Application of thrombelastography in liver injury induced by endotoxin in rat

Liver injury developing in patients with sepsis may lead to an increased risk of mortality. Thrombelastography (TEG) is generally applied to evaluate hemostatic disturbance in patients undergoing liver transplantation or cardiopulmonary bypass. The aim of this study was to investigate the development of liver injury and coagulopathy in a lipopolysaccharide (LPS)-induced animal model and to assess the relationship between TEG variables and liver injury. Male Wistar rats received LPS (30 mg/kg over a 4-h intravenous infusion) to induce experimental liver injury or isotonic saline as a control. Variables of hemodynamics and liver biochemistry were measured during the subsequent 6?h after the start of infusion. TEG variables (R-time, K-time, α-angle and maximal amplitude), thrombin-antithrombin complex and plasminogen activator inhibitor-1 were also measured. After LPS infusion, liver injury [examined by biochemical variables (e.g. alanine aminotransferase, ALT) and histological studies] was developed and inflammatory cytokines (tumor necrosis factor-α and interleukin-6) were raised. At the initial period of LPS infusion, R-time was shortened and α-angle was increased. Thereafter, α-angle and maximal amplitude were decreased progressively, demonstrating that endotoxin induced coagulation disturbances. Furthermore, there were strong positive correlation between K-time and natural log (Ln)(ALT) (r?=?0.823, P?=?0.001); also, there were strong negative correlations between α-angle and Ln(ALT) (r?=?-0.762, P?=?0.002) as well as maximal amplitude and Ln(ALT) (r?=?-0.732, P?=?0.004) at 6?h after LPS infusion. These results demonstrated that TEG could be a potential tool to evaluate the development of liver injury in endotoxemia.     

Spinal glutamate uptake is critical for maintaining normal sensory transmission in rat spinal cord

Glutamate is a major excitatory neurotransmitter in primary afferent terminals and is critical for normal spinal excitatory synaptic transmission. However, little is known about the regulation of synaptically released glutamate in the spinal cord under physiologic conditions. The sodium-dependent, high-affinity glutamate transporters are the primary mechanism for the clearance of synaptically released glutamate. In the present study, we found that intrathecal injection of glutamate transporter blockers DL-threo-beta-benzyloxyaspartate (TBOA) and dihydrokainate produced significant and dose-dependent spontaneous nociceptive behaviors, such as licking, shaking, and caudally directed biting, phenomena similar to the behaviors caused by intrathecal glutamate receptor agonists. Intrathecal TBOA also led to remarkable hypersensitivity in response to thermal and mechanical stimuli. These behavioral responses could be significantly blocked by intrathecal injection of the NMDA receptor antagonists MK-801 and AP-5, the non-NMDA receptor antagonist CNQX or the nitric oxide synthase inhibitor L-NAME. In vivo microdialysis analysis showed short-term elevation of extracellular glutamate concentration in the spinal cord after intrathecal injection of TBOA. Furthermore, topical application of TBOA on the dorsal surface of the spinal cord resulted in a significant elevation of extracellular glutamate concentration demonstrated by in vivo glutamate voltametry. The present study indicates that defective spinal glutamate uptake caused by inhibition of glutamate transporters leads to excessive glutamate accumulation in the spinal cord. The latter results in persistent over-activation of synaptic glutamate receptors, producing spontaneous nociceptive behaviors and sensory hypersensitivity. Our results suggest that glutamate uptake through spinal glutamate transporters is critical for maintaining normal sensory transmission under physiologic conditions.     

Oyster-associated outbreaks of Norovirus gastroenteritis in Singapore

Outbreaks of gastroenteritis associated with the consumption of raw imported half-shelled frozen oysters occurred in Singapore between 16 Dec 2003 and 04 Jan 2004. A total of 305 cases were reported with clinical symptoms of diarrhoea (94%), abdominal cramps (72%), vomiting (69%) and fever (54%). The median incubation period was 30.8 h and the duration of illness was 2–3 days. The overall relative risk of oyster consumption was 14.1 (95% CI: 8.3–24.0, P<0.001). Stool and oyster samples tested negative for common bacterial pathogens, including Vibrio parahaemolyticus. However, stool samples were positive for the presence of Norovirus group II RNA via RT PCR while oyster samples indicated the presence of Norovirus particles by electron microscopy. The clinical and epidemiological features were suggestive of Norovirus gastroenteritis and were subsequently confirmed by laboratory tests of stools and implicated oysters. Steps have been taken to ensure that food outlets do not thaw frozen oysters and serve them raw.     

Ticlopidine-induced cholestatic hepatitis with anti-nuclear antibody in serum.

We describe a case of severe cholestatic hepatitis following administration of ticlopidine. A 57-year-old man without known liver disease developed jaundice approximately 3 weeks after initiation of ticlopidine for secondary prevention of stroke. Hyperbilirubinemia and abnormal liver function test values resolved 5 months after withdrawal of ticlopidine. The diagnosis of ticlopidine-induced cholestasis was made after thorough investigations had excluded other causes of jaundice. He was not retreated with ticlopidine. This case may serve to illustrate the possibility of ticlopidine hepatotoxicity, which has rarely been reported. Furthermore, to the best of our knowledge, ticlopidine-induced cholestatic hepatitis accompanied by autoantibody has not been previously reported. This case suggests that regular assessment of liver function should be performed in the initial 3 months of ticlopidine treatment due to the potential risk of adverse effects. In patients with abnormal biochemical test results, autoantibodies should be assessed.     

Synthesis and characterization of new polyamides and polyimides prepared from 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane

In this work, we synthesized a new diamine containing a pendant adamantane group and a flexible aryl ether unit, 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane ( BAPA ) in three steps starting from 2-adamantanone. A series of new polyamides having inherent viscosities of 0.72–0.90 dL·g^–1 were prepared by direct polycondensation with aromatic dicarboxylic acids using triphenyl phosphite and pyridine as condensing agents. All polymers revealed an amorphous nature and were almost readily soluble in a variety of polar solvents. The glass transition temperature of these polyamides range from 254–294°C. The polyamides remain fairly stable up to a temperature around 450°C and lose 10% weight between 490 and 524°C in nitrogen atmosphere. A series of new polyimides were also synthesized from BAPA and various aromatic tetracarboxylic dianhydrides by the conventional two-step method. The inherent viscosities of polyimides were in the range of 0.66–0.77 dL·g^–1. The polyimides are amorphous and have glass transition temperatures between 276 and 310°C. Thermogravimetric analyses demonstrated that almost all polymers are stable up to 450°C, and the 10% weight loss temperatures were recorded in the range of 515 to 541°C in nitrogen.