Therapeutic time window of YGY-E neuroprotection of cerebral ischemic injury in rats.

YGY-E is an active ingredient in traditional Chinese medical herbs which have anti-ischemic activity. The present work was designed to study its therapeutic time window in cerebral ischemic injury as well as its effect on neuronal apoptosis. Animals received an intravenous injection of YGY-E at 1, 3, and 6 h, respectively, after permanent focal cerebral ischemia induced by electrocoagulation of the middle cerebral artery. Infarct ratio and neurological function were employed to assess the effects of YGY-E on the therapeutic time window in this animal model. Furthermore, we evaluated effects of this compound on neuronal apoptosis and synthesis of Bcl-2 and Bax in ischemic brain tissue with in situ DNA end labeling (TUNEL), immunohistochemistry assay, and Western blot analysis. YGY-E (2-8 mg/kg) delivered at all the three time points dosedependently decreased infarct ratio, neurological deficits, percentage of TUNEL-positive cells (p < 0.01) and Bax-positive cells (p < 0.01 or p < 0.05). In contrast, it increased the percentage of Bcl-2 positive cells (p < 0.01 or p < 0.05). These data demonstrated that YGY-E had protective effects against cerebral ischemia injuries in rats. But more importantly, they indicate that YGY-E has an unusually long (up to 6 h) therapeutic time window relative to classical drugs in treating cerebral ischemia. In addition, our results suggest that the anti-apoptotic effects of YGY-E are due to its regulation of the balance between Bcl-2 and Bax protein levels.

Pharmacokinetics and its relation to toxicity of pegylated-liposomal doxorubicin in Chinese patients with breast tumours.

OBJECTIVES: Pegylated liposomal doxorubicin (PLD) is a formulation of doxorubicin encapsulated with polyethylene glycol-coated liposomes, which has prolonged circulation time and unique toxicity profile. This study deals with the pharmacokinetics and its relation to toxicity in Chinese patients with breast tumours. METHODS: Twenty-two Chinese female patients with breast tumours were received two PLD products in single dose of 50 mg/m2 with a randomized, two-period and cross-over design. Blood was sampled immediately before and at 15, 30, 60 min, 1·17, 2, 5, 13, 25, 49, 73, 97, 121, 145 and 241 h after the PLD infusion. The plasma level of doxorubicin was determined with LC-MS. RESULTS: The pharmacokinetics of PLD was best described by a one-compartment linear structural model with a long elimination T(1/2) (64 h), a slow clearance (0·025 L/h/m2) and a small volume of distribution (2·310 L/m2). The main toxicities were neutropenia (22/44), nausea (22/44), vomiting (8/44) and pigmentation (4/44). The nausea and neutropenia were positively correlated with AUC while negatively correlated with Cl (P<0·05). CONCLUSIONS: The study confirms the different pharmacokinetic and toxicity profiles of PLD compared with non-liposomal doxorubicin. The pharmacokinetic profiles in Chinese patients with breast tumours is different from those reported for European patients with metastatic breast cancer. The correlation between toxicities, neutropenia grade and nausea and two of the pharmacokinetic parameters, AUC and Cl, may be useful for guiding the dosing of the agent.

Establishment of a new cell line for high-throughput evaluation of chemokine CCR5 receptor antagonists.

Chemokine receptors belong to a superfamily of proteins that signal through coupled heterotrimeric G proteins. Chemokine receptor CCR5 is the major co-receptor essential for HIV entry into host cells, and now chemokine CCR5 receptor has become an important target in searching for anti-HIV drugs. Here, we describe the establishment of a human embryonic kidney (HEK) 293/CCR5-HA cell line stably expressing CCR5 receptor with influenza hemagglutinin (HA) tag at the N termini on the membrane surface of HEK293 cells. Plasmid pcDNA3.0-CCR5-HA was transfected into HEK293 cells, and monoclonal HEK293 cell lines expressing CCR5 receptor were generated under G418 selection. The expression of functional CCR5 receptor was tested by GTP?S assay, and the results showed about 5 monoclonal HEK293 cell lines expressed functional CCR5 receptor, and of which No.7 monoclonal cell line is the best. The FACS analysis results further confirmed that CCR5 receptor was positive in 96.89% of No.7 monoclonal HEK293/CCR5-HA cell line. Further results showed that RANTES significantly stimulated GTP?S binding in the dose-dependent manner, and CCR5 antagonist Sch-351125 inhibited RANTES stimulated GTP?S binding in the dose-dependent manner in No.7 monoclonal HEK293/CCR5-HA cell line. Our results suggest that the established HEK293/CCR5-HA cell line is suitable for highthroughput screening and is feasible to identify CCR5 receptor antagonists.

Acute non-specific inflammation and modification of macrophage and lymphocyte functions.

The acute inflammatory response is a common phenomenon experienced by the physician in a wide variety of clinical situations. One of the major problems facing the investigator in this field of research who wishes to look at the cellular and humoral responses involved, is that in most of the animal models previously used, the inflammatory reaction has been provoked in subcutaneous tissues. Thus, a quantitative assessment of leucocyte emigration and mediator production in the inflamed area is technically difficult without resorting to complicated and artificial methods. Inflammation provoked in the pleural cavity provides a useful tool in the study of these problems since the collection of cells and analysis of humoral factors in exudates is easily accomplished. Among the irritants that may be used, we focused our interest on calcium pyrophosphate (CaPP) crystals, a non-diffusible, non-antigenic and endotoxin-free irritant, because their deposition is implicated in pseudogout and chondrocalcinosis in man (MacCarty, 1973). Calcium pyrophosphate-induced pleurisy is typified by an acute reaction, dominated by polymorphonuclear leucocytes, reaching its maximal intensity at about 5 h and disappearing within 48 h (Willoughby et al., 1975). It was found to be independent of the complement system. Examination of the known mediators of inflammation revealed no significant participation of either histamine or 5-hydroxytryptamine. There was an early rise in PGE2 followed by a greater rise in PGF2 alpha as the reaction diminished (Capasso et al., 1975). More recently, we have demonstrated the presence of a small quantity of thromboxane and a large quantity of prostacyclin during the first 2 hours of this inflammatory process. It was also shown that this type of acute inflammation was accompanied by the very rapid liberation of acute phase proteins both locally, in the exudate, and systemically in the serum (Tissot et al., 1983). Some of these events were also examined during the pleural reaction to other types of irritants (Capasso et al., 1975) and gave similar results (Tissot et al., 1983).