Synthesis of modified oligodeoxyribonucleotides containing 9-(2'-amino-2'-deoxy-beta-D-arabinofuranosyl)adenine

A method for preparing a modified derivative of 2'-amino-2'-deoxy-arabino-adenosine ready for directed insertion into an oligonucleotide chain during solid-phase synthesis was elaborated. A series of the title oligonucleotides (6-25-mers) containing a 2'-amino-2'-deoxy-arabino-adenosine fragment were prepared. A high reactivity of the 2'-amino group during the acylation with carboxylic acid anhydrides was demonstrated. It was shown that the insertion of the modified fragments into oligonucleotides did not inhibit the formation of the DNA duplex.     

Gangliocytoma--magnetic resonance imaging characteristics

An atypical presentation of a temporal lobe gangliocytoma in an adult female with headaches is reported. Computed tomography showed a hypodense enhancing mass in the right temporal lobe with vasogenic oedema and mass effect. MRI demonstrated a well demarcated mass of low signal on T1W, intermediate signal on PDW, high signal on T2W and homogeneous enhancement on post-gadolinium scan. This case is an addition to the current literature for the characteristic MR features of a ganglion cell tumour.     

A new method of nonradioactive labelling of oligonucleotides and their use as allele-specific probes for detecting mutations causing beta-thalassemia

We have developed simple and efficient methods for synthesis of biotin and horseradish peroxidase (HRP)-labeled oligonucleotides. Biotinylated oligonucleotides were obtained in quantitative yields, and oligonucleotide conjugates with HRP in 60-80% yields. Allele-specific oligonucleotide probes for the diagnostics of IVS 1-110 mutation in the beta-globin gene causing beta-thalassemia were thus obtained. Temperature conditions for the non-radioactive ASO hybridization with the amplified segment of the human beta-globin gene and wash conditions were selected. HRP-labelled probes were used in hybridization without preliminary separation after synthesis. To decrease nonspecific enzyme binding we have elaborated special conditions for membrane blocking. Detection of the biotinylated probe was carried out with the help of a streptavidin--HRP conjugate. O-Dianisidine was used as a chromogenic substrate. We have demonstrated the usefulness of this method in the analysis of amplified samples of DNA obtained from blood of patients homozygous in the mutant gene, and heterozygous carriers.     

Reversal of advanced liver fibrosis in rabbits with Schistosomiasis japonica

Advanced liver fibrosis is generally considered to be irreversible. We studied the reversibility of marked liver fibrosis in rabbits infected with Schistosoma japonicum. We determined liver collagen content, collagen biosynthesis, and collagenase activity using serial biopsy specimens obtained 20, 40, and 60 weeks after infection. Reversibility of this process was investigated in rabbits cured of infection at 21 weeks; control rabbits not cured of infection were also studied. At 20 weeks, liver collagen content was 16-fold greater than normal, with accumulation of collagen types I, III, and V. Synthesis of collagen within fibrotic liver slices was 10-fold greater than normal. Liver collagenolytic activity for a type I substrate was 19-fold greater than normal. After parasitologic cure, a striking morphologic reversal of fibrosis occurred during the subsequent 40 weeks, with the return of liver collagen content to three-fold greater than normal and a 75% decrease in synthetic rates compared with those at 20 weeks (P < 0.01). Collagenolytic activity remained elevated to the same degree noted at 20 weeks. A similar but lesser resolution of fibrosis also occurred in untreated control rabbits, coincident with a spontaneous decrease in new egg deposition known to occur in this model system. We conclude that advanced liver fibrosis in S. japonicum-infected rabbits is slowly reversible after cure or senescence of the infection. A possible mechanism for this reversal is persistently increased collagenolysis as collagen synthesis diminishes.     

Low doses of eicosapentaenoic acid, docosahexaenoic acid, and hypolipidemic eicosapentaenoic acid derivatives have no effect on lipid peroxidation in plasma

It was of interest to investigate the influence of both high doses of eicosapentaenoic acid (EPA) and low doses of 2- or 3-methylated EPA on the antioxidant status, as they all cause hypolipidemia, but the dose required is quite different. We fed low doses (250 mg/d/kg body wt) of different EPA derivatives or high doses (1500 mg/d/kg body wt) of EPA and DHA to rats for 5 and 7 d, respectively. The most potent hypolipidemic EPA derivative, 2,2-dimethyl-EPA, did not change the malondialdehyde content in liver or plasma. Plasma vitamin E decreased only after supplementation of those EPA derivatives that caused the greatest increase in the fatty acyl-CoA oxidase activity. Fatty acyl-CoA oxidase activity increased after administration of both EPA and DHA at high doses. High doses of EPA and DHA decreased plasma vitamin E content, whereas only DHA elevated lipid peroxidation. In liver, however, both EPA and DHA increased lipid peroxidation, but the hepatic level of vitamin E was unchanged. The glutathione-requiring enzymes and the glutathione level were unaffected, and no significant changes in the activities of xanthine oxidase and superoxide dismutase were observed in either low- or high-dose experiments. In conclusion, increased peroxisomal beta-oxidation in combination with high amounts of polyunsaturated fatty acids caused elevated lipid peroxidation. At low doses of polyunsaturated fatty acids, lipid peroxidation was unchanged, in spite of increased peroxisomal beta-oxidation, indicating that polyunsaturation is the most important factor for lipid peroxidation.     

The viral genome status studied under the conditions of a mixed infection in lymphoblastoid cells by adenovirus and the Epstein-Barr virus

Some indices have been studied which characterized the state of Epstein-Barr virus genome and adenovirus in the implanted lines of lymphoblastoid cells of B and T phenotype under the mixed or monoinfection. It has been shown that super infection by type 2 adenovirus rather sharply affects the state of Epstein-Barr virus genome in the Raji cells containing integrated Epstein-Barr virus genome. The state of adenovirus genome in the studied cells is less subject to changes. Its early area is revealed by hybridization using DNA-DNA method in a form of two fragments of different intensity which is maximum in the Raji and Jurkat cells, which evidences for the more expressivity of adenovirus genome in these cells.     

Antineoplastic agents. 397: Isolation and structure of sesterstatins 4 and 5 from Hyrtios erecta (the Republic of Maldives)

The wide ranging marine sponge Hyrtios erecta is the source of the spongistatins, a new class of macrocyclic lactone antineoplastic agents. Continuation of a detailed investigation of cancer cell growth inhibitory (P388 lymphocytic leukemia) fractions (trace) from H. erecta has revealed the presence (10(-5) to 10(-7)% yield) of cytotoxic pentacyclic sesterterpenes. Employing P388 leukemia and human tumor cell line-guided bioassay techniques, two new moderate inhibitors of cancer cells were isolated and named sesterstatins 4 (1a, P388 ED50 4.9 micrograms/mL) and 5 (1b, DU-145 prostate GI50 1.9 micrograms/mL). Similar to other sesterterpenes, sesterstatin 5 inhibited growth of a Gram-positive bacterium. High field (500 MHz) 2-D NMR techniques were primarily employed for initial structural assignments, and structural assignments were confirmed by X-ray crystal structure determination of sesterstatin 4 (1a) and 5 (1b).     

Efficacy of traditional rice-lentil-yogurt diet, lactose free milk protein-based formula and soy protein formula in management of secondary lactose intolerance with acute childhood diarrhoea

Gangliosides were found to be present in Entamoeba histolytica. They were extracted from lyophilized trophozoites of the pathogenic strain HM-1:IMSS and purified by high performance thin-layer chromatography. Two resorcinol-positive bands, comigrating with GM2 and GD1a were demonstrated, revealing the existence of ganglioside molecules in Entamoeba histolytica. The GM2 content, determined as lipid-bound sialic acid, was 1.5 micrograms/10(8) amoebae, the content of the GD1a comigrating band was 0.32 microgram/10(8) amoebae. The identity of the GM2 comigrating band was confirmed by TLC immunostaining, using the monoclonal anti-GM2 antibody GMB28. Furthermore, six out of ten anti-amoeba positive sera selectively reacted with the GM2 comigrating band, as revealed by immunostaining on TLC plates. Absorption tests revealed that preincubation of anti-amoeba positive sera with standard GM2 was followed by a significant decrease in the reaction with amoeba trophozoites by indirect immunofluorescence. These results demonstrate that a GM2 comigrating component of Entamoeba histolytica may be one of the antigens responsible for the appearance of circulating antibodies in patients with amoebiasis.     

Hepatic artery ligation for liver metastasis of a acinar cell carcinoma of the pancreas revealed by a nodular panniculitis

We report the case of a 67-year-old-man presenting with pancreatic acinar cell carcinoma revealed by dermatological manifestations of cytosteatonecrosis and treated by hepatic artery ligation. The pancreatic etiology of these lesions was suspected due to hyperlipasemia, and was confirmed by abdominal computerized tomography showing a pancreatic tumor and multiple liver nodules, and by histological examination of one of these lesions. Because of symptomatic treatment failure, rapid impairment of patient's general condition, and by analogy with the treatment of hepatic metastases of neuroendocrine tumors, hepatic artery ligation was performed. Lipasemia decreased markedly and symptoms disappeared for 45 days. Hepatic artery obstruction may be used for emergency treatment of secreting liver metastases.