Verification of calibration methods for determining photon-counting detection efficiency using superconducting nano-wire single photon detectors.

In recent years several ways to radiometrically calibrate optical fiber-coupled detectors have been developed. However, fiber-coupled calibration methods for single photon detectors have not been compared by national metrology institutes in order to validate their equivalence or traceability to the international systems of units yet.. Here, we present the comparison of radiometric calibration methods traceable to a NIST cryogenic radiometer at the 'few-photon' level. The calibration methods are based on metrology grade optical power meters. The expanded (k = 2) relative standard uncertainties of the calibration methods for the detection efficiency are of the order of 0.5%. However, the results changed relatively by 10% with a different set of optical fibers and mating connectors. These results stress the importance of fiber-core dimensions and fiber-connector repeatability.

A Toll-like receptor-1 variant and its characteristic cellular phenotype is associated with severe malaria in Papua New Guinean children.

Genetic factors are likely to contribute to low severe malaria case fatality rates in Melanesian populations, but association studies can be underpowered and may not provide plausible mechanistic explanations if significant associations are detected. In preparation for a genome-wide association study, 29 candidate single-nucleotide polymorphisms (SNPs) with minor allele frequencies >5% were examined in a case-control study of 504 Papua New Guinean children with severe malaria. In parallel, an immunological substudy was performed on convalescent peripheral blood mononuclear cells (PBMCs) from cases and controls. Following stimulation with a Toll-like receptor (TLR) 1/2 agonist, effector cytokines and chemokines were assayed. The only significant genetic association observed involved a nonsynonymous SNP (TLR1rs4833095) in the TLR1 gene. A recessive (TT) genotype was associated with reduced odds of severe malaria of 0.52 (95% confidence interval (0.29-0.90), P=0.006). Concentrations of pro-inflammatory cytokines interleukin-1ß and tumour necrosis factor α were significantly higher in severe malaria cases compared with healthy controls, but lower in children with the protective recessive (TT) genotype. A genetic variant in TLR1 may contribute to the low severe malaria case fatality rates in this region through a reduced pro-inflammatory cellular phenotype.

Prevalence and risk factors for Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis infection in pregnant women in Papua New Guinea.

OBJECTIVE: To determine the prevalence of, and risk factors associated with, Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis infection in pregnant women in Madang, Papua New Guinea (PNG). METHODS: A cross-sectional survey was conducted among 400 pregnant women presenting to antenatal clinics. Sociodemographic and behavioural data were collected and real-time PCR diagnostic methods were used to detect the presence of chlamydia, gonorrhoea and trichomonas in self-collected vaginal swabs. The relationships between symptoms, sociodemographic and behavioural factors and infection were assessed. RESULTS: The prevalence of C. trachomatis was 11.1%, N. gonorrhoeae was 9.7% and T. vaginalis was 21.3%. One-third of women (33.7%) had at least one infection. The most common symptom was abdominal pain (48.0%), but only abnormal vaginal discharge was consistently associated with infection (p<0.001). Women diagnosed with vaginal discharge syndrome were more likely to have at least one treatable infection (50.0% (47/94)  vs 26.8% (68/254), p<0.001), yet 59.1% of women with infection would have been missed by the current clinically-based syndromic diagnosis. Risk factors included having a partner at perceived risk of infection, maternal extramarital intercourse, early sexual debut, lack of formal education, urban residence and smoking. 78.8% of women reported never using condoms. CONCLUSIONS: The prevalences of T. vaginalis, C. trachomatis and N. gonorrhoeae were high among pregnant women in coastal PNG. The poor performance of clinically based syndromic diagnosis suggests that alternative strategies are urgently required to improve detection and reduce the burden of sexually transmitted infections and their associated adverse pregnancy outcomes in this population.

Consensus of German transplant centers on hematopoietic stem cell transplantation in Fanconi anemia.

Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only curative therapy for the severe hematopoietic complications associated with Fanconi anemia (FA). In Germany, it is estimated that 10-15 transplants are performed annually for FA. However, because FA is a DNA repair disorder, standard conditioning regimens confer a high risk of excessive regimen-related toxicities and mortality, and reduced intensity regimens are linked with graft failure in some FA patients. Moreover, development of graft-versus-host disease is a major contributing factor for secondary solid tumors. The relative rarity of the disorder limits HSCT experience at any single center. Consensus meetings were convened to develop a national approach for HSCT in FA. This manuscript outlines current experience and knowledge about HSCT in FA and, based on this analysis, general recommendations reached at these meetings.

Effect of coadministered fat on the tolerability, safety, and pharmacokinetic properties of dihydroartemisinin-piperaquine in Papua New Guinean children with uncomplicated malaria.

Coadministration of dihydroartemisinin-piperaquine (DHA-PQ) with fat may improve bioavailability and antimalarial efficacy, but it might also increase toxicity. There have been no studies of these potential effects in the pediatric age group. The tolerability, safety, efficacy, and pharmacokinetics of DHA-PQ administered with or without 8.5 g fat were investigated in 30 Papua New Guinean children aged 5 to 10 years diagnosed with uncomplicated falciparum malaria. Three daily 2.5:11.5-mg-base/kg doses were given with water (n = 14, group A) or milk (n = 16, group B), with regular clinical/laboratory assessment and blood sampling over 42 days. Plasma PQ was assayed by high-performance liquid chromatography with UV detection, and DHA was assayed using liquid chromatography-mass spectrometry. Compartmental pharmacokinetic models for PQ and DHA were developed using a population-based approach. DHA-PQ was generally well tolerated, and initial fever and parasite clearance were prompt. There were no differences in the areas under the concentration-time curve (AUC0-∞) for PQ (median, 41,906 versus 36,752 µg · h/liter in groups A and B, respectively; P = 0.24) or DHA (4,047 versus 4,190 µg · h/liter; P = 0.67). There were also no significant between-group differences in prolongation of the corrected electrocardiographic QT interval (QTc) initially during follow-up, but the QTc tended to be higher in group B children at 24 h (mean ± standard deviation [SD], 15 ± 10 versus 6 ± 15 ms(0.5) in group A, P = 0.067) and 168 h (10 ± 18 versus 1 ± 23 ms(0.5), P = 0.24) when plasma PQ concentrations were relatively low. A small amount of fat does not change the bioavailability of DHA-PQ in children, but a delayed persistent effect on ventricular repolarization cannot be excluded.

Hearts of some Antarctic fishes lack mitochondrial creatine kinase.

Creatine kinase (CK; EC 2.7.3.2) functions as a spatial and temporal energy buffer, dampening fluctuations in ATP levels as ATP supply and demand change. There are four CK isoforms in mammals, two cytosolic isoforms (muscle [M-CK] and brain [B-CK]), and two mitochondrial isoforms (ubiquitous [uMtCK] and sarcomeric [sMtCK]). Mammalian oxidative muscle couples expression of sMtCK with M-CK, creating an energy shuttle between mitochondria and myofibrils. We hypothesized that the expression pattern and activity of CK would differ between hearts of red- and white-blooded Antarctic notothenioid fishes due to their striking differences in cardiac ultrastructure. Hearts of white-blooded icefishes (family Channichthyidae) have significantly higher mitochondrial densities compared to red-blooded species, decreasing the diffusion distance for ATP between mitochondria and myofibrils and potentially minimizing the need for CK. The distribution of CK isoforms was evaluated using western blotting and maximal activity of CK was measured in mitochondrial and cytosolic fractions and tissue homogenates of heart ventricles of red- and white-blooded notothenioids. Transcript abundance of sMtCK and M-CK was also quantified. Overall, CK activity is similar between hearts of red- and white-blooded notothenioids but hearts of icefishes lack MtCK and have higher activities of M-CK in the cytosol compared to red-blooded fishes. The absence of MtCK may compromise cardiac function under stressful conditions when ATP supply becomes limiting.

Distinct distribution of killer-cell immunoglobulin-like receptor genes in the Mugil and Ilaita areas of Papua New Guinea.

The frequency of the killer-cell immunoglobulin-like receptor (KIR) genes and transmembrane alleles of KIR2DL4 were studied in coastal (Mugil community) and inland (Ilaita community) communities in Papua New Guinea. Linkage disequilibria between KIR genes and between alleles of KIR2DL4 and the KIR genes were similar to those found in other populations suggesting conservation of the usual gene order in Papua New Guinean haplotypes. Significant differences in the frequency of KIR genes were found between the two populations despite being separated by only 300 km. Examples of individuals who lacked the KIR2DL4 gene and others whose KIR2DL4 allele appeared to have 11 adenines in the polyadenine tract in exon 6 were identified. A relatively low frequency of the KIR A haplotype was found in both populations and particularly in the inland community. The KIR gene frequencies were consistent with the inland Ilaita community being closely related to Australian Aborigines and southern Indians, whereas the KIR gene frequencies of the coastal Mugil community appeared to have been influenced either by recent or ancient admixture from populations with a higher frequency of the KIR A haplotype.

Nitric oxide synthase is not expressed, nor up-regulated in response to cold acclimation in liver or muscle of threespine stickleback (Gasterosteus aculeatus).

There are three isoforms of the enzyme nitric oxide synthase (NOS) in mammals: endothelial NOS (eNOS), inducible NOS (iNOS) and neuronal NOS (nNOS). All three isoforms oxidize arginine to citrulline in a reaction producing nitric oxide (NO), which regulates multiple signaling pathways and physiological functions in mammals. Less is known about NOS in fishes, in which the existence of eNOS is controversial. Nevertheless, multiple adjustments occur during cold acclimation of fishes, several of which are known to be mediated by eNOS and NO in mammals, including mitochondrial biogenesis, vasodilation and angiogenesis. We hypothesized that if NOS was present, and NO stimulated these pathways in fishes, then the activity of NOS would increase during cold acclimation. To test this hypothesis, we measured the activity and mRNA levels of NOS in three tissues (liver, oxidative muscle, glycolytic muscle) known to undergo mitochondrial biogenesis and/or angiogenesis. Measurements were made in the threespine stickleback, Gasterosteus aculeatus acclimated to either warm (20°C) or cold (8°C) temperature for 9weeks. Cold-acclimated fish were harvested on days 1-3, and at weeks 1, 4 and 9 at 8°C, while warm-acclimated fish were harvested on day 0 and after 9 weeks at 20°C. Transcript levels of NOS were quantified using quantitative real-time PCR, and NOS activity was measured using a radiochemical assay, which detected the rate of catabolism of (14)C-labeled arginine. Neither NOS activity nor transcripts were detected in oxidative muscle or glycolytic muscle of warm- or cold-acclimated stickleback, although transcript levels of nNOS and NOS activity were detected in brain. Arginine catabolism was detected in liver of animals held at 10°C and 20°C for 9weeks, but was due to arginase activity, rather than NOS. Consistent with this, NOS transcripts were undetectable in liver. The absence of NOS in liver and muscles of stickleback indicates that signaling molecules other than NO likely mediate physiological changes during cold acclimation in stickleback.

Robert Koch redux: malaria immunology in Papua New Guinea.

Over a century ago, the malaria expedition of the brilliant microbiologist Robert Koch to the Dutch East Indies (Indonesia) and German New Guinea (now Papua New Guinea, or PNG), resulted in profound observations that are still central to our current understanding of the epidemiology and acquisition of immunity to the malaria parasite Plasmodium. The tradition of malaria research in PNG pioneered by Koch continues to this day, with a number of recent studies still continuing to elucidate his original concepts and hypotheses. These include age and exposure-related acquisition of immunity, species-specific and cross-species immunity, correlates of protective immunity and determining the prospects for anti-malaria vaccines.

Successful autologous stem cell transplantation in two patients with juvenile dermatomyositis.

Juvenile dermatomyositis (JDM) is a chronic inflammatory disorder of unknown aetiology that affects muscle and skin. We report on two patients with severe progressive JDM who developed contractures and were wheelchair dependent despite therapy including methotrexate (MTX), steroids, immunoglobulins, cyclosporin A, and rituximab. On account of the refractory disease, autologous stem cell transplantation (ASCT) was performed using a CD3/CD19-depleted graft after immunoablative conditioning with fludarabine, cyclophosphamide, and anti-thymocyte globulin. This induced a dramatic improvement and sustained remission of the disease in both patients. We demonstrate that ASCT is a therapeutic option with low toxicity for patients with severe, refractory JDM.

IgM in human immunity to Plasmodium falciparum malaria.

Most studies on human immunity to malaria have focused on the roles of immunoglobulin G (IgG), whereas the roles of IgM remain undefined. Analyzing multiple human cohorts to assess the dynamics of malaria-specific IgM during experimentally induced and naturally acquired malaria, we identified IgM activity against blood-stage parasites. We found that merozoite-specific IgM appears rapidly in Plasmodium falciparum infection and is prominent during malaria in children and adults with lifetime exposure, together with IgG. Unexpectedly, IgM persisted for extended periods of time; we found no difference in decay of merozoite-specific IgM over time compared to that of IgG. IgM blocked merozoite invasion of red blood cells in a complement-dependent manner. IgM was also associated with significantly reduced risk of clinical malaria in a longitudinal cohort of children. These findings suggest that merozoite-specific IgM is an important functional and long-lived antibody response targeting blood-stage malaria parasites that contributes to malaria immunity.

Cellular immune reconstitution after haploidentical transplantation in children.

Delayed immune reconstitution is 1 of the major contributions to the morbidity and mortality after haploidentical transplantation. Patients with a slow recovery of the innate and especially of the adaptive immune system are at high risk for severe and often lethal infections. The reason for delayed immune reconstitution after haploidentical transplantation include the T cell depletion (TCD) of the graft, the thymic dysfunction induced by pretransplant chemotherapies and by the conditioning regimens, and the occurrence of graft-versus-host disease (GVHD) and its treatment. The detailed analysis, understanding, and manipulation of the reconstitution of the cellular immune system will be of utmost importance to overcome the posttransplant immunodefcient status, and should result in a reduced risk of severe and overwhelming infections and hopefully also to a reduced risk of relapse through better immunological control of residual malignant cells.

Glycophorin C delta(exon3) is not associated with protection against severe anaemia in Papua New Guinea.

The high frequencies of mutant haemoglobin and erythrocyte surface proteins in malaria-endemic regions have indicated that polymorphisms in human genes have been under selection pressure by severe malarial disease. Glycophorin C (GYPC) is a major surface erythrocyte protein and also a receptor for the Plasmodium falciparum erythrocyte-binding antigen 140 (EBA-140, also known as BAEBL). There is no binding to GYPC in Gerbich-negative (deletion of exon 3 in GYPC gene: GYPCC delta(exon3)) erythrocytes by EBA-140, hence limiting invasion of erythrocytes by certain P. falciparum lines. The GYPCC delta(exon3) allele reaches high frequencies in two areas of Papua New Guinea (PNG) where malaria is highly endemic. There is, however, no indication that Gerbich negativity protects against malaria-related illness. Using archival blood samples collected from children (<6 years of age) in the Wosera District, East Sepik Province, PNG, we investigated GYPC C delta(exon3) as a possible genetic component of protection against severe malarial anaemia (SMA). The frequency of this human genetic polymorphism was found to be in accordance with previous studies. However, our result showed no association between SMA and GYPC C delta(exon3). Until such an association is clearly shown with severe malaria outcomes, these results raise questions regarding the role of malaria as a selective force for Gerbich negativity.

Large-scale isolation of CD133+ progenitor cells from G-CSF mobilized peripheral blood stem cells.

We have evaluated the feasibility of large-scale isolation of CD133+ progenitors from healthy mobilized adult donors for potential clinical use in autologous and allogeneic transplantation. A total of 11 healthy volunteer adult donors were mobilized with G-CSF. CD133+ stem cells were isolated from a single leukapheresis using the Clinimacs method. The median percentage of CD133 before positive selection was 0.75% (range 0.39-2.03%). After selection, the median purity and recovery was 94% (range 85.2-98.0%) and 69% (range 44-100%), respectively. The median log10 T-cell depletion obtained by CD133+ positive selection was 4.2 (range 3.8-4.7). The CD133+ progenitors were highly enriched in colony-forming units (CFU) and transplantation into NOD/SCID mice resulted in a high engraftment rate. Transplantation of sorted CD133+/CD34+ cells into NOD/SCID mice showed a higher engraftment compared to CD133-/CD34+ cells. Mobilized peripheral CD133+ stem cells can be purified in large scale for potential clinical use. The biological function of the cells is not impaired. The majority of the NOD/SCID repopulating cells are within the CD133+/CD34+ subpopulation. Therefore, clinical studies using purified CD133+ stem cells can be envisoned to further clarify the role of CD133+ stem cells in hematopoietic reconstitution after transplantation.

A large-scale method for T cell depletion: towards graft engineering of mobilized peripheral blood stem cells.

We have investigated the feasibility and efficacy of large-scale T cell depletion from granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood stem cells (PBSC). The method is based on the use of a CD3 antibody conjugated to magnetic microbeads and magnetic activated cell sorting (Clinimacs). A total of eight large-scale experiments were performed. In four experiments, CD3(+) T cells were depleted from PBSC obtained from volunteers mobilized with G-CSF whereas, in four experiments, T cells were depleted from PBSC from stem cell donors, in which the CD34(+) stem cells had been removed for allogeneic transplantation by positive selection prior to T cell depletion. The mean number of processed mononuclear cells (MNCs) was 3.3 x 10(10) (range 1.5 x 10(10)-5.1 x 10(10)) with a mean T cell proportion of 35.8% (range 16.7-64.0%). After T cell depletion, the percentage of contaminating T cells was 0.15% (range 0.01-1.01%) with a mean log(10) depletion of 3.4 (range 2.8-4.1). The mean recovery of CD3-negative MNCs after depletion was 76% (range 52-100%). The mean recovery of CD34(+) stem cells in the four evaluable experiments was 82% (range 75-92%). In vitro colony assays and in vivo NOD/SCID repopulation assays showed that this large-scale T cell depletion method has no negative impact on the function of the hematopoietic precursor cells. Therefore, we conclude that this T cell depletion method is a valuable tool for further graft engineering strategies involving mobilized PBSCs.

The Carter Center's assistance to river blindness control programs: establishing treatment objectives and goals for monitoring ivermectin delivery systems on two continents.

Periodic mass treatment with ivermectin in endemic communities prevents eye and dermal disease due to onchocerciasis. As part of an international global partnership to control onchocerciasis, The Carter Center's Global 2000 River Blindness Program (GRBP) assists the ministries of health in ten countries to distribute ivermectin (Mectizan, donated by Merck & Co.). The GRBP priorities are to maximize ivermectin treatment coverage and related health education and training efforts, and to monitor progress through regular reporting of ivermectin treatments measured against annual treatment objectives and ultimate treatment goals (e.g., full coverage, which is defined as reaching all persons residing in at risk villages who are eligible for treatment). Since the GRBP began in 1996, more than 21.2 million ivermectin treatment encounters have been reported by assisted programs. In 1999, more than 6.6 million eligible persons at risk for onchocerciasis received treatment, which represented 96% of the 1999 annual treatment objective of 6.9 million, and 78% of the ultimate treatment goal in assisted areas.

Nonparametric analysis of the absorption profile of octreotide in rabbits from long-acting release formulation OncoLAR.

Octreotide (octreotide-acetate, Sandostatin(R)) is a somatostatin analogue, used in long-term treatment of acromegaly. The present study describes the absorption profile in rabbits of octreotide after release from the long-acting formulation OncoLAR (denoted as octreotide-LAR). In a first experiment, the disposition kinetics of octreotide was studied for 24 h in six rabbits after intravenous (i. v.) injection of 0.025 mg of a solution of octreotide. In a second experiment, release kinetics was studied in eight rabbits for 49 days after an i.m. injection of 5 mg/kg of octreotide-LAR. Concentrations were determined by radioimmunoassay. After i.v. injection of octreotide, one- and two-compartment models were compared for each rabbit. A typical disposition profile was computed using the mean parameters. After i.m. injection of octreotide-LAR, deconvolution was performed using the point-area method. Individual absorption profiles were characterised using natural splines. The number of breakpoints was selected using the generalised cross-validation criterion. The two compartment model was selected based on the i.v. study. After i.m. administration, octreotide exhibited a triphasic absorption profile, with large interindividual variability. A transient peak followed the initial burst phase. The third phase covered 85% of total drug released. The approach allows a model-independent description of the in vivo absorption profile of octreotide-LAR.

Host-dependent Anopheles flavirostris larval distribution reinforces the risk of malaria near water.

Malaria control strategies are more likely to be successful if groups at high risk can be accurately predicted. Given that mosquitoes have an obligate aquatic phase we were interested in determining how vector larval abundance relates to the spatial distribution of human malaria infection. We examined the relationship between malaria parasite prevalence and distance from vector larval habitat, and vector larval abundance and distance from human habitation, in separate studies in rural, low-endemic areas of the Philippines. Parasite prevalence among symptomatic patients was significantly higher among those living in proximity (< or = 50 m) to potential larval habitats of the major vector, Anopheles flavirostris (adjusted odds ratio [AOR] = 2.64, P = 0.02 and AOR = 3.43, P = 0.04). A larval survey of A. flavirostris revealed a higher density of early and late instars near human habitation (adjusted P < 0.05). The results suggest that larvae are associated with human habitation, thereby reinforcing malaria risk in people living close to larval habitats. This has implications for understanding the interaction between vectors, hosts, and parasites, and the potential for success of localized malaria control measures.

A double-blind, placebo-controlled crossover study investigating the effect of porcine secretin in children with autism.

OBJECTIVES: A recent patient series reported the incidental findings of improved social and language skills in 3 children with autistic spectrum disorders after the administration of secretin, a peptide hormone. However, a subsequent study did not find evidence for a drug effect. Parents are seeking treatment with secretin despite the absence of empirical investigations demonstrating amelioration in autism symptomology. In order to more precisely measure the effects of secretin, this study investigated the effect of a single intravenous dose of porcine secretin on 12 autistic children through a randomized, double-blind, placebo-controlled, crossover study. Children were assessed on objective language and on social, neuropsychological, and gastrointestinal measures to evaluate drug effects. The study was conducted over a 16-week trial. The results indicated that significant differences were not observed on the majority of the dependent variables. Statistically significant differences were observed on measures of positive affect and activity level following secretin infusion. In general, the autistic children did not demonstrate the improvements described in the initial retrospective report.

Patterns of child growth in Papua New Guinea and their relation to environmental, dietary and socioeconomic factors--further analyses of the 1982-1983 Papua New Guinea National Nutrition Survey.

Child growth and nutrition in rural Papua New Guinea vary widely among different environments. The 1982-1983 National Nutrition Survey (NNS) was re-analyzed in order to relate patterns of growth to a wide range of dietary, socioeconomic, agricultural and demographic variables. Anthropometric indices of growth were calculated based on an internal Papua New Guinean growth standard constructed from the children included in the NNS. Children were subsequently classified as stunted, wasted or underweight if they were more than 1 SD below the national mean. Regression analyses on 15,975 children show that variation in growth among environments can largely be accounted for by differences in diet, although significant differences in relation to altitude, relief and rainfall patterns persist. Other important predictors of child growth and nutrition included socioeconomic status, maternal education, marital status of the mother and father's occupation. Variance components analysis revealed that most of the geographical variation in child growth was accounted for by the environmental, dietary, socioeconomic, agricultural and demographic variables included in the regression analyses. Most of the factors which were found to be associated with child growth in this study are related in one form or another to differences in local subsistence agriculture, which may therefore be the main determinant of child growth and nutrition patterns in Papua New Guinea.