Induced Burkholderia prophages detected from the hemoculture: a biomarker for Burkholderia pseudomallei infection

Bacteriophages (phages), viruses that infect bacteria, are found in abundance not only in the environment but also in the human body. The use of phages for the diagnosis of melioidosis, a tropical infectious disease caused by Burkholderia pseudomallei, is emerging as a promising novel approach, but our understanding of conditions under which Burkholderia prophages can be induced remains limited. Here, we first demonstrated the isolation of Burkholderia phages from the hemocultures of melioidosis patients. The B. pseudomallei-positive hemoculture bottles were filtered to remove bacteria, and then phages were isolated and purified by spot and double agar overlay plaque assays. Forty blood samples (hemoculture-confirmed melioidosis) were tested, and phages were found in 30% of the samples. Transmission electron microscopy and genome analysis of the isolated phages, vB_HM387 and vB_HM795, showed that both phages are Myoviruses. These two phages were stable at a pH of 5-7 and temperatures of 25-37°C, suggesting their ability to survive in human blood. The genome sizes of vB_HM387 and vB_HM795 are 36.3 and 44.0 kb, respectively. A phylogenetic analysis indicated that vB_HM387 has homologs, but vB_HM795 is a novel Myovirus, suggesting the heterogeneity of Burkholderia phages in melioidosis patients. The key finding that Burkholderia phages could be isolated from the blood of melioidosis patients highlights the potential application of phage-based assays by detecting phages in blood as a pathogen-derived biomarker of infection.

Nanopore and Illumina sequencing reveal different viral populations from human gut samples

The advent of viral metagenomics, or viromics, has improved our knowledge and understanding of global viral diversity. High-throughput sequencing technologies enable explorations of the ecological roles, contributions to host metabolism, and the influence of viruses in various environments, including the human intestinal microbiome. However, bacterial metagenomic studies frequently have the advantage. The adoption of advanced technologies like long-read sequencing has the potential to be transformative in refining viromics and metagenomics. Here, we examined the effectiveness of long-read and hybrid sequencing by comparing Illumina short-read and Oxford Nanopore Technology (ONT) long-read sequencing technologies and different assembly strategies on recovering viral genomes from human faecal samples. Our findings showed that if a single sequencing technology is to be chosen for virome analysis, Illumina is preferable due to its superior ability to recover fully resolved viral genomes and minimise erroneous genomes. While ONT assemblies were effective in recovering viral diversity, the challenges related to input requirements and the necessity for amplification made it less ideal as a standalone solution. However, using a combined, hybrid approach enabled a more authentic representation of viral diversity to be obtained within samples.

A One Health Perspective on Salmonella enterica Serovar Infantis, an Emerging Human Multidrug-Resistant Pathogen

Salmonella enterica serovar Infantis presents an ever-increasing threat to public health because of its spread throughout many countries and association with high levels of antimicrobial resistance (AMR). We analyzed whole-genome sequences of 5,284 Salmonella Infantis strains from 74 countries, isolated during 1989-2020 from a wide variety of human, animal, and food sources, to compare genetic phylogeny, AMR determinants, and plasmid presence. The global Salmonella Infantis population structure diverged into 3 clusters: a North American cluster, a European cluster, and a global cluster. The levels of AMR varied by Salmonella Infantis cluster and by isolation source; 73% of poultry isolates were multidrug resistant, compared with 35% of human isolates. This finding correlated with the presence of the pESI megaplasmid; 71% of poultry isolates contained pESI, compared with 32% of human isolates. This study provides key information for public health teams engaged in reducing the spread of this pathogen.

Identification, activity and delivery of new LysFA67 endolysin to target cheese spoilage Clostridium tyrobutyricum

Bacteriophages and their endolysins are potential biocontrol agents for the anaerobic spoilage organism Clostridium tyrobutyricum, which causes cheese late blowing defect. This study sequenced and compared the genomes of eight bacteriophages from Spanish dairy farms that were active against C. tyrobutyricum, to identify novel species and phage proteins. Phages vB_CtyS-FA67 and vB_CtyS-FA70 shared >94% intergenomic similarity to each other but neither phage had significant similarity to ΦCTP1, the unique C. tyrobutyricum phage sequenced to date. Taxonomic analysis indicated that both phages belong to the class Caudoviricetes and are related to dsDNA viruses with long non-contractile tails. vB_CtyS-FA67 had no other close relatives and encoded a novel endolysin, LysFA67, predicted to belong to the glycoside hydrolase GH24 family. LysFA67 lysed 93% of C. tyrobutyricum cells after 4 min in turbidity reduction assays, retaining lytic activity at pHs 4.2-8.1 and at 30-45 °C. The endolysin remained stable after 30 d storage at 4, 12 and 25 °C, while its activity decreased at -20 °C. LysFA67 lysed several clostridia species, while common dairy bacteria were not affected. Lactococcus lactis INIA 437, used as a cheese starter, was engineered to deliver LysFA67 and red fluorescent LysFA67-mCherry to dairy products. We demonstrated that these engineered strains were able to maintain lytic activity and fluorescence without affecting their technological properties in milk.

Differential temporal release and lipoprotein loading in B. thetaiotaomicron bacterial extracellular vesicles

Bacterial extracellular vesicles (BEVs) contribute to stress responses, quorum sensing, biofilm formation and interspecies and interkingdom communication. However, the factors that regulate their release and heterogeneity are not well understood. We set out to investigate these factors in the common gut commensal Bacteroides thetaiotaomicron by studying BEV release throughout their growth cycle. Utilising a range of methods, we demonstrate that vesicles released at different stages of growth have significantly different composition, with early vesicles enriched in specifically released outer membrane vesicles (OMVs) containing a larger proportion of lipoproteins, while late phase BEVs primarily contain lytic vesicles with enrichment of cytoplasmic proteins. Furthermore, we demonstrate that lipoproteins containing a negatively charged signal peptide are preferentially incorporated in OMVs. We use this observation to predict all Bacteroides thetaiotaomicron OMV enriched lipoproteins and analyse their function. Overall, our findings highlight the need to understand media composition and BEV release dynamics prior to functional characterisation and define the theoretical functional capacity of Bacteroides thetaiotaomicron OMVs.

Genomic characterization of colistin-resistant Klebsiella pneumoniae isolated from intensive care unit patients in Egypt

BACKGROUND

Egypt has witnessed elevated incidence rates of multidrug-resistant Klebsiella pneumoniae infections in intensive care units (ICUs). The treatment of these infections is becoming more challenging whilst colistin-carbapenem-resistant K. pneumoniae is upsurging. Due to the insufficiently available data on the genomic features of colistin-resistant K. pneumoniae in Egypt, it was important to fill in the gap and explore the genomic characteristics, as well as the antimicrobial resistance, the virulence determinants, and the molecular mechanisms of colistin resistance in such a lethal pathogen.

METHODS

Seventeen colistin-resistant clinical K. pneumoniae isolates were collected from ICUs in Alexandria, Egypt in a 6-month period in 2020. Colistin resistance was phenotypically detected by modified rapid polymyxin Nordmann/Poirel and broth microdilution techniques. The isolates susceptibility to 20 antimicrobials was determined using Kirby-Bauer disk diffusion method. Whole genome sequencing and bioinformatic analysis were employed for exploring the virulome, resistome, and the genetic basis of colistin resistance mechanisms.

RESULTS

Out of the tested K. pneumoniae isolates, 82.35% were extensively drug-resistant and 17.65% were multidrug-resistant. Promising susceptibility levels towards tigecycline (88.24%) and doxycycline (52.94%) were detected. Population structure analysis revealed seven sequence types (ST) and K-types: ST383-K30, ST147-K64, ST17-K25, ST111-K63, ST11-K15, ST14-K2, and ST525-K45. Virulome analysis revealed yersiniabactin, aerobactin, and salmochelin siderophore systems in ˃ 50% of the population. Hypervirulence biomarkers, iucA (52.94%) and rmpA/A2 (5.88%) were detected. Extended-spectrum β-lactamase- and carbapenemase-producers accounted for 94.12% of the population, with blaCTX-M-15, blaNDM-5, and blaOXA-48 reaching 64.71%, 82.35%, and 82.35%, respectively. Chromosomal alterations in mgrB (82.35%) were the most prevailing colistin resistance-associated genetic change followed by deleterious mutations in ArnT (23.53%, L54H and G164S), PmrA (11.76%, G53V and D86E), PmrB (11.76%, T89P and T134P), PmrC (11.76%, S257L), PhoQ (5.88%, L322Q and Q435H), and ArnB (5.88%, G47D) along with the acquisition of mcr-1.1 by a single isolate of ST525.

CONCLUSIONS

In this study, we present the genotypic colistin resistance mechanisms in K. pneumoniae isolated in Egypt. More effective antibiotic stewardship protocols must be implemented by Egyptian health authorities to restrain this hazard and safeguard the future utility of colistin. This is the first characterization of a complete sequence of mcr-1.1-bearing IncHI2/IncHI2A plasmid recovered from K. pneumoniae clinical isolate belonging to the emerging high-risk clone ST525.

Application of TraDIS to define the core essential genome of Campylobacter jejuni and Campylobacter coli

Campylobacter species are the major cause of bacterial gastroenteritis. As there is no effective vaccine, combined with the rapid increase in antimicrobial resistant strains, there is a need to identify new targets for intervention. Essential genes are those that are necessary for growth and/or survival, making these attractive targets. In this study, comprehensive transposon mutant libraries were created in six C. jejuni strains, four C. coli strains and one C. lari and C. hyointestinalis strain, allowing for those genes that cannot tolerate a transposon insertion being called as essential. Comparison of essential gene lists using core genome analysis can highlight those genes which are common across multiple strains and/or species. Comparison of C. jejuni and C. coli, the two species that cause the most disease, identified 316 essential genes. Genes of interest highlighted members of the purine pathway being essential for C. jejuni whilst also finding that a functional potassium uptake system is essential. Protein-protein interaction networks using these essential gene lists also highlighted proteins in the purine pathway being major 'hub' proteins which have a large number of interactors across the network. When adding in two more species (C. lari and C. hyointestinalis) the essential gene list reduces to 261. Within these 261 essential genes, there are many genes that have been found to be essential in other bacteria. These include htrB and PEB4, which have previously been found as core virulence genes across Campylobacter species in other studies. There were 21 genes which have no known function with eight of these being associated with the membrane. These surface-associated essential genes may provide attractive targets. The essential gene lists presented will help to prioritise targets for the development of novel therapeutic and preventative interventions.

Genomic analysis of Elizabethkingia species from aquatic environments: Evidence for potential clinical transmission

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Identification of closely related (< 50 SNV) clinical and environmental aquatic Elizabethkingia anophelis isolates.

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Identification of a provisional novel species Elizabethkingia umaracha.

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Novel bla_GOB and bla_B carbapenemases and extended spectrum β-lactamase bla_CME alleles identified in Elizabethkingia spp.

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Analysis of the global phylogeny and pangenome of Elizabethkingia spp.

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Identification of novel ICE elements carrying uncharacterised genetic cargo in 67 / 94 (71.3%) of the aquatic environments Elizabethkingia spp.

Elizabethkingia species are ubiquitous in aquatic environments, colonize water systems in healthcare settings and are emerging opportunistic pathogens with reports surfacing in 25 countries across six continents. Elizabethkingia infections are challenging to treat, and case fatality rates are high. Chromosomal bla_B, bla_GOB and bla_CME genes encoding carbapenemases and cephalosporinases are unique to Elizabethkingia spp. and reports of concomitant resistance to aminoglycosides, fluoroquinolones and sulfamethoxazole-trimethoprim are known. Here, we characterized whole-genome sequences of 94 Elizabethkingia isolates carrying multiple wide-spectrum metallo-β-lactamase (bla_Band bla_GOB) and extended-spectrum serine‑β-lactamase (bla_CME) genes from Australian aquatic environments and performed comparative phylogenomic analyses against national clinical and international strains. qPCR was performed to quantify the levels of Elizabethkingia species in the source environments. Antibiotic MIC testing revealed significant resistance to carbapenems and cephalosporins but susceptibility to fluoroquinolones, tetracyclines and trimethoprim-sulfamethoxazole. Phylogenetics show that three environmental E. anophelis isolates are closely related to E. anophelis from Australian clinical isolates (∼36 SNPs), and a new species, E. umeracha sp. novel, was discovered. Genomic signatures provide insight into potentially shared origins and a capacity to transfer mobile genetic elements with both national and international isolates.

CoronaHiT: high-throughput sequencing of SARS-CoV-2 genomes

We present CoronaHiT, a platform and throughput flexible method for sequencing SARS-CoV-2 genomes (≤ 96 on MinION or > 96 on Illumina NextSeq) depending on changing requirements experienced during the pandemic. CoronaHiT uses transposase-based library preparation of ARTIC PCR products. Method performance was demonstrated by sequencing 2 plates containing 95 and 59 SARS-CoV-2 genomes on nanopore and Illumina platforms and comparing to the ARTIC LoCost nanopore method. Of the 154 samples sequenced using all 3 methods, ≥ 90% genome coverage was obtained for 64.3% using ARTIC LoCost, 71.4% using CoronaHiT-ONT and 76.6% using CoronaHiT-Illumina, with almost identical clustering on a maximum likelihood tree. This protocol will aid the rapid expansion of SARS-CoV-2 genome sequencing globally.

The power to detect regional declines in common bird populations using continental monitoring data

Anthropogenic environmental change is driving the rapid loss of biodiversity. Large declines in the abundance of historically common species are now emerging as a major concern. Identifying declining populations through long-term biodiversity monitoring is vital for implementing timely conservation measures. It is, therefore, critical to evaluate the likelihood that persistent long-term population trends of a given size could be detected using existing monitoring data and methods. Here, we test the power to detect declines in Australia's common landbirds using long-term citizen science monitoring. We use spatially explicit simulations of occupancy dynamics and virtual sampling, designed to mimic bird monitoring in better-sampled regions of Australia, to assess likely power in these data to detect trends relevant for conservation. We predict the statistical power for 326 common species that meet minimum requirements for monitoring data across 10 regions of Australia, estimating the number of species for which we would have a high (≥80%) chance of detecting declines of different sizes. The power to detect declines of ≥30% per decade was predicted to be high for at least one-third of the common species in 7 of 10 regions, with a total of 103 (32% of 326) unique species sufficiently monitored in at least one region. These species spanned 12 taxonomic orders, four orders of magnitude in body mass, and a broad diversity of dietary guilds, suggesting the current species pool will likely serve as robust indicators for a broad range of environmental states and pressures. Power was strongly affected by species' detectability, and power to detect even large declines was negligible when species are detected on ≤50% of visits to an occupied site. Predicted power for many species fell just short of the 80% threshold in one or more regions, which suggests an increase in effort targeting these species could greatly enhance the species and regional representation of these data. Against the backdrop of unprecedented biodiversity losses, this study shows how critical evaluation of existing monitoring schemes is valuable both for assessing the contribution of citizen science schemes to biodiversity monitoring and for designing strategic monitoring to significantly improve the knowledge these schemes provide.

Age-associated changes in the blood-brain barrier: comparative studies in human and mouse

Aims

While vascular pathology is a common feature of a range of neurodegenerative diseases, we hypothesized that vascular changes occur in association with normal ageing. Therefore, we aimed to characterize age‐associated changes in the blood–brain barrier (BBB) in human and mouse cohorts.

Methods

Immunohistochemistry and Evans blue assays were used to characterize BBB dysfunction (tight junction protein expression and serum plasma protein accumulation), vascular pathology (pericyte loss and vascular density) and glial pathology (astrocyte and microglial density) in ageing neurological control human prefrontal cortex (a total of 23 cases from 5 age groups representing the spectrum of young adult to old age: 20–30 years, 31–45 years, 46–60 years, 61–75 years and 75+) and C57BL/6 mice (3 months, 12 months, 18 months and 24 months, n = 5/6 per group).

Results

Quantification of the tight junction protein ZO‐1 within the cortex and cerebellum of the mouse cohort showed a significant trend to both increased number (cortex P < 0.001, cerebellum P < 0.001) and length (cortex P < 0.001, cerebellum P < 0.001) of junctional breaks associated with increasing age. GFAP expression significantly correlated with ageing in the mice (P = 0.037). In the human cohort, assessment of human protein accumulation (albumin, fibrinogen and human IgG) demonstrated cells morphologically resembling clasmatodendritic astrocytes, indicative of BBB dysfunction. Semiquantitative assessment of astrogliosis in the cortex expression revealed an association with age (P = 0.003), while no age‐associated changes in microglial pathology, microvascular density or pericyte coverage were detected.

Conclusions

This study demonstrates BBB dysfunction in normal brain ageing, both in human and mouse cohorts.

Chronic glucokinase activator treatment at clinically translatable exposures gives durable glucose lowering in two animal models of type 2 diabetes

BACKGROUND AND PURPOSE

Pharmacological activation of glucokinase (GK) lowers blood glucose in animal models and humans, confirming proof of concept for this mechanism. However, recent clinical evidence from chronic studies suggests that the glucose-lowering effects mediated by glucokinase activators (GKAs) are not maintained in patients with type 2 diabetes (T2D). Existing preclinical data with GKAs do not explain this loss of sustained glucose-lowering efficacy in patients. Here, we have assessed the effects of chronic (up to 11 months) treatment with two different GKAs in two models of T2D.

EXPERIMENTAL APPROACH

Two validated animal models of T2D, insulin-resistant obese Zucker rats and hyperglycaemic gk(wt/del) mice, were treated with two different GKAs for 1 or 11 months respectively at exposures that translate to clinical exposures in humans. Blood glucose, cholesterol, triglycerides and insulin were measured. GKA pharmacokinetics were also determined.

KEY RESULTS

Treatment with either GKA provided sustained lowering of blood glucose for up to 1 month in the Zucker rat and up to 11 months in hyperglycaemic gk(wt/del) mice, with maintained compound exposures. This efficacy was achieved without increases in plasma or hepatic triglycerides, accumulation of hepatic glycogen or impairment of glucose-stimulated insulin secretion.

CONCLUSIONS AND IMPLICATIONS

Chronic treatment with two GKAs in two animal models of diabetes provided sustained lowering of blood glucose, in marked contrast to clinical findings. Therefore, either these animal models of T2D are not good predictors of responses in human T2D or we need a better understanding of the consequences of GK activation in humans.

Characterization of the heterozygous glucokinase knockout mouse as a translational disease model for glucose control in type 2 diabetes

BACKGROUND AND PURPOSE

The global heterozygous glucokinase (GK) knockout (gk(wt/del)) male mouse, fed on a high-fat (60% by energy) diet, has provided a robust and reproducible model of hyperglycaemia. This model could be highly relevant to some facets of human type 2 diabetes (T2D). We aimed to investigate the ability of standard therapeutic agents to lower blood glucose at translational doses, and to explore the glucose-lowering potential of novel glucokinase activators (GKAs) in this model.

EXPERIMENTAL APPROACH

We measured the ability of insulin, metformin, glipizide, exendin-4 and sitagliptin, after acute or repeat dose administration, to lower free-feeding glucose levels in gk(wt/del) mice. Further, we measured the ability of novel GKAs, GKA23, GKA71 and AZD6370 to control glucose either alone or in combination with some standard agents.

KEY RESULTS

A single dose of insulin (1 unit·kg(-1)), metformin (150, 300 mg·kg(-1)), glipizide (0.1, 0.3 mg·kg(-1)), exendin-4 (2, 20 μg·kg(-1)) and GKAs reduced free-feeding glucose levels. Sitagliptin (10 mg·kg(-1)), metformin (300 mg·kg(-1)) and AZD6370 (30, 400 mg·kg(-1)) reduced glucose excursions on repeat dosing. At a supra-therapeutic dose (400 mg·kg(-1)), AZD6370 also lowered basal levels of glucose without inducing hypoglycaemia.

CONCLUSION AND IMPLICATIONS

Standard glucose-lowering therapeutic agents demonstrated significant acute glucose lowering in male gk(wt/del) mice at doses corresponding to therapeutic free drug levels in man, suggesting the potential of these mice as a translatable model of human T2D. Novel GKAs also lowered glucose in this mouse model.

Senescent cells: a novel therapeutic target for aging and age-related diseases

Aging is the main risk factor for most chronic diseases, disabilities, and declining health. It has been proposed that senescent cells--damaged cells that have lost the ability to divide--drive the deterioration that underlies aging and age-related diseases. However, definitive evidence for this relationship has been lacking. The use of a progeroid mouse model (which expresses low amounts of the mitotic checkpoint protein BubR1) has been instrumental in demonstrating that p16(Ink4a)-positive senescent cells drive age-related pathologies and that selective elimination of these cells can prevent or delay age-related deterioration. These studies identify senescent cells as potential therapeutic targets in the treatment of aging and age-related diseases. Here, we describe how senescent cells develop, the experimental evidence that causally implicates senescent cells in age-related dysfunction, the chronic diseases and disorders that are characterized by the accumulation of senescent cells at sites of pathology, and the therapeutic approaches that could specifically target senescent cells.

Possible involvement of GLP-1(9-36) in the regional haemodynamic effects of GLP-1(7-36) in conscious rats

BACKGROUND AND PURPOSE

The incretin hormone, glucagon-like peptide (GLP)-1(7-36), is rapidly cleaved by dipeptidyl peptidase 4 (DPP-4) into GLP-1(9-36), and although it is agreed that most, if not all, of the metabolic effects are attributable to the intact peptide, the degree to which the cardiovascular effects are due to the cleavage product is unclear. The purpose of this study was to measure the regional haemodynamic effects of GLP-1(7-36), and determine the extent to which the cardiovascular effects of GLP-1(7-36) were influenced by DPP-4 inhibition and reproduced by GLP-1(9-36). Additional experiments investigated the involvement of autonomic mechanisms in the cardiovascular effects of GLP-1(7-36).

EXPERIMENTAL APPROACH

Regional haemodynamic effects of bolus doses and 4 h infusions of GLP-1(7-36) amide and GLP-1(9-36) amide were measured in conscious, chronically instrumented rats; the influence of DPP-4 inhibition and autonomic blockade on responses to GLP-1(7-36) were also assessed.

KEY RESULTS

Glucagon-like peptide-1(7-36) had clear regional haemodynamic effects comprising tachycardia, a rise in blood pressure, renal and mesenteric vasoconstriction and hindquarters vasodilatation, whereas GLP-1(9-36) was devoid of any cardiovascular actions. The effects of GLP-1(7-36) were enhanced by DPP-4 inhibition, and the tachycardia and hindquarters vasodilatation were beta-adrenoceptor-mediated.

CONCLUSIONS AND IMPLICATIONS

In conscious rats, the cardiovascular effects of GLP-1(7-36) resemble those of the GLP analogue, exendin-4, and are attributable to the intact peptide rather than the cleavage product, GLP-1(9-36).

Surface modification of ZnO using triethoxysilane-based molecules

Zinc oxide (ZnO) is an important material for hybrid inorganic-organic devices in which the characteristics of the interface can dominate both the structural and electronic properties of the system. These characteristics can be modified through chemical functionalization of the ZnO surface. One of the possible strategies involves covalent bonding of the modifier using silane chemistry. Whereas a significant body of work has been published regarding silane attachments to glass and SiO2, there is less information about the efficacy of this method for controlling the surface of metal oxides. Here we report our investigation of molecular layers attached to polycrystalline ZnO through silane bonding, controlled by an amine catalyst. The catalyst enables us to use triethoxysilane precursors and thereby avoid undesirable multilayer formation. The polycrystalline surface is a practical material, grown by sol-gel processing, that is under active exploration for device applications. Our study included terminations with alkyl and phenyl groups. We used water contact angles, infrared spectroscopy, and X-ray photoemission spectroscopy to evaluate the modified surfaces. Alkyltriethoxysilane functionalization of ZnO produced molecular layers with submonolayer coverage and evidence of disorder. Nevertheless, a very stable hydrophobic surface with contact angles approaching 106 degrees resulted. Phenyltriethoxysilane was found to deposit in a similar manner. The resulting surface, however, exhibited significantly different wetting as a result of the nature of the end group. Molecular layers of this type, with a variety of surface terminations that use the same molecular attachment scheme, should enable interface engineering that optimizes the chemical selectivity of ZnO biosensors or the charge-transfer properties of ZnO-polymer interfaces found in oxide-organic electronics.

Mitotic regulation of the anaphase-promoting complex

Orderly progression through mitosis is regulated by the anaphase-promoting complex/cyclosome (APC/C), a large multiprotein E3 ubiquitin ligase that targets key mitotic regulators for destruction by the proteasome. APC/C has two activating subunits, Cdc20 and Cdh1. The well-established view is that Cdc20 activates APC/C from the onset of mitosis through the metaphase-anaphase transition, and that Cdh1 does so from anaphase through G1. Recent work, however, indicates that Cdh1 also activates APC/C in early mitosis and that this APC/C pool targets the anaphase inhibitor securin. To prevent premature degradation of securin, the nuclear transport factors Nup98 and Rae1 associate with APC/C(Cdh1)-securin complexes. In late metaphase, when all kinetochores are attached to spindle microtubules and the spindle assembly checkpoint is satisfied, Nup98 and Rae1 are released from these complexes, thereby allowing for prompt ubiquitination of securin by APC/C(Cdh1). This, and other mechanisms by which the catalytic activity of APC/C is tightly regulated to ensure proper timing of degradation of each of its mitotic substrates, are highlighted.

The Effect of the β2-Adrenoceptor Agonist Prodrug BRL-47672 on Cardiovascular Function, Skeletal Muscle Myosin Heavy Chain, and MyoD Expression in the Rat

The intracellular mechanisms that regulate changes in postnatal myosin heavy chain (MHC) expression are not well established. The major objective of this study was to examine the acute and chronic effects of administration of BRL-47672, the prodrug of the beta2-adrenoceptor agonist clenbuterol on MHC and MyoD transcription factor expression to determine whether or not changes in MHC composition are preceded by changes in MyoD protein expression. To assess to what extent the use of BRL-47672 minimized cardiovascular effects, its hemodynamic actions were compared with those of clenbuterol. The effect of BRL-47672 on heart rate, mean arterial blood pressure, and hindquarters vascular conductance was significantly less than that of clenbuterol after a single i.p. injection (250 microg kg(-1) body mass). In the main study, 4-week old rats were given BRL-47672 (900 microg kg(-1) body mass) or an equivalent volume of saline (control) daily for 1, 28, or 56 days. Soleus muscle (SOL) was excised and MHC and MyoD expression analyzed. After 4 weeks, SOL from the BRL-47672-treated animals had significantly faster MHC composition (49 +/- 2% MHCIIA) compared with those from the control animal (39 +/- 3% MHCIIA, P <0.05). MyoD expression increased by 40% after 1 day of BRL-47672 administration (P <0.05) before a change in MHC composition. In conclusion, these data suggest that increased expression of fast-type MHCIIA expression in rat SOL induced by BRL-47672 administration is preceded by changes in the level of MyoD transcription factor expression.

Possible therapeutic benefits of adenosine-potentiating drugs in reducing age-related degenerative disease in dogs and cats

Adenosine is a ubiquitous, biologically important molecule that is a precursor of other biologically active molecules. It also is a component of some co-factors and has distinct physiological actions in its own right. Levels are maintained by synthesis from dietary precursors and re-cycling. The daily turnover of adenosine is very high. Adenosine can act either as a hormone by binding to adenosine receptors, four adenosine receptor subtypes have been identified, and as an intracellular modulator, after transport into the cell by membrane transporter proteins. One of the principal intracellular actions of adenosine is inhibition of the enzyme phosphodiesterase. Extracellular adenosine also has specific neuromodulatory actions on dopamine and glutamate. Selective and nonselective agonists and antagonists of adenosine are available. The tasks of developing, evaluating and exploiting the therapeutic potential of these compounds is still in its infancy. Adenosine has actions in the central nervous system (CNS), heart and vascular system, skeletal muscle and the immune system and the presence of receptors suggests potential actions in the gonads and other organs. Adenosine agonists improve tissue perfusion through actions on vascular smooth muscle and erythrocyte fluidity and they can be used to improve the quality of life in aged dogs. This article reviews the therapeutic potential of adenosine-potentiating drugs in the treatment of age-related conditions in companion animals, some of which may be exacerbated by castration or spaying at an early age.

Comparative performance of herpes simplex virus type 2-specific serologic assays from Meridian Diagnostics and MRL diagnostics

MRL Diagnostics and Meridian Diagnostics have recently designed herpes simplex virus type 2 (HSV-2)-specific enzyme immunoassays for HSV-2 antibody detection. Blood donor sera were assayed for HSV-2 antibodies by both methods. The sensitivity, specificity, and efficiency were 97.9, 95.4, and 95.9% for the MRL assay and 83.2, 98.2, and 95.5% for the Meridian assay, respectively.

Six-year study of the incidence of herpes in genital and nongenital cultures in a central Kentucky medical center patient population

Herpes infections are among the most common sexually transmitted diseases and are the most common cause of genital ulcer disease in the United States. This study addresses the changing distribution of herpes simplex virus type 1 (HSV-1) and HSV-2 in patients presenting for evaluation of herpetic infections. Viral culture results from the University of Kentucky Clinical Microbiology Laboratory were reviewed for a 6-year period (1994 through 1999). Data were collected on patient sex, site of culture, and culture result. These data were analyzed statistically to identify yearly trends. Of the 4,498 cultures analyzed, nearly equal proportions of HSV-1 (13.3%) and HSV-2 (12.0%) were detected for an overall culture positivity rate of 25.3%. Approximately two-thirds of all positive cultures were from women. Although HSV-2 remained the predominant type of genital herpes, over the 6-year span of this study, there was a trend toward increasing proportions of HSV-1 genitalis, with 31.8% of male patients and 44.8% of female patients demonstrating HSV-1 genitalis by 1999. The majority of patients with HSV in nongenital sites grew HSV-1. Although there was significant yearly variation, HSV-2 was isolated from only 9.4% of patients with nongenital HSV for the entire 6-year period. This study therefore concludes that HSV-2 remains primarily a genital pathogen, while HSV-1 is taking on an increasingly important role in causing genital ulcer disease in addition to being the primary nongenital HSV.

Evidence for hyaluronan production in the air pouch model in rats

OBJECTIVE

The aim of our work was to investigate the presence of hyaluronan (HA) in the rat air pouch and its behaviour in response to inflammatory stimuli.

METHODS

HA levels (by a microplate assay) and the leucocyte count were determined in the fluid obtained from air pouches in which acute or subacute inflammation had been induced by the injection of monosodium urate crystals (MSU) or high density polyethylene (HDPE) debris respectively and in relative controls.

RESULTS

In control pouches of both groups, remarkable levels of HA were found; these levels were higher in the very first hours (2475 and 1850 micrograms/l at 6 hrs) and then gradually decreased. In pouches injected with MSU, HA moderately increased (p < 0.001) after 6 hrs, reached a peak after 12 hrs (p < 0.001) and began to taper at 24 hrs (p < 0.001). The leucocyte count was also increased at 6 hrs (p < 0.001), became higher at 12 hrs (p < 0.001) and tapered at 24 hrs (p < 0.001). In the HDPE pouches, HA levels were significantly reduced with respect to controls after 6 hours (p < 0.001), increasing later (p < 0.001) to reach a peak at 24 hrs (p < 0.001), and returning to the original levels, or even below, in the following 72 hours.

CONCLUSIONS

These data confirm that the pouch lining produces fair amounts of HA and provide evidence that, in this system, HA levels seem to be influenced by the degree of inflammation even if with variable behaviour in relation to the different characteristics and phases of phlogosis. The present data suggest that the air pouch is a useful experimental model for studies on HA metabolism in either acute or chronic inflammation.

Toxic trauma

Hazardous materials (HAZMAT) carry many inherent dangers. Such materials are distributed widely in industrial and military sites. Toxic trauma (TT) denotes the complex of systemic and organ injury caused by toxic agents. Often, TT is associated with other injuries that also require the application of life-support techniques. Rapid onset of acute respiratory failure and consequent cardiovascular failure are of primary concern. Management of TT casualties is dependent upon the characteristics of the toxic agents involved and on the demographics surrounding the HAZMAT incident. Agents that can produce TT possess two pairs of salient characteristics: (1) causality (toxicity and latency), and (2) EMS system (persistency and transmissibility). Two characteristics of presentations are important: (1) incident presentation, and (2) casualty presentation. In addition, many of these agents complicate the processes associated with anaesthesia and must be dealt with. Failure of recognition of these factors may result in the development of respiratory distress syndromes and multiorgan system failure, or even death.

Resident-directed communication patterns in community homes for persons with disabilities

A descriptive assessment of environmental variables influencing patterns of staff communication with people living in three community-based residential facilities supporting persons with disabilities was presented. Each of the 16 participating staff persons was observed for 2 hours, and all resident-directed communication behaviors were coded according to staff person, activity context, and resident. Statistical analyses were performed examining frequencies of interaction across these variables. Frequencies of communication were found to differ across activities and residents (communicative partners), but not staff persons or homes. Directions for future research and clinical implications are given, including the development of a model of staff performance and the creation of self-reinforcing social communities in residential settings for persons with disabilities.

Risk factors for equine influenza serum antibody titres in young thoroughbred racehorses given an inactivated vaccine

Young Thoroughbred racehorses (222 yearlings entering training and 246 2-year-old horses already in training) from eight flat-training yards in Newmarket, UK were used to monitor serological responses to vaccination with an inactivated influenza virus vaccine. Blood samples taken prior to and after vaccination were tested by single radial haemolysis (SRH) to determine antibody titres (expressed as area of haemolysis in mm(2)). Prior to vaccination, yearlings had mean antibody titres (64+/-4 mm(2)) that were approximately half of those of 2-year-olds (115+/-3 mm(2)) and 89% of yearlings and 73% of 2-year-olds had SRH titres <140 mm(2). Extrapolation from experimental and field studies suggests that these levels would not protect against homologous influenza virus infection. Both age-groups showed anamnestic responses to vaccination resulting in similar peak mean titres ( approximately 160+/-2mm(2)) with 67% of yearlings and 73% of 2-year-olds achieving levels > or =140 mm(2). A second dose of vaccine administered a month after the first in yearlings did not increase the mean titre but 75% of horses had levels of antibody > or =140 mm(2). The vaccination history in the official passport of yearlings showed that 23% had no record of previous vaccination and were probably fully susceptible to infection. For yearlings entering training, the important predictors from multiple-regression analyses of SRH titres prior to vaccination were "Time since last vaccination," "Total number of previous vaccines" and "Age at first vaccination." In 2-year-olds and following two doses of vaccine in yearlings, there was no significant relationship between these factors and SRH titre.

Zygomycetes in human disease

The Zygomycetes represent relatively uncommon isolates in the clinical laboratory, reflecting either environmental contaminants or, less commonly, a clinical disease called zygomycosis. There are two orders of Zygomycetes containing organisms that cause human disease, the Mucorales and the Entomophthorales. The majority of human illness is caused by the Mucorales. While disease is most commonly linked to Rhizopus spp., other organisms are also associated with human infection, including Mucor, Rhizomucor, Absidia, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. Although Mortierella spp. do cause disease in animals, there is no longer sufficient evidence to suggest that they are true human pathogens. The spores from these molds are transmitted by inhalation, via a variety of percutaneous routes, or by ingestion of spores. Human zygomycosis caused by the Mucorales generally occurs in immunocompromised hosts as opportunistic infections. Host risk factors include diabetes mellitus, neutropenia, sustained immunosuppressive therapy, chronic prednisone use, iron chelation therapy, broad-spectrum antibiotic use, severe malnutrition, and primary breakdown in the integrity of the cutaneous barrier such as trauma, surgical wounds, needle sticks, or burns. Zygomycosis occurs only rarely in immunocompetent hosts. The disease manifestations reflect the mode of transmission, with rhinocerebral and pulmonary diseases being the most common manifestations. Cutaneous, gastrointestinal, and allergic diseases are also seen. The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins. If the diagnosis is not made early, dissemination often occurs. Therapy, if it is to be effective, must be started early and requires combinations of antifungal drugs, surgical intervention, and reversal of the underlying risk factors. The Entomophthorales are closely related to the Mucorales on the basis of sexual growth by production of zygospores and by the production of coenocytic hyphae. Despite these similarities, the Entomophthorales and Mucorales have dramatically different gross morphologies, asexual reproductive characteristics, and disease manifestations. In comparison to the floccose aerial mycelium of the Mucorales, the Entomophthorales produce a compact, glabrous mycelium. The asexually produced spores of the Entomophthorales may be passively released or actively expelled into the environment. Human disease with these organisms occurs predominantly in tropical regions, with transmission occurring by implantation of spores via minor trauma such as insect bites or by inhalation of spores into the sinuses. Conidiobolus typically infects mucocutaneous sites to produce sinusitis disease, while Basidiobolus infections occur as subcutaneous mycosis of the trunk and extremities. The Entomophthorales are true pathogens, infecting primarily immunocompetent hosts. They generally do not invade blood vessels and rarely disseminate. Occasional cases of disseminated and angioinvasive disease have recently been described, primarily in immunocompromised patients, suggesting a possible emerging role for this organism as an opportunist.

The pre-hospital management of injury following mass toxic release; a comparison of military and civil approaches

Mass release of toxic substances may occur either accidentally or deliberately in both peace and war. Different approaches to the management of casualties from such an event have been developed by civil and military emergency medical teams, and reflect the different circumstances in which they operate. The nature and classification of toxic hazards is considered and the civil and military operational and medical responses compared. Both systems have different aspects that can contribute to early casualty management in a contaminated environment.

Management of respiratory failure in toxic disasters

Accidental or deliberate release of toxic substances may be a cause of mass casualties, some of which may involve partial or complete respiratory failure. Life support measures may be delayed by the need for containment of the toxic release and decontamination. Advanced life support (ALS) may be provided in such circumstances using the TOXALS protocol. With proper training and equipment, emergency medical personnel can provide effective prehospital care during decontamination of chemical casualties.

Clinical analogies for the management of toxic trauma

The management of injuries from toxic release (HAZMAT) incidents is unfamiliar to many emergency medical responders owing to the relative rarity of such incidents. However, the risks from toxic release in both industrial and other metropolitan areas are increasing and emergency medical services (EMS) personnel should be trained to be aware of the dangers to both victims and responders alike. Many examples exist of analogies for the management of HAZMAT situations from conventional prehospital and hospital emergency medicine. Application of the lessons learned in more familiar situations will be of benefit for the preparation of an effective EMS response for HAZMAT.

Linear childhood discoid lupus erythematosus following the lines of Blaschko: a case report with review of the linear manifestations of lupus erythematosus

Seventeen cases of childhood discoid lupus erythematosus (DLE) have been previously reported in the literature. We describe the first reported case of childhood linear DLE following the lines of Blaschko. The clinical and histologic characteristics of childhood DLE are discussed and a review of the linear manifestations of childhood LE is presented.

Initiating a chaplaincy program for a hospital police department

The authors discuss the creation of a police chaplain program at their hospital--why it was needed, the preparations that were necessary, the recruitment process, and the important role the police chaplain plays.

The production and characterisation of an immobilised chaperonin system

Here we report a method of immobilising the chaperonins GroEL and GroES to a glass matrix. The immobilised chaperone system has been used to successfully refold target proteins denatured by guanidine hydrochloride and produce substantially higher levels of active protein than occur on dilution into aqueous solution alone. The chaperone system has been shown to refold proteins from each of the three categories of GroEL substrate. The refolding of the enzyme glycerol dehydrogenase from Bacillus stearothermophilus shows a two-fold increase in activity in the presence of immobilised GroEL compared to that in free solution. The lactate dehydrogenase from B. stearothermophilus also shows a two-fold higher yield of activity in the presence of the immobilised GroEL and ATP. The presence of immobilised GroEL in the absence of ATP arrests the refolding of LDH. The enzyme citrate synthetase from porcine heart demonstrates a three-fold increase in activity when refolded in the presence of immobilised GroEL, ATP and free GroES. Similar results are obtained in the presence of free GroEL, immobilised GroES and ATP. The matrix-bound chaperone can be removed from the refolding mixture by centrifugation, producing a reusable system that can be easily isolated and purified from the refolded substrate.

Evaluation of an immunoseparation method for quantitative measurement of remnant-like particle-cholesterol in serum and plasma

Substantial evidence indicates that triglyceride-rich lipoprotein remnants are atherogenic. Additional research has, however, been limited by available methods for separation and quantification of remnants. We have evaluated an immunoseparation assay developed to measure cholesterol in remnant-like particles (RLP-C). This method uses monoclonal antibodies to human apolipoproteins B-100 and A-I to remove most of the apolipoprotein B-100-containing lipoproteins (namely LDL and nascent VLDL) and apolipoprotein A-I-containing lipoproteins (namely chylomicrons and HDL), leaving behind a fraction of triglyceride-rich lipoproteins, including chylomicron and VLDL remnants, both of which are enriched in apolipoprotein E. Cholesterol in the unbound fraction is measured with a sensitive enzymatic assay. The RLP-C concentration was highly correlated with total triglyceride-rich lipoproteins (sum of VLDL-cholesterol and IDL-cholesterol) separated by ultracentrifugation and by polyacrylamide gel electrophoresis (r = 0.86 and 0.76, respectively). The within-run and run-to-run imprecision (CV) of the assay was approximately 6% and 10%, respectively. The assay was not affected by hemoglobin up to 5000 mg/L (500 mg/dL), bilirubin up to 342 mmol/L (20 mg/dL), glucose up to 67 mmol/L (1200 mg/dL), or ascorbic acid up to 170 mmol/L (3.0 mg/dL). In 726 subjects (men, n = 364; women, n = 362) in the US, the 75th percentiles of RLP-C concentration were 0.17 mmol/L (6.6 mg/dL) and 0.23 mmol/L (8.8 mg/dL) in sera obtained after overnight fasting or randomly, respectively. A group of 151 patients from nine US centers and one Canadian center with coronary artery atherosclerosis established by angiography had higher median RLP-C concentrations than 302 gender- and age-matched controls (P <0.05). We conclude that the RLP-C assay compares favorably to ultracentrifugation and electrophoresis and provides a convenient and economical approach to measure triglyceride-rich lipoprotein remnants in routine clinical laboratories.

Case study: shaken baby syndrome--one disorder with two victims

Shaken Baby Syndrome is a complex disorder with implications for family members (especially the victim's mother) that are felt long after the emergency diagnosis and treatment of the child are concluded. The authors conducted a Women's Support Group for parolees over a two year period. Included in its group membership were several women who had been jailed for child abuse related crimes. This article synthesizes the significant progress in the research from the medical, legal, social, nursing, and preventive health perspectives on Shaken Baby Syndrome. A case study is used to illustrate the phenomenon of victimization of the mother, typically the nonoffending parent in Shaken Baby Syndrome. The difficulties of diagnosing Shaken Baby Syndrome in a timely manner are presented with emphasis on the diagnostic ambiguities confronting the various medical and nursing providers and nonoffending perpetrators. The case study attempts to raise the consciousness of nurses, with whom the nonoffending parents come into contact in the vast array of health service settings, as well as provide specific recommendations for enhancing community health nursing practice.

Effects of video-based staff training with manager-led exercises in residential support

The effectiveness of video-based staff training with manager-led exercises in improving staff performance in residential support for persons with disabilities was examined. Research staff assisted two residential program managers to implement staff training in health and safety, basic support, and residential support values. Results showed improvement in (a) staff members' washing hands when appropriate, (b) wearing gloves when appropriate, and (c) frequency of positive interactions with residents. These changes in staff behavior maintained over a 6-month follow-up. Following the values training, in one house, brief increases were observed in frequency of residents' community activities. These changes did not maintain. No improvements in these measures were noted in the other house. Implications of these findings for assurance of competent staff performance with residents were discussed.

Stalling of human DNA (cytosine-5) methyltransferase at single-strand conformers from a site of dynamic mutation

Single-strand conformers (SSCs) from the C-rich strand of the triplet repeat at the FMR-1 locus are rapidly and selectively methylated by the human DNA (cytosine-5) methyltransferase. The apparent affinity of the enzyme for the FMR-1 SSC is about tenfold higher than it is for a control Watson-Crick paired duplex. The de novo methylation rate for the SSC is over 150-fold higher than the de novo rate for the control duplex. Methylation of what is generally called a hemi-methylated duplex occurs with a rate enhancement of over 100-fold, while methylation of what can be viewed as a hemi-methylated FMR-1 SSC is actually slower than the de novo rate. The pronounced inhibition of the methyltransferase by the methylated SSC suggests that the enzyme has a higher affinity for the methylated product of its reaction with the SSC than it has for the unmethylated SSC substrate. Gel retardation studies show that the methyltransferase binds selectively to SSCs from the C-rich strand of the FMR-1 triplet repeat. This suggests a two-step stalling process in which the human methyltransferase first selectively methlyates and subsequently stalls at the C-rich strand SSC. Stalling may reflect the inability of the enzyme to release a DNA product that is fixed in a conformation resembling its transition state by the unusual structure of the substrate. In particular, the data suggest that DNA methyltransferase may physically participate in biological processes that lead to dynamic mutation at FMR-1. In general, the data raise the possibility that a two-step stalling process occurs at secondary structures associated with chromosome instability, chromosome remodelling, viral replication or viral integration and may account for the local hypermethylation and global hypomethylation associated with viral and non-viral tumorigenesis.

Growth of Pakistani children in relation to the 1990 growth standards

This study was designed to compare the growth of Pakistani schoolchildren in the UK with the 1990 UK growth standards. Measurements of height, weight, and sitting height were performed on 785 Pakistani schoolchildren aged 5-14 years with the mean values for each age and sex being plotted on the UK growth standards. The results were expressed as SD scores relative to the 1990 reference data. The mean height for the boys was only 0.2 SD scores below the mean for the new growth standards with the mean height for the girls being 0.4 SD scores below the mean. The mean values for weight and body mass index were 0.3 and 0.5 SD scores less than the mean for boys and girls respectively. This study demonstrates that the growth of Pakistani schoolchildren in the UK is comparable to the 1990 UK growth standards with only minor differences. It is not safe to assume that short stature or low body weight in a Pakistani child is due to his or her ethnic background.

Reproductive laboratory technology: an alternative career

OBJECTIVES

Define the job description for reproductive laboratory technologist (RLT); describe the RLT laboratory setting; identify education level and certification of the respondents; establish level of job satisfaction and job security; determine if certification and position affect performance and job satisfaction; compare RLT job with any previous clinical laboratory position; and document education and training important for the position.

SURVEY INSTRUMENT

A questionnaire was developed with questions targeted to answer objectives. SURVEY POPULATION: The questionnaire was mailed to a random sample of 300 non-physician members from the Reproductive Biology Professional Group and the Reproductive Laboratory Technology Group from membership lists provided by the American Society for Reproductive Medicine.

STUDY POPULATION

81 survey respondents.

RESULTS

RLTs are mostly college-educated, certified and non-certified laboratory professionals, trained on the job for specialty work in andrology and assisted reproductive technology (ART). Position, but not certification, correlate with job performance and job satisfaction. Respondents describe the position of RLT as stressful, but very interesting, exciting, fulfilling, and secure. Respondents with previous clinical laboratory experience rated level of job satisfaction higher for the reproductive laboratory. The CLS curriculum is an excellent background for RLT.

CONCLUSIONS

RLT is an exciting career alternative for CLSs. Newly formed laws and regulations, and the demand for more stringent regulation, will continue to increase the demand for certified CLSs for this position. Formal education and certification requirements are anticipated for RLT. The specialty is being incorporated in CLS training programs.