ABSTRACT
Current models of recombination between viral RNAs are based on replicative template-switch mechanisms. The existence of nonreplicative RNA recombination in poliovirus is demonstrated in the present study by the rescue of viable viruses after cotransfections with different pairs of genomic RNA fragments with suppressed translatable and replicating capacities. Approximately 100 distinct recombinant genomes have been identified. The majority of crossovers occurred between nonhomologous segments of the partners and might have resulted from transesterification reactions, not necessarily involving an enzymatic activity. Some of the crossover loci are clustered. The origin of some of these "hot spots" could be explained by invoking structures similar to known ribozymes. A significant proportion of recombinant RNAs contained the entire 5' partner, if its 3' end was oxidized or phosphorylated prior to being mixed with the 3' partner. All of these observations are consistent with a mechanism that involves intermediary formation of the 2',3'-cyclic phosphate and 5'-hydroxyl termini. It is proposed that nonreplicative RNA recombination may contribute to evolutionarily significant RNA rearrangements.
Subject(s)
Poliovirus/genetics , Recombination, Genetic , Virus Replication , 3' Untranslated Regions/genetics , 5' Untranslated Regions/genetics , Base Sequence , Crossing Over, Genetic , Molecular Sequence Data , Poliovirus/physiology , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , Templates, Genetic , Transcription, Genetic , TransfectionABSTRACT
Rat experiments with ether anaesthesia (EA) indicate that EA induces enlargement of hepatic sinusoids, stasis and perivascular edema of the triad vessels and other changes in the liver. Right hypochondrium exposure to electromagnetic waves (4.76-5.08 mm) up to 20 days in rats given simultaneously ether anaesthesia showed that livers from the irradiated rats did not differ from control. Thus, millimetric wave radiation may prevent pathological alterations arising in white rat liver after ether anaesthesia.
Subject(s)
Anesthetics, Inhalation/toxicity , Ether/toxicity , Liver/drug effects , Liver/radiation effects , Microwaves/therapeutic use , Animals , Histocytochemistry , Liver/metabolism , Liver/pathology , Male , Rats , Time FactorsABSTRACT
An analysis of 158 completed esophagoplastics has shown that necroses of the transplant made their appearance in 7.8% of cases, fistulas of anastomoses--in 38%. The basis of pathogenesis of these complications is microthromboses of venules and small veins of the intramural blood circulation of the mobilized small intestine transplant (syndrome of local hypercoagulation). The novocain-heparin blockade and postoperative antiaggregation infusion therapy is an effective method for prevention of intestinal necroses in the postoperative period.
Subject(s)
Blood Coagulation , Esophagoplasty , Intestine, Small/transplantation , Postoperative Complications/etiology , Animals , Dogs , Humans , Intestine, Small/blood supply , Intestine, Small/pathology , Necrosis , Postoperative Care , Postoperative Complications/prevention & control , Preoperative CareSubject(s)
Esophagoplasty , Surgical Wound Dehiscence/etiology , Adult , Aged , Humans , Middle AgedABSTRACT
A classification of diseases of the artificial esophagus is made on the basis of the observation of 319 patients with the artificial esophagus. Causes of the disease are analysed in 75 patients. Methods of diagnostics, treatment and prevention of the disease are recommended.
