Optimal packetisation of MPEG-4 using RTP over mobile networks

The introduction of third-generation wireless networks should result in real-time mobile video communications becoming a reality. Delivery of such video is likely to be facilitated by the realtime transport protocol (RTP). Careful packetisation of the video data is necessary to ensure the optimal trade-off between channel utilisation and error robustness. Theoretical analyses for two basic schemes of MPEG-4 data encapsulation within RTP packets are presented. Simulations over a GPRS (general packet radio service) network are used to validate the analysis of the most efficient scheme. Finally, a motion adaptive system for deriving MPEG-4 video packet sizes is presented. Further simulations demonstrate the benefits of the adaptive system

GalNAc/Gal-Binding Rhizoctonia solani Agglutinin Has Antiproliferative Activity in Drosophila melanogaster S2 Cells via MAPK and JAK/STAT Signaling

Rhizoctonia solani agglutinin, further referred to as RSA, is a lectin isolated from the plant pathogenic fungus Rhizoctonia solani. Previously, we reported a high entomotoxic activity of RSA towards the cotton leafworm Spodoptera littoralis. To better understand the mechanism of action of RSA, Drosophila melanogaster Schneider S2 cells were treated with different concentrations of the lectin and FITC-labeled RSA binding was examined using confocal fluorescence microscopy. RSA has antiproliferative activity with a median effect concentration (EC50) of 0.35 µM. In addition, the lectin was typically bound to the cell surface but not internalized. In contrast, the N-acetylglucosamine-binding lectin WGA and the galactose-binding lectin PNA, which were both also inhibitory for S2 cell proliferation, were internalized whereas the mannose-binding lectin GNA did not show any activity on these cells, although it was internalized. Extracted DNA and nuclei from S2 cells treated with RSA were not different from untreated cells, confirming inhibition of proliferation without apoptosis. Pre-incubation of RSA with N-acetylgalactosamine clearly inhibited the antiproliferative activity by RSA in S2 cells, demonstrating the importance of carbohydrate binding. Similarly, the use of MEK and JAK inhibitors reduced the activity of RSA. Finally, RSA affinity chromatography of membrane proteins from S2 cells allowed the identification of several cell surface receptors involved in both signaling transduction pathways

Position paper: The potential role of optical biopsy in the study and diagnosis of environmental enteric dysfunction

Environmental enteric dysfunction (EED) is a disease of the small intestine affecting children and adults in low and middle income countries. Arising as a consequence of repeated infections, gut inflammation results in impaired intestinal absorptive and barrier function, leading to poor nutrient uptake and ultimately to stunting and other developmental limitations. Progress towards new biomarkers and interventions for EED is hampered by the practical and ethical difficulties of cross-validation with the gold standard of biopsy and histology. Optical biopsy techniques — which can provide minimally invasive or noninvasive alternatives to biopsy — could offer other routes to validation and could potentially be used as point-of-care tests among the general population. This Consensus Statement identifies and reviews the most promising candidate optical biopsy technologies for applications in EED, critically assesses them against criteria identified for successful deployment in developing world settings, and proposes further lines of enquiry. Importantly, many of the techniques discussed could also be adapted to monitor the impaired intestinal barrier in other settings such as IBD, autoimmune enteropathies, coeliac disease, graft-versus-host disease, small intestinal transplantation or critical care

Fifty cases of primary hyperaldosteronism in Hong Kong Chinese with a high frequency of periodic paralysis. Evaluation of techniques for tumour localisation

Fifty consecutive Chinese patients with primary hyperaldosteronism were studied. All were considered to have an adrenal cortical adenoma, this being proven by surgery in 46 cases. In contrast to other reports, periodic paralysis was a presenting feature in 42 per cent of patients. Other notable symptoms were palpitations (30 per cent) and syncope (12 per cent). Vascular complications were present in 20 per cent of cases. Mean serum potassium level at presentation was 2.1 ± 0.1 (mean ± SEM) and sodium 145.0 ± 0.1 mmol/l. Serum potassium was significantly lower and plasma aldosterone higher in patients with periodic paralysis. Adrenal venography in order to localise the tumour was unreliable and was misleading in two cases. Adrenal venous sampling for steroid analysis was much more helpful, despite the difficulty of obtaining right adrenal venous blood. The side of the adenoma could be predicted in 97 per cent of cases from measurements of left adrenal venous and vena caval aldosterone levels. The use of high resolution CT gave 100 per cent accuracy in all 18 patients who underwent surgery, the smallest detected tumour being 0.8 cm in diameter. Surgery corrected hypokalaemia in all cases, and 37 of the 46 patients required no further antihypertensive treatment.link_to_subscribed_fulltex

Hypothalamic defects in two adult patients with septo-optic dysplasia

Two adult patients with unilateral hypoplastic optic nerves, absent septa pellucida and hypopituitarism are described. Patient 1, aged 20, presented with diabetes insipidus due to partial vasopressin deficiency. Patient 2, aged 29, presented with focal epilepsy. Both had short stature. They showed absent growth hormone (GH) response to insulin-hypoglycaemia or glucagon, but responded to 100 μg growth hormone releasing factor (GRF-44) with a rise in circulating GH, suggesting a hypothalamic defect in GH release though a co-existing pituitary defect cannot be excluded. Other hypothalamic-pituitary functions were normal. These two patients probably represent the milder form of the clinical spectrum of septo-optic dysplasia which, with the extensive use of CT brain scans, will be increasingly encountered by physians attending adult patients.link_to_subscribed_fulltex

Long-term effects of megavoltage radiotherapy in acromegaly

link_to_subscribed_fulltex

Primary hyperparathyroidism: Its clinical pattern and results of surgical treatment in Hong Kong Chinese

Primary hyperparathyroidism has been increasingly diagnosed among whites since the advent of the biochemical autoanalyzer. However, the condition remains uncommon among Orientals. Our experience with 31 patients at the Queen Mary Hospital, University of Hong Kong, in the periods before and after we began to use the biochemical autoanalyzer was reviewed. The prevalence of primary hyperparathyroidism rose slightly from 3.1 to 3.7 per 100,000 hospital population. In both periods skeletal manifestation was the major clinical presentation, followed by hypercalcemic symptoms and urologic disease. Asymptomatic hypercalcemia occurred in three of 31 patients despite the use of biochemical autoanalyzer. Preoperative localization was carried out in 27 patients and was helpful in nine (33.3%) of them. The surgeon explored all four parathyroids, removed the diseased gland(s), and examined a biopsy specimen of one normal-appearing gland. There were 27 adenomas, two carcinomas, one four-gland hyperplasia, and one sarcoidosis. Twenty-eight patients had transient hypocalcemia after parathyroidectomy and required calcium supplements for variable periods. Before and after we began to use the biochemical autoanalyzer, there was a minimal change in the prevalence and clinical pattern of primary hyperparathyroidism seen in our hospital. In our experience, successful parathyroidectomy depends more on the surgeon's operative technique than on preoperative localization.link_to_subscribed_fulltex

Long-term treatment of hyperprolactinaemia with bromocriptine: Effect of drug withdrawal

Fifty-one patients with hyperprolactinaemia (23 with macroadenoma, 23 with microadenoma, and five with idiopathic hyperprolactinaemia) were treated with bromocriptine for 2-12 years (4.9 ± 2.9 years, mean ± SD). During therapy, the serum PRL levels were suppressed into the normal range in all but five patients. In these five patients, despite the high circulating PRL, gonadal function returned to normal in three, while in the other two gonadotrophin reserve was impaired even before therapy. Gel chromatography showed that one of these patients had a high proportion of a large molecular weight form of PRL. Twenty-four patients received bromocriptine as the sole method of treatment for over 2 years (3.4 ± 2.3 years). In five out of the 24 subjects (21%), serum PRL remained normal with no clinical symptoms after prolonged drug withdrawal (1-4 years). Twenty-one patients received radiotherapy in conjunction with bromocriptine therapy. Of these 11 had prior surgery. After a follow-up of 6.0 ± 3.0 years after radiotherapy, serum PRL remained within the normal range in 6 out of 21 subjects (29%), 1-4 years after bromocriptine withdrawal. One of the patients had impaired GH response to insulin hypoglycaemia developing after radiotherapy. We conclude that prolonged bromocriptine treatment is an effective treatment for prolactinomas.link_to_subscribed_fulltex