The burden of end-stage osteoarthritis in Australia: a population-based study on the incidence of total knee replacement attributable to overweight/obesity

OBJECTIVES

To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population.

METHODS

This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015 and 2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence.

RESULTS

The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 14,287 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category.

CONCLUSIONS

Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided.

Pain, Analgesic Use, and Patient Satisfaction With Spinal Versus General Anesthesia for Hip Fracture Surgery : A Randomized Clinical Trial

BACKGROUND

The REGAIN (Regional versus General Anesthesia for Promoting Independence after Hip Fracture) trial found similar ambulation and survival at 60 days with spinal versus general anesthesia for hip fracture surgery. Trial outcomes evaluating pain, prescription analgesic use, and patient satisfaction have not yet been reported.

OBJECTIVE

To compare pain, analgesic use, and satisfaction after hip fracture surgery with spinal versus general anesthesia.

DESIGN

Preplanned secondary analysis of a pragmatic randomized trial. (ClinicalTrials.gov: NCT02507505).

SETTING

46 U.S. and Canadian hospitals.

PARTICIPANTS

Patients aged 50 years or older undergoing hip fracture surgery.

INTERVENTION

Spinal or general anesthesia.

MEASUREMENTS

Pain on postoperative days 1 through 3; 60-, 180-, and 365-day pain and prescription analgesic use; and satisfaction with care.

RESULTS

A total of 1600 patients were enrolled. The average age was 78 years, and 77% were women. A total of 73.5% (1050 of 1428) of patients reported severe pain during the first 24 hours after surgery. Worst pain over the first 24 hours after surgery was greater with spinal anesthesia (rated from 0 [no pain] to 10 [worst pain imaginable]; mean difference, 0.40 [95% CI, 0.12 to 0.68]). Pain did not differ across groups at other time points. Prescription analgesic use at 60 days occurred in 25% (141 of 563) and 18.8% (108 of 574) of patients assigned to spinal and general anesthesia, respectively (relative risk, 1.33 [CI, 1.06 to 1.65]). Satisfaction was similar across groups.

LIMITATION

Missing outcome data and multiple outcomes assessed.

CONCLUSION

Severe pain is common after hip fracture. Spinal anesthesia was associated with more pain in the first 24 hours after surgery and more prescription analgesic use at 60 days compared with general anesthesia.

PRIMARY FUNDING SOURCE

Patient-Centered Outcomes Research Institute.

OP0226 TRAJECTORIES OF BODY MASS INDEX FROM EARLY ADULTHOOD TO LATE MIDLIFE AND INCIDENCE OF TOTAL KNEE ARTHROPLASTY FOR OSTEOARTHRITIS: FINDINGS FROM A PROSPECTIVE COHORT STUDY

Background

There is limited evidence regarding the association between trajectories of body mass index (BMI) across adulthood and knee osteoarthritis.

Objectives

We examined the association between body mass index (BMI) trajectories across early adulthood to midlife and risk of total knee arthroplasty (TKA) for osteoarthritis.

Methods

This study examined 24,368 participants (40-70 years at recruitment) in the Melbourne Collaborative Cohort Study who had weight collected at 1990–1994, 1995–1998, and 2003–2007 and recalled weight at age 18–21 years. BMI trajectories were derived using weight data at the four timepoints. Incidence of TKA after 2003–2007 until December 2018 was determined by linking cohort records to the National Joint Replacement Registry.

Results

Using group-based trajectory modelling, six distinct trajectories (TR) of BMI from early adulthood to late midlife were identified: lower normal to normal BMI (TR1: BMI at age 18-21 years to BMI at approximately 62 years (kg/m2), 20.0±1.9 to 22.1±1.7; 19.7%); normal BMI to borderline overweight (TR2: 21.5±2.3 to 25.8±1.7; 36.7%), normal BMI to overweight (TR3: 22.0±2.2 to 29.5±1.9; 26.8%), overweight to borderline obese (TR4: 28.5±2.7 to 30.5±2.3; 3.5%), normal BMI to class 1 obesity (TR5: 22.8±2.5 to 34.3±2.3; 10.1%), and overweight to class 2 obesity (TR6: 25.6±3.9 to 39.2±2.9; 3.2%). Over 12.4 years, 1,328 (5.4%) participants had TKA. The hazard ratios for TKA increased in all TR compared with TR1: TR2 2.03 (95% CI 1.64-2.52), TR3 4.00 (3.19-4.91), TR4 5.17 (3.77-7.10), TR5 7.00 (5.54-8.80), and TR6 8.59 (6.44-11.46). It is estimated that 28.4% TKA would be reduced if individuals followed the trajectory that was one lower, a national health system savings of $AUD 373 million. Most of this reduction would occur in TR2 (population attributable fraction 37.9% (26.7%-47.3%) and TR3 PAF 26.8% (20.0%, 31.2%) (Table 1).

Table 1.

Reduction in TKA if individuals followed the trajectory that was one lower

Population counterfactualsPopulation at risk, n (%)TKA under the original scenario, n (%)TKA under the new scenario*, n (%)Difference in risk, n (%)PAF** (95% CI), %TR14811 (19.7)124 (2.6%)No change 124 (2.6%)0-If TR2 followed TR1 trajectory and rate of TKA*8943 (36.7)378 (4.2%)2.6% of 8943 = 233145 (10.9)37.9 (26.7, 47.3)If TR3 followed TR2 trajectory and rate of TKA*6526 (26.8)416 (6.4%)4.2% of 6526 = 274142 (10.7)26.8 (20.0, 31.2)If TR4 followed TR3 trajectory and rate of TKA*845 (3.5)64 (7.6%)6.4% of 845 = 5410 (0.8)3.1 (0, 6.0)If TR5 followed TR4 trajectory and rate of TKA*2466 (10.1)253 (10.3%)7.6% of 2466 =18766 (5.0)20.2 (0, 36.3)If TR6 followed TR5 trajectory and rate of TKA*777 (3.2)93 (12.0%)10.3% of 777 = 8013 (1.0)0.4 (0.0, 10.0)Total population243681328952376 (28.4)-

*if the trajectory is changed, ** PAFs and related 95%CIs were calculated by the Stata punafcc package using the formula ∑pKRi[(HRi − 1)/HRi], where pKRi is the proportion of total knee replacements observed in the ith obesity trajectory and HRi is the hazard ratio (HR) associated with that category. PAFs were calculated using pKRi and HRi estimated from the entire sample. All HRi values were generated from Cox proportional hazards regression models adjusted for covariates (age at baseline, sex, country of birth, physical activity, smoking history, and comorbidity) and postestimation analyses.

Conclusion

Our study suggests that prevention of weight gain from young adulthood to midlife in order to reduce overweight and obesity could have a major impact on reducing the burden of severe knee osteoarthritis and associated healthcare costs.

Figure 1.

A. Proportion of Total Knee Arthroplasties in each trajectory category B. Speculated patters and associated percentages represents the proportion of Total Knee Arthroplasties that could be avoided in each trajectory category if the participants followed the lower trajectory category i.e. TR2 followed TR1

Disclosure of Interests

None declared

Relationship of weight and obesity with the risk of knee and hip arthroplasty for osteoarthritis across different levels of physical performance: a prospective cohort study

OBJECTIVE

To examine the association between obesity and knee and hip arthroplasty for osteoarthritis across a range of physical performance.

METHOD

The body mass index and physical performance (on the 36-item Short Form Health Survey) of 9135 Australian Diabetes, Obesity and Lifestyle Study participants were measured in 1999-2000. The incidence of knee and hip arthroplasty during 2002-2011 was determined by linking the cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.

RESULTS

Over 9.1 ± 2.3 years (mean ± sd)) of follow-up, 317 participants had knee and 202 had hip arthroplasty for osteoarthritis. Using those with neither obesity nor significantly impaired physical performance as the reference group, participants with both obesity and significantly impaired physical performance had a higher knee arthroplasty risk [hazard ratio (HR) = 5.25, 95% confidence interval (CI) 3.85-7.14] than those with obesity alone (HR = 2.49, 95% CI 1.81-3.44) or impaired physical performance alone (HR = 2.19, 95% CI 1.59-3.02). Similar results were observed for hip arthroplasty (obesity and impaired physical performance: HR = 2.67, 95% CI 1.72-4.15; obesity alone: HR = 1.65, 95% CI 1.08-2.51; impaired physical performance alone: HR = 1.83, 95% CI 1.26-2.66). Among overweight/obese patients, 5 kg greater baseline weight increased the knee arthroplasty risk across all levels of physical performance, and hip arthroplasty risk in those with the highest level of physical performance.

CONCLUSION

Although impaired physical performance is an independent risk factor for knee and hip arthroplasty, greater weight increased knee arthroplasty for overweight/obese participants at all levels of physical performance, but hip arthroplasty only in those with good physical performance. Targeting weight loss has the potential to reduce the risk of knee arthroplasty and improve patient outcomes, even in those with poor physical performance.

Cyclotron production and radiochemical separation of 55Co and 58mCo from 54Fe, 58Ni and 57Fe targets

This work presents the production with a cyclotron of the positron emitter ⁵⁵Co via the ⁵⁴Fe(d,n) and ⁵⁸Ni(p,α) reactions and the Auger electron emitter ^58mCo via the ⁵⁷Fe(d,n) reaction after high current (40μA p and 60μA d) irradiation on electroplated targets. High specific activity radionuclides (up to 55.6 GBq/μmol ⁵⁵Co and 31.8GBq/μmol ^58mCo) with high radionuclidic purity (99.995% ⁵⁵Co from ⁵⁴Fe, 98.8% ⁵⁵Co from ⁵⁸Ni, and 98.7% ^58mCo from ⁵⁷Fe at end of bombardment, EoB), in high activity concentration (final separated radionuclide in < 0.6mL) and with almost quantitative overall activity separation yield (> 92%) were obtained after processing of the irradiated targets with novel radiochemical separation methods based on HCl dissolution and the resin N,N,N',N'-tetrakis-2-ethylhexyldiglycolamide (DGA, branched). One hour long irradiations using 38-65, 110-214 and 59-78mg of enriched ⁵⁴Fe (99.93%), ⁵⁸Ni (99.48%) and ⁵⁷Fe (95.06%), respectively, electroplated over a 1.0cm² surface, yielded 58² ± 66MBq ⁵⁵Co, 372 ± 14MBq ⁵⁵Co and 810 ± 186MBq ^58mCo, respectively, decay corrected to EoB. The separation methods allow for the recovery of the costly enriched target materials, which were reconstituted into metallic targets after novel electroplating methods, with an overall recycling efficiency of 93 ± 4% for iron. The produced radionuclides were used to radiolabel the angiogenesis marker antibody TRC105 conjugated to the chelator NOTA as a demonstration of their quality.

The natural history of acute Q fever: a prospective Australian cohort

BACKGROUND

A detailed description of the natural history of acute Q fever, caused by infection with Coxiella burnetii, AIM: : To significantly increase understanding of the illness.

DESIGN

Subjects with provisional acute Q fever (n = 115) were recruited from primary care in rural Australia, and followed prospectively by interview and blood collection including for serological confirmation. A nested series of subjects with prolonged illness (cases), and those without (controls), were investigated in detail.

METHODS

Total phase I and phase II anti-C. burnetii antibodies were detected by complement fixation test; and IgG, IgM and IgA phase I and phase II titres by immunofluorescence. Flow cytometric analysis was conducted to enumerate circulating T cells subsets, B cells, monocytes and natural killer cells.

RESULTS

Serological testing confirmed acute Q fever in 73 subjects (63%). The acute illness featured fever, headache, sweats, fatigue and anorexia; and varied widely in severity, causing an average of 8 days in bed and 15 days out of work or other role in the first month of illness. The illness course varied from 2 days to greater than a year. No cases of chronic, localized Q fever infection, such as endocarditis, were identified. Neither severe nor prolonged illness were associated with persistence of C. burnetii DNA, altered patterns of C. burnetii-specific IgG, IgM or IgA antibody production, or altered leucocyte subsets.

CONCLUSIONS

The severity of acute Q fever alone predicted prolonged duration. Further studies are warranted to better understand the pathophysiology of prolonged illness after acute Q fever.

Association between serum concentration of 25-hydroxyvitamin D and the risk of hip arthroplasty for osteoarthritis: result from a prospective cohort study

OBJECTIVES

There is ongoing debate regarding the optimal serum concentrations of 25-hydroxy-vitamin D for musculoskeletal health, including osteoarthritis (OA). The aim of this prospective cohort study was to determine whether serum 25-hydroxy-vitamin D concentrations were associated with the risk of hip arthroplasty for OA.

DESIGN

This study examined 9135 participants from the Australian Diabetes, Obesity and Lifestyle Study who had serum 25-hydroxy-vitamin D measured in 1999-2000 and were aged ≥40 years at the commencement of arthroplasty data collection. The incidence of hip arthroplasty for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.

RESULTS

Over an average 9.1 (standard deviation (SD) 2.7) years of follow-up, 201 hip arthroplasties for OA were identified (males n = 90; females n = 111). In males, a one-standard-deviation increase in 25-hydroxy-vitamin D was associated with a 25% increased incidence (HR 1.25, 95% CI 1.02-1.56), with a dose response relationship evident by quartiles of 25-hydroxy-vitamin D concentration (P for trend 0.04). These results were independent of age, body mass index (BMI), ethnicity, smoking status, physical activity, season of blood collection, latitude, hypertension and diabetes, area level disadvantage or after excluding those with extreme low 25-hydroxy-vitamin D concentrations. No significant association was observed in women (HR 1.10, 95% CI 0.87, 1.39).

CONCLUSIONS

Increasing serum 25-hydroxy-vitamin D concentrations were associated with an increased risk of hip arthroplasty for OA in males, while no significant association was observed in females. The mechanism for the association warrants further investigation.

Retinal arteriolar narrowing and incidence of knee replacement for osteoarthritis: a prospective cohort study

OBJECTIVES

The role of the microcirculation in the pathogenesis of osteoarthritis (OA) remains unclear. This prospective cohort study examined the association between retinal vascular calibre and incidence of knee replacement for OA.

DESIGN

1838 participants of the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study had retinal vascular calibre measured using a nonmydriatic digital fundus camera in 1999-2000 and were aged ≥ 40 years at joint replacement data collection commencement. The incidence of knee replacement for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).

RESULTS

77 participants underwent knee replacement for OA. They had narrower retinal arteriolar calibre compared with those without knee replacement (166.1 ± 24.8 μm vs 174.3 ± 24.5 μm, P = 0.004). For every one standard deviation reduction in retinal arteriolar calibre, the incidence of knee replacement increased by 25% (HR 1.25, 95% confidence interval (CI) 1.00-1.56). Participants in the narrower two-thirds of arteriolar calibre had twice the risk of knee replacement compared with those in the widest one-third (HR 2.00, 95% CI 1.07-3.74, P = 0.03) after adjustment for sex, body mass index (BMI), physical activity and HbA1c. There was no association for retinal venular calibre.

CONCLUSIONS

Retinal arteriolar narrowing is associated with increased risk of knee replacement for OA suggesting that further work is warranted to determine the role of the microcirculation in the pathogenesis of knee OA.

Separation of cyclotron-produced 44Sc from a natural calcium target using a dipentyl pentylphosphonate functionalized extraction resin

Significant interest in ⁴⁴Sc as a radioactive synthon to label small molecules for positron emission tomography (PET) imaging has been recently observed. Despite the efforts of several research groups, the ideal ⁴⁴Sc production and separation method remains elusive. Herein, we propose a novel separation method to obtain ⁴⁴Sc from the proton irradiation of calcium targets based on extraction chromatography, which promises to greatly simplify current production methodologies. Using the commercially available Uranium and Tetravalent Actinides (UTEVA) extraction resin we were able to rapidly (<20min) recover >80% of the activity generated at end of bombardment (EoB) in small ~1M HCl fractions (400μL). The chemical purity of the ⁴⁴Sc eluates was evaluated through chelation with DOTA and DTPA, and by trace metal analysis using microwave induced plasma atomic emission spectrometry. The distribution coefficients (K_d) of Sc(III) and Ca(II) in UTEVA were determined in HCl medium in a range of concentrations from zero to 12.1M. The ⁴⁴Sc obtained with our method proved to be suitable for the direct labeling of small biomolecules for PET imaging, with excellent specific activities and radiochemical purity.

Queensland tick typhus: three cases with unusual clinical features

Queensland tick typhus (QTT), caused by Rickettsia australis, is usually a relatively mild illness but can occasionally be severe. We describe three cases of probable QTT with unusual clinical features, namely splenic infarction, fulminant myopericarditis and severe leukocytoclastic vasculitis. QTT may present with uncommon clinical features in addition to the more common manifestations. A high index of suspicion enables specific antibiotic therapy that may hasten recovery.

An analysis of Q fever patients 6 years after an outbreak in Newport, Wales, UK

BACKGROUND

A cohort of 211 factory workers was exposed to a point source of Q fever in 2002. A total of 38 cases and 14 controls took part in a follow-up study 6 years after the outbreak.

AIM

To compare Q fever serology, the presence of viable Coxiella burnetii, its DNA and fatigue between patients and controls.

DESIGN

Laboratory case study.

METHODS

Q fever serology was by microimmunofluroescence. Viable C. burnetii was detected by VERO cell culture and SCID mice inoculation with patient blood samples. Coxiella burnetii DNA was detected by qPCR (com1 gene) on patients' PBMC and on VERO cultures after 6 weeks incubation. Fatigue was measured by the Chalder Fatigue Scale.

RESULT

At 6 years after the outbreak, 7 of the 38 patients had become seronegative and 4 of the 14 of the controls had become seropositive for Q fever. None of the patient/control peripheral blood mononuclear cells (PBMC) contained viable C. burnetii by VERO cell culture or by SCID mouse inoculation (death or splenomegaly) and none contained C. burnetii DNA by qPCR.

CONCLUSION

Six years after acute Q fever, some patients had become seronegative but none contained viable C. burnetii or its DNA in their PBMC.

Long-term persistence after acute Q fever of non-infective Coxiella burnetii cell components, including antigens

BACKGROUND

Previous studies of inciting factors for a prolonged post-infection fatigue syndrome after Q fever (variously termed QFS or Q fever associated CFS/ME in the literature) showed that after the acute infection a high proportion of asymptomatic and QFS patients had Q fever antibody and also low levels in PBMC and bone marrow of Coxiella burnetii (C.b.) DNA with PCR assays directed against three different target sequences in different parts of the coxiella genome. Attempts to isolate a strain of C.b. in A/J mice, and cell culture from PCR positive PBMC and bone marrow were consistently negative. The detailed composition of the persisting coxiella residues remains to be defined.

AIM

To retest and provide detailed results on selected PCR positive samples from the Birmingham Q fever outbreak patients tested by a highly sensitive method to detect viable organisms and to determine the nature of the residual coxiella cell components.

DESIGN

Laboratory case study.

METHODS

NOD/SCID mice were inoculated with samples from the 1989 Q fever outbreak in Birmingham and followed for evidence of infection and the presence of coxiella DNA and specific antigens in spleen and liver macrophages. A significant, unexpected finding of specific antigen was followed by assessment of its ability to provoke production of inflammatory and non-inflammatory cytokines in mice, in THP-1 human macrophage cell cultures and to induce inflammatory lesions in the skin of guinea pigs hyperimmunized against Q fever vaccine.

RESULTS

Culture of samples from 10 Birmingham Q fever patients in NOD/SCID mice, 12 years from infection did not yield viable Coxiella burnetii, as shown earlier. However complexes of material with coxiella antigens were found in mouse spleens in all cases but in significantly greater amounts in samples from those with post Q fever fatigue syndrome. The antigenic complexes [now designated 'immunomodulatory complexes' (IMC)] were shown to stimulate cytokine release in the mice and in the THP-1 macrophages and to provoke an inflammatory reaction on intradermal injection into the skin of Q fever hyperimmunized guinea pigs.

CONCLUSION

The study identifies a non-infective complex of C.b. antigens able to survive in the host and provoke aberrant humoral and cell medicated immunity responses - a possible pathogenic link between initial infection and a subsequent long-term post Q fever fatigue syndrome.

Serological prevalence study of exposure of cats and dogs in Launceston, Tasmania, Australia to spotted fever group rickettsiae

A sero-epidemiological study of cats and dogs in the Launceston area of Tasmania, Australia was undertaken to determine the prevalence of antibodies to spotted fever group (SFG) rickettsiae. Results showed that 59% of cats and 57% of dogs were positive for antibodies, but there was no correlation between the animal's health and seropositivity at the time of testing, suggesting that rickettsial exposure is unrelated to ill-health in these two species of domestic animals.

Q fever: persistence of antigenic non-viable cell residues of Coxiella burnetii in the host--implications for post Q fever infection fatigue syndrome and other chronic sequelae

BACKGROUND

Our previous studies of persistence of Coxiella burnetii in humans after an initial acute Q fever infection revealed raised, maintained antibody levels and low levels of coxiella genomic DNA at the age of 5 years from onset in Australian patients and at 12 years in patients in the 1989 Birmingham UK Q fever outbreak. Attempts to isolate the coxiella in standard cell culture and susceptible mice by serial passage of PCR positive PBMC and bone marrow were negative.

AIM

To retest PCR positive patient samples by more sensitive methods for viable coxiellas and for the coxiella cell components of antigen and specific lipopolysaccharide (LPS). To re-interpret the previous results in the light of the new information. To review the pertinent literature for a concept of an immuno-modulatory complex generated by the current studies.

DESIGN

Laboratory case study.

METHODS

Stored patient samples were inoculated into SCID mice that were followed for 60 days. Mouse spleen and liver samples were then examined by PCR assay for targets in the COM1 and IS1111a sequences and for antigens by IFA with a polyclonal rabbit antiserum to C. burnetii Phase 1 and a monoclonal antiserum to Phase 1 LPS (details; O. Sukocheva et al., unpublished data).

RESULTS

All specimens, including a recently excised heart valve from a Birmingham patient with late developing endocarditis, were infection negative in SCID mice. Dilutions of SCID mouse spleen and liver homogenates titrated in PCR assays were negative at dilutions attained by control mice inoculated with an endpoint dilution of a viable prototype strain of C. burnetii. Sections of the spleens from all specimens showed a complex of coxiella antigen-LPS by IFA. DISCUSSION/REVIEW: We advance a concept of long-term persistence of a non-infective, non-biodegraded complex of coxiella cell components with its antigens and specific LPS [so called Immunomodulatory complex (IMC)] associated with traces of genomic DNA that signalled its presence in our earlier studies. The IMC's survival in patients for at least 12 years, and in one patient for 70 years implies a capacity for serial passage in macrophages with effective down-regulation of their biodegrading functions. The review assesses the compatibility of the IMC concept in relation to cogent literature on C. burnetii interactions with macrophage and cell-mediated immunity. Some remaining gaps in our knowledge of the organ sites and duration of carriage of viable coxiellas after initial infection are also identified.

Markers of exposure to spotted fever rickettsiae in patients with chronic illness, including fatigue, in two Australian populations

BACKGROUND

Some investigators believe that a proportion of chronically unwell patients, many with fatigue, have an underlying rickettsial disease.

AIM

To investigate the prevalence of markers of rickettsial infection in patients with chronic illnesses.

DESIGN

Observational study.

METHODS

A 526 patient cohort with chronic illnesses from Melbourne, Australia and 400 control patients from Newcastle, Australia were assessed using serology, culture and PCR for the detection of rickettsiae. Rickettsial serology was performed on another cohort of 581 chronically unwell patients (and 34 non-fatigued patients from the same practice) from Adelaide, Australia.

RESULTS

Of the Melbourne patient cohort, 14/526 (3%) were real-time PCR positive for rickettsial DNA compared to none of the 400 control patients (P < 0.001). Of these 14 patients, Rickettsia honei strain 'marmionii' was detected in 5 and isolated from 2. Rickettsaemia was seasonal, with more in winter (8/145; P < 0.03) and less in spring (0/143; P < 0.03). Positive rickettsial serology titres of >or=1:256 were seen in 206 (39%) patients. Of the Adelaide patient cohort, 238/581 (41%) had positive rickettsial antibodies titres. Of the 34 control sera, 5 (15%) were serologically positive (P < 0.002). Both Melbourne and Adelaide patient cohorts had significantly higher seropositivity than the Newcastle control cohort (3/399; P < 0.0001).

CONCLUSION

In patients with chronic illness, rickettsial DNA in peripheral blood and/or rickettsial seropositivity may represent exposure to rickettsiae or underlying rickettsial diseases. It is not known whether the presence of rickettsiae is causally related to the patients' chronic illnesses, or reactivation of a latent rickettsial infection.

Patients with artificial joints: do they need antibiotic cover for dental treatment?

This study reviews whether patients with artificial joints need antibiotic cover for dental treatment. Generally in Australia the practice has developed of giving most patients with artificial joints antibiotic prophylaxis for a wide range of dental procedures. This is partly on anecdotal grounds, partly historical and partly for legal concerns. It has been encouraged by some guidelines. Scientifically, the risk and the benefit of each step in the process needs to be analysed. This review shows that the risk of an artificial joint becoming infected from a bacteraemia of oral origin is exceedingly low whereas the risk of an adverse reaction to the antibiotic prophylaxis is higher than the risk of infection. If all patients with artificial joints receive antibiotic prophylaxis then more will die from anaphylaxis than develop infections. Factors which balance the risk benefit are if the patient is seriously immunocompromised, if the joint prosthesis is failing or chronically inflamed and if the dental procedures, such as from extractions and deep periodontal scaling, produce high level bacteraemias. Recommendations to rationalize antibiotic prophylaxis for patients with artificial joints are presented.

Structure of concentrated nanoemulsions

We use extreme shear to create a dispersion of nanoscale droplets of silicone oil in an immiscible water phase containing an anionic surfactant sodium dodecylsulfate. Using centrifugal size fractionation, we obtain nanoemulsions having a well-defined average radius of a=75 nm. We measure the structure of concentrated nanoemulsions over a wide range of volume fractions, 0<phi<0.6, using small angle neutron scattering, and we determine the structure factor S(q) of disordered glassy dispersions of uniform deformable droplets interacting through screened surface charge repulsions. Although the low-q behavior of S(q,phi) resembles that predicted for hard spheres, the height of the primary peak does not. Instead, it exhibits a maximum as phi is increased. This difference cannot be explained solely by the droplet size polydispersity and is likely related to the deformability of the droplets that have been locked into a glassy structure.

Sensitivity of fresh isolates of soft tissue sarcoma, osteosarcoma and giant cell tumour cells to Apo2L/TRAIL and doxorubicin

Chemotherapy is an established treatment modality for bone sarcomas such as osteosarcoma (OS). However, the use of chemotherapy in high-grade soft tissue sarcomas remains controversial, with the most active chemotherapeutic agent, doxorubicin (DOX), reported to have a response rate of, at best only 34% and most studies reporting lower response rates. Apo2L/TRAIL is a member of the tumour necrosis factor (TNF) family of cytokines and induces death of tumour cells, but not normal cells. Its potent apoptotic activity is mediated through cell surface death domain-containing receptors, DR4/TRAIL-R1 and DR5/TRAIL-R2. We investigated the efficacy of Apo2L/TRAIL as a single agent, and in combination with clinically relevant chemotherapeutic drugs, in fresh isolates of primary malignant cells obtained from biopsy material. The data presented here demonstrate that, in a range of primary bone related tumours, as well as soft tissue sarcomas, chemotherapeutic agents were only moderately effective, in terms of induction of cell death. Apo2L/TRAIL alone had little or no effect on any bone-related tumour or sarcoma in culture. In contrast, the combination of Apo2L/TRAIL and chemotherapeutic drugs produced a significant increase in tumour cell death, with DOX and Apo2L/TRAIL proving to be the most effective combination. These data suggest the potential for Apo2L/TRAIL to increase the effectiveness of chemotherapeutic drugs in bone and soft tissue sarcomas, while perhaps concurrently allowing a reduction in the exposure to drugs such as DOX, and a consequent reduction in toxicity. The synergistic action between these two different classes of agents has yet to be tested in vivo but may prove clinically relevant in the treatment of this refractive class of malignancies.

Washing of gloved hands in antiseptic solution prior to central venous line insertion reduces contamination

Glove contamination at the time a central venous catheter is handled is highly undesirable and likely to increase the risk of subsequent line infection. This study was designed to determine how frequently gloves become contaminated during central venous line insertion and to demonstrate the value of glove decontamination immediately prior to handling of the central venous catheter During twenty routine internal jugular catheter insertions the sterility of the operator's gloved fingertips (just prior to handling the intravenous catheter) was assessed by touching the fingertips onto blood agar plates. The gloved hands were then rinsed in chlorhexidine/alcohol and after drying were placed onto a further plate. Contamination was detected in 55% of the prewash plates but in none of the postwash plates. Procedures performed by less experienced resident staff had a higher contamination rate despite there being no evident breach of sterile technique. It is likely that glove contamination results from the persistance of bacteria within the deeper layers of the skin, despite surface disinfection. These bacteria may be released by manipulation of the skin when identifying landmarks. This hypothesis was supported by a subsequent observation that gloves were more highly contaminated after firm touching of the skin rather than light touching. Glove contamination during central line insertion is frequent. Catheter contamination rates could be reduced (without risk or additional cost) by rinsing gloved hands in a solution of chlorhexidine (0.5%) in alcohol (70%) prior to handling the catheter.

A study of 178 consecutive vasovagal syncopal reactions from the perspective of safety

BACKGROUND

While vasovagal syncopal reactions have been studied in the past, there are several safety questions that could be further addressed. The purpose of this study was to address these safety questions.

STUDY DESIGN AND METHODS

One hundred seventy-eight vasovagal reactions were reported in 1999 from 194,000 blood donations. The reactions were retrospectively reviewed for 38 variables that included donor demographics, symptoms, injury, and final disposition.

RESULTS

Sixty-one percent of the syncopal reactions occurred at the refreshment table and 12 percent offsite. Fourteen percent of the donors sustained an injury, usually to the head (10%). Eleven donors (6%) had additional medical care in an emergency room: 4 for injuries, 3 for delayed recovery, and 4 for offsite syncope. None of the donors was admitted to the hospital. One of the injured donors developed postconcussion syndrome and had later sequelae.

CONCLUSION

Syncopal reactions most commonly occur at the refreshment table, where preventive safety measures against trauma could be applied. A significant number of syncopal reactions occur offsite, where the environment is less safe. The injuries that occur, particularly to the head, may in rare cases lead to long-term sequelae.

Identification and in vivo characterization of the Epiphyas postvittana nucleopolyhedrovirus Ecdysteroid UDP-glucosyltransferase

The genome of Epiphyas postvittana Nucleopolyhedrovirus (EppoMNPV) contains an ecdysteroid UDP-glucosyltransferase (egt) gene. The egt gene was completely sequenced and surrounding open reading frames identified. EppoMNPV egt is 1479 nucleotides in length encoding a protein with a predicted molecular mass of 55 kDa. Analysis of upstream sequence revealed dual TATA boxes and two CGT upstream activating region motifs. Mapping of the 5' terminus of the egt transcript identified a major transcript produced from an adenine residue 29 nucleotides downstream from the distal TATA box. No transcript was detected from a late promoter motif (GTAAG). Characterization of egt transcripts showed that poly-adenylation occurs at the 3' terminus. EppoMNPV egt transcripts were first detected in infected Epiphyas postvittana larvae by Northern hybridization at 9 h post-infection (hpi) and EGT enzyme activity was detected at 9 hpi in haemolymph from infected larvae. EppoMNPV EGT can conjugate the sugars from both UDP-glucose and UDP-galactose to ecdysone in vitro. Localization assays performed using radiolabelled ecdysone demonstrated that the conjugation of glucose or galactose, from the respective UDP-sugar, led to the prevention of the uptake of ecdysone by SF-21 cells. We propose that EGT functions to prevent the uptake of ecdysone or 20-hydroxyecdysone by metabolite and target cells respectively.

Oral administration of dimethylvinyl chloride increases frequency of forestomach papillomas in Tg.AC mice

This work was initiated to determine the potential for the Tg.AC mouse model to identify chemical carcinogens by an oral route of administration. Tg.AC v-Ha-ras transgenic mice were exposed to dimethyvinyl chloride (DMVC; 1-chloro-2-methylpropene), a structural analog of the human carcinogen vinyl chloride. In the National Toxicology Program 2-yr bioassay, DMVC induced tumors in the oral, nasal, and gastric epithelia of rats and mice. Initial studies were performed in female Tg.AC mice to determine an appropriate oral dose of DMVC to evaluate the potential for stratified gastric or oral epithelia of Tg.AC mice to serve as a target tissue for a transgene-dependent induced tumorigenic response. DMVC was administered to 13- to14-wk-old Tg.AC mice by gavage at doses of 0, 50, 100, and 200 mg/kg five times a week for 20 wk. The forestomachs of DMVC-treated Tg.AC mice had an increasing number of papillomas, which were associated with an increase in the dose of DMVC. The average numbers of papillomas per mouse per dose were 2.4, 7.6, 14.1, and 12.6 for the 0, 50, 100, and 200-mg/kg dose groups, respectively. The optimum papillomagenic dose of 100 mg/kg DMVC was established and administered for 5, 10, and 15/wk to investigate the kinetics of papilloma induction in Tg.AC mice. The average numbers of papillomas per animal were 1.8, 8.8, and 19.0 at 5, 10, and 15 wk, respectively. Reverse transcription-polymerase chain reaction assays determined that the v-Ha-ras transgene was transcriptionally active in all tumor tissues but not in nontumor tissues. In situ hybridization assays performed in conjunction with bromodeoxyuridine in vivo labeling localized the transgene-expressing cells of the forestomach papillomas to the proliferating cellular component of the tumors, as previously seen in skin papillomas of Tg.AC mice. The present results confirm that DMVC is tumorigenic and that oral routes of administration can be used to rapidly elicit a transgene-associated tumor response in the forestomach of Tg.AC mice.

Therapeutic monitoring of sirolimus in human whole-blood samples by high-performance liquid chromatography

BACKGROUND

Sirolimus is a macrolide antibiotic isolated from Streptomyces hygroscopicus that has demonstrated immunosuppressive activity. Human and animal studies have shown a good correlation of trough sirolimus concentrations with immunosuppressive efficacy.

OBJECTIVE

This report describes a reverse-phase high-performance liquid chromatography (HPLC) method used for therapeutic drug monitoring of sirolimus.

METHODS

A reverse-phase C18 column method was developed using an automated HPLC system and ultraviolet (UV) detection. Whole-blood samples collected in ethylenediamine-tetraacetic acid (EDTA) are first hemolyzed, and an internal standard (desmethoxysirolimus) is added to 1.0 mL of sample, which is then extracted with 1-chlorobutane and, after the organic layer is removed, evaporated to dryness. The residue is reconstituted in a 70% methanol/water mixture. Reconstituted extracts are analyzed by HPLC at a column temperature of 60 degrees C and a flow rate of 1.0 mL/min. Typically, chromatography requires 35 minutes between each sample injection. The UV detector is set at 278 nm with a response sensitivity of 0.010 AUFS (absorbance units full scale). Standards and controls prepared in hemolyzed EDTA-anticoagulated whole blood are extracted and run in parallel. Identification of peaks of interest is by retention time; quantification of sirolimus in controls and clinical samples uses a peak-height ratio (sirolimus/internal standard).

RESULTS

The assay's precision (coefficients of variation, 5.7%-14.4%) and sensitivity (2.5 ng/mL) were found to be appropriate for therapeutic monitoring purposes. Analytical recovery of 88.0% to 106.3% was observed throughout the assay's linear range (2.5-150.0 ng/mL). Stability studies at 20 degrees C to 25 degrees C and 2 degrees C to 8 degrees C showed an estimated recovery of sirolimus ranging from 85% to 110% of target concentrations (10-90 ng/mL). In a study comparing the results of 194 samples from kidney transplant recipients assayed by the HPLC-UV assay and by a microparticle enzyme immunoassay, the HPLC-UV method provided approximately 10% lower values.

CONCLUSION

The HPLC-UV assay is analytically capable of providing useful data for the clinical assessment of patients receiving sirolimus.

DNAssist: the integrated editing and analysis of molecular biology sequences in windows

MOTIVATION

The programs currently available for the analysis of nucleic acid and protein sequences suffer from a variety of problems: Web-based programs often require inconvenient reformatting of sequences when proceeding from one analysis to the next, and commercial-console-based programs are cost prohibitive. Here, we report the development of DNASSIST:, an inexpensive, multiple-document, interface program for the fully integrated editing and analysis of nucleic acid and protein sequences in the familiar environment of Microsoft Windows.

DNAssist, a C++ program for editing and analysis of nucleic acid and protein sequences on PC-compatible computers running Windows 95, 98, NT4.0 or 2000

The size of sequence databases, the rapid rate of generating sequence data and the need to routinely construct recombinant DNA molecules in molecular biological research necessitate the frequent handling and analysis of nucleotide and protein sequences on a computer. Although several console or Web-based utility programs are available, the application of these programs generally requires reformatting the data when proceeding from one such program to the next. The acquisition of elaborate, integrated program suites is financially prohibitive to smaller laboratories. Here, we report the development of DNAssist, a shareware program for editing and analysis of nucleic acid and protein sequences. It was developed as a multiple-document interface program--similar to a word processor--where sequences are entered, edited and analyzed in a single integrated environment. DNAssist can calculate the physicochemical properties of a sequence, convert between nucleic acid and protein sequences, translate DNA in multiple frames, identify open reading frames and locate ambiguous sequence patterns allowing gaps and mismatches. DNAssist also performs restriction enzyme and transcription factor-binding site analyses of DNA sequences, the multiple alignment of nucleic acid and protein sequences and the analysis of DNA sequences for nucleosome positioning sites.

Modular robotic workcell for coagulation analysis

BACKGROUND

Total laboratory automation (TLA) has been shown to increase laboratory efficiency and quality. However, modular automation is smaller, requires less initial capital, and requires less planning than TLA. We engineered and performed clinical trials on a modular robotic preanalytical workcell for coagulation analysis.

METHODS

Timing studies were used to quantify the efficiency of the manual processes and to identify areas in the processing of coagulation specimens where bottlenecks and long waiting periods were encountered. We then designed our modular robotic system to eliminate these bottlenecks. Our robotic modular workcell was engineered to allow a choice of specimen introduction manually, by conveyor, or by mobile robot. Additional timing studies were performed during clinical trials of the robotic system.

RESULTS

Prior to automation, the time required for preanalytical processing time was 18-107 min; after automation, it was 45-50 min. Additional improvements in workcell efficiency could be realized when high quality, prelabeled specimens were introduced into the system.

CONCLUSION

Compared with manual methods, modular automation provides more predictable variation in specimen processing.

Clinical optimization of pretargeted radioimmunotherapy with antibody-streptavidin conjugate and 90Y-DOTA-biotin

Pretargeted radioimmunotherapy (PRIT) was evaluated using an antibody-streptavidin conjugate, followed by a biotin-galactose-human serum albumin clearing agent and 90Y-dodecane tetraacetic acid (DOTA)-biotin as the final step for therapy. The objective was to develop a clinical protocol that could show an improved tumor-to-red marrow therapeutic ratio compared with conventional radioimmunotherapy (RIT) and at the same time preserve the efficiency of tumor targeting.

METHOD

Forty-three patients with adenocarcinomas reactive to NR-LU-10 murine monoclonal antibody received the 3 components. Doses and timing parameters were varied to develop an optimized schema. In some patients, the conjugate was radiolabeled with 186Re as an imaging tracer to assess biodistribution of the conjugate and effectiveness of the clearing agent. 111In-DOTA-biotin was coinjected with 90Y-DOTA-biotin for quantitative imaging. Safety, biodistribution, pharmacokinetics, dosimetry, and antiglobulin formation were evaluated.

RESULTS

The optimal schema was defined as a conjugate dose of 125 microg/mL plasma volume followed at 48 h by a clearing agent in a 10:1 molar ratio of clearing agent to serum conjugate. The therapeutic third step was 0.5 mg radiobiotin administered 24 h later. No significant adverse events were observed after administration of any of the components. The mean tumor-to-marrow absorbed dose ratio when using the optimized PRIT schema was 63:1, compared with a 6:1 ratio reported previously for conventional RIT. Antiglobulin to murine antibody and to streptavidin developed in most patients.

CONCLUSION

This initial study confirmed that the PRIT approach is safe and feasible and achieved a higher therapeutic ratio than that achieved with conventional RIT using the same antibody.

Reading the future: the increased relevance of laboratory medicine in the next century

Through intelligent process control and data management, the laboratory may become the most frequently used--and the most important--source of diagnostic information in medicine. The central laboratory of the future is destined to become an esoteric testing center, whereas routine testing--administered at the patient bedside or at home--will become more economical. Point-of-care testing will soon become the most profitable way to provide laboratory services. Novel phlebotomy techniques and noninvasive tests may allow some diagnostic testing to be done through automated robotic companions that serve homebound patients or the elderly.