Problematic Internet Use Among University Students in Jamaica.

The prevalence of problematic Internet use (PIU) and its associated negative outcomes among college students has been heavily researched in developed countries. However, despite the increased accessibility of the Internet and indicators which may suggest PIU in developing countries such as Jamaica, PIU in this context remains grossly understudied. This study surveyed 277 Jamaican university students and found evidence of PIU, with younger respondents (ages 18-23) at risk. The findings also indicate that the predictors of PIU in this sample are depressive symptomatology, avoidant-attachment, and low social connectedness (R 2 = .208, F[7, 269] = 10.112, p < .001). Findings from the current study highlight that problematic Internet use is of concern in this developing context and warrants further exploration.

Responses of soil fungi to logging and oil palm agriculture in Southeast Asian tropical forests.

Human land use alters soil microbial composition and function in a variety of systems, although few comparable studies have been done in tropical forests and tropical agricultural production areas. Logging and the expansion of oil palm agriculture are two of the most significant drivers of tropical deforestation, and the latter is most prevalent in Southeast Asia. The aim of this study was to compare soil fungal communities from three sites in Malaysia that represent three of the most dominant land-use types in the Southeast Asia tropics: a primary forest, a regenerating forest that had been selectively logged 50 years previously, and a 25-year-old oil palm plantation. Soil cores were collected from three replicate plots at each site, and fungal communities were sequenced using the Illumina platform. Extracellular enzyme assays were assessed as a proxy for soil microbial function. We found that fungal communities were distinct across all sites, although fungal composition in the regenerating forest was more similar to the primary forest than either forest community was to the oil palm site. Ectomycorrhizal fungi, which are important associates of the dominant Dipterocarpaceae tree family in this region, were compositionally distinct across forests, but were nearly absent from oil palm soils. Extracellular enzyme assays indicated that the soil ecosystem in oil palm plantations experienced altered nutrient cycling dynamics, but there were few differences between regenerating and primary forest soils. Together, these results show that logging and the replacement of primary forest with oil palm plantations alter fungal community and function, although forests regenerating from logging had more similarities with primary forests in terms of fungal composition and nutrient cycling potential. Since oil palm agriculture is currently the mostly rapidly expanding equatorial crop and logging is pervasive across tropical ecosystems, these findings may have broad applicability.

Clonal origins of ETV6-RUNX1⁺ acute lymphoblastic leukemia: studies in monozygotic twins.

Studies on twins with concordant acute lymphoblastic leukemia (ALL) have revealed that ETV6-RUNX1 gene fusion is a common, prenatal genetic event with other driver aberrations occurring subclonally and probably postnatally. The fetal cell type that is transformed by ETV6-RUNX1 is not identified by such studies or by the analysis of early B-cell lineage phenotype of derived progeny. Ongoing, clonal immunoglobulin (IG) and cross-lineage T-cell receptor (TCR) gene rearrangements are features of B-cell precursor leukemia and commence at the pro-B-cell stage of normal B-cell lineage development. We reasoned that shared clonal rearrangements of IG or TCR genes by concordant ALL in twins would be informative about the fetal cell type in which clonal advantage is elicited by ETV6-RUNX1. Five pairs of twins were analyzed for all varieties of IG and TCR gene rearrangements. All pairs showed identical incomplete or complete variable-diversity-joining junctions coupled with substantial, subclonal and divergent rearrangements. This pattern was endorsed by single-cell genetic scrutiny in one twin pair. Our data suggest that the pre-leukemic initiating function of ETV6-RUNX1 fusion is associated with clonal expansion early in the fetal B-cell lineage.

Evolutionary trajectories of hyperdiploid ALL in monozygotic twins.

Identical twins have provided unique insights on timing or sequence of genetic events in acute lymphoblastic leukaemia (ALL). To date, this has mainly focused on ALL with MLL or ETV6-RUNX1 fusions, with hyperdiploid ALL remaining less well characterised. We examined three pairs of monozygotic twins, two concordant and one discordant for hyperdiploid ALL, for single-nucleotide polymorphism (SNP)-defined copy number alterations (CNAs), IGH/L plus TCR gene rearrangements and mutations in NRAS, KRAS, FLT3 and PTPN11 genes. We performed whole exome sequencing in one concordant twin pair. Potential 'driver' CNAs were low, 0-3 per case, and all were different within a pair. One patient had an NRAS mutation that was lacking from leukaemic cells of the twin sibling. By exome sequencing, there were 12 nonsynonymous mutations found in one twin and 5 in the other, one of which in SCL44A2 was shared or identical. Concordant pairs had some identical IGH/L and TCR rearrangements. In the twin pair with discordant hyperdiploid ALL, the healthy co-twin had persistent low level hyperdiploid CD19+ cells that lacked a CNA present in the ALL cells of her sibling. From these data, we propose that hyperdiploid ALL arises in a pre-B cell in utero and mutational changes necessary for clinical ALL accumulate subclonally and postnatally.

New thrombopoietin receptor agonists for platelet disorders.

Since thrombopoietin (TPO) was cloned in 1994, TPO receptor (TPO-R) agonists have been developed which have shown significant clinical activity in various conditions characterized by thrombocytopenia. First-generation TPO-R agonists were recombinant forms of human TPO. The clinical development of these molecules was discontinued after one of them, pegylated recombinant human megakaryocyte growth and development factor, was associated with the development of neutralizing autoantibodies cross-reacting with endogenous TPO. Second-generation TPO-R agonists are now available, which present no sequence homology to endogenous TPO. Two of these new agents, romiplostim and eltrombopag, have been granted marketing authorization for use in patients with primary immune thrombocytopenia unresponsive to conventional treatments. Clinical trials with TPO-R agonists are also ongoing in other thrombocytopenias, such as hepatitis C virus-related thrombocytopenia and the myelodysplastic syndromes.

Optimization of metal artefact reduction (MAR) sequences for MRI of total hip prostheses.

AIM: To describe the relative contribution of matrix size and bandwidth to artefact reduction in order to define optimal sequence parameters for metal artefact reduction (MAR) sequences for MRI of total hip prostheses. METHODS AND MATERIALS: A phantom was created using a Charnley total hip replacement. Mid-coronal T1-weighted (echo time 12ms, repetition time 400ms) images through the prosthesis were acquired with increasing bandwidths (150, 300, 454, 592, and 781Hz/pixel) and increasing matrixes of 128, 256, 384, 512, 640, and 768 pixels square. Signal loss from the prosthesis and susceptibility artefact was segmented using an automated tool. RESULTS: Over 90% of the achievable reduction in artefacts was obtained with matrixes of 256x256 or greater and a receiver bandwidth of approximately 400Hz/pixel or greater. Thereafter increasing the receiver bandwidth or matrix had little impact on reducing susceptibility artefacts. Increasing the bandwidth produced a relative fall in the signal-to-noise ratio (SNR) of between 49 and 56% for a given matrix, but, in practice, the image quality was still satisfactory even with the highest bandwidth and largest matrix sizes. The acquisition time increased linearly with increasing matrix parameters. CONCLUSION: Over 90% of the achievable metal artefact reduction can be realized with mid-range matrices and receiver bandwidths on a clinical 1.5T system. The loss of SNR from increasing receiver bandwidth, is preferable to long acquisition times, and therefore, should be the main tool for reducing metal artefact.

Social and trauma-related pathways leading to psychological distress and functional limitations four years after the humanitarian emergency in Timor-Leste.

There is growing acknowledgment that research in the postconflict field needs to include a focus on social conditions. The authors applied structural equation modeling to epidemiologic data obtained from postconflict Timor-Leste, to examine for links involving potentially traumatic events and sociodemographic factors (age, gender, educational levels, and unemployment) with psychological symptoms and functioning. Exposure to trauma and lack of education emerged as most relevant with psychological distress impacting on education in the urban area. Age and gender exerted influences at different points in the model consistent with the known history of Timor. Although based on cross-sectional data, the model supports the relevance of past trauma, posttraumatic distress, and postconflict social conditions to functioning in societies such as Timor-Leste.

Long-term use of a cannabis-based medicine in the treatment of spasticity and other symptoms in multiple sclerosis.

The object of this study was to monitor the safety and efficacy of long-term use of an oromucosal cannabis-based medicine (CBM) in patients with multiple sclerosis (MS). A total of 137 MS patients with symptoms not controlled satisfactorily using standard drugs entered this open-label trial following a 10-week, placebo-controlled study. Patients were assessed every eight weeks using visual analogue scales and diary scores of main symptoms, and were followed for an average of 434 days (range: 21 -814). A total of 58 patients (42.3%) withdrew due to lack of efficacy (24); adverse events (17); withdrew consent (6); lost to follow-up (3); and other (8). Patients reported 292 unwanted effects, of which 251 (86%) were mild to moderate, including oral pain (28), dizziness (20), diarrhoea (17), nausea (15) and oromucosal disorder (12). Three patients had five 'serious adverse events' between them--two seizures, one fall, one aspiration pneumonia, one gastroenteritis. Four patients had first-ever seizures. The improvements recorded and dosage taken in the acute study remained stable. Planned, sudden interruption of CBM for two weeks in 25 patients (of 62 approached) did not cause a consistent withdrawal syndrome, although 11 (46%) patients reported at least one of--tiredness, interrupted sleep, hot and cold flushes, mood alteration, reduced appetite, emotional lability, intoxication or vivid dreams. Twenty-two (88%) patients re-started CBM treatment. We conclude that long-term use of an oromucosal CBM (Sativex) maintains its effect in those patients who perceive initial benefit. The precise nature and rate of risks with long-term use, especially epilepsy, will require larger and longer-term studies.

Pancreatitis and adenoviral infection in children after blood and marrow transplantation.

Pancreatitis is a well-recognized consequence of blood and marrow transplantation (BMT). In a 4-year period, between January 2001 and December 2004, five children who received a BMT in our institution were diagnosed as having pancreatitis. Four of these five children also had adenoviral infection. We report these four cases and highlight the importance of investigating for pancreatitis patients who have any abdominal symptoms post BMT, and include specific stool culture for viral isolation, if it is not already known.