Dracunculiasis eradication: delayed, not denied

By the end of 1998, Asia was free of dracunculiasis (Guinea worm disease), with Pakistan, India, and Yemen having interrupted transmission in 1993, 1996, and 1997, respectively. Transmission of the disease was also interrupted in Cameroon and Senegal during 1997. Chad reported only 3 cases during 1998. Dracunculiasis is now confined to only 13 countries in Africa. The overall number of cases has been reduced by more than 97% from the 3.2 million cases estimated to have occurred in 1986 to 78,557 cases reported in 1998. Because the civil war in Sudan remains the major impediment to eradication of dracunculiasis, the interim goal is to stop all transmission outside that country by the end of 2000. The most important operational need now is for national programs to improve the frequency and quality of supervision of village-based health workers in order to enhance the sensitivity of surveillance and effectiveness of case containment.     

The Peculiar Epidemiology of Dracunculiasis in Chad

Dracunculiasis was rediscovered in Chad in 2010 after an apparent absence of 10 years. In April 2012 active village-based surveillance was initiated to determine where, when, and how transmission of the disease was occurring, and to implement interventions to interrupt it. The current epidemiologic pattern of the disease in Chad is unlike that seen previously in Chad or other endemic countries, i.e., no clustering of cases by village or association with a common water source, the average number of worms per person was small, and a large number of dogs were found to be infected. Molecular sequencing suggests these infections were all caused by Dracunculus medinensis. It appears that the infection in dogs is serving as the major driving force sustaining transmission in Chad, that an aberrant life cycle involving a paratenic host common to people and dogs is occurring, and that the cases in humans are sporadic and incidental.     

Supramolecular structure of stacked and unstacked regions of the photosynthetic membranes of Prochloron sp., a prokaryote

Freeze-fracture replicas of the photosynthetic prokaryote Prochloron sp., collected at Coconut Island, Hawaii, show that the thylakoids are differentiated into stacked and unstacked regions much like the thylakoids of green algae and higher plants. On the exoplasmic (E) fracture face, the particle density is greater in stacked regions (≈3100 particles/μm²) than in unstacked regions (≈925 particles/μm²). On the complementary protoplasmic (P) fracture face, the particle density is lower in stacked regions (≈2265 particles/μm² than in unstacked regions (≈4980 particles/μm²). The histogram of the diameters of E face particles in unstacked regions shows a single broad peak centered at 80 Å. In stacked regions, four distinct peaks, at 75, 105, 130, and 160 Å, are observed. These size classes are virtually identical to those found on E faces of thylakoids of the green alga Chlamydomonas and of greening pea chloroplasts. In the latter systems, the different size classes of E face particles are believed to represent photosystem II units surrounded by variable amounts of chlorophyll a/b light-harvesting complex. We propose that the same interpretation applies to the thylakoids of Prochloron, which contain a similar chlorophyll a/b complex. Our results add to the evidence supporting the view of the chlorophyll a/b complex as both a light-harvesting complex and a membrane adhesion factor. The similarity of the architecture of the thylakoids of Prochloron to that of green algal and plant chloroplasts also provides additional evidence of an evolutionary relationship between Prochloron and the chloroplasts of green plants.     

School‐Related Parental Involvement and Adolescent Academic Achievement: The Role of Community Poverty

Although most current studies have established the importance of school‐related parental involvement to adolescents' academic achievement, they are limited in that they do not address macrolevel community influences on such an association. This may be due in part to the lack of community‐level data or the use of inappropriate statistical strategies that cannot account for the influence of factors at the community level. To address this limitation, in this study, the authors examined the influence of community poverty on the association between school‐related parental involvement and adolescents' academic achievement. Using a large, nationally representative sample, results from a multilevel model suggested that, compared to adolescents living in more affluent communities, the positive effect of school‐related parental involvement on adolescents' academic achievement was significantly weaker for adolescents living in poor communities. Such findings suggested the importance of community poverty in influencing the effectiveness of school‐related parental involvement on adolescents' academic achievement.     

Audit of eosinophilic oesophagitis in children post-liver transplant

Abstract:  Pediatric liver transplantation has proven so successful that 10-yr survival post-transplantation is in excess of 70% and following transplantation, emphasis of medical care switches from life saving to promotion of good quality of life. EE is an increasingly recognised phenomenon in the general population. Eosinophilic disorders of the GI tract are increasingly recognised in patient's post-solid organ transplantation but the contribution of EE to morbidity in this population has not been addressed to date. The objective of this study was to identify the incidence of EE in children receiving liver transplantation by the QLTS over the last 15.5 yr. Comprehensive review of medical records of all liver transplant recipients during study period via cross-checking procedural and electronic laboratory results was performed. All oesophageal biopsies reporting mucosal inflammation were reviewed. EE can be diagnosed when oesophageal biopsy reveals ≥5 eosinophils per HPF; however, we used a cut-off of 20 eosinophils per HPF, which is in accordance with current opinion. In the 159 children who received DD OLT, 130 survived and four have been diagnosed with EE (3%). Only 34 are currently followed in Queensland and all four patients diagnosed are in this cohort representing 12% of our follow-up clinic. Many patients are followed elsewhere so occurrence of EE in our total surviving population is an underestimate. EE is clinically important in the post-liver transplant community. Children post-OLT who have upper GI symptoms should be considered for endoscopic evaluation and biopsy to exclude EE.     

Choriocarcinoma brain metastasis in a patient with viable intrauterine pregnancy. Case report

The authors report the case of a woman who presented during her 30th week of pregnancy with a large brain metastasis from a previously undetected metastatic choriocarcinoma. The metastasis caused significant neurological deficit due to mass effect, necessitating rapid intervention. Medical management included a regimen of high-dose corticosteroid medications for 36 hours, followed by cesarean delivery of the fetus and craniotomy to remove the metastatic tumor, chemotherapy and radiation therapy were begun within 1 week postsurgery. Both the baby and mother survived, and as of the 1-year follow-up examination, there was no evidence of disease in the mother. This is only the second report of a metastatic choriocarcinoma associated with a simultaneous viable intrauterine pregnancy, and the only case in which surgical removal of a brain metastasis was required. Coordinated multidisciplinary treatment of mother and fetus by members of the neurosurgery, medical oncology, neonatology, and obstetrics services facilitated a good outcome in this case.     

Air-braked cycle ergometers: validity of the correction factor for barometric pressure

Barometric pressure exerts by far the greatest influence of the three environmental factors (barometric pressure, temperature and humidity) on power outputs from air-braked ergometers. The barometric pressure correction factor for power outputs from air-braked ergometers is in widespread use but apparently has never been empirically validated. Our experiment validated this correction factor by calibrating two air-braked cycle ergometers in a hypobaric chamber using a dynamic calibration rig. The results showed that if the power output correction for changes in air resistance at barometric pressures corresponding to altitudes of 38, 600, 1,200 and 1,800 m above mean sea level were applied, then the coefficients of variation were 0.8-1.9% over the range of 160-1,597 W. The overall mean error was 3.0 % but this included up to 0.73 % for the propagated error that was associated with errors in the measurement of: a) temperature b) relative humidity c) barometric pressure d) force, distance and angular velocity by the dynamic calibration rig. The overall mean error therefore approximated the +/- 2.0% of true load that was specified by the Laboratory Standards Assistance Scheme of the Australian Sports Commission. The validity of the correction factor for barometric pressure on power output was therefore demonstrated over the altitude range of 38-1,800 m.     

The biological effectiveness of antiproton irradiation.

BACKGROUND AND PURPOSE: Antiprotons travel through tissue in a manner similar to that for protons until they reach the end of their range where they annihilate and deposit additional energy. This makes them potentially interesting for radiotherapy. The aim of this study was to conduct the first ever measurements of the biological effectiveness of antiprotons. MATERIALS AND METHODS: V79 cells were suspended in a semi-solid matrix and irradiated with 46.7MeV antiprotons, 48MeV protons, or (60)Co gamma-rays. Clonogenic survival was determined as a function of depth along the particle beams. Dose and particle fluence response relationships were constructed from data in the plateau and Bragg peak regions of the beams and used to assess the biological effectiveness. RESULTS: Due to uncertainties in antiproton dosimetry we defined a new term, called the biologically effective dose ratio (BEDR), which compares the response in a minimally spread out Bragg peak (SOBP) to that in the plateau as a function of particle fluence. This value was approximately 3.75 times larger for antiprotons than for protons. This increase arises due to the increased dose deposited in the Bragg peak by annihilation and because this dose has a higher relative biological effectiveness (RBE). CONCLUSION: We have produced the first measurements of the biological consequences of antiproton irradiation. These data substantiate theoretical predictions of the biological effects of antiproton annihilation within the Bragg peak, and suggest antiprotons warrant further investigation.