Successful separation of craniopagus conjoined twins.

Craniopagus conjoined twins represent a rare phenom- enon of congenital malformation/ dysmorphism. The clinical pathology of this complex entity is reviewed and placed in perspective. Confusion surrounds the severity of craniopagus conjoined twins especially in relation to the difficulty of separation and subsequent outcome. Successful separation of craniopagus twins remains a rarity, however modern neurosurgical tech- niques have created opportunities for successful sepa- ration and brought hope for a normal survival of these children who in the past were often left as historical footnotes or put on display as oddities of nature. We report on a craniopagus conjoined twins from Sudan who had been successfully separated.

Accumulation of cyanobacterial hepatotoxins by Daphnia in some Egyptian irrigation canals.

In this study, microcosm experiments were run in the laboratory to test the possibility of feeding of Daphnia parvula on toxic Microcystis aeruginosa in some Egyptian irrigation canal at Sohag city. The results demonstrated that Daphnia has a priority of feeding on green algae and the diatom Melosira granulata over toxic M. aeruginosa during the first 10 days. Thereafter, when the green algae and diatom were depleted from the water, Daphnia started to feed on toxic Microcystis. This presumably indicates that Daphnia feeds facultatively on toxic cyanobacteria under the conditions of depletion of edible food. Additionally, the results indicated that Daphnia accumulates the Microcystis toxins "microcystins" in its body with a level of 1.78 microg toxin/25 daphnids. No release of toxin into the water was detected during the experimental period. This emphasizes that the disappearance of toxic Microcystis was due to the feeding by Daphnia, not to death or cell lysis. Such an accumulation of cyanobacterial hepatotoxins in the primary consumers (Daphnia) should be taken into consideration when zooplankton are used in the biomanipulation of toxic phytoplankton.

Removal of cadmium and manganese by a non-toxic strain of the freshwater cyanobacterium Gloeothece magna.

The ability of both living and dry cells of Gloeothece magna, a non-toxic freshwater cyanobacterium, to adsorb cadmium and manganese is demonstrated in this study. Chlorophyll a content of living cells was not influenced by either cadmium or manganese concentrations, indicating that adsorption of both Cd2+ and Mn2+ by living cells of G. magna, was independent of the metabolic state of the organism. Moreover, the adsorption of both Cd2+ and Mn2+ to living cells and dry cells, was dependent on the metal concentrations, and fitted the Freundlich adsorption isotherm. However, dry cells had larger binding capacity for both Cd2+ (Kf = 912.6) and Mn2+ (Kf = 2,398) than living cells (Kf = 151.4 & 63, respectively). The role of the capsular polysaccharides, the main constituents of the cyanobacterial envelope, in binding these two metals was also studied. Polysaccharide extracts of this organism adsorbed high amounts of both Cd2+ (I15-425 microgmg(-1)) and Mn2+ (473-906 microgmg(-1)). This study suggests that G. magna would probably be cultured in water bodies contaminated by heavy metals to ameliorate their toxicity. Also dry material of this cyanobacterium being a non-toxic species, could be used as a safe biofilter to remove toxic metals from drinking water.

Isolation and characterization of microcystins from a river nile strain of Oscillatoria tenuis Agardh ex Gomont.

The River Nile is the major source of drinking water in Egypt, however, increased eutrophication due to agricultural, municipal and industrial runoff has contributed to the growth of toxin producing cyanobacteria. This study describes the isolation and characterization of microcystins (MCYSTs), cyclic heptapeptide hepatotoxins, from a rare strain of Oscillatoria tenuis, isolated from the River Nile at Sohag province in July 1995. The MCYST concentration of laboratory-cultured O. tenuis strain E6 was found to be 0.3 mg/g freeze-dried weight determined by enzyme-linked immunosorbent assay (ELISA). Two microcystins, 1 and 2, were isolated from lyophilized cells using solid phase extraction and reversed-phase high performance liquid chromatography (HPLC). Structures were assigned based upon their amino acid analyses, electrospray ionization mass spectrometry (ESIMS, ESIMS-CID-MS), high resolution fast atom bombardment mass spectrometry, and nuclear magnetic resonance data ((1)H and (1)H COSY NMR). Toxin 1 was identified as MCYST-LR, and toxin 2, a new MCYST, as MCYST-LHArg ([L-homoarginine(4)]). Previous studies indicate that Oscillatoria agardhii strains produce demethylated MCYSTs (containing D-Asp and/or dehydroalanine). This is the first report of a toxic O. tenuis, strain E6, one which produces a fully methylated MCYST, MCYST-LR and a new L-homoarginine containing MCYST, MCYST-LHArg.

Antibacterial effect and toxicity of synthesized salicylanilide derivatives.

5 nitro- and chloro-salicylanilide derivatives were synthesized by a simple condensation reaction between phenylsalicylate and the required nitroaniline derivative. The compounds were subjected to direct chlorination in CCl4 without any catalyst and were identified by microanalysis, m. p. and spectral studies. The antibacterial activity was investigated against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus. The prepared derivatives were evaluated for their acute toxicity on Swiss albino mice. The compounds 5,2'-dichloro-4'-nitrosalicylanilide and salicyl-3'-nitroanilide were the most active against the test organisms, but they showed fluctuating toxicity effect at the dose of 500 mg/kg. The structure-activity relationship and the toxicity tests verified the compound salicyl-4'-nitroanilide as a reasonable antibacterial agent against the four test organisms without any sign of toxicity symptoms up to the dose of 1000 mg/kg.