Sorption behavior of Co and Eu radionuclides onto chitosan derivatives

Chitosan benzoyl thiourea derivative has been synthesized and used successfully for the removal of the hazardous ⁶⁰Co and ^152+154Eu radionuclides from aqueous solutions. Different parameters were applied for studying the adsorbitivity of these radionuclides, including change in pH, time, ion concentration, and equilibrium concentration. Freundlich and Langmuir isotherms were applied successfully to fit the experimental data. Two more isotherm models, Lagergren and Morris–Webber, have been applied. All the parameters and the constants calculated for the kinetic isotherms and models are evaluated and listed. A mechanism for the complex formation of Co⁺² with the chitosan derivative has been suggested.     

Ischemic bowel disease

The clinical, radiologic and pathologic features of 25 cases of ischemic bowel disease are presented. The majority of patients presented with the triad of abdominal pain, diarrhea and vomiting. In 13 patients the diarrhea was associated with the passage of bright red blood per rectum. There were 10 cases of infarction, 11 of enterocolitis and 4 had resulted in stricture formation. In five cases of enterocolitis the lesion was transient; symptoms improved with conservative medical management and the radiologic findings returned to normal. Barium enema examination yielded abnormal findings in the majority of the cases in which it was performed. Plain films of the abdomen, however, were not helpful. The actual mortality in this group of patients was 44%, 80% in those with infarction of the bowel and 20% in the other two groups.     

Immunoregulatory functions of paf-acether. IV. Enhancement of IL-1 production by muramyl dipeptide-stimulated monocytes

paf-Acether (paf) is a phospholipid mediator of inflammation released from monocytes along with IL-1. In this study, we have examined the role of paf on IL-1 production by human monocytes. When paf from 1 nM to 5 microM, but not its precursor lyso paf, was added to monocytes in the presence of muramyl dipeptide (MDP) or LPS, a marked increase in IL-1 activity over the value with MDP alone was observed. In contrast, paf alone had minimal activity over the same dose range. Antibodies against rHu IL-1 alpha and rHu IL-1 beta neutralized the increased IL-1 activity. Interestingly, MDP that prompts monocytes to synthesize IL-1, induced the synthesis of paf, as well. Most of the paf produced remained cell-associated and always preceded IL-1 synthesis. When the paf receptor antagonist, L-652,731 was added to monocytes, it prevented the enhancement of IL-1 activity induced by exogenous paf. In contrast, L-652,731 had little effect on MDP-induced IL-1 synthesis in the absence of exogenous paf. This may indicate that there are alternative mechanisms involved in the sequences of events leading to IL-1 production. It is also conceivable that the paf receptor antagonist is not able to compete or inhibit endogenous paf as well as it does for exogenous paf. Nevertheless, exogenous paf in association with a second signal, modulates IL-1 production from human monocytes in a positive manner. This may constitute another means through which paf can modulate inflammatory and immune reactions.     

Validated spectrofluorimetric and resonance Rayleigh scattering methods for determining naftidrofuryl in varied pharmaceutical samples based on its interaction with erythrosin B

Naftidrofuryl is a vasodilator medication used for treating cerebral and peripheral vascular diseases. In this study, two spectroscopical techniques, spectrofluorimetric and resonance Rayleigh scattering (RRS), were utilized to quantify naftidrofuryl in its pharmaceutical samples. The developed methodologies in this study rely on a facile process of forming an association complex between erythrosine B reagent and naftidrofuryl under acidic conditions. The fluorimetric assay is based on the ability of naftidrofuryl to quench and decrease the native fluorescence intensity of the reagent when measured at ${\lambda }_{\mathit{\text{emis}}.}$ = 550 nm ( ${\lambda }_{\mathit{\text{excit}}.}$ = 526 nm). Under similar reaction conditions, the RRS method relies on the observed amplification in the RRS spectrum of the reagent at a wavelength of 577 nm following its interaction with naftidrofuryl. The methods exhibited linearity within the ranges 0.2–1.6 μg/ml (r² = 0.999) and 0.1–1.4 μg/ml (r² = 0.9994), with limit of quantitation values of 0.146 and 0.099 μg/ml, and limit of detection values of 0.048 and 0.032 μg/ml, for the fluorometric and the RRS methods, respectively. Moreover, the quenching between the dye and naftidrofuryl was studied using Stern–Volmer analysis, and the methodologies were experimentally optimized and validated. Additionally, acceptable recoveries were achieved when the procedures were applied to determine naftidrofuryl in pharmaceutical samples.     

Rapid Construction of a Random Genomic Library from Date-Palm (Phoenix Dactylifera L.)

A random genomic library of Tunisian date-palm varieties has been built from total cellular DNA, previously amplified according to an RAPD procedure. The resultant recombinant DNA is characterised by a size ranging from 200 to 1600 bp inserts. This DNA would constitute a large number of anonymous probes useful in Southern hybridisation experiments. It would also provide potential markers aimed at the molecular characterisation of date-palm varieties, aid the search of those associated with bayoud disease and suggest a sex determination of trees.     

Cloning and characterization of a bifunctional RelA/SpoT homologue from Mycobacterium tuberculosis.

A 2.2kb relA/spoT homologue was isolated from Mycobacterium tuberculosis (Mtb) genomic DNA by PCR-amplification. The Mtb gene encodes a protein of 738 amino acid residues, and is flanked upstream by an ORF that is highly similar to the apt gene, and downstream by an ORF that is highly similar to the cypH gene. This dual function Mtb homologue belongs to the relA/spoT family of genes that mediate the stringent response by regulating the synthesis and degradation of guanosine 3',5'-bis(diphosphate) (ppGpp) and pppGpp. In vitro biochemical data indicate that purified RelMtb is a ribosome- and tRNA-independent ATP:GTP/GDP/ITP 3'-pyrophosphoryltransferase. Additionally, purified RelMtb is an Mn2+-dependent, ribosome and tRNA-independent, (p)ppGpp 3'-pyrophosphohydrolase. These reactions were also assessed in vivo in E. coli deleted in both the relA and spoT genes, which generates a (p)ppGpp0 phenotype. RelMtb can suppress this phenotype and can generate more (p)ppGpp than relA in the wild type E. coli control.     

In situ lymphophagocytosis by nonlymphoreticular neoplasms

Lymphophagocytosis by nonlymphoreticular neoplasms has been observed. Twenty cancer patients having either adenocarcinoma or epidermoid carcinoma were the subjects of our study. Malignant cells were found to phagocytize autologous lymphocytes, polymorphonuclear cells (PMNs) and red blood cells (RBCs). Papanicolaou smears from cancer patients revealed that 30% (6/20) of the patients had phagocytic malignant cells in situ, the mean phagocytosis for this group was 3.7%. Different cellular elements showed differences in their susceptibility towards phagocytic activity of tumor cells: 2.6% for lymphocytes, 0.7% for PMNs and 0.4% for RBCs. The patients having phagocytic malignant cells showed complete absence of monocytes in their peripheral blood. In contrast, other patients had peripheral blood monocyte percentages within the limits of control values (7.2). However, there was no correlation between development of phagocytic activity of malignant cells and age and sex of patients or type of tumor. This study further confirms that phagocytic activity of nonlymphoreticular neoplasms is a general phenomenon which can be directed against erythroid elements. In addition, we have demonstrated that these tumor cells also phagocytize autologous leukocytes.     

Sargassan: A sulphated heteropolysaccharide from Sargassum linifolium

A new sulphated heteropolysaccharide containing glucuronic acid, mannose, galactose, xylose, fucose and a protein moiety has been extracted from Sargassum linifolium. The polysaccharide extracted with HCl was richer in its carbohydrate and protein contents and contained lower amounts of ash than that extracted with oxalic acid.