoxic T lymphocyte (CTL) activity against CEA could be elicited in CEA-transgenic and nontransgenic mice. CEA-transgenic [C57BL/6-TGN(CEAGe)18FJP] and nontransgenic mice were primed with CEA-transfected syngeneic fibroblasts in combination with Corynebacterium parvum. Spleen cells from immunized mice were cultured with irradiated syngeneic MC-38 colon carcinoma cells transfected with CEA (MC-38.CEA) as stimulators prior to the measurement of CTL activity. Primed nontransgenic spleen cells showed augmented CTL activity against MC-38.CEA cells as compared with control parental MC-38 cells, nontransfected or transfected with vector only. Moreover, primed CEA transgenic spleen cells showed augmented CTL activity against MC-38.CEA cells that was similar to that observed in nontransgenic mice. All CTL clones derived from either transgenic or nontransgenic mice showed cross-reactivity with MC-38 cells expressing the CEA-related antigen, nonspecific cross-reacting antigen, but not biliary glycoprotein. CEA-specific CTL clones were not identified. Adoptive transfer of cloned CTL resulted in inhibition of MC-38.CEA but not MC-38.BGP tumor growth. Tumor cures were elicited in mice treated with a combination of cloned CTL and cyclophosphamide. Histopathological examination of CEA-expressing colons from either immunized mice or recipients of cloned CTL did not reveal any autoimmune reactions. These studies demonstrate that CTL recognizing cross-reactive class I epitopes on the CEA molecule can be induced in transgenic mice. The expression of these epitopes on tumor cells creates effective targets for CTL in vivo without inducing adverse reactions in CEA-expressing normal tissues. Since anti-CEA CTL have been generated in humans, CEA-transgenic mice may be a useful model to study vaccines that are based on CTL effector mechanisms. Received: 7 January 2000 / Accepted: 8 March 2000     

Interferon-gamma is a major regulator of C1-inhibitor synthesis by human blood monocytes

C1 inhibitor (C1INH) is the major control factor for the activation of the classical pathway of complement and for contact system activation. Hepatocytes and blood monocytes are known to synthesize this protease inhibitor. We studied the regulation of monocyte C1INH production by mediators that are generated during inflammatory responses. Purified blood monocytes spontaneously synthesized and secreted C1INH only after prolonged culture. In the presence of interferon (IFN)-gamma, C1INH was detectable within 24 hr and continued to be released at high levels throughout an 8-day culture period. Monocyte C1INH was newly synthesized and was functionally active as determined by forming stable complex with C1s. Other monocyte stimuli were either less potent (IFN-alpha, IFN-beta) or not capable of increasing C1INH release (lipopolysaccharide, interleukin 1, and tumor necrosis factor). The second component of complement, C2, was induced by IFN-gamma to a similar extent as C1INH. These findings demonstrate that IFN-gamma is a major regulator of monocyte C1INH production and may warrant consideration of IFN-gamma in the treatment of C1INH deficiency states.     

Preprinting is positively associated with early career researcher status in ecology and evolution

The usage of preprint servers in ecology and evolution is increasing, allowing research to be rapidly disseminated and available through open access at no cost. Early Career Researchers (ECRs) often have limited experience with the peer review process, which can be challenging when trying to build publication records and demonstrate research ability for funding opportunities, scholarships, grants, or faculty positions. ECRs face different challenges relative to researchers with permanent positions and established research programs. These challenges might also vary according to institution size and country, which are factors associated with the availability of funding for open access journals. We predicted that the career stage and institution size impact the relative usage of preprint servers among researchers in ecology and evolution. Using data collected from 500 articles (100 from each of two open access journals, two closed access journals, and a preprint server), we showed that ECRs generated more preprints relative to non‐ECRs, for both first and last authors. We speculate that this pattern is reflective of the advantages of quick and open access research that is disproportionately beneficial to ECRs. There is also a marginal association between first author, institution size, and preprint usage, whereby the number of preprints tends to increase with institution size for ECRs. The United States and United Kingdom contributed the greatest number of preprints by ECRs, whereas non‐Western countries contributed relatively fewer preprints. This empirical evidence that preprint usage varies with the career stage, institution size, and country helps to identify barriers surrounding large‐scale adoption of preprinting in ecology and evolution.     

Changing patterns of teenage pregnancy: population based study of small areas

ObjectivesTo measure the impact of socioeconomic deprivation on rates of teenage pregnancy and the extent of local variation in pregnancy rates in Scotland, and to examine how both have changed over time.Design Population study using routine data from hospital records, aggregated for small areas.Subjects Female teenagers resident in Scotland who were treated for pregnancy in an NHS hospital in either 1981-5 (62 338 teenagers) or 1991-5 (48 514) and who were aged 13-19 at the time of conception.Results From the 1980s to the 1990s pregnancy rates increased differentially according to levels of local deprivation, as measured by the Carstairs index. Among teenagers aged less than 18 the annual pregnancy rate increased in the most deprived areas (from 7.0 to 12.5 pregnancies per 1000 13-15 year olds and from 67.6 to 84.6 per 1000 16-17 year olds), but there was no change, on average, among teenagers in the most affluent areas (3.8 per 1000 13-15 year olds and 28.9 per 1000 16-17 year olds). Among 18-19 year olds the pregnancy rate decreased in the most affluent areas (from 60.0 to 46.3 per 1000) and increased in the most deprived areas (from 112.4 to 116.0 per 1000). The amount of local variation explained by deprivation more than doubled from the 1980s to the 1990s. The proportion of pregnancies resulting in a maternity was positively associated with level of deprivation, but the effect remained similar over time.Conclusion From the 1980s to the 1990s the difference in rates of teenage pregnancy between more affluent and more deprived areas widened. This has implications for allocating resources to achieve government targets and points to important social processes behind the general increase in the number of teenage pregnancies in Scotland.

What is already known on this topic

Rates of teenage pregnancy are considerably higher in the United Kingdom than in other western European countriesIn the United Kingdom rates of teenage pregnancy are known to be higher in areas of greater socioeconomic deprivation, although local variation may also reflect differential access to family planning services

What this study adds

From 1981-5 to 1991-5 rates of teenage pregnancy in Scotland increased more rapidly in areas of greater socioeconomic deprivationIn the 1990s socioeconomic deprivation explained more than 50% of local variation in rates of teenage pregnancy, more than double the amount explained by it in the 1980s     

Effect of Lyophilization and Freeze-thawing on the Stability of siRNA-liposome Complexes

The purpose of this research was to describe the application of lyophilization in the delivery of siRNA using cationic lipids by addressing the long-term formulation/stability issues associated with cationic lipids and to understand the mechanism of lyoprotection. siRNA liposomes complexes were formed in different potential cyro/lyoprotectants and subjected to either lyophilization or freeze thaw cycles. siRNA, liposomes and/or lipoplexes were tested for activity, SYBR Green I binding, cellular uptake and particle size. The lipoplexes when lyophilized in the presence of sugars as lyoprotectants could be lyophilized and reconstituted without loss of transfection efficacy but in ionic solutions they lost 65–75% of their functionality. The mechanism of this loss of activity was further investigated. The lyophilization process did not alter siRNA’s intrinsic biological activity as was evident by the ability of lyophilized siRNA to retain functionality and SYBR green I binding ability. While the lipoplex size dramatically increased (∼50–70 times) after lyophilization in the absence of non-ionic lyoprotectants. This increase in size correlated to the decrease in cellular accumulation of siRNA and a decrease in activity. In conclusion, siRNAs can be applied in cationic lipid lyophilized formulations and these complexes represent a potential method of increasing the stability of pre-formed complex.     

Are there any consistent predictors of invasion success?

This article summarises the results of 49 studies that together test the significance of 115 characteristics in 7 biological groups: birds, finfish, insects, mammals, plants, reptiles/amphibians and shellfish. Climate/habitat match, history of invasive success and number of arriving/released individuals are associated with establishment success in at least four independent data sets, both within and across biological groups, and none are contraindicated by other studies. In the introduced-invasive control group, two species level characteristics—taxon and geographic range size—were significantly associated with establishment success across two biological groups. These characteristics, however, were not supported by independent data sets, or were contraindicated by these data sets, within the biological groups examined here. In the introduced-native control group, three species level characteristics—geographic range size, leaf surface area and fertilisation system (monoecious, hermaphroditic or dioecious)—were consistently supported within plants but were either not supported by independent data sets or contraindicated by datasets within or across other biological groups. Climate/habitat match is the only characteristic that is consistently significantly associated with invasive behaviour (in this case exotic range size) across biological groups. This finding, however, is not supported by two or more independent data sets within any of the biological groups examined here. Within plants there are a suite of characteristics, predominately associated with reproduction, that are significantly associated with a range of invasion metrics, predominately abundance in the invaded range. None of these characteristics, however, are supported across any other biological groups. We note the confounding effects of phylogeny, residence time and propagule pressure and suggest that site- and taxa-specific analysis will provide further useful insights.     

The Human Frontier Science Program: its aims and a proposal for its implementation

Reactions to the Human Frontier Science Program have been mixed. It has been welcomed as an important initiative in basic biological research yet regarded with suspicion by some outside Japan who see it as facilitating access to European and North American fundamental research. However, suspicion is clearing away and the governments concerned are looking forward to the Program's implementation. In this article, the Program's aims and the mechanisms for its execution are outlined as proposed in the light of a recent feasibility study.