Physical activity and nutritional status of adolescents on Guam

The 1999 Safe & Drug Free Schools and Communities Youth Risk Behavior Study collected data from representative samples of both high school (n=590) and middle school students (n=643) on Guam in May, 1999. Results showed that the dietary and exercise habits of Guam's adolescents were sub-optimal. Out of the 643 middle school students surveyed, 26% consumed at least 3 meals per week at a fast food restaurant and 53.3% consumed at least 2 cans of sweetened soda per day. Guam adolescents had a very low intake of fruits and vegetables. As many as 75.3% of high school students reported consuming fruits and vegetables less than once a day. Students who practiced unsafe weight loss practices were significantly more likely to smoke cigarettes, and use illegal drugs. In addition, 26.9% of adolescents surveyed were considered 'overweight'--similar to the prevalence of overweight reported among U.S. Mainland adolescents. Finally, data from survey showed that adolescents on Guam spent more time watching television and less time performing various physical activities than adolescents in the U.S. mainland. These suboptimal practices put Guam's adolescents at increased risk for immediate and long-term health problems.     

A review of peripartum cardiomyopathy

Peripartum cardiomyopathy is a rare form of cardiomyopathy, of unknown aetiology, which is associated with a significant morbidity and mortality. It is characterised by the presentation of heart failure, within a month of delivery and up to 5 months post-partum, secondary to left ventricular impairment. It is essentially a diagnosis of exclusion and can only be made in the absence of any other demonstrable cause. One of the most challenging areas is in pre-natal counselling, when a woman wishes to undertake a further pregnancy, because recovery of left ventricular function gives no guarantee of safety.     

Optimization of technetium-99m Sestamibi single-photon emission tomography to define multidrug resistance with confidence

BACKGROUND: The efflux rate of technetium-99m Sestamibi (99mTc-Sestamibi) is a kinetic phenomenon related to the response of cancer cells to chemotherapy, and may be used to determine drug resistance. Measurement of the efflux rate requires accurate quantitative single-photon emission tomography (SPET) imaging within the time constraints imposed by the kinetics of the process. METHODS: A phantom study, at activity concentrations typically found with 99mTc-Sestamibi in vivo, was undertaken to optimize the SPET parameters and, in particular, to determine whether 180 degrees acquisition arcs with heads in 'L' configuration could be used for accurate quantification. Following the development of the most appropriate SPET protocol, a small patient pilot study was undertaken. RESULTS: Studies designed to evaluate statistical uncertainty (noise), contrast restitution and spatial resolution of the data sets, using different acquisition and reconstruction parameters, showed that 180 degrees SPET using a 64 x 64 matrix, 6 degrees angular sampling and iterative reconstruction was optimal. Finer linear and/or angular sampling afforded negligible improvement in resolution, but markedly increased the statistical uncertainty. Comparison of 360 degrees and 180 degrees acquisitions, utilizing conventional filtered backprojection and iterative reconstruction algorithms, demonstrated that the statistical uncertainty was reduced to a greater extent for 180 degrees data collection. For 360 degrees (64 x 64) data acquisition, statistical uncertainty decreased from 15% to 11% using the iterative algorithm, whilst the 180 degrees (64 x 64) data showed a reduction from 20% to 7%, and approached values obtained by planar imaging. The efflux measurements obtained in the patient pilot study were consistent with the observed chemotherapy response. CONCLUSION: Our study shows that 180 degrees acquisition arcs are a practical option for accurate quantitative SPET kinetic imaging for potential studies of chemotherapy response in patients with lung cancer.     

Identification of an HLA-A*0201 cytotoxic T lymphocyte epitope specific to the endothelial antigen Tie-2

Tie-2 stabilises pericyte-endothelial interactions during angiogenesis and is highly expressed on endothelium during several diseases, including arthritis, age-related macular degeneration and cancer. A vaccine that targets endothelium overexpressing Tie-2 may result in vessel damage and stimulate an inflammatory cascade resulting in disease regression. We have identified a region unique to Tie-2 (amino acids 1-196) that is homologous in humans and mice. Using computer algorithms, several HLA-A*0201 epitopes that are identical in mice and humans were predicted within this region; however, binding assays showed that the majority of these epitopes were of low affinity. Modification of the anchor residues of 4 epitopes enhanced HLA binding. These epitopes were incorporated by site-directed mutagenesis into a Tie-2 DNA construct. Immunisation of HLA*0201 transgenic mice with one of the modified Tie-2 constructs stimulated CTLs that recognised both wild-type and modified peptide-pulsed target cells. In contrast, no CTLs were generated in mice immunised with wild-type Tie-2 construct, demonstrating that the modified epitope was necessary in the generation of CTLs. Moreover, CTLs from mice immunised with the modified construct killed HLA-A*0201 endothelial cells overexpressing Tie-2. Our study demonstrates that it is possible to break tolerance to the endothelial antigen Tie-2, suggesting that it may be feasible to design a vaccine to activate CTLs to kill endothelial cells overexpressing Tie-2.     

A new wrestler in the battle between alpha- and beta-secretases for cleavage of APP

Modulation of the proteases that process the amyloid precursor protein (APP) is a major therapeutic strategy for the treatment and prevention of Alzheimer's disease (AD). The discovery of a novel endogenous modulator of alpha-secretase-mediated, in preference to beta-secretase-mediated, cleavage of APP implicates sumoylation in the etiology of AD, and offers a new therapeutic target for intervention in APP processing.     

Comparison of echo-enhanced ultrasound with fluoroscopic MCU for the detection of vesicoureteral reflux in neonates

BACKGROUND: Fluoroscopic micturating cystourethrography (MCU) is used for screening and grading of vesicoureteral reflux (VUR). It involves ionizing radiation. This study was designed to assess the efficacy of contrast-enhanced sonography in predicting the presence or absence of VUR. OBJECTIVE: To compare an ultrasound contrast agent for detection of VUR in at-risk infants, and to compare these findings with fluoroscopic MCU with the aim of determining whether echo-enhanced sonography could be used instead of fluoroscopic MCU to identify neonates who do not have VUR, thus avoiding the use of radiation in this group. MATERIALS AND METHODS: From August 1999 to August 2000, 97 neonates (69 male, 31 female), aged 28-90 days (mean 48 days), referred for MCU and renal ultrasonography for investigation of VUR were recruited consecutively. Echo-enhanced sonography using stabilized microbubbles was followed immediately by fluoroscopic MCU. VUR was diagnosed if transient hyperechogenicity appeared within the pelvicalyceal system or ureter. The mean number of micturitions was 2.7 (range 1-6). RESULTS: Reflux was detected in 19 kidneys (14 babies) by one or other technique. The findings were concordant in 181 kidneys (94.2%). Echo-enhanced sonography had a sensitivity of 64% (95% CI 35-87%), a specificity of 100% (95-100%), a positive predictive value of 100% (66-100%), and a negative predictive value of 94% (87-98%). CONCLUSIONS: The role of echo-enhanced sonography is limited at present in our neonatal population as a screening examination. Its ability to detect cases of high-grade reflux may make it an attractive alternative in follow-up of known cases of VUR, and may help to reduce radiation exposure in this group.