Isohemagglutinin titration in pooled and apheresis platelets

BACKGROUND

Platelet inventory constraints necessitate ABO-incompatible platelet transfusion. Many minimize the hemolytic impact by confirming low titre (LT) donor isohemagglutinins. This process is costly. Pathogen-reduced platelets (PRP) in platelet additive solutions (PAS) will dilute plasma and decrease high-titre isohemagglutinins (HT). We determined the proportion of HT platelets and incompatible transfusions for units suspended in plasma to reassess the need for titres following introduction of PRP/PAS.

STUDY DESIGN AND METHODS

Our titre method is manual tube (1:50) dilution of platelet supernatant from apheresis or whole blood derived buffy coat pools suspended in plasma, tested with A1/B red cells. Testing included 49,058 pooled and 11,738 apheresis platelets over 4 years. The HT proportion, rate of out-of-group transfusions, and hemolytic reactions were determined. The impact of PAS dilution was estimated.

RESULTS

Totally 60,796 platelet units were tested. Group O pooled and group B apheresis platelets had HT in 6.6% and 5.7%, respectively. Group A pooled and apheresis platelets included 2% with HT. Approximately 25% of platelets transfused were ABO-incompatible and no hemolytic reactions were reported. Based on the proportions of PAS-E and plasma for PRP platelets, plasma from each donor comprises 11 mL (6% of total volume) vs 20-257 mL in untreated pools. PAS-E will replace and dilute residual plasma by at least 50%.

DISCUSSION

Rare platelet pools may demonstrate HT. PRP platelets with PAS will reduce titres and may abrogate the need for titration. A strategy of group specific transfusion or transfusion of group A PRP platelet transfusions may be a safe alternative.

Assessing Enhanced Acoustic Absorption From Sonosensitive Perfluorocarbon Emulsion With Magnetic Resonance-Guided High-Intensity Focused Ultrasound and a Percolated Tissue-Mimicking Flow Phantom

OBJECTIVE

Sonosensitive high-boiling point perfluorocarbon F₈TAC₁₈-PFOB emulsions previously exhibited thermal enhancement during focused ultrasound heating in ex vivo pig livers, kidneys and a laminar flow phantom. The main objectives of this study were to evaluate heating under turbulent conditions, observe perfusion effects, quantify heating in terms of acoustic absorption and model the experimental data.

METHODS

In this study, similar perfluorocarbon emulsions were circulated at incremental concentrations of 0.07, 0.13, 0.19 and 0.25% v:v through a percolated turbulent flow phantom, more representative of the biological tissue than a laminar flow phantom. The concentrations represent the droplet content in only the perfused fluid, rather than the droplet concentration throughout the entire cross-section. The temperature was measured with magnetic resonance thermometry, during focused ultrasound sonications of 67 W, 95% duty cycle and 33 s duration. These were used in Bioheat equation simulations to investigate in silico the thermal phenomena. The temperature change was compared with the control condition by circulating de-gassed and de-ionized water through the flow phantom without droplets.

RESULTS

With these 1.24 µm diameter droplets at 0.25% v:v, the acoustic absorption coefficient increased from 0.93 ± 0.05 at 0.0% v:v to 1.82 ± 0.22 m^-1 at 0.25% v:v using a 0.1 mL s^-1 flow rate. Without perfusion at 0.25% v:v, an increase was observed from 1.23 ± 0.07 m^-1 at 0.0% v:v to 1.65 ± 0.17 m^-1.

CONCLUSION

The results further support previously reported thermal enhancement with F₈TAC₁₈-PFOB emulsion, quantified the increased absorption at small concentration intervals, illustrated that the effects can be observed in a variety of visceral tissue models and provided a method to simulate untested scenarios.

A Novel Concept of a Phased-Array HIFU Transducer Optimized for MR-Guided Hepatic Ablation: Embodiment and First In-Vivo Studies

Purpose

High-intensity focused ultrasound (HIFU) is challenging in the liver due to the respiratory motion and risks of near-/far-field burns, particularly on the ribs. We implemented a novel design of a HIFU phased-array transducer, dedicated to transcostal hepatic thermo-ablation. Due to its large acoustic window and strong focusing, the transducer should perform safely for this application.

Material and Methods

The new HIFU transducer is composed of 256 elements distributed on 5 concentric segments of a specific radius (either 100, 111, or 125 mm). It has been optimally shaped to fit the abdominal wall. The shape and size of the acoustic elements were optimized for the largest emitting surface and the lowest symmetry. Calibration tests have been conducted on tissue-mimicking gels under 3-T magnetic resonance (MR) guidance. In-vivo MR-guided HIFU treatment was conducted in two pigs, aiming to create thermal ablation deep in the liver without significant side effects. Imaging follow-up was performed at D0 and D7. Sacrifice and post-mortem macroscopic examination occurred at D7, with the ablated tissue being fixed for pathology.

Results

The device showed −3-dB focusing capacities in a volume of 27 × 46 × 50 mm³ as compared with the numerical simulation volume of 18 × 48 × 60 mm³. The shape of the focal area was in millimeter-range agreement with the numerical simulations. No interference was detected between the HIFU sonication and the MR acquisition. In vivo, the temperature elevation in perivascular liver parenchyma reached 28°C above physiological temperature, within one breath-hold. The lesion was visible on Gd contrast-enhanced MRI sequences and post-mortem examination. The non-perfused volume was found in pig #1 and pig #2 of 8/11, 6/8, and 7/7 mm along the LR, AP, and HF directions, respectively. No rib burns or other near-field side effects were visually observed on post-mortem gross examination. High-resolution contrast-enhanced 3D MRI indicated a minor lesion on the sternum.

Conclusion

The performance of this new HIFU transducer has been demonstrated in vitro and in vivo. The transducer meets the requirement to perform thermal lesions in deep tissues, without the need for rib-sparing means.

PFOB sonosensitive microdroplets: determining their interaction radii with focused ultrasound using MR thermometry and a Gaussian convolution kernel computation

Purpose: Micron-sized perfluorocarbon droplet adjuvants to focused ultrasound therapies allow lower applied power, circumvent unwanted prefocal heating, and enhance thermal dose in highly perfused tissues. The heat enhancement has been shown to saturate at increasing concentrations. Experiments were performed to empirically model the saturating heating effects during focused ultrasound.Materials and methods: The measurements were made at varying concentrations using magnetic resonance thermometry and focused ultrasound by circulating droplets of mean diameter 1.9 to 2.3 µm through a perfused phantom. A simulation was performed to estimate the interaction radius size, empirically.Results: The interaction radius, representing the radius of a sphere encompassing 90% of the probability for the transformation of acoustic energy into heat deposition around a single droplet, was determined experimentally from ultrasonic absorption coefficient measurements The simulations suggest the interaction radius was approximately 12.5-fold larger than the geometrical radius of droplets, corresponding to an interaction volume on the order of 2000 larger than the geometrical volume.Conclusions: The results provide information regarding the dose-response relationship from the droplets, a measure with 15% precision of their interaction radii with focused ultrasound, and subsequent insights into the underlying physical heating mechanism.

Perfluorocarbon Emulsion Contrast Agents: A Mini Review

Perfluorocarbon emulsions offer a variety of applications in medical imaging. The substances can be useful for most radiological imaging modalities; including, magnetic resonance imaging, ultrasonography, computed tomography, and positron emission tomography. Recently, the substance has gained much interest for theranostics, with both imaging and therapeutic potential. As MRI sequences improve and more widespread access to ¹⁹F-MRI coils become available, perfluorocarbon emulsions have great potential for new commercial imaging agents, due to high fluorine content and previous regulatory approval as antihypoxants and blood substitutes. This mini review aims to discuss the chemistry and physics of these contrast agents, in addition to highlighting some of the past, recent, and potential applications.

Perfluorocarbon emulsion enhances MR-ARFI displacement and temperature in vitro: Evaluating the response with MRI, NMR, and hydrophone

Sonosensitive perfluorocarbon F₈TAC₁₈-PFOB emulsion is under development to enhance heating, increase thermal contrast, and reduce treatment times during focused ultrasound tumor ablation of highly perfused tissue. The emulsion previously showed enhanced heating during ex vivo and in vitro studies. Experiments were designed to observe the response in additional scenarios by varying focused ultrasound conditions, emulsion concentrations, and surfactants. Most notably, changes in acoustic absorption were assessed with MR-ARFI. Phantoms were developed to have thermal, elastic, and relaxometry properties similar to those of ex vivo pig tissue. The phantoms were embedded with varying amounts of F₈TAC₁₈-PFOB emulsion or lecithin-PFOB emulsion, between about 0.0-0.3% v:w, in 0.05% v:w increments. MR-ARFI measurements were performed using a FLASH-ARFI-MRT sequence to obtain simultaneous displacement and temperature measurements. A Fabry-Perot hydrophone was utilized to observe the acoustic emissions. Susceptibility-weighted imaging and relaxometry mapping were performed to observe concentration-dependent effects. ¹⁹F diffusion-ordered spectroscopy NMR was used to measure the diffusion coefficient of perfluorocarbon droplets in a water emulsion. Increased displacement and temperature were observed with higher emulsion concentration. In semi-rigid MR-ARFI phantoms, a linear response was observed with low-duty cycle MR-ARFI sonications and a mono-exponential saturating response was observed with sustained sonications. The emulsifiers did not have a significant effect on acoustic absorption in semi-rigid gels. Stable cavitation might also contribute to enhanced heating.

Enhancement of HIFU thermal therapy in perfused tissue models using micron-sized FTAC-stabilized PFOB-core endovascular sonosensitizers

BACKGROUND

High intensity focused ultrasound (HIFU) is clinically accepted for the treatment of solid tumors but remains challenging in highly perfused tissue due to the heat sink effect. Endovascular liquid-core sonosensitizers have been previously suggested to enhance the thermal energy deposition at the focal area and to lower the near-/far-field heating. We are investigating the therapeutic potential of PFOB-FTAC micro-droplets in a perfused tissue-mimicking model and postmortem excised organs.

METHOD

A custom-made in vitro perfused tissue-mimicking model, freshly excised pig kidneys (n = 3) and liver (n = 1) were perfused and subjected to focused ultrasound generated by an MR-compatible HIFU transducer. PFOB-FTAC sonosensitizers were injected in the perfusion fluid up to 0.235% v/v ratio. Targeting and on-line PRFS thermometry were performed on a 3 T MR scanner. Assessment of the fluid perfusion was performed with pulsed color Doppler in vitro and with dynamic contrast-enhanced (DCE)-MRI in excised organs.

RESULTS

Our in vitro model of perfused tissue demonstrated re-usability. Sonosensitizer concentration and perfusion rate were tunable in situ. Differential heating under equivalent HIFU sonications demonstrated a dramatic improvement in the thermal deposition due to the sonosensitizers activity. Typically, the energy deposition was multiplied by a factor between 2.5 and 3 in perfused organs after the administration of micro-droplets, while DCE-MRI indicated an effective perfusion.

CONCLUSION

The current PFOB-FTAC micro-droplet sonosensitizers provided a large and sustained enhancement of the HIFU thermal deposition at the focal area, suggesting solutions for less technological constraints, lower risk for the near-/far- field heating. We also report a suitable experimental model for other MRgHIFU studies.

Low incidence of the immune reconstitution inflammatory syndrome among HIV-infected patients starting antiretroviral therapy in Gabon: a prospective cohort study

There is a paucity of data on the immune reconstitution inflammatory syndrome (IRIS) in the Central African region. We followed ART-naive HIV-infected patients initiating antiretroviral therapy in an HIV clinic in Gabon, for 6 months. Among 101 patients, IRIS was diagnosed in five. All IRIS cases were mucocutaneous manifestations. There were no cases of tuberculosis (TB) IRIS, but active TB (n = 20) was associated with developing other forms of IRIS (p = 0.02). Six patients died. The incidence of IRIS is low in Gabon, with mild, mucocutaneous manifestations.

Early intervention leads to long-term developmental improvements in very preterm infants, especially infants with bronchopulmonary dysplasia

AIM

Various early intervention programmes have been developed in response to the high rate of neurodevelopmental problems in very preterm infants. We investigated longitudinal effects of the Infant Behavioral Assessment and Intervention Program on cognitive and motor development of very preterm infants at the corrected ages of six months to five and a half years.

METHODS

This randomised controlled trial divided 176 infants with a gestational age <32 weeks or birthweight <1500 g into intervention (n = 86) and control (n = 90) groups. Cognitive development and motor development were assessed with the Bayley Scales of Infant Development at the CAs of six, 12 and 24 months and at five and a half years with the Wechsler Preschool and Primary Scale of Intelligence and the Movement Assessment Battery for Children.

RESULTS

We found significant longitudinal intervention effects (0.4 SD, p = 0.006) on motor development, but no significant impact on cognitive development (p = 0.063). Infants with bronchopulmonary dysplasia showed significant longitudinal intervention effects for cognitive (0.7 SD; p = 0.019) and motor (0.9 SD; p = 0.026) outcomes. Maternal education had little effect on intervention effects over time.

CONCLUSION

The Infant Behavioral Assessment and Intervention Program led to long-term developmental improvements in the intervention group, especially in infants with BPD.

Spinodal instabilities and super-Planckian excursions in natural inflation

Models such as Natural Inflation that use pseudo-Nambu-Goldstone bosons as the inflaton are attractive for many reasons. However, they typically require trans-Planckian field excursions ΔΦ>MPl, due to the need for an axion decay constant f>MPl to have both a sufficient number of e-folds and values of ns,r consistent with data. Such excursions would in general require the addition of all other higher dimension operators consistent with symmetries, thus disrupting the required flatness of the potential and rendering the theory nonpredictive. We show that in the case of Natural Inflation, the existence of spinodal instabilities (modes with tachyonic masses) can modify the inflaton equations of motion to the point that versions of the model with f<MPl can still inflate for the required number of e-folds. The instabilities naturally give rise to two separate phases of inflation with different values of the Hubble parameter H, one driven by the zero mode, the other by the unstable fluctuation modes. The values of ns and r typically depend on the initial conditions for the zero mode, and, at least for those examined here, the values of r tend to be unobservably small.

Improved risk stratification by the integration of the revised international prognostic scoring system with the myelodysplastic syndromes comorbidity index

Myelodysplastic syndromes (MDS) comprise bone marrow failure diseases with a diverse clinical outcome. For improved risk stratification, the International Prognostic Scoring System (IPSS) has recently been revised (IPSS-R). This single-centre study aimed to validate the IPSS-R and to evaluate prior prognostic scoring systems for MDS. We retrospectively analysed 363 patients diagnosed with MDS according to the FAB criteria between 2000 and 2012. The IPSS, MD Anderson Risk Model Score (MDAS), World Health Organisation (WHO)-classification based Prognostic Scoring System (WPSS), refined WPSS (WPSS-R), IPSS-R and MDS-Comorbidity Index (MDS-CI) were applied to 222 patients considered with primary MDS following the WHO criteria and their prognostic power was investigated. According to the IPSS-R, 18 (8%), 81 (37%), 50 (23%), 43 (19%) and 30 (13%) patients were classified as very low, low, intermediate, high and very high risk with, respectively, a median overall survival of 96 (95% Confidence interval (CI) not reached), 49 (95% CI 34-64), 22 (95% CI 0-49), 19 (95% CI 11-27) and 10 (95% CI 6-13) months (p<.000). The IPSS-R showed improved prognostic power as compared to the IPSS, MDAS, WPSS and WPSS-R. Furthermore, the MDS-CI refined the risk stratification of MDS patients stratified according to the IPSS-R. In conclusion, accounting for the disease status by means of the IPSS-R and comorbidity through the MDS-CI considerably improves the prognostic assessment in MDS patients.

Design, history and results of the Thiazolidinedione Intervention with vitamin D Evaluation (TIDE) randomised controlled trial

AIMS/OBJECTIVE

Conflicting data regarding cardiovascular effects of thiazolidinediones (TZDs) and extra-skeletal effects of vitamin D supported the need for a definitive trial. The Thiazolidinedione Intervention with vitamin D Evaluation (TIDE) trial aimed to assess the effects of TZDs (rosiglitazone and pioglitazone) on cardiovascular outcomes and the effects of vitamin D (cholecalciferol) on cancers and mortality.

METHODS

A large multicentre 3 × 2 factorial double-blind placebo-controlled randomised trial recruited from outpatient primary care and specialty clinics in 33 countries. From June 2009 to July 2010, 1,332 people with type 2 diabetes and other cardiovascular risk factors aged ≥ 50 years whose HbA(1c) was 6.5-9.5% (48-80 mmol/mol) when using two or fewer glucose-lowering drugs were randomised by a central computer system to placebo (n = 541), rosiglitazone 4-8 mg/day (n = 399) or pioglitazone 30-45 mg/day (n = 392); 1,221 participants were randomised to placebo (n = 614) or vitamin D 1,000 IU/day (n = 607). Participants and all study personnel were blind to treatment allocation. The primary outcome for the TZD arm was the composite of myocardial infarction, stroke or cardiovascular death, and for the vitamin D arm it was cancer or all-cause death. All randomised participants were included in the primary analysis.

RESULTS

From the study design, 16,000 people were to be followed for approximately 5.5 years. However, the trial was stopped prematurely because of regulatory concerns after a mean of 162 days without consideration of the accrued data. In the TZD arm, the cardiovascular outcome occurred in five participants (0.9%) in the placebo groups and three participants (0.4%) in the TZD groups (two allocated to pioglitazone, one to rosiglitazone). In the vitamin D arm, the primary outcome occurred in three participants (0.5%) in the placebo group and in two participants (0.3%) receiving vitamin D. Adverse events were comparable in all groups.

CONCLUSIONS/INTERPRETATION

Uncertainty persists regarding the clinically relevant risks and benefits of TZDs and vitamin D because of the early cancellation of this comprehensive trial.

Effects of ramipril and rosiglitazone on cardiovascular and renal outcomes in people with impaired glucose tolerance or impaired fasting glucose: results of the Diabetes REduction Assessment with ramipril and rosiglitazone Medication (DREAM) trial

OBJECTIVE

Impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) are risk factors for diabetes, cardiovascular disease (CVD), and kidney disease. We determined the effects of ramipril and rosiglitazone on combined and individual CVD and renal outcomes in people with IGT and/or IFG in the Diabetes REduction Assessment With ramipril and rosiglitazone Medication (DREAM) trial.

RESEARCH DESIGN AND METHODS

A total of 5,269 people aged >or=30 years, with IGT and/or IFG without known CVD or renal insufficiency, were randomized to 15 mg/day ramipril versus placebo and 8 mg/day rosiglitazone versus placebo. A composite cardiorenal outcome and its CVD and renal components were assessed during the 3-year follow-up.

RESULTS

Compared with placebo, neither ramipril (15.7% [412 of 2,623] vs. 16.0% [424 of 2,646]; hazard ratio [HR] 0.98 [95% CI 0.84-1.13]; P = 0.75) nor rosiglitazone (15.0% [394 of 2,635] vs. 16.8% [442 of 2,634]; 0.87 [0.75-1.01]; P = 0.07) reduced the risk of the cardiorenal composite outcome. Ramipril had no impact on the CVD and renal components. Rosiglitazone increased heart failure (0.53 vs. 0.08%; HR 7.04 [95% CI 1.60-31.0]; P = 0.01) but reduced the risk of the renal component (0.80 [0.68-0.93]; P = 0.005); prevention of diabetes was independently associated with prevention of the renal component (P < 0.001).

CONCLUSIONS

Ramipril did not alter the cardiorenal outcome or its components. Rosiglitazone, which reduced diabetes, also reduced the development of renal disease but not the cardiorenal outcome and increased the risk of heart failure.

Impaired drinking capacity in patients with functional dyspepsia: intragastric distribution and distal stomach volume

The water drink test is a good tool to evoke dyspeptic symptoms. To what extent these symptoms are related to altered gastric distribution is not clear. Therefore, we determined gastric volumes after a drink test using SPECT. After a baseline scan 20 healthy volunteers (HV) and 18 patients with functional dyspepsia (FD) underwent a drink test (100 mL min(-1)) followed by five scans up to 2 h. Dyspeptic symptoms were scored before every scan. A Wilcoxon signed rank test (P < 0.05) and a mixed effects model were used for statistical analyses. Fasting volumes were significantly higher in FD compared to HV for total, proximal and distal stomach (P < 0.001). Functional dyspeptic patients ingested significantly less water (P < 0.001) and had an impaired filling of the distal part of the stomach (P = 0.001) after the drink test. In FD, bloating (prox. 80%, dist. 56%), pain (prox. 87%, dist. 62%) and fullness (prox. 80%, dist. 59%) were determined more by proximal stomach volume rather than distal stomach volume. These data suggest that drinking capacity is mainly determined by antral volume, with a reduced antral filling in FD compared to HV. The persisting symptoms of bloating, pain and fullness in FD are predominantly associated with proximal stomach volume.

Metformin as first choice in oral diabetes treatment: the UKPDS experience

Metformin has been used successfully since the 1950s as first line pharmacotherapy to treat people with type 2 diabetes. It is a biguanide that decreases blood glucose concentration by mechanisms different from those of insulin secretagogues, such as sulphonylureas, or exogenous insulin therapy. Metformin lowers, rather than increases, fasting plasma insulin concentrations and acts by enhancing insulin sensitivity, inducing greater peripheral uptake of glucose, and decreasing hepatic glucose output. By reducing hepatic glucose output it lowers blood glucose and insulin levels with minimal risk of hypoglycaemia, and when used as monotherapy can lower HbAlc by around 1.5%. It is usually well tolerated, the most common side effects being gastrointestinal. Of particular value is that the improved glucose control seen with metformin is achieved without weight gain. Concerns that it may increase the risk of lactic acidosis have largely been allayed with recent studies suggesting less than one case per 100,000 treated patients. The UK Prospective Diabetes Study (UKPDS) demonstrated a substantial beneficial effect of metformin therapy on cardiovascular disease (CVD) outcomes, with a 36% relative risk reduction in all cause mortality and a 39% relative risk reduction in myocardial infarction . The first ever joint ADA (American Diabetes Association) and EASD (European Association for the Study of Diabetes) consensus guidelines on the management of hyperglycaemia in type 2 diabetes state explicitly that metformin should be used as first-line foundation therapy, in addition to lifestyle interventions.

A Diabetes Outcome Progression Trial (ADOPT): baseline characteristics of Type 2 diabetic patients in North America and Europe

AIMS

To examine baseline characteristics of patients recruited into ADOPT, a multinational trial comparing three oral glucose-lowering monotherapies.

METHODS

Between April 2000 and June 2002, 4360 patients aged 30-75 years with Type 2 diabetes diagnosed for < 3 years and remaining on diet therapy alone with fasting plasma glucose levels (FPG) between 7.0 and 10.0 mmol/l were enrolled by 488 North American and European centres. Medical histories, anthropometric data and laboratory measurements were determined using common methodologies.

RESULTS

The mean (SD) age of the patients was 57 (10) years, body mass index 32.2 (6.4) kg/m(2), HbA(1c) 7.4 (0.9)%; 58% were male, 88% Caucasian and 15% smoked. North American Caucasians (NAC) were younger, more obese, and more insulin resistant than European Caucasians (EUC), but had better pancreatic B-cell function. NAC had lower total, low-density lipoprotein- and high-density liporpotein-cholesterol concentrations with higher triglyceride concentrations and were more often on lipid-lowering treatment. They had lower blood pressure levels but were equally likely to be on antihypertensive treatment. Metabolic syndrome was more frequent and microalbuminuria less frequent in NAC. Within North America, NAC had lower HbA(1c) concentrations than Blacks, Hispanics and Asians despite similar or higher FPG and 30-min postchallenge glucose concentrations.

CONCLUSIONS

Caucasian North American and European ADOPT patients differ with respect to adiposity, insulin resistance and metabolic syndrome prevalence. North American Blacks, Hispanics and Asians had lower HbA(1c) concentrations than NAC despite similar or higher glucose concentrations. These phenotypic differences may influence the progression of Type 2 diabetes and the response to initial oral glucose-lowering monotherapy.

Comparison of the efficacies of disinfectants to control microbial contamination in dental unit water systems in general dental practices across the European Union

Water delivered by dental unit water systems (DUWS) in general dental practices can harbor high numbers of bacteria, including opportunistic pathogens. Biofilms on tubing within DUWS provide a reservoir for microorganisms and should be controlled. This study compared disinfection products for their ability to meet the American Dental Association's guideline of <200 CFU x ml(-1) for DUWS water. Alpron, BioBlue, Dentosept, Oxygenal, Sanosil, Sterilex Ultra, and Ster4Spray were tested in DUWS (n = 134) in Denmark, Germany, Greece, Ireland, The Netherlands, Spain, and the United Kingdom. Weekly water samples were tested for total viable counts (TVCs) on yeast extract agar, and, where possible, the effects of products on established biofilm (TVCs) were measured. A 4- to 5-week baseline measurement period was followed by 6 to 8 weeks of disinfection (intermittent or continuous product application). DUWS water TVCs before disinfection ranged from 0 to 5.41 log CFU x ml(-1). Disinfectants achieved reductions in the median water TVC ranging from 0.69 (Ster4Spray) to 3.11 (Dentosept) log CFU x ml(-1), although occasional high values (up to 4.88 log CFU x ml(-1)) occurred with all products. Before treatment, 64% of all baseline samples exceeded American Dental Association guidelines, compared to only 17% following commencement of treatment; where tested, biofilm TVCs were reduced to below detectable levels. The antimicrobial efficacies of products varied (e.g., 91% of water samples from DUWS treated with Dentosept or Oxygenal met American Dental Association guidelines, compared to 60% of those treated with Ster4Spray). Overall, the continuously applied products performed better than those applied intermittently. The most effective products were Dentosept and Oxygenal, although Dentosept gave the most consistent and sustained antimicrobial effect over time.

Assessment of visceral sensitivity using radio telemetry in a rat model of maternal separation

Stress plays an important role in the development of visceral hypersensitivity, a key mechanism underlying the pathophysiology of the irritable bowel syndrome. Visceral sensitivity in rats is generally assessed under restrain conditions. To avoid this potential stress factor, we developed a model using implanted radio telemetry for remote measurement of the visceromotor response (VMR) to colorectal distention (CRD). Ten days after implantation of a radio telemetry transmitter and EMG electrodes, visceral sensitivity was evaluated by applying a standardized distension protocol (1, 1.5 and 2 mL) on three different days. In a second series, visceral sensitivity was assessed in maternally separated rats before, directly after and at 6 and 24 h after water avoidance (WA) stress. CRD resulted in a reproducible VMR response on the three different study days. In separated but not in non-handled rats, WA significantly increased visceral sensitivity at 6 h (P=0.006) and 24 h (P=0.004) after WA. Our results show that radio telemetry is a reliable and well tolerated new tool for evaluating visceral sensitivity in rats. These data further confirm that maternal separation is a good model for evaluating the mechanisms underlying visceral hypersensitivity.

Reproducibility of meal-induced transient lower oesophageal sphincter relaxations in patients with gastro-oesophageal reflux disease

AIM

To calculate the number of subjects required in trials investigating drugs reducing the number of transient lower oesophageal sphincter relaxations (TLOSRs), the inter- and intra-individual variability of TLOSRs were determined, using meal ingestion as a trigger of TLOSRs and reflux.

METHODS

A total of 23 gastro-oesophageal reflux disease (GORD) patients with no to grade B oesophagitis and a hiatal hernia < or =3 cm underwent oesophageal manometry and pHmetry 1 h before and 3 h after ingestion of a solid meal on two separate days approximately 4 weeks apart. Reflux episodes and the underlying mechanisms and the number of TLOSRs were evaluated.

RESULTS

The number of TLOSRs, reflux episodes and % time with pH < 4 after meal ingestion did not differ significantly between the two sessions. The intra-individual variation of TLOSRs in the 3 h postprandial period (24.4) was smaller compared with the inter-individual variation (47.5). Transient lower oesophageal sphincter relaxations were the predominant cause of reflux accounting for 61 +/- 7 and 70 +/- 5% of the reflux episodes in visits 1 and 2, respectively.

CONCLUSIONS

These data for the first time provide information on the variability of TLOSRs and reflux evoked by meal ingestion, which is of crucial importance for the design and power calculations of future clinical studies evaluating the efficacy of new drugs targeting TLOSRs.

Rationale, design and recruitment characteristics of a large, simple international trial of diabetes prevention: the DREAM trial

AIMS/HYPOTHESIS

Diabetes is a rapidly rising independent risk factor for atherosclerosis and serious illness. This risk can be reduced by lifestyle changes and/or various drugs. Novel therapies to prevent diabetes, as well as new risk factors for diabetes, atherosclerosis and obesity require testing and identification.

METHODS

People with impaired fasting glucose or impaired glucose tolerance were randomised to ramipril (15 mg/day) or placebo and rosiglitazone (8 mg/day) or placebo with a 2x2 factorial design. They are assessed semi-annually for the primary outcome (diabetes or death). Diabetes is diagnosed if two consecutive plasma glucose levels exceed diagnostic thresholds (i.e. fasting >/=7.0 mmol/l or 2-h >/=11.1 mmol/l) within a 3-month period. Assuming an annual primary outcome incidence of 5%, there is more than 90% power to detect a 22% reduction. Approximately 20% of participants are having annual carotid ultrasounds to assess the effects on atherosclerosis. Patients screened but not randomised are being followed prospectively to identify determinants of obesity, diabetes and related disorders.

RESULTS

A total of 24,872 individuals in 21 countries were screened over 2 years and are eligible for follow-up. Of these, 5269 were randomised: 1835 (35%) had isolated impaired glucose tolerance, 739 (14%) had isolated impaired fasting glucose, and 2692 (51%) had both disorders. Annual carotid ultrasounds are currently being performed in 1406 randomised individuals.

CONCLUSIONS/INTERPRETATION

The DREAM trial and related studies will determine if ramipril or rosiglitazone reduces the number of cases of diabetes and atherosclerosis, and will identify novel risk factors for diabetes.

Improved brief assessment of cognition in aging and dementia

To enhance the score interpretation and practicality of the Cambridge Cognitive Examination (CAMCOG) neuropsychological test, the authors used item response theory (IRT) to calibrate the difficulty of the items using the scores of 797 subjects. Forty-seven items fitted the IRT model. Score agreement with equally difficult short forms was excellent. The practicality and interpretability of the CAMCOG was improved, while the diagnostic accuracy of the short forms was similar to that of the original 60-item instrument.

Artesunate with mefloquine at various intervals for non-severe Plasmodium falciparum malaria

To study the efficacy, tolerance, population pharmacokinetics and pharmacodynamics of artesunate followed by mefloquine at various intervals, 360 patients with Plasmodium falciparum malaria received 4 mg/kg of artesunate and thereafter 15 mg/kg of mefloquine simultaneously (group A), after 8 hours (after group B), and after 24 hours (group C). Three dosages were completed with placebo. Follow-up was 28 days. All patients recovered rapidly except one case of failure within the first 24 hours. Mefloquine pharmacokinetics was similar in the three regimens. Parasites reappeared in 26%, 26%, and 33% of the patients in groups A, B, and C, respectively. Early recrudescence was associated with high initial parasite density, slow parasite clearance, and rapid mefloquine clearance and low plasma concentrations at day 28. Mefloquine plasma concentrations all reached therapeutic ranges, suggesting reduced parasite sensitivity. In conclusion, there is no interaction between artesunate and mefloquine with respect to tolerance, efficacy, and pharmacokinetics. Single-dose combination therapy with artemisinin drugs and 15 mg/kg of mefloquine does not completely prevent parasite recurrence and may not prevent mefloquine resistance.

[Qualitative malnutrition due to incorrect complementary feeding in Bush Negro children in Suriname]

OBJECTIVE

To determine whether the increase in the percentage of stunted growth in Bush Negro infants in the interior of Surinam is related to an absolute food (i.e. energy) shortage or to a shortage of protein.

DESIGN

Descriptive.

METHOD

In the villages of Dan and Botopasi, children aged 2-5 years from two schools and their mothers were examined. Growth during the first year of life, duration of breastfeeding, age of introduction of and composition of complementary feeding and current nutritional status of mother and child were determined.

RESULTS

Sixteen children and their mothers were included. Compared to the Dutch growth charts, birth weight was significantly lower (p = 0.03). After the age of 6 months there was a significant dropping off in weight gain (p = 0.018). Five of the 16 children received protein-poor complementary feeding, which did not lead to catch-up growth. Between the ages of 2-5, 6 of the 16 children showed stunted growth but none of the children or their mothers was wasted. Five of the 16 mothers had a body mass index > 25.

CONCLUSION

The nutritional status of the mothers showed that there was no absolute shortage of energy. The protein content coming from the complementary food for the Bush Negroes in our research group was below recommended levels. Stunted growth in these children is better explained by a shortage of well-balanced complementary feeding rather than by an absolute shortage of energy. Education about food recommendations for the young child is of great importance in the prevention of chronic malnutrition.

Scaling the sickness impact profile using item response theory: an exploration of linearity, adaptive use, and patient driven item weights

BACKGROUND AND OBJECTIVE

The objective of the study was to enhance the clinical interpretation and practicality of the widely used comprehensive Sickness Impact Profile.

METHOD

Item Response Theory (extension of the Rasch model) was used to calibrate the severity of the SIP items, to assess item bias and to construct equally severe short forms of the SIP that can be used interchangeably. The scores of 1507 subjects were analyzed.

RESULTS

Of the 127 SIP items, 82 items fitted the extended Rasch model, i.e., the observed proportions of sickness level groups endorsing the items corresponded to the proportions expected by the model. The item severity hierarchy allowed a more straightforward interpretation of the calibrated SIP-82 scores. Some items showed bias in age, gender, or diagnosis groups. The equivalent short forms agreed sufficiently well with the calibrated SIP-82 item pool to be used interchangeably. We observed a moderate correlation between the original SIP item severity weights and the Rasch item severity calibrations (r=0.53).

CONCLUSION

The interpretability and practicality of the SIP was enhanced by the IRT calibration. Using the item calibrations, short forms can be assembled that can be used interchangeably.

Neuropathology of the brain and spinal cord in human West Nile virus infection

OBJECTIVE

To describe the histopathology of the brain and spinal cord in human West Nile virus (WNV) infection.

MATERIALS AND METHODS

Single case report, including premortem clinical and laboratory findings, and autopsy.

RESULTS

An 83-year-old female presented with acute confusion, high fevers, dysarthria and generalized subjective weakness, with decreased deep tendon reflexes and weakness on physical examination. Electromyography showed evidence of a sensorimotor axonal polyneuropathy of the right-sided extremities. She became ventilator-dependent and died after a 2-week ICU stay, following withdrawal of life support. WNV infection was confirmed premortem by detection of IgM antibodies from serum and CSF and postmortem by RT-PCR from brain tissue. Examination of the brain parenchyma showed scattered microglial aggregates accompanied by perivascular chronic inflammation. The leptomeninges showed focal lymphocytic infiltrates. Examination of the spinal cord showed lymphocytic infiltrates in nerve roots and within the cord proper, with focal microglial nodules and neuronophagia in the ventral horns. Special stains were negative for a demyelinating process. General autopsy revealed only emphysema and atelectasis.

CONCLUSIONS

The findings in this case suggest direct viral infection of the spinal cord and nerve roots as the mechanism of the flaccid paralysis often observed in patients infected with WNV. Findings are reviewed in comparison with other reports of neuropathologic findings in human WNV infection.

Radion-induced brane preheating

When the interbrane separation in the compact Randall-Sundrum model is stabilized using the Goldberger-Wise mechanism, a potential is generated for the four-dimensional field, the radion, that encodes this separation. Coherent oscillations of the radion in the early universe will produce an exponential growth in the number of brane particles due to parametric amplification. We describe the conditions necessary for this process, which resembles the preheating phase in inflation, and show the exponential growth in the case of a scalar field confined to a brane.

The impact of diabetes-related complications on healthcare costs: results from the United Kingdom Prospective Diabetes Study (UKPDS Study No. 65)

AIMS

To develop a model for estimating the immediate and long-term healthcare costs associated with seven diabetes-related complications in patients with Type 2 diabetes participating in the UK Prospective Diabetes Study (UKPDS).

METHODS

The costs associated with some major complications were estimated using data on 5102 UKPDS patients (mean age 52.4 years at diagnosis). In-patient and out-patient costs were estimated using multiple regression analysis based on costs calculated from the length of admission multiplied by the average specialty cost and a survey of 3488 UKPDS patients' healthcare usage conducted in 1996-1997.

RESULTS

Using the model, the estimate of the cost of first complications were as follows: amputation pound 8459 (95% confidence interval pound 5295, pound 13 200); non-fatal myocardial infarction pound 4070 ( pound 3580, pound 4722); fatal myocardial infarction pound 1152 ( pound 941, pound 1396); fatal stroke pound 3383 ( pound 1935, pound 5431); non-fatal stroke pound 2367 ( pound 1599, pound 3274); ischaemic heart disease pound 1959 ( pound 1467, pound 2541); heart failure pound 2221 ( pound 1690, pound 2896); cataract extraction pound 1553 ( pound 1320, pound 1855); and blindness in one eye pound 872 ( pound 526, pound 1299). The annual average in-patient cost of events in subsequent years ranged from pound 631 ( pound 403, pound 896) for heart failure to pound 105 ( pound 80, pound 142) for cataract extraction. Non-in-patient costs for macrovascular complications were pound 315 ( pound 247, pound 394) and for microvascular complications were pound 273 ( pound 215, pound 343) in the year of the event. In each subsequent year the costs were, respectively, pound 258 ( pound 228, pound 297) and pound 204 ( pound 181, pound 255).

CONCLUSIONS

These results provide estimates of the immediate and long-term healthcare costs associated with seven diabetes-related complications.

Activities of daily living instruments:optimizing scales for neurologic assessments

The ability to perform activities of daily living (ADL) is an important part of assessment in neurologic patients. A literature search was carried out to identify multi-item ADL scales developed for the assessment of neurologic patients, comparing item content, range, and detail of ADL scales. Of the 113 ADL scales identified, 27 (24%) were designed for use in neurology. In the basic ADL (BADL) domains (basic mobility and self-care), individual items were present in 44% to 81% of instruments. In the extended ADL (EADL) domains (e.g., outdoor mobility, housekeeping), items were present in up to 67% of the instruments identified. A typical trade-off was observed between the range, the detail (number of items), and hence the practicality of a scale. In general, scales focus on either BADL or EADL domains or, on occasion, some of both, rather than measuring the full range of functioning. There are many ADL scales in neurology, with much overlap in item content, leading to redundancy. New scales developed with the traditional methods will not solve the existing difficulties associated with range and detail, ordinal scale scores, and cross-instrument comparability. The possibilities of a modern psychometric method known as item response theory that was designed to solve these problems are discussed.

Effect of the low-affinity, noncompetitive N-methyl-d-aspartate receptor antagonist dextromethorphan on visceral perception in healthy volunteers

BACKGROUND

The use of N-methyl-d-aspartate (NMDA) receptor antagonists may hold promise for the treatment of pain of visceral origin, in particular in conditions characterized by visceral hypersensitivity.

AIM

To study the effect of dextromethorphan, a low affinity, non-competitive NMDA receptor antagonist, on visceral perception in healthy volunteers.

METHODS

Nine healthy volunteers (5 female, median age 22 years) underwent a gastric barostat study after oral administration of placebo, dextromethorphan 10 mg or dextromethorphan 30 mg, on three separate days in a double-blind, randomised order. Sensations induced by step-wise isobaric gastric distension (2 mmHg/2 min) were studied during fasting and 30 min after a meal. In addition, proximal gastric tone was measured during fasting and postprandially.

RESULTS

Compared to placebo, dextromethorphan 30 mg significantly increased the distension-evoked sensation scores for nausea (P=0.004) and satiation (P=0.004) during fasting; and for bloating (P= 0.001), nausea (P=0.000) and satiation (P=0.01) 30 min postprandially. Dextromethorphan did not alter pain scores, proximal gastric tone or gastric compliance.

CONCLUSIONS

Dextromethorphan increases the perception of non-painful sensations during gastric distension, without altering the perception of pain. Therefore, application of dextromethorphan as a visceral analgesic is questionable. Future studies with more specific NMDA receptor antagonist are warranted.

Identification of HLA-B*1566

A novel polymorphism was identified in a B*15 allele. B*1566 possesses a nucleotide substitution of C to G at nucleotide 272. This polymorphism encodes an amino acid difference from serine in B*1501101 to cysteine in B*1566 at residue 67. Residue 67 is a constituent of the B pocket and is situated on the alpha1 helix facing into the groove. This mutation may have arisen through interallelic recombination as it has been seen in other B*15 alleles and is also present in most B*14, B*27, B*38, B*39 alleles and in B*7301.

[Measuring the functional status of patients in clinical trials using modern clinimetric methods]

In clinical medicine numerous measurement instruments have been developed to assess the functional outcome of patients in clinical trials. The majority are questionnaires with multiple-choice items. The responses of the patients are used to calculate a sum score. However, there are some disadvantages associated with the use of sum scores. Modern clinimetric methods, based on item response theory (IRT) in combination with a calibrated item bank, can overcome these problems. When using this measurement technique, it is possible to arrange both the item difficulty and the patient's ability on a single, hierarchical linear scale. This allows the user to obtain a sufficiently detailed clinical picture using a small number of items. In addition to being efficient, this method makes it possible to present different sets of items to different groups of patients. Since all of the items are calibrated, the measurements remain comparable. The application of this innovative method of measuring is being studied in the ongoing 'Amsterdam linear disability score' (ALDS) project.

Sequence of two new HLA-Cw alleles: HLA-Cw*0313 and HLA-Cw*1208

Two new HLA-C alleles have been identified by reverse line blot assay and direct sequencing of polymerase chain reaction (PCR) products. The first polymorphism encodes an amino acid change from lysine in Cw*12022 to asparagine in Cw*1208 at residue 66. The second polymorphism encodes two amino acid changes from isoleucine in Cw*03031 to threonine in Cw*0313 at residue 93 and isoleucine to leucine at residue 94. The functional significance of these polymorphisms on peptide-binding and/or T-cell recognition is unknown.

Underestimation of the importance of homocysteine as a risk factor for cardiovascular disease in epidemiological studies

BACKGROUND

In epidemiological studies, within-person variability in plasma total homocysteine (tHcy) measurements may dilute the association of 'usual' levels of tHcy with risk of cardiovascular disease, referred to as 'regression dilution'. The aim of this report was to estimate the magnitude of regression dilution after varying intervals of follow-up.

METHODS

Regression dilution ratios (RDR) for tHcy were calculated using replicate tHcy measurements obtained after 3, 6 and 8 years from the Rotterdam, Hordaland and Framingham studies, respectively, and after 3, 6, 9 and 12 years from the United Kingdom Prospective Study of type 2 Diabetes Mellitus (UKPDS).

RESULTS

The RDR for tHcy decreased with increasing interval in the three population-based studies and in the UKPDS. Moreover, the rate of decline of the RDR in the population-based studies was similar to that obtained in the UKPDS. Using linear regression analysis for the population-based studies, these results suggest an RDR of 0.83 at 2 years, 0.71 at 6 years and 0.53 at 12 years.

CONCLUSIONS

These results have important implications for the interpretation of prospective studies of tHcy and cardiovascular disease. Failure to correct for increasing regression dilution using lower RDRs for longer follow-up may underestimate the relative risks of cardiovascular disease associated with tHcy by about one-fifth after 2 years and one-half after 10 years.

An economic evaluation of atenolol vs. captopril in patients with Type 2 diabetes (UKPDS 54)

AIMS

To compare the net cost of a tight blood pressure control policy with an angiotensin converting enzyme inhibitor (captopril) or beta blocker (atenolol) in patients with Type 2 diabetes.

DESIGN

A cost-effectiveness analysis based on outcomes and resources used in a randomized controlled trial and assumptions regarding the use of these therapies in a general practice setting.

SETTING

Twenty United Kingdom Prospective Diabetes Study Hospital-based clinics in England, Scotland and Northern Ireland.

SUBJECTS

Hypertensive patients (n = 758) with Type 2 diabetes (mean age 56 years, mean blood pressure 159/94 mmHg), 400 of whom were allocated to the angiotensin converting enzyme inhibitor captopril and 358 to the beta blocker atenolol.

MAIN OUTCOME MEASURES

Life expectancy and mean cost per patient.

RESULTS

There was no statistically significant difference in life expectancy between groups. The cost per patient over the trial period was 6485 UK pounds in the captopril group, compared with 5550 UK pounds in the atenolol group, an average cost difference of 935 UK pounds (95% confidence interval 188 UK pounds, 1682 UK pounds). This 14% reduction arose partly because of lower drug prices, and also because of significantly fewer and shorter hospitalizations in the atenolol group, and despite higher antidiabetic drug costs in the atenolol group.

CONCLUSIONS

Treatment of hypertensive patients with Type 2 diabetes using atenolol or captopril was equally effective. However, total costs were significantly lower in the atenolol group. Diabet. Med. 18, 438-444 (2001)

Cost-effectiveness analysis of intensive blood-glucose control with metformin in overweight patients with type II diabetes (UKPDS No. 51)

AIMS/HYPOTHESIS

To estimate the economic efficiency of intensive blood-glucose control with metformin compared with conventional therapy primarily with diet in overweight patients with Type II (non-insulin-dependent) diabetes mellitus.

METHODS

Cost-effectiveness analysis based on patient level data from a randomised clinical controlled trial involving 753 overweight (> 120% ideal body weight) patients with newly diagnosed Type II diabetes conducted in 15 hospital-based clinics in England, Scotland and Northern Ireland as part of the UK Prospective Diabetes Study. Subjects were allocated at random to an intensive blood-glucose control policy with metformin (n = 342) or a conventional policy primarily with diet (n = 411). The analysis was based on the cost of health care resources associated with metformin and conventional therapy and the estimated effectiveness in terms of life expectancy gained from within-trial effects.

RESULTS

Intensive blood-glucose control with metformin produced a net saving of 258 Pounds per patient (1997 United Kingdom prices) over the trial period (median duration of 10.7 years) due to lower complication costs, and increased life expectancy by 0.4 years (costs and benefits discounted at 6%).

CONCLUSIONS/INTERPRETATION

As metformin is both cost-saving in the United Kingdom and extends life expectancy when used as first line pharmacological therapy in overweight Type II diabetic patients, its use should be attractive to clinicians and health care managers alike.