Effect of the volumetric dielectric properties of the medium on stability of the globular proteins and membranes

Analysis of the temperature dependences of the denaturation enthalpy of three domains of albumin molecule showed significant distinctions in the destabilizing effect of ethanol on certain domains of the nondefatted and defatted albumin molecules. A linear relationships were found among the parameters of proteins and membranes stability and bulk dielectric constants of the solvents. It has been suggested that the dielectric characteristics of the medium play a significant role in the maintaining of the certain conformation of proteins and membranes.     

Effect of exogamy on morbidity among children during the first three years of life

The yeast Saccharomyces cerevisiae mRNA capping enzyme is composed of two subunits of alpha (52 kDa, mRNA guanylyltransferase) and beta (80 kDa, RNA 5'-triphosphatase). We have isolated the alpha subunit gene (CEG1) by immunological screening. In this report, with the aid of partial amino acid sequences of purified yeast capping enzyme, we isolated the gene, designated CET1, encoding the S. cerevisiae capping enzyme beta subunit. Amino acid sequence analysis revealed that the gene encodes for 549 amino acids with a calculated M(r) of 61,800 which is unexpectedly smaller than the size estimated by SDS-PAGE. Gene disruption experiment showed that CET1 is essential for yeast cell growth. The purified recombinant CET1 gene product, Cet1, exhibited an RNA 5'-triphosphatase activity which specifically removed the gamma-phosphate from the triphosphate-terminated RNA substrate, but not from nucleoside triphosphates, confirming the identity of the gene. Interaction between the Cet1 and the Ceg1 was also studied by the West-Western procedure using recombinant Ceg1-[32P]GMP as probe.     

The effect of frusemide on oxytocin-induced contractions of the rat myometrium

Oxytocin-induced contractions of isolated strips of oestradiol-treated rat myometrium were found to be affected by exposure to the diuretic frusemide. At a concentration of 20 microM. frusemide transiently increased the force of contraction over a period of approximately 10 min. After this time there was a progressive fall in contractile force. At a higher concentration of 200 microM, only the progressive fall in force was seen until contractions were completely abolished. Frusemide has been reported to increase the activity of cAMP-phosphodiesterase in tissue extracts from oestradiol-treated rat myometrium. Therefore, the changes in contraction due to exposure to frusemide may be a reflection of the changes in intracellular cAMP resulting from a stimulation of cAMP-phosphodiesterase activity. In support of this idea, addition of dibutyryl cAMP was found to partially restore contractions after frusemide treatment. These data suggest that frusemide may be a useful tool in the manipulation of tissue cAMP levels in order to determine the different roles of cAMP in the oestradiol-treated rat myometrium.     

A murine model of accelerated periodontal disease in diabetes

Diabetes is a risk factor for periodontal disease in humans. In hyperglycemia, glycoxidation of proteins and lipids results in the formation of advanced glycation endproducts, or AGEs. The accumulation of AGEs in the plasma and tissues, and their interaction with their cellular receptor for AGE (RAGE), has been implicated in diabetic complications. In order to establish a model with which to delineate the specific host response factors that underlie the development of periodontal disease in diabetes, male C57BL/6J mice were rendered diabetic with streptozotocin. One month after documentation of diabetes or control state, mice were inoculated with the human periodontal pathogen Porphyromonas gingivalis, strain 381 (P. gingivalis) or treated with vehicle. Infection with P. gingivalis was achieved, as demonstrated by infiltration of gingival tissue with granulocytes, presence of DNA specific for P. gingivalis as well as increased serum antibody titer to P. gingivalis. At 2 and 3 months after infection, increased alveolar bone loss was demonstrated in P. gingivalis-inoculated diabetic vs. non-diabetic mice, along with enhanced tissue-destructive capacity, as demonstrated by increased collagenolytic activity in gingival extracts. Consistent with an important role for AGE-RAGE interaction, increased AGE deposition and expression of vascular and monocyte RAGE were demonstrated in diabetic gingiva compared with non-diabetic controls. Taken together, these data indicate that we have established a murine model of enhanced periodontal disease in diabetes. This model will serve to delineate molecular mechanisms which account for the increased susceptibility of diabetic patients to periodontal disease.     

Studies on the Bacillus sphaericus larvicidal activity against malarial vector species in Amazonia

INTRODUCTION: Syncope occasionally may occur in the supine patient due to severe brady- or tachyarrhythmia. However, recurrent syncope upon assumption of the supine position as a result of a neurally mediated reflex mechanism has not been reported previously. METHODS AND RESULTS: Two young patients, both of whom had significant systemic illnesses, experienced recurrent episodes of presyncope and/or syncope shortly after assuming the supine position. During ambulatory ECG monitoring, symptoms were provoked only by lying down and were associated with transient bradycardia. Head-up tilt table testing was undertaken as part of the syncope evaluation and was nondiagnostic in both cases. However, both patients exhibited a transient cardioinhibitory response with reproduction of typical symptoms upon return of the table to the supine position ("reverse tilt"). During follow-up (8 and 14 months), both patients improved with pharmacologic treatment (disopyramide in one case and midodrine in the other). CONCLUSION: Presyncope or syncope upon lying down can be an unusual manifestation of the neurally mediated faint.