Findings From an Accelerated _In Vivo_ Corrosion Model of Magnesium

In this article, we are presenting some findings of magnesium corrosion in an _in vivo_ model. While there is consensus that subcutaneous bubbles will occur, it was found in our corrosion-accelerated model that magnesium corrosion is more severe in areas under the gas bubbles. This finding may bring insights to novel methods in reducing the uneven corrosion

Theoretical risk assessment of magnesium alloys as degradable biomedical implants

The theoretical tolerable implant masses for ten magnesium alloys as degradable biomedical implant materials are evaluated in this study. Dose-response assessment is conducted using toxicological data from authoritative public health agencies such as the US Agency for Toxic Substances and Disease Registry and the USEPA Integrated Risk Information System, and assuming 1 year of even corrosion. Uncertainty factors adopted by the agencies are used. The tolerable limits corresponding to various component elements in an alloy are considered separately, and the lowest tolerable limit is selected as the tolerable limit of the alloy. The results show that aluminum is usually the component element with the lowest tolerance, and the tolerable mass for Al-containing magnesium alloys fall to around or below 1 g per person per year, while the limit for other magnesium alloys can well exceed 10 g. Deficits in the toxicological data of some component elements are noted. This study illustrates that toxicological calculations should be taken into consideration when developing novel degradable metallic implants. © 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.postprin

The African Lungfish (\u3cem\u3eProtopterus dolloi\u3c/em\u3e): Ionoregulation and Osmoregulation in a Fish out of Water

Although urea production and metabolism in lungish have been thoroughly studied, we have little knowledge of how internal osmotic and electrolyte balance are controlled during estivation or in water. We tested the hypothesis that, compared with the body surface of teleosts, the slender African lungfish (Protopterus dolloi) body surface was relatively impermeable to water, Na+ and Cl- due to its greatly reduced gills. Accordingly, we measured the tritiated water (3H-H2O) flux in P. dolloi in water and during air exposure. In water, 3H-H2O efflux was comparable with the lowest measurements reported in freshwater teleosts, with a rate constant (K) of 17.6% body water h-1. Unidirectional ion fluxes, measured using 22Na+ and 36Cl-, indicated that Na+ and Cl- influx was more than 90% lower than values reported in most freshwater teleosts. During air exposure, a cocoon formed within 1 wk that completely covered the dorsolateral body surface. However, there were no disturbances to blood osmotic or ion (Na+, Cl-) balance, despite seven- to eightfold increases in plasma urea after 20 wk. Up to 13-fold increases in muscle urea (on a dry-weight basis) were the likely explanation for the 56% increase in muscle water content observed after 20 wk of air exposure. The possibility that muscle acted as a “water reservoir” during air exposure was supported by the 20% decline in body mass observed during subsequent reimmersion in water. This decline in body mass was equivalent to 28 mL water in a 100-g animal and was very close to the calculated net water gain (approximately 32 mL) observed during the 20-wk period of air exposure. Tritiated water and unidirectional ion fluxes on air-exposed lungfish revealed that the majority of water and ion exchange was via the ventral body surface at rates that were initially similar to aquatic rates. The 3H-H2O flux declined over time but increased upon reimmersion. We conclude that the slender lungfish body surface, including the gills, has relatively low permeability to water and ions but that the ventral surface is an important site of osmoregulation and ionoregulation. We further propose that an amphibian-like combination of ventral skin water and ion permeability, plus internal urea accumulation during air exposure, allows P. dolloi to extract water from its surroundings and to store water in the muscle when the water supply becomes limited

Differential gene expression in the liver of the African lungfish, Protopterus annectens, after 6 months of aestivation in air or 1 day of arousal from 6 months of aestivation

10.1371/journal.pone.0121224PLoS ONE103e012122

High hepatitis B surface antigen levels predict insignificant fibrosis in hepatitis B e antigen positive chronic hepatitis B

INTRODUCTION: There is no data on the relationship between hepatitis B surface antigen (HBsAg) levels and liver fibrosis in hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B (CHB). METHODS: Serum HBsAg and HBV DNA levels in HBeAg-positive CHB patients with liver biopsies were analyzed. The upper limit of normal (ULN) of alanine aminotransferase (ALT) was 30 and 19 U/L for men and women respectively. Histologic assessment was based on Ishak fibrosis staging for fibrosis and Knodell histologic activity index (HAI) for necroinflammation. RESULTS: 140 patients (65% male, median age 32.7 years) were recruited. 56 (40%) had ALT 1, had significantly higher median HBsAg levels (50,320 and 7,820 IU/mL respectively, p/= 25,000 IU/mL was independently associated with fibrosis score </= 1 (p=0.025, odds ratio 9.042).Using this cut-off HBsAg level in patients with ALT </=2xULN, positive and negative predictive values for predicting fibrosis score </= 1 were 92.7% and 60.0% respectively. HBV DNA levels had no association with liver histology. CONCLUSION: Among HBeAg-positive patients with ALT </=2xULN, high serum HBsAg levels can accurately predict fibrosis score </= 1, and could potentially influence decisions concerning treatment commencement and reduce the need for liver biopsy.published_or_final_versio

Indigenising social work education : experiences of the students from the People’s Republic of China in Hong Kong

Author name used in this publication: Angelina Yuen-TsangAuthor name used in this publication: David IpVersion of RecordPublishe

Increased gene expression of a facilitated diffusion urea transporter in the skin of the African lungfish (Protopterus annectens) during massively elevated post-terrestrialization urea excretion

The full-length cDNA sequence of a putative urea transporter (IfUl) of the facilitated diffusion UT-A type has been cloned from the African lungfish Protopterus annectens. The IFUTcDNA is 1990bp in length and its open reading frame encodes a 409 amino acid long protein, with a calculated molecular mass of 44,723 Da. The sequence is closest to those of amphibians (∼65% amino acid homology), followed by mammals and elasmobranchs (∼60%), and then teleosts (∼50%). IfUT was clearly expressed in gill, kidney, liver, skeletal muscle and skin. Upon re-immersion in water after 33days of air exposure (\u27terrestrialization\u27), lungfish exhibited a massive rise in urea-N excretion which peaked at 12-30h with rates of 2000-5000μmol-N kg-1 h -1 (versus normal aquatic rates of \u3c130μmol-Nkg -1h-1) and persisted until 70h. This appears to occur mainly through the skin. Total \u27excess\u27 urea-N excretion amounted to ∼81,000-91,000 μmol-N kg-1 over 3 days. By real-time PCR, there was no difference in IfUT expression in the ventral abdominal skin between aquatic ammoniotelic controls and terrestrialized lungfish immediately after return to water (0h), and no elevation of urea-N excretion at this time. However, skin biopsies revealed a significant 2.55-fold elevation of IfUT expression at 14h, coincident with peak urea-N excretion. At 48h, there was no longer any significant difference in IFUT mRNA levels from those at 0 and 14h, or from aquatic fed controls. In accordance with earlier studies, which identified elevated urea-N excretion w\u27athe skin of P. dolloi with pharmacology typical of UT-A carriers, these results argue that transcriptional activation of a facilitated diffusion type urea transporter (IfUT) occurs in the skin during re-immersion. This serves to clear the body burden of urea-N accumulated during terrestrialization

Clinical predictors of sputum microbiology in chronic Chinese bronchiectasis

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The relationship between sputum microbial load and leucocyte count in stable bronchiectasis

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Efficacy And Safety Of Hylan G-F 20 Injection In Treatment Of Knee Osteoarthritis In Chinese Patients: Results Of A Prospective, Multicentre, Longitudinal Study

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