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PubMed1990

A mathematical model for the evolutions of anthelmintic resistance in a direct life cycle nematode parasite.

Some of the elements required of a mathematical model for the evolution of anthelmintic resistance in strongylid nematodes are described. The model comprises a series of coupled first order differential equations and assumes the parasite has a direct life cycle with overlapping generations. The parasite-host system involved only a single host. In all the cases considered, drug resistance was assumed to be determined by two alleles at a single autosomal locus. The pretreatment allelic frequencies were maintained by heterozygote advantage involving the mortality of the free-living stages of the parasite. The model suggests that alternating anthelmintic with different modes of action may be a less effective resistance management strategy than administering the same drugs simultaneously.

Animals↗

PubMed1996

An emergency medicine approach to violence throughout the life cycle. SAEM Public Health and Education Committee.

This document by the SAEM Public Health and Education Committee outlines the public health impact of interpersonal violence as it pertains to acute emergency care. This paper provides an overview of violence through the life cycle (i.e., child abuse, youth violence, intimate violence, and elderly abuse). It also makes specific recommendations regarding the role emergency physicians can play in reducing violence through medical education, research, surveillance, public education, advocacy, and clinical practice.

Aged↗

PubMed2001

Solutions to health care waste: life-cycle thinking and "green" purchasing.

Health care waste treatment is linked to bioaccumulative toxic substances, such as mercury and dioxins, which suggests the need for a new approach to product selection. To address environmental issues proactively, all stages of the product life cycle should be considered during material selection. The purchasing mechanism is a promising channel for action that can be used to promote the use of environmentally preferable products in the health care industry; health care facilities can improve environmental performance and still decrease costs. Tools that focus on environmentally preferable purchasing are now emerging for the health care industry. These tools can help hospitals select products that create the least amount of environmental pollution. Environmental performance should be incorporated into the evolving definition of quality for health care.

Conservation of Natural Resources↗

PubMed2004

Fish full life-cycle testing for androgen methyltestosterone on medaka (Oryzias latipes).

Abstract-We studied the chronic effects of methyltestosterone (MT) on reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure to verify the applicability of the fish full life-cycle test (FFLC) for this androgen with this species. The exposure of parental (F0) medaka to MT was begun on embryos within 12 h postfertilization and continued for up to 101 d; assessment endpoints included embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to MT at each mean measured concentration of 0.35, 1.09, 3.29, 9.98, and 27.75 ng/L. Eggs (F1) spawned from the F0 fish at 98, 99, and 100 d posthatch were examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG level until 60 d posthatch. In the FFLC with medaka, MT induced masculinization of both secondary sex characteristics and gonads. We observed that all F0 fish in the 27.75-ng/L treatment group showed male secondary sex characteristics in which no fish with ovary could be discerned. Several fish with ovaries in F0 and F1 generations treated with 9.98 ng/L showed male secondary sex characteristics. We also observed swollen abdomens in the F0 and F1 female fish in the 9.98-ng/L treatment group. These swollen abdomens were induced by enlarged ovaries and were accompanied with declined fecundity and fertility in the F0 generation. These results indicate that MT reduces the reproductive potential of medaka and that the FFLC with this species is applicable to the evaluation of androgens.

Animals↗

PubMed2004

Life cycle assessment as a tool for the environmental improvement of the tannery industry in developing countries.

A representative leather tannery industry in a Latin American developing country has been studied from an environmental point of view, including both technical and economic analysis. Life Cycle Analysis (LCA) methodology has been used for the quantification and evaluation of the impacts of the chromium tanning process as a basis to propose further improvement actions. Four main subsystems were considered: beamhouse, tanyard, retanning, and wood furnace. Damages to human health, ecosystem quality, and resources are mainly produced by the tanyard subsystem. The control and reduction of chromium and ammonia emissions are the critical points to be considered to improve the environmental performance of the process. Technologies available for improved management of chromium tanning were profoundly studied, and improvement actions related to optimized operational conditions and a high exhaustion chrome-tanning process were selected. These actions related to the implementation of internal procedures affected the economy of the process with savings ranging from US dollars 8.63 to US dollars 22.5 for the processing of 1 ton of wet salt hides, meanwhile the global environmental impact was reduced to 44-50%. Moreover, the treatment of wastewaters was considered in two scenarios. Primary treatment presented the largest reduction of the environmental impact of the tanning process, while no significant improvement for the evaluated impact categories was achieved when combining primary and secondary treatments.

Animals↗

PubMed2005

Life-cycle inventory of waste solvent distillation: statistical analysis of empirical data.

Distillation is one of the most important processes in the chemical industry. An environmental assessment of distillation processes is difficult because of the highly specific features of each distillation process. Life-cycle inventory (LCI) information is therefore scarce. The goal of this paper is to provide reliable data ranges for inventory flows of waste solvent distillation (i.e. amount of recovered distillate, consumption of steam, electricity, nitrogen, cooling water and ancillary product, and the generation of organic waste, wastewater, and outlet air). For this purpose, we collected data from approximately 150 waste solvent distillation processes from chemical industry and analyzed them statistically. The results of the statistical analysis compose generic data ranges for each LCI parameter. Where appropriate, the data of each LCI parameter have been subdivided according to the distillation technology or the waste solvent composition. Additionally, probability distributions have been fitted to the data of each LCI parameter, thus enabling quantitative uncertainty analysis (e.g. Monte Carlo Simulation). In a case study we illustrate the application of the inventory data ranges according to situations of differing data availability.

Chemical Industry↗

PubMed2003

Regulation of eIF2alpha phosphorylation by different functions that act during discrete phases in the herpes simplex virus type 1 life cycle.

Multiple herpes simplex virus type 1 functions control translation by regulating phosphorylation of the initiation factor eIF2 on its alpha subunit. Both of the two known regulators, the gamma(1)34.5 and Us11 gene products, are produced late in the viral life cycle, although the gamma(1)34.5 gene is expressed prior to the gamma(2) Us11 gene, as gamma(2) genes require viral DNA replication for their expression while gamma(1) genes do not. The gamma(1)34.5 protein, through a GADD34-related domain, binds a cellular phosphatase (PP1alpha), maintaining pools of active, unphosphorylated eIF2. Infection of a variety of cultured cells with a gamma(1)34.5 mutant virus results in the accumulation of phosphorylated eIF2alpha and the inhibition of translation prior to the completion of the viral lytic program. Ectopic, immediate-early Us11 expression prevents eIF2alpha phosphorylation and the inhibition of translation observed in cells infected with a gamma(1)34.5 mutant by inhibiting activation of the cellular kinase PKR and the subsequent phosphorylation of eIF2alpha; however, a requirement for the Us11 protein, produced in its natural context as a gamma(2) polypeptide, remains to be demonstrated. To determine if Us11 regulates late translation, we generated two Us11 null viruses. In cells infected with a Us11 mutant, elevated levels of activated PKR and phosphorylated eIF2alpha were detected, viral translation rates were reduced 6- to 7-fold, and viral replication was reduced 13-fold compared to replication in cells infected with either wild-type virus or a virus in which the Us11 mutation was repaired. This establishes that the Us11 protein is critical for proper late translation rates. Moreover, it demonstrates that the shutoff of protein synthesis observed in cells infected with a gamma(1)34.5 mutant virus, previously ascribed solely to the gamma(1)34.5 mutation, actually results from the combined loss of gamma(1)34.5 and Us11 functions, as the gamma(2) Us11 mRNA is not translated in cells infected with a gamma(1)34.5 mutant.

Cells, Cultured↗

PubMed1980

Morphological changes during the life cycle of Aureobasidium pullulans (de Bary) Arnaud.

Aureobasidium pullulans (de Bary) Arnaud was isolated from different natural materials plant blossoms in particular. Elements of vegetative multiplication, structure of colonies and cultures in liquid media were analyzed in detail, leading to construction of the life cycle of this organism. Morphological polymorphism was found to be combined with the production of melanin and the polysaccharide pullulan. Morphological analysis served for a directed selection for studies of physiological properties of this organism and its practical application.

Culture Media↗

PubMed1981

Differential activity of DNA methyltransferase in the life cycle of Chlamydomonas reinhardi.

Two molecular weight forms of DNA (cytosine-5-)-methyltransferase [S-adenosyl-L-methionine:DNA (cytosine-5-)- methyltransferase, EC 2.1.1.37], both active in assays in vitro, were isolated from the green alga Chlamydomonas reinhardi at various stages of the life cycle. The enzyme with Mr 60,000 was found in vegetative cells and gametes of both male (mt-) and female (mt+) mating types. The enzyme with Mr 200,000 was specific to gametic cells and zygotes, which are the only stages at which methylation of chloroplast DNA occurs in vivo. Chloroplast DNA from gametes was shown to be methylated on both strands at most if not all methylation sites and the Mr 200,000 enzyme was shown to methylate both unmethylated and hemimethylated sites, the latter at an elevated rate. Micrococcus luteus DNA showed the same nearest-neighbor frequencies of methylation after methylation by each molecular weight component. The data suggest strongly that the Mr 200,000 enzyme is the active multimeric form of the Mr 60,000 enzyme and that it acts as both initiation and maintenance methylase. It is proposed that methylation of chloroplast DNA in female gametes and zygotes is regulated by assembly of the multimeric Mr 200,000 active enzyme, which in turm determines the maternal inheritance of chloroplast DNA.

Chlamydomonas↗

PubMed2003

Life cycle analysis of Municipal Solid Waste management possibilities in Asturias, Spain.

Directive 1994/62 concerning packaging and packaging waste and Directive 1999/31 related to waste disposal will substantially modify the management and treatment of Municipal Solid Waste (MSW) in Europe. In this study, a life cycle analysis has been carried out of the different possibilities of managing Municipal Solid Waste in Asturias. The "Integrated Waste Management" (IWM-1) model was employed, analysing the different alternatives for collection and treatment of MSW. This model predicts overall environmental burdens of MSW management systems and includes a parallel economical model. The sources of costs in the different systems of collection and treatment of MSW were considered in the economical analysis, as well as the sources of resource gathering that may be obtained via the sale of recovered materials. What emerges from this study is the soundness of management strategies based on biological treatment technologies in comparison with thermal treatments, together with the need to increase the level of collection at source.

Costs and Cost Analysis↗

PubMed2002

Life cycle assessment of an industrial water recycling plant.

An industrial water recycling plant was recently commissioned in Durban, South Africa. As with any industrial activity there are environmental burdens associated with water recycling. To assess these burdens a relatively new environmental tool--the life cycle assessment (LCA)--was used. LCA is a systematic way to evaluate the environmental impact of a product or process. This study presents the environmental burdens associated with industrial water and identifies the areas for improvement for the processes involved for recycling water. It was shown that the majority of the environmental burdens for producing industrial water could be traced back to the consumption of electricity for the operation of the plant.

Conservation of Natural Resources↗

PubMed2006

Preventing obesity: a life cycle perspective.

Traditional approaches to treating overweight and obese adults by focusing on individual weight loss have not been effective in stemming the tide of obesity in the population. Recent research has identified critical factors that, as they accumulate and interact over an individual's life span, may put a person at risk for obesity. These factors include rapid weight gain in infancy and childhood, early puberty, and excessive weight gain in pregnancy. Based on this research, a life cycle perspective can be used to develop comprehensive interventions that address the multiple determinants of obesity. Because obesity tracks across generations, it is essential to adopt effective obesity prevention measures now to prevent even higher rates of obesity in future generations. Dietetics professionals can reduce individual risks by providing nutritional services that support appropriate weight gain in childhood and pregnancy. We can also advocate for policies in communities, schools, and worksites that support breastfeeding, ensure access to health-promoting foods, and provide opportunities to be physically active.

Adolescent↗

PubMed1967

Nucleolar and nuclear RNA synthesis during the cell life cycle in monkey and pig kidney cells in vitro.

The incorporation of 5-(3)H-uridine and 5-(3)H-cytidine into nucleolar and nonnucleolar RNA in the nucleus of monkey and pig kidney cells was measured in vitro during the cell life cycle. Time-lapse cinematographic records were made of cells during asynchronous exponential proliferation, in order to identify the temporal position of individual cells in relation to the preceding mitosis. Immediately following cinematography, cells were labeled with uridine-(3)H and cytidine-(3)H for a short period, fixed, and analyzed by radioautography. Since the data permit correlation of the rate of RNA labeling with the position of a cell within the cycle, curves could be constructed describing the rate of RNA synthesis over the average cell cycle. RNA synthesis was absent in early telophase, and rose very abruptly in rate in late telophase and in very early G(1) in both the nucleus and the reconstituting nucleolus. Thereafter, through the G(1) and S periods the rate of nuclear RNA synthesis rose gradually. When we used a 10-min pulse, there was no detectable change in the rate for nucleolar RNA labeling in monkey kidney cells during G(1) or S. When we used a 30-min labeling time, the rate of nucleolar RNA labeling rose gradually in pig kidney cells. With increasing time after mitosis, the data became more variable, which may, in part, be related to the variation in generation times for individual cells.

Animals↗

PubMed2004

Environmental impact assessment of salmonid feeds using Life Cycle Assessment (LCA).

Understanding the environmental burdens associated with aquafeeds is a critical component for assessing and improving the environmental performance of aquaculture. The aim of the study was to assess the environmental impacts associated with feeds for rainbow trout production in France, using Life Cycle Assessment (LCA). The stages assessed are: the extraction of the raw materials, the production and transformation of the primary ingredients used, the manufacturing of the feeds, the use of the feeds at the farm, transport at all stages, and the production and use of energy resources. The assessment revealed that the use of fishery resources (such as biotic resource use) and nutrient emissions at the farm (such as eutrophication potential) contribute most to the potential environmental impacts of salmonid aquafeeds. Improvements in feed composition and management practices seem to be the best ways for improving the environmental profile of aquafeeds.

Animal Feed↗

PubMed2000

Experimental infections of farmed eels with different Trypanosoma granulosum life-cycle stages and investigation of pleomorphism.

Trypanosoma granulosum, a flagellate protozoon commonly found in the blood of the European eel Anguilla anguilla, was injected experimentally into uninfected eels purchased from a local farm. In order to investigate the infectivity of different stages in the life cycle, trypanosomes from various sources were used for inoculation. Infectivity was greatly reduced in in vitro culture stages inoculated at 20 C. Isolated bloodstream stages injected into groups of animals held at 12 and 20 C could be detected for over 70 days but did not appear to multiply. Naturally infected Hemiclepsis marginata, a piscivorous leech known to serve as vector, produced detectable, single-peak infections in eels held at 20 C. Infections were characterized by a prepatent stage and a phase of rising parasitemia. Peak infection intensities ranged between 1 and 7 x 10(4) trypanosomes/ml. Trypanosomes in the bloodstream of eels experimentally infected with leeches, divided at a very low rate during the early stages of infection. Small morphs present during the early phase of rising parasitemia were gradually replaced by larger trypanosomes. The overall length frequency distribution of trypanosomes was unimodal.

Anguilla↗

PubMed1995

Pets, attachment, and well-being across the life cycle.

Using an ethological framework of attachment developed by Bowlby and the social provisions of relationships delineated by Weiss, this article explores the ways in which family pets, in particular dogs and cats, provide certain components of attachment that contribute to emotional and social well-being throughout the life cycle. Pets may supply ongoing comfort and reduce feelings of loneliness during adversity or stressful transitions such as divorce or bereavement. They can also provide an opportunity to nurture others. In clinical practice it helps to be aware of how significant a pet may be to a client. Implications are identified for social policies that will protect and maintain this bond for particular populations, such as elderly people in nursing homes or retirement communities and individuals going through a life transition.

Animals↗

PubMed1980

Cryptosporidiosis in man: parasite life cycle and fine structural pathology.

The Cryptosporidium here described is a very small (3-4 micron) opportunistic pathogenic coccidian parasite. Through seven known human enteric infections it is now associated with diarrhoea in immunosuppressed or immunodeficient individuals. Neither the full pathogenic potential nor the complete life cycle of this parasite are known, and there is no adequate chemotherapeutic agent with which to eradicate it. What is known of its intracellular intestinal forms and the fine structural changes occurring in parasitised epithelial cells has been described. A viral complication of the infection is discussed and mention is made of relevant cryptosporidial infections of domestic and other animals.

Adenovirus Infections, Human↗

PubMed1994

Crystallization and preliminary X-ray analysis of GAP 31. A protein which inhibits the life cycle of HIV-1.

GAP 31 is an anti-HIV plant protein that we have identified and purified to homogeneity from Gelonium multiflorum. It is the first reported example of an anti-HIV agent capable of acting against multiple stages of the viral life cycle, on viral infection and viral replication. GAP 31 is a unique paragon of multi-functional protein. In addition to anti-HIV activity, it also exhibits anti-tumor action, DNA binding, RNA binding and ribosome inactivation. The present crystals diffract up to 2.0 A resolution and belong to monoclinic space group P2(1). The cell dimensions are a = 49.30(2) A, b = 44.57(2) A, c = 137.78(7) A and beta = 98.32(3) degrees. There are two molecules of molecular weight 31 kDa in an asymmetric unit with a solvent content of 49%.

Antiviral Agents↗