Testing Precision and Accuracy of an Upper Extremity Proprioceptive Targeting Task Assessment

Objective

To develop and test an assessment measuring extended physiological proprioception (EPP). EPP is a learned skill that allows one to extend proprioception to an external tool, which is important for controlling prosthetic devices. The current study examines the ability of this assessment to measure EPP in a nonamputee population for translation into the affected population.

Design

Measuring precision and accuracy of an upper extremity (UE) proprioceptive targeting task assessment. Participants completed 2 sessions of a targeting task while seated at a table. The targeting was completed with the dominant and nondominant hand and with eyes open and eyes closed during the task. Participants completed 2 sessions of the clinical test with a 1-week washout period to simulate reasonable time between clinical visits.

Setting

Research laboratory.

Participants

Twenty right-handed participants (N=20) with no neurologic or orthopedic deficits that would interfere with proprioception, median age of 25 years (range, 19-33 years), completed the assessment (10 men, 10 women).

Interventions

Not applicable.

Main Outcome Measures

Precision (consistency in targeting) and accuracy (distance between the intended target and participant result) in UE targeting task using EPP; test-retest repeatability between sessions.

Results

Both precision and accuracy were significantly decreased in the eyes-closed condition compared with the eyes-open condition regardless of targeting with dominant or nondominant hand (all P<.001). In the eyes-open condition, there was a dominance effect relating to the accuracy; however, in the eyes-closed condition, accuracy between dominant and nondominant hands was statistically equivalent. Based on minimum detectable change with 95% confidence, there was no change in either metric between the first and second sessions.

Conclusions

The results of this study support the feasibility of using this assessment to measure EPP-based on the definition of EPP as a learned skill that indicates control over an external, simple tool-because they demonstrate reliance on proprioception in the eyes-closed condition, symmetry in proprioceptive accuracy between hands for within-participant control, and test-retest reliability for longitudinal measurements. The results also establish normative values for this assessment in young, healthy adults. Further research is required in a clinical population to evaluate the UE proprioceptive targeting task assessment further and collect objective data on EPP.

Determination of the Discriminating Concentration Towards Permethrin for Surveying Resistance in Amblyomma americanum

Amblyomma americanum Linnaeus (Ixodida: Ixodidae) is ubiquitously present throughout the southeastern United States and is capable of vectoring several pathogens. White-tailed deer are the main host for adult A. americanum. However, this tick species is a generalist that will feed on most vertebrates, including humans, deer, livestock, and pets. Management of this species can be challenging due to a lack of cost-effective strategies. Acaricides are often utilized, however, this may lead to pesticide resistance. The Food and Agriculture Organization of the United Nations (FAO) larval packet test (LPT) was performed on susceptible A. americanum to determine the lethal concentration (LC) and discriminating concentration (DC) values for permethrin. The FAO LPT was used at these pre-established values to compare levels of resistance in ticks collected from a captive deer farm and wild areas representing high and low permethrin exposure settings, respectively. Resistance ratios (RR) calculated from the LC values for the ticks collected from farmed and wild deer ranged between 1 and 2. A. americanum collected from farmed and wild deer were not found to be resistant, however, some samples had slightly elevated RRs as compared to the susceptible laboratory strain, which may suggest tolerance development. Although the A. americanum sampled in this study were not resistant to permethrin, the DC calculated in this study will allow for rapid evaluation of resistance in a permethrin resistance monitoring program such that alternate management strategies can be adopted if resistance is detected.

Finite Element Analysis of Transhumeral and Transtibial Percutaneous Osseointegrated Endoprosthesis Implantation

Cadaveric mechanical testing of a percutaneous osseointegration docking system (PODS) for osseointegration (OI) prosthetic limb attachment revealed that translation of the exact system from the humerus to the tibia may not be suitable. The PODS, designed specifically for the humerus achieved 1.4-4.8 times greater mechanical stability in the humerus than in the tibia despite morphology that indicated translational feasibility. To better understand this discrepancy, finite element analyses (FEAs) modeled the implantation of the PODS into the bones. Models from cadaveric humeri (n = 3) and tibia (n = 3) were constructed from CT scans, and virtual implantation preparation of an array of endoprosthesis sizes that made contact with the endosteal surface but did not penetrate the outer cortex was performed. Final impaction of the endoprosthesis was simulated using a displacement ramp function to press the endoprosthesis model into the bone. Impaction force and maximum first principal (circumferential) stress were recorded to estimate stability and assess fracture risk of the system. We hypothesized that the humerus and tibia would have different optimal PODS sizing criteria that maximized impaction force and minimized first principal stress. The optimal sizing for the humerus corresponded to implantation instructions, whereas for the tibia optimal sizing was three times larger than the guidelines indicated. This FEA examination of impaction force and stress distribution lead us to believe that the same endoprosthesis strategy for the humerus is not suitable for the tibia because of thin medial and lateral cortices that compromise implantation.

Virtual implantation technique to estimate endoprosthetic contact of percutaneous osseointegrated devices in the tibia

Percutaneous osseointegrated (OI) devices have an endoprosthesis attached to the residual bone of an amputated limb, then pass permanently through the skin to be connected to the distal prosthetic componentry outside of the body. Whether the bone-anchoring region of current OI endoprostheses are cylindrical, and/or conical, they require intimate bone-endoprosthesis contact to promote stabilizing bone attachment. However, removing too much cortical bone to achieve more contact leads to thinner and, subsequently, weaker cortical walls. Endoprostheses need to be designed to balance these factors, namely maximizing the contact, while minimizing the volume of bone removed. In this study, 27 human tibias were used to develop and validate a virtual implantation method. Then, 40 additional tibias were virtually implanted with mock cylindrical and conical bone-anchoring regions at seven residual limb lengths to measure resultant bone-endoprosthesis contact and bone removal. The ratio of bone-endoprosthesis contact to bone volume removed showed the conical geometry had more contact area per volume bone removed for all amputation levels (p ≤ 0.001). In both mock devices, cortical penetration of the endoprosthesis at 20% residual length occurred in 74% of cases evaluated, indicating that alternative endoprosthesis geometries may be needed for clinical success in that region of bone.

Upper extremity prosthetic selection influences loading of transhumeral osseointegrated systems

Percutaneous osseointegrated (OI) implants are increasingly viable as an alternative to socket suspension of prosthetic limbs. Upper extremity prostheses have also become more complex to better replicate hand and arm function and attempt to recreate pre-amputation functional levels. With more functionality comes heavier devices that put more stress on the bone-implant interface, which could be an issue for implant stability. This study quantified transhumeral loading at defined amputation levels using four simulated prosthetic limb-types: (1) body powered hook, (2) myoelectric hook, (3) myoelectric hand, and (4) advanced prosthetic limb. Computational models were constructed to replicate the weight distribution of each prosthesis type, then applied to motion capture data collected during Advanced Activities of Daily Living (AADLs). For activities that did not include a handheld weight, the body powered prosthesis bending moments were 13–33% (range of means for each activity across amputation levels) of the intact arm moments (reference 100%), torsional moments were 12–15%, and axial pullout forces were 30–40% of the intact case (p≤0.001). The myoelectric hook and hand bending moments were 60–99%, torsional moments were 44–97%, and axial pullout forces were 62–101% of the intact case. The advanced prosthesis bending moments were 177–201%, torsional moments were 164–326%, and axial pullout forces were 133–185% of the intact case (p≤0.001). The addition of a handheld weight for briefcase carry and jug lift activities reduced the overall impact of the prosthetic model itself, where the body powered forces and moments were much closer to those of the intact model, and more complex prostheses further increased forces and moments beyond the intact arm levels. These results reveal a ranked order in loading magnitude according to complexity of the prosthetic device, and highlight the importance of considering the patient’s desired terminal device when planning post-operative percutaneous OI rehabilitation and training.

Cortical and medullary morphology of the tibia

Bone resorption caused by stress shielding and insufficient bone-implant contact continues to be problematic for orthopedic endoprostheses that utilize osseointegration (OI) for skeletal fixation. Morphologic analyses have helped combat this issue by defining anatomic parameters to optimize endoprosthesis loading by maximizing bone-implant contact. These studies have not typically included diaphyseal medullary morphology, as this region is not pertinent to total joint replacement. To the contrary, percutaneous OI endoprostheses for prosthetic limb attachment are placed in the diaphysis of the long bone. This study examined the cortical and medullary morphology of 116 fresh-frozen human cadaveric tibia using computed tomography. Anatomic landmarks were selected and custom MATLAB scripts were used to analyze the cross-sectional cortical and medullary morphology normalized to biomechanical length (BML). BML measured the distance between the tibial plateau and the tibial plafond. Properties such as cortical thickness, medullary diameter, and circularity of the medullary canal were quantified. We tested the influence of sex and laterality on morphology, and examined variations along the length of the bone. Results showed that while both sex and laterality impacted the location of anatomic landmarks, only sex influenced cross-sectional morphology. Overall, morphology significantly affected shape along the length of the bone for all examined properties except medullary circularity. This analysis found that distal to 35% BML, the canal is conducive to a circular implant, with medullary diameter ranging from 13 to 32 mm between 20 and 80% BML. A large size range is necessary for sufficient implant contact in order to accommodate residual limb length after amputation.

Estimated forces and moments experienced by osseointegrated endoprostheses for lower extremity amputees

BACKGROUND

Percutaneous osseointegrated (OI) docking of prosthetic limbs returns loading directly to the residual bone of individuals with amputations. Lower limb diaphyseal biomechanics have not been studied during the wide range of daily activities performed by individuals with lower extremity amputations; therefore, little is known about the loads experienced at the bone-endoprosthetic interface of a percutaneous OI device.

RESEARCH QUESTION

Does residual limb length and/or gender influence loading magnitudes in the diaphysis of the femur or tibia during daily activities?

METHODS

This observational study used motion capture data from 40 non-amputee volunteers performing nine activities ranging from low to high demand, to virtually simulate residual limbs of amputees. To simulate diaphyseal bone loading in individuals with lower limb amputations, virtual joints were defined during post-processing at 25, 50, and 75 % of residual limb length of both the femur and the tibia, representing six clinically relevant residual limb lengths for OI device placement. Peak axial distractive and compressive forces, torsional moments, and bending moments were calculated for each activity. Comparisons were made between genders and between different levels of the simulated residual limb.

RESULTS

For simulated above and below knee amputations, short residual limbs showed the highest average bending, torsion, and axial distractive loads, while axial compressive loads were highest for long residual limbs. Absolute maxima for all subjects showed this same trend, except in below knee torsion, where 75 % residual tibia length showed the maximum. The highest demand activities yielding peaks in all directions were cutting with right leg planted, jump, run, and fall.

SIGNIFICANCE

Overall, individuals with shorter residual limbs experienced higher diaphyseal forces. This should be taken into consideration during surgical implantation of percutaneous OI devices where residual limb length can potentially be shortened, and during rehabilitation of percutaneous OI patients.

Abstract P3-10-25: Clinicopathologic factors associated with pCR to neoadjuvant anti-HER2-directed chemotherapy

Background: While the use of neoadjuvant therapy has become the standard of care in certain locally advanced breast cancers, questions remain regarding the optimal chemotherapeutic regimen as well as biologic and patient-specific predictors of pathologic complete response. In this study, we examined patient and tumor-specific characteristics associated with increased prediction of pathologic complete response (pCR) to neoadjuvant anti-HER2-directed chemotherapy.

Methods: 204 patients who received neoadjuvant anti-HER2-directed chemotherapy at our institution from 2006-2016 were included in this retrospective study. Univariate analyses were performed to analyze the relationships of multiple clinical and pathologic features to pCR rate. Multivariate analysis was also performed to evaluate the relative impact of specific pathologic characteristics on pCR rate.

Results: Among 204 patients with HER2 overexpressing breast cancers treated with neoadjuvant chemotherapy, 52.7% achieved pCR. Pathologic complete response was positively associated with high tumor grade (61.0% grade 3 in pCR group vs 39.0% in non-pCR group, P=0.23) and high Ki67 index (mean Ki67 59.1 in pCR group vs 47.4 in non-pCR; P= 0.015). It was also associated with HER2 IHC 3+ (57.1% in pCR group vs 42.9% in non-pCR, p=0.029), HER2 copy number (mean copy number 16.8 in pCR group vs 12.4 in non-PCR, p-0.004), and HER2/CEP 17 ratio (mean ratio 6.42 in pCR group vs 5.17 in non-pCR; P= 0.046). Rates of HER2 FISH positivity were equal in the pCR and non-pCR groups (50.8% vs 49.2%, p=0.062). Multivariate analysis demonstrated that higher Ki67 index and higher HER2/CEP17 ratio are significant predictors of pCR after adjusting for other covariates (odds ratio for Ki67 1.03 (1.06-1.49), p=0.002; for HER2/CEP17 ratio OR 1.26 (1.06-1.49), p=0.009).

Conclusions: In HER2 positive breast cancers, a higher Ki67 index as well as higher HER2/CEP17 ratios are associated with an increased pCR rate and may be useful as predictors of response prior to neoadjuvant therapy. Our results also demonstrate HER2 IHC to be a stronger predictor than HER2 FISH of response to upfront therapy. Larger studies would be useful as this association, if confirmed, may have relevance to clinical practice.

Citation Format: Meisel JL, Suo A, Taylor CE, Zhang C, Li X. Clinicopathologic factors associated with pCR to neoadjuvant anti-HER2-directed chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-25.

Effect of concussion and blast exposure on symptoms after military deployment

Objective:

To examine whether blast exposure alone and blast-associated concussion result in similar neurologic and mental health symptoms.

Methods:

A 14-item questionnaire was administered to male US Marines on their return from deployment in Iraq and/or Afghanistan.

Results:

A total of 2,612 Marines (median age 22 years) completed the survey. Of those, 2,320 (88.9%) reported exposure to ≥1 blast during their current and/or prior deployments. In addition, 1,022 (39.1%) reported ≥1 concussion during the current deployment, and 731 (28.0%) had experienced at least 1 prior lifetime concussion. Marines were more likely to have sustained a concussion during the current deployment if they had a history of 1 (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.2–2.0) or ≥1 (OR 2.3, 95% CI 1.7–3.0) prior concussion. The most common symptoms were trouble sleeping (38.4%), irritability (37.9%), tinnitus (33.8%), and headaches (33.3%). Compared to those experiencing blast exposure without injury, Marines either experiencing a concussion during the current deployment or being moved or injured by a blast had an increased risk of postinjury symptoms.

Conclusions:

There appears to be a continuum of increasing total symptoms from no exposure to blast exposure plus both current deployment concussion and past concussion. Concussion had a greater influence than blast exposure alone on the presence of postdeployment symptoms. A high blast injury score can be used to triage those exposed to explosive blasts for evaluation.

Hard two-body photodisintegration of 3He

We have measured cross sections for the γ(3)He → pd reaction at photon energies of 0.4-1.4 GeV and a center-of-mass angle of 90°. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

The effectiveness of local child weight management programmes: an audit study

BACKGROUND

  Many different child weight management programmes exist, with varying degrees of evaluation to provide evidence of their success. The purpose of this research was to use a standardized approach to audit the effectiveness of weight management intervention programmes in the West Midlands region of the UK, specifically to assess the benefits to participating children in terms of health improvement and behaviour change.

METHODS

  An audit of seven family-based intervention programmes currently in place in the West Midlands. Programmes were audited against the Standard Evaluation Framework.

RESULTS

  The programmes provided a partial data set relating to a change in weight from the baseline to the end of the programme; none of the programmes provided all of the measures indicated by the Standard Evaluation Form as being essential for evaluation. Weight change ranged from an increase in group mean of 0.4 kg to a decrease of 0.9 kg. Body Mass Index SD decreased by 0.1-0.2 points in four programmes and remained unchanged in two programmes. Four programmes collected long-term follow-up data at 6 months. This was often limited because of participant dropout. Improvement in diet and exercise were reported by participants in all programmes which measured these behaviours.

CONCLUSIONS

  Ongoing evaluation of all programmes, using a standard approach, is essential in order to improve the evidence base and support future commissioning.

Measurement of exclusive π(0) electroproduction structure functions and their relationship to transverse generalized parton distributions

Exclusive π(0) electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in Q(2), x(B), t, and ϕ(π), in the Q(2) range from 1.0 to 4.6  GeV(2), -t up to 2  GeV(2), and x(B) from 0.1 to 0.58. Structure functions σ(T)+ϵσ(L), σ(TT), and σ(LT) were extracted as functions of t for each of 17 combinations of Q(2) and x(B). The data were compared directly with two handbag-based calculations including both longitudinal and transversity generalized parton distributions (GPDs). Inclusion of only longitudinal GPDs very strongly underestimates σ(T)+ϵσ(L) and fails to account for σ(TT) and σ(LT), while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity-flip and helicity nonflip processes. The results confirm that exclusive π(0) electroproduction offers direct experimental access to the transversity GPDs.

Pre-race dietary carbohydrate intake can independently influence sub-elite marathon running performance

We examined whether selected anthropometric and nutritional factors influenced field-based marathon running performance. An internet-based data collection tool allowed competitors in the 2009 London Marathon (n=257, mean ± SD age: 39 ± 8 years, finish time: 273.8 ± 59.5 min) to record a range of anthropometric, training and nutritional predictors. Multivariate statistical methods were used to quantify the change in running speed mediated by a unit change in each predictor via the 95% confidence interval for each covariate-controlled regression slope ( B). Gender ( B=1.22 to 1.95 km/h), body mass index ( B=-0.14 to -0.27 km/h), training distance ( B=0.01 to 0.04 km/h) and the amount of carbohydrate consumed the day before the race ( B=0.08 to 0.26 km/h) were significant predictors, collectively accounting for 56% of the inter-individual variability in running speed (P<0.0005). Further covariate-adjusted analysis revealed that those competitors who consumed carbohydrate the day before the race at a quantity of >7 g/kg body mass had significantly faster overall race speeds (P=0.01) and maintained their running speed during the race to a greater extent than with those who consumed <7 g/kg body mass (P=0.02). We conclude that, in addition to gender, body size and training, pre-race day carbohydrate intake can significantly and independently influence marathon running performance.

Neurovascular coupling and distribution of cerebral blood flow during exercise

We examined how cerebral blood flow velocity (CBV) and neurovascular coupling is influenced by exercise. Blood velocities in the posterior and middle cerebral arteries (PCAv and MCAv) during rest and cycling exercise at 60% estimated maximal oxygen consumption were measured. Neurovascular coupling was quantified as the ΔPCAv with visual stimulation. During exercise, despite a 15.2±13.6% and 26.1±22.5% increase from rest in the MCAv and PCAv, respectively, neurovascular coupling was unaltered. Thus, despite regionally heterogeneous elevations in CBV during exercise, neurometabolic coupling is maintained.

Tensor correlations measured in 3He(e,e' pp)n

We have measured the 3He(e,e' pp)n reaction at an incident energy of 4.7 GeV over a wide kinematic range. We identified spectator correlated pp and pn nucleon pairs by using kinematic cuts and measured their relative and total momentum distributions. This is the first measurement of the ratio of pp to pn pairs as a function of pair total momentum p(tot). For pair relative momenta between 0.3 and 0.5  GeV/c, the ratio is very small at low p(tot) and rises to approximately 0.5 at large p(tot). This shows the dominance of tensor over central correlations at this relative momentum.

Absorption of the ω and ϕ mesons in nuclei

Because of their long lifetimes, the ω and ϕ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from 2H, C, Ti, Fe, and Pb targets. This Letter reports the first measurement of the ratio of nuclear transparencies for the e+e- channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the ω meson is stronger than that reported by the CBELSA-TAPS experiment and cannot be explained by recent theoretical models.

Carbohydrate Moieties as Vaccine Candidates: meeting summary

In September 2007, a meeting entitled 'Carbohydrate Moieties as Vaccine Candidates' was held at the National Institutes of Health (Bethesda, MD). This meeting brought together scientists from a number of disciplines to address issues concerning carbohydrate moieties as targets for vaccines for a variety of pathogens and tumors. In addition, the meeting participants addressed fundamental topics of glycoimmunology including the recognition of glycotopes by B and T lymphocytes, the ontogeny of anti-carbohydrate immune responses, peptide mimicry, carbohydrate antigen processing pathways and adjuvants. One session reported progress in the development of new tools such as computational algorithms, glycan arrays and oligosaccharide synthesis and their application to carbohydrate vaccine research. The session titles were: (1) immune response to bacterial carbohydrate antigens; (2) immune response to glycolipids; (3) immune response to carbohydrate antigens on other microbes and on tumors; (4) novel vaccine approaches; (5) novel tools in carbohydrate vaccine research; (6) bench to bedside: carbohydrate moieties as vaccine immunopotentiators.

Diagnosis of human metapneumovirus by immunofluorescence staining with monoclonal antibodies in the North-East of England

BACKGROUND

Since its discovery in 2001 human metapneumovirus (hMPV) has been shown to be a significant cause of human respiratory disease, responsible for 5-8% of respiratory infections in hospitalised children. Diagnosis hitherto has been largely carried out by reverse tanscriptase polymerase chain reaction (RT-PCR) but immunofluorescence staining of cells from nasopharyngeal secretions (IF) offers advantages for some laboratories and may produce a more rapid result in urgent cases. We have recently demonstrated that IF with a rabbit antiserum gave sensitivity equal to that of RT-PCR. However, monoclonal antibodies offer a more plentiful, uniform IF reagent.

OBJECTIVES

Here we have evaluated a pool of anti-hMPV monoclonal antibodies in the routine diagnosis of respiratory infections in hospitalised infants and children.

STUDY DESIGN

Eight hundred and fifty-seven routine respiratory specimens were tested by IF with rabbit polyclonal antiserum and monoclonal antibody pool in parallel. A further 1003 specimens were tested with the monoclonal antibody pool alone. All specimens were also tested for a panel of other respiratory viruses by IF.

RESULTS

Both rabbit polyclonal antiserum and monoclonal antibody pool gave positive results in 56 and negative results in 797 specimens. The rabbit polyclonal antibody detected virus in a further two specimens which were negative when tested with the monoclonal pool giving a concordance of 96.6% and a specificity of 100% for the monoclonal antibody pool. Overall hMPV was detected in 5% of specimens whilst 18.4% were positive for hRSV.

CONCLUSIONS

The monoclonal antibody pool-based IF is a robust assay suitable for routine use with a sensitivity only slightly less than that of the other major diagnostic methodologies available.

Value of bronchoalveolar lavage before haematopoietic stem cell transplantation for primary immunodeficiency or autoimmune diseases

Pulmonary infection, often insidious, is frequent in primary immunodeficiency (PID) and acquired immunodeficiency. Pulmonary complications are serious obstacles to success of haematopoietic SCT (HSCT) for these conditions. Bronchoalveolar lavage (BAL) permits identification of lower respiratory tract pathogens that may direct specific treatment and influence prognosis. There are no reports about the utility of pre-HSCT BAL for immunodeficient patients. We prospectively studied the value of 'routine' BAL before commencing transplantation in patients undergoing HSCT for severe immunological disease. Routine non-bronchoscopic BAL was performed under general anaesthetic, a few days before commencing pre-HSCT cytoreductive chemotherapy. Patients were categorized as symptomatic or asymptomatic with respect to pulmonary disease or infection. Samples were sent for microbiological processing. Complications arising from the procedure, pathogens isolated and treatments instituted were recorded. Results were available from 69/75 patients transplanted during the study period; 26 (38%) had pathogens identified (six asymptomatic patients), 10 (14.5%) developed complications post-procedure (two asymptomatic patients)-all recovered, 21 had management changes. There was no statistically significant difference in the number of positive isolates from severe combined or other immunodeficient patients, or of symptomatic or asymptomatic patients. Routine non-bronchoscopic BAL is safe in immunodeficient patients about to undergo HSCT, and leads to management changes.

Molecular Dynamics Simulations of Methane Hydrate Using Polarizable Force Fields

Molecular dynamics simulations of methane hydrate have been carried out using the polarizable AMOEBA and COS/G2 force fields. Properties calculated include the temperature dependence of the lattice constant, the OC and OO radial distribution functions, and the vibrational spectra. Both the AMOEBA and COS/G2 force fields are found to successfully account for the available experimental data, with overall somewhat better agreement with experiment being found for the AMOEBA model. Comparison is made with previous results obtained using TIP4P and SPC/E effective two-body force fields and the polarizable TIP4P-FQ force field, which allows for in-plane polarization only. Significant differences are found between the properties calculated using the TIP4P-FQ model and those obtained using the other models, indicating an inadequacy of restricting explicit polarization to in-plane only.

Patterns of irrigated rice growth and malaria vector breeding in Mali using multi-temporal ERS-2 synthetic aperture radar

We explored the use of the European Remote Sensing Satellite 2 Synthetic Aperture Radar (ERS-2 SAR) to trace the development of rice plants in an irrigated area near Niono, Mali and relate that to the density of anopheline mosquitoes, especially An. gambiae. This is important because such mosquitoes are the major vectors of malaria in sub-Saharan Africa, and their development is often coupled to the cycle of rice development. We collected larval samples, mapped rice fields using GPS and recorded rice growth stages simultaneously with eight ERS-2 SAR acquisitions. We were able to discriminate among rice growth stages using ERS-2 SAR backscatter data, especially among the early stages of rice growth, which produce the largest numbers of larvae. We could also distinguish between basins that produced high and low numbers of anophelines within the stage of peak production. After the peak, larval numbers dropped as rice plants grew taller and thicker, reducing the amount of light reaching the water surface. ERS-2 SAR backscatter increased concomitantly. Our data support the belief that ERS-2 SAR data may be helpful for mapping the spatial patterns of rice growth, distinguishing different agricultural practices, and monitoring the abundance of vectors in nearby villages.

Genetic differentiation of Anopheles gambiae s.s. populations in Mali, West Africa, using microsatellite loci

Anopheles gambiae sensu stricto is a principal vector of malaria through much of sub-Saharan Africa, where this disease is a major cause of morbidity and mortality in human populations. Accordingly, population sizes and gene flow in this species have received special attention, as these parameters are important in attempts to control malaria by impacting its mosquito vector. Past measures of genetic differentiation have sometimes yielded conflicting results, in some cases suggesting that gene flow is extensive over vast distances (6000 km) and is disrupted only by major geological disturbances and/or barriers. Using microsatellite DNA loci from populations in Mali, West Africa, we measured genetic differentiation over uniform habitats favorable to the species across distances ranging from 62 to 536 km. Gene flow was strongly correlated with distance (r(2) = 0.77), with no major differences among chromosomes. We conclude that in this part of Africa, at least, genetic differentiation for microsatellite DNA loci is consistent with traditional models of isolation by distance.

DNA analysis of transferred sperm reveals significant levels of gene flow between molecular forms of Anopheles gambiae

Anopheles gambiae populations in west Africa are complex, being composed of multiple, sympatric subpopulations. Recent studies have failed to reveal significant genetic differences among subpopulations, stimulating a debate regarding the levels of gene flow among them. The observed homogeneity may be the consequence of substantial contemporary gene flow or it may be that reproductive isolation is complete, but too recent for the accumulation of significant levels of genic divergence. Here, we report the results of a study estimating contemporary levels of gene flow between An. gambiae subpopulations by analysing females and transferred sperm removed from their reproductive systems. A total of 251 female and associated sperm extracts was analysed from a single site in Mali. Two molecular forms of An. gambiae, the M- and S-forms, occurred in sympatry at this site. Overall, we found very strong positive assortative mating within forms, however, we did observe significant hybridization between forms. In the M subpopulation 2/195 females (1.03%) contained sperm from S-form males and in 55 S-form females we found one female containing M-form sperm (1.82%). We also identified a mated M xS hybrid adult female. From mating frequencies, we estimate the Nem between the M- and S-form at 16.8, and from the adult hybrid frequency at 5.6. These values are consistent with our earlier estimate, based on FST for 21 microsatellite loci in which Nem = 5.8. We conclude that the general lack of genetic divergence between the M and S subpopulations of An. gambiae can be explained entirely by contemporary gene flow.

Smoking cessation in China: findings from the 1996 national prevalence survey

OBJECTIVES

To describe patterns of smoking and smoking cessation in China within the context of the stages of change model, using data from the 1996 national prevalence survey.

DESIGN

A cross sectional survey was carried out using the 145 preselected disease surveillance points, which provide a representative sample for the entire country. A standardised questionnaire on smoking was interviewer administered.

SETTING

The country of China.

SUBJECTS

122,220 people aged 15-69 years. MAINTENANCE MEASURES: Smoking cessation patterns, as defined by smoking status (current or former) and stage of change (precontemplation, contemplation, and action).

RESULTS

The sample included 45,995 ever smokers of whom 4336 had quit. About 72% of current smokers reported not intending to give up their smoking behaviour, and about 16% of current smokers said they intended to do so, but have not taken any action. Of all ever smokers, the percentage of former smokers was 9.5%, and 12% of current smokers had quit at least once, but relapsed by the time of the survey. The patterns were similar in men and women with regard to the stated intent to quit. Among males, the percentage of former smokers increased with age but the percentage intending to quit was constant at about 15% across age strata. The most common reason for quitting was illness. Participants with a university education were more likely to have made an attempt to quit.

CONCLUSIONS

The percentage of smokers contemplating quitting was low in China in 1996. The study shows that smokers in China must be mobilised to contemplate quitting and then to take action.

Microstructure determination of AOT + phenol organogels utilizing small-angle X-ray scattering and atomic force microscopy

Dry reverse micelles of the anionic twin-tailed surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) dissolved in nonpolar solvents spontaneously form an organogel when p-chlorophenol is added in a 1:1 AOT:phenol molar ratio. The solvents used were benzene, toluene, m-xylene, 2,2,4-trimethylpentane (isooctane), decane, dodecane, tetradecane, hexadecane, and 2,6,10,14-tetramethylpentadecane (TMPD). The proposed microstructure of the gel is based on strands of stacked phenols linked to AOT through hydrogen bonding. Small-angle X-ray scattering (SAXS) spectra of the organogels suggest a characteristic length scale for these phenol-AOT strands that is independent of concentration but dependent on the chemical nature of the nonpolar solvent used. Correlation lengths determined from the SAXS spectra indicate that the strands self-assemble into fibers. Direct visualization of the gel in its native state is accomplished by using tapping mode atomic force microscopy (AFM). It is shown that these organogels consist of fiber bundle assemblies. The SAXS and AFM data reinforce the theory of a molecular architecture consisting of three length scales-AOT/phenolic strands (ca. 2 nm in diameter) that self-assemble into fibers (ca. 10 nm in diameter), which then aggregate into fiber bundles (ca. 20-100 nm in diameter) and form the organogel.

Respiratory viral infections in primary immune deficiencies: significance and relevance to clinical outcome in a single BMT unit

Respiratory viral infections are major causes of morbidity and mortality in children with SCID and other primary immunodeficiencies who require BMT. Twenty-two of 73 (30%) such children were admitted with respiratory viral infections, of whom 13/22 (59%) died. All viruses were detected in nasopharyngeal aspirate (NPA). Virus was only found in BAL in those with LRTI. Eleven of 22 (50%) had paramyxovirus infections, all with severe viral pneumonitis which worsened post BMT. Five of 11 (45.5%) survived overall. All 11 received aerosolised ribavirin; five of 11 received additional inhaled immunoglobulin and corticosteroid. Three of 5 (60%) survived compared with two of six (33.3%) not thus treated. Three of 22 (13.6%) had adenoviruses; one died of disseminated disease, including pneumonia despite intravenous ribavirin. Eleven patients had rhinovirus detected; nine of 11 (82%) were asymptomatic or coryzal and survived. Two patients with additional severe lung pathologies had LRT rhinovirus and died. All patients received intravenous immunoglobulin. No treatments resulted in viral clearance without successful T cell engraftment. Respiratory viruses, particularly paramyxoviruses and adenoviruses are common, significant pathogens in these patients, significantly worsening outcome of BMT. NPA is an ideal specimen for diagnosis and monitoring of infection. Aggressive treatments may reduce viral replication and damage. Nebulised immunoglobulin and corticosteroid in LRTI may improve respiratory function and outcome.

Micronutrients and infectious diseases: thoughts on integration of mechanistic approaches into micronutrient research

Results of field and laboratory studies provide convincing evidence that micronutrient deficiencies contribute to the mortality and morbidity of infectious diseases. Despite encouraging results in large trials, understanding the mechanisms by which micronutrients contribute to the outcome of the encounter between an individual and an infectious agent requires additional hypothesis-driven research. Presumably, such understanding should lead to translational studies with targeted nutritional therapy. Although these mechanistic studies are varied and complex, they must be done systematically and should include examination of the mechanisms by which micronutrients affect host-pathogen interactions, development of appropriate animal models and reliable methods for the assessment of micronutrient levels, and translation of the results of basic research findings into clinical studies. Moving the frontiers of micronutrient research from the laboratory to the field will be challenging. However, sound scientific research should lead toward better human health.

Effects of compression on language evolution

For many adaptive complex systems information about the environment is not simply recorded in a look-up table, but is rather encoded in a theory, schema, or model, which compresses information. The grammar of a language can be viewed as such a schema or theory. In a prior study [Teal et al., 1999] we proposed several conjectures about the learning and evolution of language that should follow from these observations: (C1) compression aids in generalization; (C2) compression occurs more easily in a "smooth," as opposed to a "rugged," problem space: and (C3) constraints from compression make it likely that natural languages evolve towards smooth string spaces. This previous work found general, if not complete support for these three conjectures. Here we build on that study to clarify the relationship between Minimum Description Length (MDL) and error in our model and examine evolution of certain languages in more detail. Our results suggest a fourth conjecture: that all else being equal, (C4) more complex languages change more rapidly during evolution.

Smoking in China: findings of the 1996 National Prevalence Survey

CONTEXT

As the world's largest producer and consumer of tobacco products, China bears a large proportion of the global burden of smoking-related disease and may be experiencing a tobacco epidemic.

OBJECTIVE

To develop an evidence-based approach supporting tobacco control initiatives in China.

DESIGN AND SETTING

A population-based survey consisting of a 52-item questionnaire that included information on demographics, smoking history, smoking-related knowledge and attitudes, cessation, passive smoke exposure, and health status was administered in 145 disease surveillance points in the 30 provinces of China from March through July 1996.

PARTICIPANTS

A nationally representative random sample of 128766 persons aged 15 to 69 years were asked to participate; 120298 (93.8%) provided data and were included in the final analysis. About two thirds of those sampled were from rural areas and one third were from urban areas.

MAIN OUTCOME MEASURES

Current smoking patterns and attitudes; changes in smoking patterns and attitudes compared with results of a previous national survey conducted in 1984.

RESULTS

A total of 41187 respondents smoked at least 1 cigarette per day, accounting for 34.1% of the total number of respondents, an increase of 3.4 percentage points since 1984. Current smoking continues to be prevalent among more men (63%) than women (3.8%). Age at smoking initiation declined by about 3 years for both men and women (from 28 to 25 years). Only a minority of smokers recognized that lung cancer (36%) and heart disease (4%) can be caused by smoking. Of the nonsmokers, 53.5% were exposed to environmental tobacco smoke at least 15 minutes per day on more than 1 day per week. Respondents were generally supportive of tobacco control measures.

CONCLUSION

The high rates of smoking in men found in this study signal an urgent need for smoking prevention and cessation efforts; tobacco control initiatives are needed to maintain or decrease the currently low smoking prevalence in women.

Complexities in the genetic structure of Anopheles gambiae populations in west Africa as revealed by microsatellite DNA analysis

Chromosomal forms of Anopheles gambiae, given the informal designations Bamako, Mopti, and Savannah, have been recognized by the presence or absence of four paracentric inversions on chromosome 2. Studies of karyotype frequencies at sites where the forms occur in sympatry have led to the suggestion that these forms represent species. We conducted a study of the genetic structure of populations of An. gambiae from two villages in Mali, west Africa. Populations at each site were composed of the Bamako and Mopti forms and the sibling species, Anopheles arabiensis. Karyotypes were determined for each individual mosquito and genotypes at 21 microsatellite loci determined. A number of the microsatellites have been physically mapped to polytene chromosomes, making it possible to select loci based on their position relative to the inversions used to define forms. We found that the chromosomal forms differ at all loci on chromosome 2, but there were few differences for loci on other chromosomes. Geographic variation was small. Gene flow appears to vary among different regions within the genome, being lowest on chromosome 2, probably due to hitchhiking with the inversions. We conclude that the majority of observed genetic divergence between chromosomal forms can be explained by forces that need not involve reproductive isolation, although reproductive isolation is not ruled out. We found low levels of gene flow between the sibling species Anopheles gambiae and Anopheles arabiensis, similar to estimates based on observed frequencies of hybrid karyotypes in natural populations.

Parainfluenza virus and respiratory syncytial virus infection in infants undergoing bone marrow transplantation for severe combined immunodeficiency

Respiratory syncytial virus and parainfluenza virus infection carry a poor prognosis in severe combined immunodeficiency (SCID), particularly if the viral load is high. Patients with high viral load develop severe pneumonitis at engraftment which may possibly be modulated by immunotherapy, including high dose nebulised corticosteroids. Further work is required to develop effective treatment for this severe condition.

Multicenter evaluation of the Amplicor Enterovirus PCR test with cerebrospinal fluid from patients with aseptic meningitis. The European Union Concerted Action on Viral Meningitis and Encephalitis

The Amplicor Enterovirus PCR test was compared with viral culture for the detection of enteroviruses in cerebrospinal fluid (CSF) specimens. In a multicenter study in which nine laboratories participated, a total of 476 CSF specimens were collected from patients with suspected aseptic meningitis. Sixty-eight samples were positive by PCR (14.4%), whereas 49 samples were positive by culture (10.4%), demonstrating that the Amplicor Enterovirus PCR test was significantly more sensitive than culture (P < 0.001). After discrepancy analysis the sensitivity and specificity of the Amplicor Enterovirus PCR test obtained by using viral culture as the "gold standard" were 85.7 and 93.9%, respectively. Our results with the CSF specimens collected in different countries demonstrate that the Amplicor test is capable of detecting a large variety of enterovirus serotypes and epidemiologically unrelated isolates in CSF specimens from patients with aseptic meningitis. The Amplicor Enterovirus PCR test is a rapid assay which can be routinely performed with CSF samples and is an important improvement for the rapid diagnosis of enteroviral meningitis.

Mark-release-recapture experiments with Anopheles gambiae s.l. in Banambani Village, Mali, to determine population size and structure

Mark-release-recapture experiments with Anopheles gambiae s.l. were performed during the wet seasons of 1993 and 1994 in Banambani, Mali. All recaptured mosquitoes were identified to species by PCR analysis and, when possible, by chromosomal analysis to chromosomal form. Two species of the An. gambiae complex were present: An. gambiae s.s. and An. arabiensis; their ratio differed greatly from one year to the next. Three chromosomal forms of An. gambiae s.s. were found--Bamako, Savanna and Mopti. The drier 1993 was characterized by a high frequency of An. arabiensis and of the Mopti chromosomal forms of An. gambiae s.s. These trends were consistent with large-scale geographical patterns of abundance along a precipitation gradient. We observed no difference in dispersal between the two species, nor among the chromosomal forms of An. gambiae s.s. Therefore, in this situation at least, it is reasonable to group such data on the An. gambiae complex as a whole for analysis. Population size of An. gambiae s.l. females in the village was estimated to be 9000-11,000 in 1993 and 28,000 in 1994. The corresponding numbers were somewhat higher when independently-derived values of daily survival were used. These were consistent with estimates of effective population size obtained from patterns of gene frequency change.

Correlation between the detection of viral DNA by the polymerase chain reaction in peripheral blood leukocytes and serological responses to human herpesvirus 6, human herpesvirus 7, and cytomegalovirus in renal allograft recipients

Diagnosis of significant infections by human herpesvirus 6 (HHV6) and 7 (HHV7) in transplant patients has proved difficult because both viruses are ubiquitous and can cause persistent infections in their hosts. The significance of viral DNA detected in peripheral blood leukocytes (PBLs; DNAemia) by PCR is therefore unclear. The interpretation of serological results is complicated by the fact that both primary and secondary infections with other herpesviruses may be associated with a concurrent antibody response to HHV6. Fifty-four renal allograft recipients were studied prospectively and their serological response to HHV6, HHV7 and CMV were compared with the detection of viral DNAemia from the homologous and heterologous viruses. Serum and heparinished blood samples were collected prospectively from 54 renal allograft recipients. DNA was extracted from PBLs and tested for the presence of HHV6, HHV7 and CMV DNA by PCR. Antibodies to HHV6 and HHV7 were measured by an indirect immunofluorescence test and to CMV by an anticomplement immunofluorescence (ACIF) test. CMV IgM antibodies were detected by a commercial enzyme immunoassay. CMV and HHV7 DNAemia were each significantly associated with serological responses to the homologous virus but no such association was found for HHV6 DNAemia. However, patients with consecutively positive DNAemia to any of the viruses (including HHV6) were more likely to have a homologous serological response. Patients who had detectable CMV IgM without a concurrent rise in CMV antibodies were significantly less likely to have CMV DNAemia (odds ratio = 0.16; 95% CI 0.02-0.9). CMV IgM antibodies may be associated with HHV6 or HHV7 DNAemia (odds ratio 2.3; 95% CI 0.5-15). This serological profile may reflect a crossreactive response to HHV6, HHV7 or other herpesviruses. CMV IgM should not be used in isolation for the diagnosis of CMV infection or disease in this group of patients.

Ethical dilemmas in current planning for polio eradication

Intensification of polio eradication efforts worldwide raises concerns about costs and benefits for poor countries. A major argument for global funding is the high benefit-cost ratio of eradication; however, financial benefits are greatest for rich countries. By contrast, the greatest costs are borne by poor countries; the Pan American Health Organization has estimated that host countries bore 80% of costs for polio eradication in the Americas. The 1988 World Health Assembly resolution setting up the Polio Eradication Initiative carried the proviso that programs should strengthen health infrastructures. Drastic cuts in donor funding for health make this commitment even more important. Two international evaluations have reported both positive and negative effects of polio and Expanded Programme on Immunization programs on the functioning and sustainability of primary health care. Negative effects were greatest in poor countries with many other diseases of public health importance. If poor countries are expected to divert funds from their own urgent priorities, donors should make solid commitments to long-term support for sustainable health development.

Incidence and significance of noncytomegalovirus viral respiratory infection after adult lung transplantation

Lower respiratory tract infection is a major cause of morbidity and death after lung transplantation. The incidence and significance of noncytomegalovirus viral respiratory tract infections has not been reported to date. We report our center's experience with these infections.

Density, survival and dispersal of Anopheles gambiae complex mosquitoes in a west African Sudan savanna village

To obtain information on adult populations of Afrotropical malaria vector mosquitoes, mark-release-recapture experiments were performed with Anopheles females collected from indoor resting-sites in a savanna area near Ouagadougou, Burkina Faso, during September 1991 and 1992. Results were used to estimate the absolute population densities, daily survival rates, and dispersal parameters of malaria vectors in that area. In 1991 a total of 7260 female Anopheles were marked and released, of which 106 were recaptured in the release village and 6 in the neighbouring villages, a total recapture rate of 1.5%. The following year 13,854 female Anopheles were released and 116 recaptured in Goundri and 8 in the neighbouring villages, a total recapture rate of 0.9%. Recaptures were found in three of eight villages near Goundri. Nearly all of the recaptured mosquitoes were An gambiae s.l. Of these, molecular determination revealed that An.gambiae s.s. and An.arabiensis were present in a ratio of approximately 2:3. Two simple random models of dispersal were simulated and the parameters of the models determined by searching for the least-squared fit between simulated and observed distributions. The mean distance moved by individual mosquitoes, estimated in this way, ranged 350-650 m day-1, depending on the model and the year considered. Population densities were estimated using the Lincoln Index, Fisher-Ford and Jolly's methods. The estimates of population size had high standard errors and were not particularly consistent A "consensus' value of 150,000-350,000 mosquitoes is believed to apply for the An.gambiae s.l. female population. Survival was estimated to be 80-88% per day.

"Cytomegalovirus disease" in renal allograft recipients: is human herpesvirus 7 a co-factor for disease progression?

Fifty-six renal allograft recipients were studied prospectively for 3 months or longer after transplant. The polymerase chain reaction (PCR) was used to screen peripheral blood leucocyte (PBL) specimens for CMV, human herpesvirus 6 (HHV6) and human herpesvirus 7 (HHV7) DNA (DNAemia) in 67 healthy controls and in serial (fortnightly) PBL specimens from the 56 allograft recipients. None of the healthy controls had detectable CMV DNAemia, although HHV6 and HHV7 DNAemia was found in 7% and 9% of individuals respectively. In contrast, DNAemia due to CMV, HHV6 and HHV7 was found in 50%, 36% and 39% of patients respectively, at some time during the post-transplant period. Of the 28 patients who had CMV DNAemia, eight developed "CMV disease". The risk of progression to "CMV disease" was increased in patients with concurrent DNAemia to all three viruses (relative risk 3.7; 95% CI 1.3-10.5). The relative risk of "CMV disease" for patients with concurrent CMV and HHV7 was also increased (RR = 3.5; 95% CI = 1.1-11.6), while the association between CMV and HHV6 was inconclusive (RR = v2.1; 95% CI = 0.7-6.6). The first 26 patients recruited to the study also had serial serum samples tested for antibody responses to the three viruses. "CMV disease" was associated with rising antibody titres to HHV7 (Fisher's exact test, P = 0.02), and weakly so with HHV6 (P = 0.07). It is concluded that in patients with CMV DNAemia, concurrent infection/reactivation HHV7 (and possibly HHV6) is associated with an increased risk of progression to "CMV disease".

Human herpes virus-6 infection in marrow graft recipients: role in pathogenesis of graft-versus-host disease. Newcastle upon Tyne Bone Marrow Transport Group

To investigate the hypothesis that target organ infection with human herpes virus-6 (HHV-6) exacerbates the clinical severity of GVHD, skin and rectal biopsies from 34 allogeneic bone marrow transplant (BMT) recipients and 23 comparative autologous recipients were studied. Biopsies and heparinised blood samples were obtained from all patients prior to and at regular intervals after BMT, and whenever GVHD was suspected. HHV-6 antigen was detected in cryostat sections by immunohistochemistry, and HHV-6 DNA in peripheral blood leucocytes (PBL) and biopsies by nested PCR. Twenty-eight (90%) of the 31 patients who engrafted developed clinical GVHD, which was mild in five, moderately severe in nine and severe in 14. Overall, HHV-6 DNA was detected in PBl in 74% of autologous recipients and 76% of allogeneic recipients, and in biopsy tissue in 48% of autos and 71% of allos. However, HHV-6 DNA was detected in skin and/or rectal biopsies more frequently in allogeneic recipients with severe GVHD (92%) than in those with either moderate (55%) or mild GVHD (22%), suggesting an association (P = 0.004) between HHV-6 DNA in biopsy tissue and GVHD severity. A significant linear trend (P = 0.03) was identified between detection of HHV-6 DNA in biopsy tissue obtained prior to or concomitant with the onset of GVHD and increased GVHD severity, suggesting that HHV-6 was causally linked to GVHD rather than reactivated as a consequence of GVHD therapy. Thus this study supports a role for HHV-6 in the initiation and/or exacerbation of GVHD, and suggests that the presence of HHV-6 DNA in the skin or rectum may be a factor in determining GVHD severity. If confirmed, these findings may have implications for the management of allogeneic BMT recipients.

Cytokines as adjuvants for vaccines: antigen-specific responses differ from polyclonal responses

The use of cytokines in the administration of vaccines has a unique value in obtaining the appropriate immune response and in ensuring a protective outcome. Earlier studies indicating that cytokines can influence the generation of a particular antibody isotype may represent an oversimplification of a more complex problem. Several studies discussed in this review show that the effect of a given cytokine on the immune response depends on whether one examines the antigen-specific response or the polyclonal response (i.e., total serum immunoglobulins). Further, a balanced regulation of immune responsiveness is important in maintaining homeostasis of the immune system. Consequently, for any vaccine that uses cytokines to boost the response, due consideration must be given to these important variables.

E.H. Christopherson Lecture: lessons for the United States From the Worldwide Child Survival Revolution

It is time to apply in the United States' principles that are emerging from a series of World Summits and United Nations Conference on Children, Environment, Population, Women, and Social Development. After years of top-down programs supported by international agencies, which have made some significant contributions in promoting activities such as childhood immunization but are having problems of sustainability, we need to focus now on integrated human development. The past tendency in international assistance to concentrate on economic development has not helped the people in greatest need. There is growing realization that what improves the quality of life most is what people do for themselves. Sustainability requires social mobilization at the local level. There are thousands of integrated, social development projects around the world that demonstrate the power of community-based, participatory approaches and we know how such local programs can be made to work under any political or economic system. What we haven't learned is how to "go to scale" in extending such projects to cover larger populations. A promising approach seems to be using successful local projects upgraded into Centers for Action Learning to promote the adaptation of science-based innovations to everyday life in a whole region of a country.