DNA-protein cross-links as a possible reason for genomic damage during its protonation]

The change in survival of bacteriophages with DNA of different GC-contents after their incubation in media of different acidities with subsequent neutralization was studied. It was shown that the higher the GC-content, the more sensitive is the phage to the action of H(+)-ions. Evidence is presented that the acidic inactivation of virions is not connected with the helix-coil transition of the intraphage DNA due to its protonation. The extractability of DNA from phages subjected to different concentrations of H(+)-ions with subsequent neutralization of the medium to pH 8 was determined. The changes in: transfection ability, UV-spectra, the quantity of the residual proteins, and the contents of glutamic and lysine amino acid residues in these proteins were investigated. The effect of glutamic acid on the parameters of DNA melting curves was followed for different pH values. Proceeding from the data obtained, we concluded that acidification of the medium from neutral tp pH congruent to 4 leads to formation of non-covalent DNA-protein cross-links due to interaction of the GC base pairs of DNA with glutamic and aspartic amino acid residues, whereas acidification of the medium to pH less than 4 with subsequent neutralization to pH 8 results in the formation of covalent DNA-protein cross-links of Schiff base type. The influence of non-covalent DNA-protein cross-links on the properties of DNA and their regulatory role in genome functioning are discussed.     

Salicyloylaspartate as an endogenous component in the leaves of Phaseolus vulgaris

An amide conjugate of o-methoxybenzoic acid and aspartic acid has been isolated from bean leaves. After extraction and methylation of plant material, this compound was isolated as two isomeric monoethyl monomethyl esters. The ethylation of the aspartyl carboxyl groups was shown to be a likely result of an extraction procedure utilising acidified ethanol, the methylation of the aromatic hydroxy of the methoxy group to be due to the derivatisation procedure. Studies with pentafluorobenzylation confirmed that the endogenous compound is o-hydroxybenzoylaspartate.     

Avianca flight No. 052 accident: a plastic surgical perspective

The crash of Avianca Airlines flight no. 052 en route to JFK Airport on January 25, 1990, in Cove Neck, New York, resulted in the death of 72 passengers. Eighty-nine victims were admitted to 13 regional hospitals. Despite difficult access to the wooded crash site, early warning and prompt response by 37 volunteer fire and rescue units resulted in organized EMS triage and rapid hospital transport. This report reviews the specific injuries incurred, highlights the team management approach to a major aviation accident in a suburban area, and studies the likelihood of accidents of this magnitude. Thirty-eight patients triaged to two level I trauma centers, North Shore University Hospital-Cornell University Medical Center and Nassau County Medical Center, form the basis of this report. Seventeen patients were male; 21 were female. The average patient age was 33 years. Eight patients were children. The average length of stay was 30.9 days (range 2 to greater than 90 days). Twenty-six patients (including nonsurvivors) (68 percent) sustained significant multiple orthopedic injuries. The majority of fractures were open grade II to III tibia-fibula fractures. Bilaterality was commonly seen. Soft-tissue coverage of open long bone fractures was required in 10 patients (11 extremities) and included 3 microvascular muscle transfers, 7 muscle transposition flaps, and 3 skin grafts. Seven patients required open reduction and fixation of complex facial fractures (two of Le Fort II to III type, four of complex naso-orbital-ethmoid type). Plastic surgical repair of complex lacerations was common. Peripheral nerve exploration was required in three patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

The "cricket bat" flap: a one-stage free forearm flap phalloplasty

Total and subtotal penile reconstruction represents a major surgical challenge. We present a new method and two illustrative cases using a modified design of the radial forearm free-tissue transfer: the "cricket bat" flap.     

Comparison of Modeled and Observed Environmental Influences on the Stable Oxygen and Hydrogen Isotope Composition of Leaf Water in Phaseolus vulgaris L

In this paper we describe how a model of stable isotope fractionation processes, originally developed by H. Craig and L. I. Gordon ([1965] in E Tongiorgi, ed, Proceedings of a Conference on Stable Isotopes in Oceanographic Studies and Paleotemperature, Spoleto, Italy, pp 9-130) for evaporation of water from the ocean, can be applied to leaf transpiration. The original model was modified to account for turbulent conditions in the leaf boundary layer. Experiments were conducted to test the factors influencing the stable isotopic composition of leaf water under controlled environment conditions. At steady state, the observed leaf water isotopic composition was enriched above that of stem water with the extent of the enrichment dependent on the leaf-air vapor pressure difference (VPD) and the isotopic composition of atmospheric water vapor (AWV). The higher the VPD, the larger was the observed heavy isotope content of leaf water. At a constant VPD, leaf water was relatively depleted in heavy isotopes when exposed to AWV with a low heavy isotope composition, and leaf water was relatively enriched in heavy isotopes when exposed to AWV with a large heavy isotope composition. However, the observed heavy isotope composition of leaf water was always less than that predicted by the model. The extent of the discrepancy between the modeled and observed leaf water isotopic composition was a strong linear function of the leaf transpiration rate.     

Malonyl-CoA in skeletal muscle and liver of streptozotocin-diabetic rats.

Malonyl-CoA, the inhibitor of carnitine palmitoyl transferase I, has been examined in this study in the muscle and liver of diabetic rats. Male Sprague-Dawley rats were rendered diabetic with streptozotocin (6 mg/100 g body wt). The gastrocnemius/plantaris muscles and liver samples were frozen at liquid nitrogen temperature. Muscle malonyl-CoA was 1.8 +/- 0.2 pmol/mg in control rats and 1.5 +/- 0.2 pmol/mg in the diabetic rats. This difference was not statistically significant. Liver malonyl-CoA of control rats was 8.6 +/- 0.8 pmol/mg, in comparison to 4.3 +/- 0.6 pmol/mg in diabetic rats. In the liver, high concentrations of malonyl-CoA inhibit fatty acid oxidation and ketogenesis. Failure of malonyl-CoA to decline in muscle in the diabetic may be responsible in part for the diversion of fatty acids to the liver, thereby enhancing hepatic fatty acid oxidation and ketogenesis.     

Effect of neutron and gamma radiation on physical endurance of rats in the swimming test

Three groups of adult male Wistar rats were exposed to neutrons (a single dose of 2 Gy) and gamma radiation (a continuous dose of 6 Gy delivered within 10.5 days) and a combination of both types of radiation. The physical fitness of irradiated and control rats was measured using a forced swimming test in the course and after the termination of the irradiation. A marked decrease in the physical fitness of all irradiated animals was followed by its normalization 3 weeks after irradiation.     

The effect of intracoronary injections of x-ray contrast media on cardiac rhythm and conductivity during different variations of myocardial blood supply]

A study of the correlation between electrophysiologic effects of intracoronary injections of radiopaque agents and anatomical features of blood supply of cardiac conduction was carried out in 60 patients with intact coronary arteries. Coronary angiography was performed in all the patients. Disorders in cardiac conduction and repolarization in the myocardium were observed in intracoronary injection of radiopaque agents, which was accompanied by the development of S-A bradycardia. A bradyarrhythmic reaction type depends on prevalence of the left or right coronary artery in the atrial blood supply and cardiac conduction. The bradyarrhythmic effect was more pronounced in injection of a radiopaque agent in the right artery than in the left one.