Environmental benchmarks for buildings: a critical literature review

Purpose

To reduce the environmental impact of the building sector, environmental targets considering the full life cycle of buildings can be supportive. In recent years, various benchmarks based on Life Cycle Assessment (LCA) have been developed as part of regulations, labelling systems, sustainability rating tools and research studies. The objective of this paper is to critically analyse 23 existing benchmarking systems focusing on the benchmark methodology but also on the benchmark applications and communication.

Methods

The critical literature review consists of two parts. In a first part, the choices related to the assessment method, functional equivalent, definition of benchmark values, benchmark scope, benchmark applications and benchmark communication are compared. In the second part, benchmark values are compiled from literature and statistically analysed.

Results and discussion

The comparative analysis allows to identify the main approaches and methods used in benchmarking systems. For each evaluation aspect, the strengths and weaknesses of the various approaches are highlighted. The statistical analysis provides insight in the spread of benchmark values. Important variations are found between the literature sources which can be explained by differences in benchmark approach, scope, system boundaries and applications.

Conclusions

Based on the comparative analysis, recommendations are formulated for the development of LCA benchmarks for the building sector. The results of the statistical analysis furthermore provide reference values which can be used for the validation of future benchmarks. For global warming, the statistical values for the full life cycle impacts (i.e. embodied and operational impacts) range from about 15 up to 35 kg CO₂ eq/m².a.

     

Cultivation of Plasmodium vivax

Establishment of a continuous line of Plasmodium vivax parasite is crucial to understand the parasite's biology; however, this has not yet been achieved. Beginning in the 19th century, there were several efforts to cultivate this malaria parasite but without much success until the late 1980s. In addition, to date, only minor modifications of the methodology have been investigated, which has resulted in extending the cultivation period to around four weeks by supplying reticulocytes obtained from normal blood or rare hemochromatotic blood. However, the use of laboratory-produced erythroblasts to cultivate P. vivax enables maintenance of a continuous line of the parasite stably in the laboratory. Here, we summarize and compare the available methodologies and conditions for the in vitro cultivation of P. vivax.     

Plasmodium vivax under the microscope: the Aotus model

The Aotus model for vivax malaria is extremely useful both as a source of living parasites in non-endemic areas, and as a model for vaccine and drug development research. Several species of New World primates can be infected with numerous different strains of Plasmodium vivax. This article reviews some aspects of the Aotus model, discusses the frequently observed hematological changes that can confound interpretation of hemogram data during the course of vivax infection, and provides a partial atlas of parasite forms and Aotus nancymai blood cells.     

Targeting the Plasmodium vivax Duffy-binding protein

Plasmodium vivax requires interaction with the Duffy antigen receptor for chemokines (DARC) to enable its invasion of human erythrocytes. Interaction with DARC is mediated by the P. vivax Duffy-binding protein (PvDBP) and is essential for junction formation, which is a key step in the invasion process. The receptor-binding domain of PvDBP maps to a conserved cysteine-rich region, referred to as region II (PvRII). Here, we review data on the interaction of PvRII with DARC and explore the potential of targeting this crucial receptor-ligand interaction to develop new intervention strategies against P. vivax.     

Neglect of Plasmodium vivax malaria

Plasmodium vivax infects 130-435 million of the 2.6 billion people living at risk of infection. Recent studies suggest that vivax malaria can become lethal in a similar way to severe falciparum malaria. First-line therapies remain unchanged after 50 years. Despite evidence of failing chloroquine efficacy, little work has assessed the problem or explored alternative therapies. Primaquine treatment, the only therapeutic option against relapse, might also be failing. No licensed primary chemoprophylactic agent protects travelers from relapse. Misdiagnosis of species now affects clinical decisions resulting in inadequate therapy for P. falciparum and P. vivax. All of these factors demonstrate the lack of research on P. vivax.     

Plasmodium vivax: microsatellite analysis of multiple-clone infections

We used mixtures of genomic DNA from two genetically distinct isolates from Brazil, 42M and 312M, to investigate how accurately 12-locus microsatellite typing describes the overall genetic diversity and characterizes multilocus haplotypes in multiple-clone Plasmodium vivax infections. We found varying PCR amplification efficiencies of microsatellite alleles; for example, from the same 1:1 mixture of 42M and 312M DNA we amplified predominantly 312M-type alleles at 10 loci and 42M-type alleles at 2 loci. All microsatellite alleles were accurately scored in 1:0.5 and 1:0.25 312M:42M DNA mixtures, even when minor peak heights did not meet previously suggested criteria for minor allele detection in multiple-clone infections. Relative proportions of major and minor alleles were unaffected by multiple displacement amplification of template DNA prior to PCR-based microsatellite typing. Although microsatellite typing may detect minor alleles in clone mixtures, amplification biases may lead to inaccurate assignment of predominant haplotypes in multiple-clone P. vivax infections.     

Plasmodium vivax: karyotype polymorphism of field isolates

Pulse-field gradient electrophoresis (PFG) has been applied to the karyotype analysis of Plasmodium vivax isolates obtained directly from infected patients in Sri Lanka. Detection of separated chromosomes was performed either by ethidium bromide staining of gels or by hybridization with a telomer specific probe. Each of the 15 different isolates examined exhibited a different chromosome migration pattern, indicating that a high level of polymorphism prevailed in wild populations of P. vivax. Chromosome size variation was further confirmed using a P. vivax chromosome-specific probe which also demonstrated that, in each isolate, the parasite population appeared to be homogeneous. These observations were made directly on parasites from infected blood, without the necessity for culture amplification, indicating that PFG can be used on a large scale for the epidemiological analysis of wild parasite populations.     

Saguinus geoffroyi as a host for Plasmodium vivax

A monkey-adapted strain of Plasmodium vivax (Achiote) was transferred by trophozoites through 11 serial passages in Saguinus geoffroyi (Titi marmoset). Patent infections developed in both normal (23 of 24) and splenectomized (8 of 9) marmosets. The infections in the altered animals were of greater severity than in the intact subjects as indicated by patent periods ($\text{x}\text{?}\text{= 87}\text{vs}\text{61}\text{days}$) and maximum parasitemias ($\text{x}\text{?}\text{= 35,018}\text{vs}\text{16,218}\text{per mm}{}^3$).Relapses were recorded in 13 of 14 unaltered and 4 of 4 splenectomized animals that survived the primary attack. As evidence for acquired immunity, the mean maximum parasitemias during relapse in the normal animals were $\text{1}\text{8}$ of the values during the primary attack; patent periods were shorter than those in the initial infection. There was also some indication of an acquired immunity in the splenectomized group of animals. However, one splenectomized marmoset experienced a patent period of 325 days during the first relapse.There was considerable variation of infection parameters among the animals in each group.     

Spatially selective alteration of the mitral cell layer: a critical review of the literature

Evidence that chronic odor exposure alters mitral cell morphologyin young rats is reviewed. The functional origin of the mitralcell alteration is discussed in conjunction with the developmentof the olfactory bulb. It is concluded that odor exposure inyoung rats can alter the mitral cell layer in spatially selectivezones. Mitral cell alteration (primarily measured as penkaryaldiminution) appears to be a consequence of reduced stimulationand may be related to other activity-dependent ontogenetic effects.Chronic odor exposure provides an approach by which both spatialcoding of odor quality and functional development in the mammalianolfactory bulb can be examined.     

Causality,menopause, and depression: a critical review of the literature.

OBJECTIVE: To assess whether causal criteria can be used to find out whether there is support in published research for maintaining that menopause causes depression. DESIGN: Ninety four articles from 30 years of research examining the relation of natural menopause to depression were traced by using Medline and systematic follow up of reference lists. Specified exclusion and inclusion criteria were applied, and the resulting 43 epidemiological primary research articles were classified and tabulated according to sample and measures used and the researchers'' own conclusion as to whether or not an association had been established. This material was qualitatively evaluated with Hill''s nine criteria for causality. RESULT: There is insufficient evidence at present to maintain that menopause causes depression. In addition to methodological and statistical problems, a temporal problem in the menopause concept hinders research in this area. CONCLUSION: Causal criteria can usefully be used to structure a literature review. Further theoretical work is required to integrate standard clinical epidemiological concepts.     

Congenital Plasmodium vivax malaria mimicking neonatal sepsis: a case report

A recently published comment on a report of Plasmodium knowlesi infections in Vietnam states that this may not accurately represent the situation in the study area because the PCR primers used may cross-hybridize with Plasmodium vivax. Nevertheless, P. knowlesi infections have been confirmed by sequencing. In addition, a neighbour-joining tree based on the 18S S-Type SSUrRNA gene shows that the Vietnamese samples clearly cluster with the P. knowlesi isolates identified in Malaysia and are distinct from the corresponding P. vivax sequences. All samples came from asymptomatic individuals who did not consult for fever during the months preceding or following the survey, indicating that asymptomatic P. knowlesi infections occur in this population, although this does not exclude the occurrence of symptomatic cases. Large-scale studies to determine the extent and the epidemiology of P. knowlesi malaria in Vietnam are further needed.     

Plasmodium vivax genetic diversity: microsatellite length matters

The Plasmodium vivax genome is very diverse but has a relatively low abundance of microsatellites. Leclerc et al. had shown that these di-nucleotide repeats have a low level of polymorphism, suggesting a recent bottleneck event in the evolutionary history of P. vivax. By contrast, in a recent paper, Imwong et al. show that there is a very high level of microsatellite diversity. The difference in these results is probably due to the set array lengths chosen by each group. Longer arrays are more diverse than are shorter ones because slippage mutations become exponentially more common with an increase in array length. These studies highlight the need to consider carefully the application and design of studies involving microsatellites.     

Plasmodium vivax: cloning and expression of a major blood-stage surface antigen

Plasmodium vivax is a highly prevalent malaria pathogen of man; the following report is the first to describe the cloning and expression of a major asexual erythrocytic stage antigen of this species. The screening of a genomic DNA expression library with a monoclonal antibody directed against a 200-kDa surface component (Pv200) of the more mature schizonts of P. vivax led to the selection of a recombinant bacterial clone which produced a fusion protein. Mouse and rabbit immune sera raised against the purified fusion protein recognized the 200-kDa parasite antigen on Western blots and reacted with the surface of segmenters by immunofluorescence. Sequencing of the 1.9-kb P. vivax DNA insert coding for this fusion protein revealed a 45-47% homology at the nucleotide level with the P. falciparum gene of a parasite surface antigen, Pf195, which has been shown to be a promising candidate for a malaria vaccine in primates and in man.     

Plasmodium vivax sub-patent infections after radical treatment are common in Peruvian patients: results of a 1-year prospective cohort study

Background

There is an increasing body of literature reporting treatment failure of the currently recommended radical treatment of Plasmodium vivax infections. As P. vivax is the main malaria species outside the African continent, emerging tolerance to its radical treatment regime could have major consequences in countries like Peru, where 80% of malaria cases are due to P. vivax. Here we describe the results of a 1-year longitudinal follow up of 51 confirmed P. vivax patients living around Iquitos, Peruvian Amazon, and treated according to the Peruvian national guidelines.

Methodology

Each month a blood sample for microscopy and later genotyping was systematically collected. Recent exposure to infection was estimated by detecting antibodies against the P. vivax circumsporozoite protein (CSP) and all PCR confirmed P. vivax infections were genotyped with 16 polymorphic microsatellites.

Results

During a 1-year period, 84 recurrent infections, 22 positive also by microscopy, were identified, with a median survival time to first recurrent infection of 203 days. Most of them (71%) were asymptomatic; in 13 patients the infection persisted undetected by microscopy for several consecutive months. The genotype of mostly recurrent infections differed from that at day 0 while fewer differences were seen between the recurrent infections. The average expected heterozygosity was 0.56. There was strong linkage disequilibrium (I_A^s = 0.29, p<1.10⁻⁴) that remained also when analyzing only the unique haplotypes, suggesting common inbreeding.

Conclusion

In Peru, the P. vivax recurrent infections were common and displayed a high turnover of parasite genotypes compared to day 0. Plasmodium vivax patients, even when treated according to the national guidelines, may still represent an important parasite reservoir that can maintain transmission. Any elimination effort should consider such a hidden reservoir.     

The paroxysm of Plasmodium vivax malaria

The paroxysms of Plasmodium vivax malaria are antiparasite responses that, although distressing to the human host, almost never impart serious acute pathology. Using plasma and blood cells from P. vivax patients, the cellular and noncellular mediators of these events have been studied ex vivo. The host response during a P. vivax paroxysm was found to involve T cells, monocytes and neutrophils, and the activity, among others, of the pyrogenic cytokines tumor necrosis factor alpha and interleukin 2 in addition to granulocyte macrophage-colony stimulating factor. However, interferon gamma activity, associated with serious acute pathogenesis in other studies on malaria, was absent. Induction of the cytokines active during a P. vivax paroxysm depends upon the presence of parasite products, which are released into the plasma before the paroxysm. Chemical identification of these natural parasite products will be important for our understanding of pathogenesis and protection in malaria.     

Identifying and characterising the Plasmodium falciparum RhopH3 Plasmodium vivax homologue

Four Plasmodium species cause malaria in humans, Plasmodium falciparum being the most widely studied to date. All Plasmodium species have paired club-shaped organelles towards their apical extreme named rhoptries that contain many lipids and proteins which are released during target cell invasion. P. falciparum RhopH3 is a rhoptry protein triggering important immune responses in patients from endemic regions. It has also been shown that anti-RhopH3 antibodies inhibit in vitro invasion of erythrocytes. Recent immunisation studies in mice with the Plasmodium yoelii and Plasmodium berghei RhopH3 P. falciparum homologue proteins found that they are able to induce protection in murine models. This study described identifying and characterising RhopH3 protein in Plasmodium vivax; it is encoded by a seven exon gene and expressed during the parasite's asexual stage. PvRhopH3 has similar processing to its homologue in P. falciparum and presents a cellular immunolocalisation pattern characteristic of rhoptry proteins.