Arsenic Fractionation and Bioaccessibility in Two Alkaline Texas Soils Incubated with Sodium Arsenate

Elevated arsenic (As) concentrations in urban soils with prolonged arsenical pesticide application history have increased the risk associated with accidental hand-to-mouth soil ingestion by children. Earlier work by the authors suggested that the conservative statement of 100% As bioaccessibility in soils was not valid for a set of acidic soils incubated with sodium arsenate. In this study, two alkaline Texas soils incubated with a commonly used As pesticide (sodium arsenate) were evaluated for their potential in reducing soil As bioaccessibility. The objective of this study was to evaluate the effects of incubation time and As load on soil As fractionation and bioaccessibility. Soils were subjected to a sequential As fractionation scheme, and bioaccessible As was quantified using an in vitro stomach phase test. Results showed a reduction in the water-soluble As fraction with incubation time (after 4 months), which remained unchanged after 12 months. This reduction with time was accompanied by an increase in the NaOH- and H₂SO₄-extractable As fractions, suggesting As sorption by amorphous Fe/Al hydroxides and/or Ca/Mg compounds, respectively. Organic/sulfides-bound As increased with incubation time after 12 months but not after 4 months of incubation. The aging effect was also observed with the amount of bioaccessible As at all As loads, showing significant positive correlations with the water-extractable and exchangeable As fractions. Bioaccessible As concentrations even after 12 months of incubation were not significantly reduced, suggesting that natural attenuation might prove inadequate to control As bioaccessibility in these alkaline soils.     

Prevention of mother to child transmission of HIV infection in Pacific countries

Introduction: A generalized epidemic of HIV infection has been evolving in Papua New Guinea over the last decade, whereas in other Pacific Island countries and territories (PICT) HIV transmission has generally been less widespread. Programmes to detect HIV infection in pregnant women and to prevent mother to child transmission (MTCT) during either delivery or breast‐feeding can decrease the incidence of infection in infants. The limited health infrastructure present in some PICT may delay the implementation of effective programmes to decrease MTCT of HIV. Methods: We used a standardized questionnaire to survey health‐care providers in 22 PICT for information on the epidemiology of HIV infection and strategies used during 2004 to prevent MTCT of HIV infection in their country. We supplemented these survey responses with data obtained from regional organizations supporting national responses to HIV. Results: We obtained responses from 21 PICT. The reported prevalence of known HIV infection was >150 per 100 000 persons in Papua New Guinea, approximately 100 per 100 000 persons in French Polynesia, Guam, New Caledonia and Tuvalu and <50 per 100 000 persons in the remaining 14 PICT. Other than in Papua New Guinea, where an estimated 500 pregnant women had HIV infection diagnosed in 2004, reported HIV infection among pregnant women was rare. Ten PICT reported that an HIV antibody test was offered as a routine component of antenatal care and 11 reported that antiretroviral medications were available for the prevention of MTCT of HIV infection. Conclusion: The prevalence of HIV infection differs greatly between PICT with a varying risk of MTCT of HIV infection. Successful prevention of MTCT of HIV infection throughout the PICT will require improved uptake of antenatal HIV antibody testing and better access to antiretroviral medications.     

Outcome of thyroglossal duct cyst excision is independent of presenting age or symptomatology

BACKGROUND: Thyroglossal duct cysts (TGDCs) are the most common form of congenital neck cyst, accounting for up to 70% of such lesions. There has been no consensus on which factors predict outcome of thyroglossal duct cyst excision. The objective of the current study is to evaluate the relevance of symptomatology and age at presentation with outcome of TGDCs. METHODS: Retrospective review of patients with TGDC at a tertiary care children's hospital. Data collected included patient's age, gender, clinical presentation, presence or absence of preoperative infection, imaging modality, type of procedure performed, size and location of the lesion, postoperative infection, complications, and recurrence of disease. RESULTS: Twenty-nine patients were identified (59% female, 41% male). Age of presentation was bimodal and ranged from 18 months to 14 years. The most common presenting symptom was the presence of an asymptomatic midline neck mass (76%). A history of preoperative TGDC infection was present in 22% of patients /=5 years of age. Recurrence rate after the Sistrunk procedure was 3.4%. CONCLUSIONS: The finding of a midline neck mass is the most common presentation of TGDCs in toddlers, whereas infection is the most common presenting symptoms in school-aged children. The incidence of preoperative infection was 41% in our series, much higher than previously reported. Independent of presenting age and symptomatology, recurrence of TGDC remains low when the Sistrunk procedure is employed.     

Spatiotemporal mapping the neural correlates of acupuncture with MEG

Acupuncture is an ancient Eastern healing modality with putative therapeutic applications. Unfortunately, little is known about the central mechanisms by which acupuncture may exert its effects. In this study, 16 [corrected] healthy subjects were evaluated with magnetoencephalography (MEG) to map the location and timing of brain activity during low-frequency electroacupuncture (EA) and mechanical, noninsertive, sham acupuncture (SA) given at acupoint PC-6. Both EA and SA evoked brain responses that localized to contralateral primary somatosensory (SI) cortex. However, initial responses for EA peaked slightly earlier than those for SA and were located inferiorly within SI. Average equivalent current dipole strength was stronger (particularly at latencies >60 ms) for SA. These spatiotemporal differences between activations elicited by EA and SA are likely attributable to stimulus modality (electrical versus mechanical) and differences in the underlying somatosensory fibers transmitting these signals. The present data confirm that acupuncture modulates activity within somatosensory cortex, providing support for previous studies that suggest that the therapeutic effects of acupuncture are linked to SI modulation. Thus, MEG provides excellent spatiotemporal characterization of the somatosensory component of acupuncture, and future studies can contrast derived brain response parameters in healthy controls with those found in a diseased state.     

Predicting the outcome of physeal fractures of the distal femur

BACKGROUND:: Distal femoral epiphyseal fractures are uncommon but have a high incidence rate of complications. It is not clear whether there are any reliable predictor factors and whether the type of fracture, displacement (degree and direction), and treatment method alter the outcome. METHODS:: We retrospectively reviewed the medical charts and images of all patients who sustained a distal femoral epiphyseal fracture and were treated at 2 large level I pediatric centers during the past 10 years. RESULTS:: The selected group included 73 patients (boys, 59; mean age, 10 years). On the basis of the Salter-Harris classification (SH), 43 fractures (59%) were of type II. Fifty-nine percent of the fractures were displaced; 36 fractures were managed conservatively with long leg cast (with or without pelvic band) in 33 patients, cylinder cast in 2, and posterior splint in 1. Thirty-seven patients underwent surgery, and 34 underwent closed reduction followed by percutaneous fixation (crossed Steinman pins, 20; cannulated screws, 13; open reduction, 3; external fixation, 1). The overall complication rate was 40% (29/73), and growth arrest was the most frequent. The SH classification significantly correlated with the incidence of complications (P = 0.031). There was also a significantly higher (P < 0.0001) incidence rate of complications among displaced fractures (48.8% vs 26.6%); the amount and direction of displacement did not correlate with the outcome (P > 0.05). The group treated conservatively had a lower incidence rate of complications (25%) than did the surgical group (54%) (P < 0.05). Among the surgical group, a higher incidence rate of complications occurred when the physis was violated by hardware (65% vs 30%; P = 0.06). CONCLUSIONS:: Both SH classification and displacement of the fracture are significant predictors of the final outcome. The degree and the direction of displacement do not statistically correlate with outcome. The treatment method may influence the final outcome.     

Biocompatibility of polymethylmethacrylate resins used in dentistry

Biocompatibility or tissue compatibility describes the ability of a material to perform with an appropriate host response when applied as intended. Poly-methylmethacrylate (PMMA) based resins are most widely used resins in dentistry, especially in fabrication of dentures and orthodontic appliances. They are considered cytotoxic on account of leaching of various potential toxic substances, most common being residual monomer. Various in vitro and in vivo experiments and cell based studies conducted on acrylic based resins or their leached components have shown them to have cytotoxic effects. They can cause mucosal irritation and tissue sensitization. These studies are not only important to evaluate the long term clinical effect of these materials, but also help in further development of alternate resins. This article reviews information from scientific full articles, reviews, or abstracts published in dental literature, associated with biocompatibility of PMMA resins and it is leached out components. Published materials were searched in dental literature using general and specialist databases, like the PubMED database.     

Glucose activates a protein phosphatase-1-mediated signaling pathway to enhance overall translation in pancreatic beta-cells

Both the rate of overall translation and the specific acceleration of proinsulin synthesis are known to be glucose-regulated processes in the beta-cell. In this study, we propose that glucose-induced stimulation of overall translation in beta-cells depends on a protein phosphatase-1-mediated decrease in serine-51 phosphorylation of eukaryotic translation initiation factor 2alpha (eIF2alpha), a pivotal translation initiation factor. The decrease was rapid and detectable within 15 min and proportional to the range of glucose concentrations that also stimulate translation. Lowered net eIF2alpha phosphorylation was not associated with a detectable decrease in activity of any eIF2alpha kinase. Moreover, okadaic acid blocked glucose-induced eIF2alpha dephosphorylation, suggesting that the net effect was mediated by a protein phosphatase. Experiments with salubrinal on intact cells and nuclear inhibitor of protein phosphatase-1 (PP1) on cell extracts suggested that this phosphatase was PP1. The net effect contained, however, a component of glucose-induced folding load in the endoplasmic reticulum because coincubation with cycloheximide further amplified the effect of glucose on eIF2alpha dephosphorylation. Thus, the steady-state level of eIF2alpha phosphorylation in beta-cells is the result of a balance between folding-load-induced phosphorylation and PP1-dependent dephosphorylation. Because defects in the pancreatic endoplasmic reticulum kinase-eIF2alpha signaling system lead to beta-cell failure and diabetes, deregulation of the PP1 system could likewise lead to cellular dysfunction and disease.