ABSTRACT
Paralytic shellfish poisoning (PSP) toxins are secondary metabolites of the toxic species of phytoplankton. The consumption of shellfish accumulating these toxins can cause neurological symptoms and even death. Within the framework of the surveillance program of seafood safety along the Moroccan littoral environment established by National Institute of Fisheries Research (INRH), a study of PST was conducted from 2004 to 2016 in south Moroccan’s shellfish, mussels from south Agadir region and Razor Shell from Dakhla bay. The surveillance was carried out bi-monthly or weekly using the AOAC official method of analysis (AOAC 959.08) mouse bioassay (MBA). In parallel, monitoring of toxic phytoplankton in water was conducted. With the aim to determine the shellfish toxin profile, ion-pair high-performance liquid chromatography with post-column derivatisation and fluorescence detection (HPLC-FD) was performed. The Receptor Binding Assay (RBA) also was used for determination of total toxicity of PSP toxins in Agadir’s mussels.In both regions, the analysis of seawater revealed the presence of the toxic algae Alexandrium spp during toxics events. Along the coast of Agadir, PSP toxins in shellfish were associated with the presence of Alexandrium cf. minutum in seawater. These toxic events were widely distributed in time and space and mainly detected during the summer and fall seasons. In some samples concentrations exceeded the sanitary threshold (ST) of 800 ?g eq STX /kg. HPLC analysis revealed that Saxitoxin and Gonyautoxins dominated the toxin profile. The comparison between different methods showed a strong uphill (positive) linear relationship, with a coefficient correlation of r=0.79 between MBA and HPLC and r = 0.809 between MBA and RBA
ABSTRACT
Drug-receptor interaction plays an important role in a series of biological effects, such as cell pro-liferation, immune response, tumor metastasis, and drug delivery. Therefore, the research on drug-re-ceptor interaction is growing rapidly. The equilibrium dissociation constant (KD) is the basic parameter to evaluate the binding property of the drug-receptor. Thus, a variety of analytical methods have been established to determine the KD values, including radioligand binding assay, surface plasmon resonance method, fluorescence energy resonance transfer method, affinity chromatography, and isothermal ti-tration calorimetry. With the invention and innovation of new technology and analysis method, there is a deep exploration and comprehension about drug-receptor interaction. This review discusses the differ-ent methods of determining the KD values, and analyzes the applicability and the characteristic of each analytical method. Conclusively, the aim is to provide the guidance for researchers to utilize the most appropriate analytical tool to determine the KD values.
ABSTRACT
Aim To study the effect of tetramethylpyrazine(TMP) on binding of 125I-VEGF to VEGF receptor. Methods The mice sera were collected after peritoneal injection with big-dose TMP,low-dose TMP,protamine and NS. A reversed-phase high performance liquid chromatography(RP-HPLC) method was used to determine the TMP in mice serum. The culture medium of ECV304 was treated with the mice sera in different groups. Radioligand binding assay(RBA) of receptor and Scatchard pot were performed to observe the changes of the maximum binding capacity(B_ max) and dissociation constant(K_d).Results The sera of big-dose TMP inhibited 125I-VEGF binding to its receptor, K_d=343.30?36.64 pmol?L-1,B_ max=46.26?5.85 fmol/2?10~5 cells(P0.05),but B_ max decreased(P
ABSTRACT
Objective: To evaluate the effect of RBa-I, an extract of Rosa bracteata Wend1, against withdrawa1 syndrome in morphine-dependent rats and to explore its mechanism. Methods: The mode1 rats of morphine dependent were established. The scores of withdrawa1 syndrome,?-EP level in hypotha1amus and pituitary body were observed to evaluate the effect of RBa-I in rats. Results: RBa-I can antagonize the urging withdrawa1 syndrome in morphine-dependent rats (ora1ly, 5 mg?kg -1 ), and the effect was inferior to chlonidine (oral1y, 0.2 mg?kg -1 ). It can a1so antagonize the natural withdrawal syndrome, decrease the tota1 scores of withdrawa1 syndrome and inhibit the decreasing of body weight. After a seven-day treatment course, the tota1 scores of withdrawa1 syndrome were decreased remarkab1y. The content of ?-EP in hypotha1amus and pituitary body were increased. Conclusion: RBa-I can antagonize the withdrawa1 syndrome of morphine-dependent rats and this may be related to the increase of ?-EP level in hypothalamus and pituitary body in rats.