Development of monoclonal antibodies against Vibrio pathogens

Monoclonal antibodies were developed against pathogenic vibrios for use in rapid identification in disease situations of humans, fish and shellfish. Of the 12 fusions performed using V. alginolyticus, V. anguillarum, V. carchariae, V. cholerae, V. damsela, V. furnissii, V. harveyi, V. ordalii, V. parahaemolyticus and V. vulnificus, a total of 102 hybridomas were obtained. Based on cross-reactivity of a wide range of Vibrio strains and other gram-negative bacteria, three broad types of monoclonal antibodies were found. The three categories were: (1) ones that were species-specific or specific to a particular surface antigen, (2) a large number that reacted with several Vibrio species, and (3) three that reacted with most Vibrio strains but no other gram-negative bacteria. Each species-specific monoclonal antibody only recognized its corresponding Vibrio species and was used for identifying unknown species, confirming diagnosis of clinical isolates. In addition, several monoclonal antibodies only cross-reacted with similar Vibrio species, e.g. V. parahaemolyticus and V. alginolyticus which share a common H-antigen. Monoclonal antibodies reacting with several Vibrio species were not of particular use in diagnostic situations. Three monoclonal antibodies of the last group did not react with other genera of the family Vibrionaceae, namely Aeromonas, Photobacterium and Plesiomonas nor a wide range of gram-negative enteric bacteria. These data indicated the existence of an antigenic surface determinant common to Vibrio species. One monoclonal reacted with the heat-stable antigenic determinants on the cell surface as v as lipopolysaccharide extracted from all the vibrios studied, thus making it useful for large- scale screening of acute infections of vibrios. In a blind test, seven Vibrio species, isolated from 6 marine and a freshwater source were identified by two laboratories using phenetic tests. Results of immunotyping using monoclonals, three of seven were diagnosed as the same species, another three were designated as Vibrio species but could not be classified further due to the library not having the corresponding monoclonal, and one was diagnostically questionable. Two further tests were carried out. An unknown Vibrio formalin-fixed isolated from diseased marine animal was identified as V. parahaemolyticus by ELISA and FITC. Clinical human isolates of V. alginolyticus, V. parahaemolyticus and V. vulnificus were confirmed by monoclonals. Australian isolates of V. anguillarum appeared to be mostly of serotype O1. monoclonals raised to V. anguillarum AFHRL 1 reacted with only serotype O1 from Denmark but also most Australian isolates. All vibrios pathogenic to fish and shellfish, i.e. V. anguillarum, V. ordalii, V. alginolyticus, V. carchariae, V. cholerae, V. damsela, V. harveyi, V. parahaemolyticus and V. vulnificus, were used for attachment studies to fish cells using phase contrast and FITC-immunofluorescence microscopy. Of these vibrios, V. anguillarum, V. ordalii and V. perahaemolyticus, were found to adhere to different cells and tissues of rainbow trout while others did not appear to attach. However, attachment was inhibited by monoclonal antibodies specific to only these three vibrios. Lipopolysaccharide is well known as being a contributing factor in pathogenicity of gram-negative bacteria. PAGE electrophoresis of extracted LPS from 9 strains covering 6 Vibrio species showed the presence of a common 15,000 D fragment. This fragment was verified by immunoblotting with a genus-specific monoclonal antibody (i.e. F11P411F) recognizing nearly all vibrios. The common LPS fragment was separated and used to raise polyclonal antisera in mouse which reacted strongly with LPS itself, live as well as sodium azide-killed vibrios, but not with other gram-negative bacteria. This raised the possibility of developing vaccine from Vibrio LPS. Monoclonal antibodies developed in the present study enabled rapid identification of a number of pathogenic Vibrio species. There is still further work to produce monoclonal antibodies against additional vibrios that are probably pathogenic. These included V. fluvialis, V. hollisae, V. metschnikovii, V. minicus, V. salmonella and V. tubiashii. Together the application will be of significance in clinical diagnostic work, in the monitoring of vibriosis in fish farms and in quarantine.

Determinants of bone density in 30- to 65-year-old women: A co-twin study

Introduction: Reported effects of body composition and lifestyle of bone mineral density in pre-elderly adult women have been inconsistent.

Methods: In a co-twin study of 146 female twin pairs aged 30 to 65 years, DXA was used to measure bone mineral density at the lumbar spine, total hip, and forearm, total body bone mineral content, and lean and fat mass. Height and weight were measured. Menopausal status, dietary calcium intake, physical activity, current tobacco use, and alcohol consumption were determined by questionnaire. Within-pair differences in bone measures were regressed through the origin against within-pair differences in putative determinants.

Results: Lean mass and fat mass were associated with greater bone mass at all sites. A discordance of 10 pack-years smoking was related to a 2.3-3.3% (SE, 0.8-1.0) decrease in bone density at all sites except the forearm, with the effects more evident in postmenopausal women. In all women, a 0.8% (SE, 0.3) difference in hip bone mineral density was associated with each hour per week difference in sporting activity, with effects more evident in premenopausal women. Daily dietary calcium intake was related to total body bone mineral content and forearm bone mineral density (1.4 ± 0.7% increase for every 1000 mg). Lifetime alcohol consumption and walking were not consistently related to bone mass.

Conclusion: Several lifestyle and dietary factors, in particular tobacco use, were related to bone mineral density. Effect sizes varied by site. Characterization of determinants of bone mineral density in midlife and thereafter may lead to interventions that could minimize postmenopausal bone loss and reduce osteoporotic fracture risk.

Discharge planning: from the acute sector for people over the age of 65

This paper reports the findings relating to discharge planning from a larger study (Hegney et al 2001) that aimed to investigate options to improve care co-ordination between the aged, community, acute and primary care sectors for the elderly residents of a large provincial town. The data, which were collected from a wide variety of aged care stakeholders in the region, are consistent with previous Australian studies. First, it appears that inappropriate discharge from acute hospitals occurs in Toowoomba because there is a perceived lack of information regarding the available community care options and a lack of suitable models to support people's care needs within their own homes. Second, inappropriate discharge practices from acute hospitals occur due to a lack of knowledge and communication on the part of health professionals employed in these settings with regard to the on- going health care needs of elderly people. Third, there is little discharge planning occurring that includes the general practitioner in post-discharge care. Finally, inappropriate discharge can also be attributed to the lack of sub-acute/step-down/rehabilitation options and long waiting lists for community home care services in the region.

Quality of life amongst people over 65 years of age : does constipation make a difference?

Aims
The aims of this study was to determine whether quality of life for people 65 years and over is affected by constipation and laxative use and to identify dimensions or functions of quality of life that were specifically affected by constipation.

Method
Of the 79 subjects who completed the pre-screening questionnaire to determine their bowel function and laxative use status , 58 agreed to participate in the phase of the study (73%) of which 22 were females and 36 were males. Subjects completed a quality of life questionnaire, comprising of ComQoL questions and SF36 questions during a face to face interview conducted in their own homes.

Results
ComQoL importance and satisfaction scores were compared by bowel health status and gender. The most important dimensions for all subjects were health (mean score 9.4), family (mean score 9.3) and their own happiness (mean score 8.7). The total mean for satisfaction score for the whole group was 69%, fractionally lower that the bottom end of the normative range (70-80%). Constipated subjects scored satisfaction with their health significantly lower than the not constipated group (p =0.02) and subjects who took laxatives once a fortnight or more also had significantly lower satisfaction with their health (p=0.03).

Conclusion
Overall the subjects reported a high level of satisfaction with their lives, constipation and laxative use affected their satisfaction with their health. Further exploration is needed to determine how this will affect lifestyle and health behaviours.

Fluoride-assisted synthesis of mullite (Al5.65 Si0.35 O9.175) nanowires

Novel silicon-deficient mullite (Al_5.65Si_0.35O_9.175) single crystal nanowires were synthesized in large quantities on mica substrates assisted by the intermediate fluoride species. The nanowires have diameters in the range 50–100 nm and typical lengths of several µm. Aligned nanowires were observed at the substrate edge. The nanowires have strong photoluminescence (PL) emission bands at 310, 397, 452 and 468 nm.

Probing the flexibility of the DsbA oxidoreductase from Vibrio cholerae - a 15N -1H heteronuclear NMR relaxation analysis of oxidised and reduced forms of DsbA

We have determined the structure of the reduced form of the DsbA oxidoreductase from Vibrio cholerae. The reduced structure shows a high level of similarity to the crystal structure of the oxidized form and is typical of this class of enzyme containing a thioredoxin domain with an inserted α-helical domain. Proteolytic and thermal stability measurements show that the reduced form of DsbA is considerably more stable than the oxidized form. NMR relaxation data have been collected and analyzed using a model-free approach to probe the dynamics of the reduced and oxidized states of DsbA. Akaike's information criteria have been applied both in the selection of the model-free models and the diffusion tensors that describe the global motions of each redox form. Analysis of the dynamics reveals that the oxidized protein shows increased disorder on the pico- to nanosecond and micro- to millisecond timescale. Many significant changes in dynamics are located either close to the active site or at the insertion points between the domains. In addition, analysis of the diffusion data shows there is a clear difference in the degree of interdomain movement between oxidized and reduced DsbA with the oxidized form being the more rigid. Principal components analysis has been employed to indicate possible concerted movements in the DsbA structure, which suggests that the modeled interdomain motions affect the catalytic cleft of the enzyme. Taken together, these data provide compelling evidence of a role for dynamics in the catalytic cycle of DsbA.

Socio-economic inequalities in mortality persist into old age in New Zealand : study of all 65 years plus, 2001-04

A number of studies have explored the relationship between socioeconomic status (SES) and mortality, although these have mostly been based on the working age population, despite the fact that the burden of mortality is highest in older people. Using Poisson regression on linked New Zealand census and mortality data (2001 to 2004, 1.3 million person years) with a comprehensive set of socioeconomic indicators (education, income, car access, housing tenure, neighourhood deprivation) we examined the association of socioeconomic characteristics and older adult mortality (65+ years) in New Zealand. We found that socioeconomic mortality gradients persist into old age. Substantial relative risks of mortality were observed for all socioeconomic factors, except housing tenure. Most relative risk associations decreased in strength with aging (e.g. most deprived compared to least deprived rate ratio for males reducing from 1.40 (95% CI 1.28 to 1.53) for 65-74 year olds to 1.13 (1.00 to 1.28) for 85+ year olds), except for income and education among women where the rate ratios changed little with increasing age. This suggests individual level measures of SES are more closely related to mortality in older women than older men. Comparing across genders, the only statistically significantly different association between men and women was for a weaker association for women for car access.

Associations between the perceived environment and physical activity among adults aged 55-65 years : does urban-rural area of residence matter?

This study aimed to determine whether associations between the perceived environment and physical activity are moderated by urban-rural status among midolder aged adults. Environmental (safety, aesthetics, physical activity environment) and physical activity (total, leisure, transport) data from 3,888 adults (55 to 65 years) from urban and rural areas of Victoria, Australia, were analyzed. Multinomial logistic regression examined interactions between urban-rural status and environments in associations with physical activity. Significant (P < .05) interactions were evident and indicated positive associations only among older rural adults for both safety and aesthetics with total and transport physical activity (e.g., rural adults reporting higher safety were 91% to 118% more likely to have higher activity than rural adults reporting low safety). In contrast, the physical activity environment was positively associated with leisure activity among only urban adults. Findings suggest that some tailoring of physical activity promotion strategies targeting the environment may be required for urban and rural midolder aged adults.