Induction of ermAMR from a clinical strain of Enterococcus faecalis by 16-membered-ring macrolide antibiotics

We cloned the MLSB resistance determinant by PCR from a clinical isolate of Enterococcus faecalis 373, which is induced more strongly by a 16-membered-ring macrolide, tylosin, than by erythromycin. To elucidate the molecular basis of resistance of E. faecalis 373, we analyzed the cloned gene, designated ermAMR, by site-directed mutagenesis and reporter gene assay. Our results showed that an arginine-to-cysteine change in the seventh codon of the putative leader peptide endowed tylosin with resistance inducibility and that TAAA duplication enabled the control region to express the downstream methylase gene at a drastically increased level.     

Synthesis of phosphoramide mustard analogues of daunomycin and carminomycin

New phosphoramide mustards (6-8) have been prepared from the antibiotics 2 and 3, and from 5. The mixture of cyclophosphamides could be separated by preparative layer and column chromatography. The assignments of configuration to the isomeric phosphoramidates was based on the magnetic anisotropy of the P = O bond. The synthesized compounds 6a,b-8a,b (mixture of isomers) were tested for inhibitory activity on the [3H]-thymidine incorporation into the DNA of tumor cells, using ovarian carcinoma cell line.     

The adaptive capacities of patients with panic disorders (a psychophysiological study)

Contingent-negative deviation (CND) and orientational reaction (OR) were studied in 9 women suffering from typical (according to DSM-III-R) panic disorders (PD) and 12 healthy females. CND recording was made after giving neutral (70 dB, 1000 Hz) and stress (120 dB, 2000 Hz) pairs of sounds. Patients with PD were divided in two groups depending upon CND amplitudes. The first group (4 patients) was distinguished from healthy individuals by high CND amplitude (which significantly decreased after reaction on stress sound), by delay of extinction of cutaneogalvanic reaction (CGR) and by higher electromyogram amplitude. The second group (5 patients with more severe course of PD) was characterized by low amplitudes of CND and electromyogram, by absence of changes in CND after stress sound, by delay of extinction of CGR and nonspecific response. Above-mentioned data were evidence of psychophysiological heterogeneity of typical PD. The results were interpreted from a position of adaptive abilities of patients with PD, using ineffective and immature psychophysiological strategies of overcoming stress.     

Dens invaginatus--a pathway to pulpal pathology: a literature review

Dens invaginatus is the most common dental anomaly in a group of dental anomalies, related by their embryologic development and by the fact that their defects provide a potential pathway for bacteria to cause pulpal pathology. It occurs when the inner enamel epithelium invaginates into the dental papilla prior to calcification. It exists in erupted teeth as an enamel-lined tract, which either ends in a blind sac inside the crown or root or exits into the periodontal ligament. The lining may be incomplete in areas and may not protect the pulp. Methods of providing preventive treatment for teeth with dens invaginatus are described. When pulpal pathosis occurs, the dens may displace the pulp and complicate access cavity preparation and subsequent endodontic treatment, adversely affecting the prognosis. The learning objective of this article is to present treatment planning considerations and suggestions.     

DNA-protein interactions in CpG islands and DNAse I sensitive chromatin]

DNA-protein interactions were studied in the chromatin preparations obtained according to different procedures by means of nucleoprotein-celite chromatography. Three discrete fractions dissociating in 1M, 2M and 3M NaCl were observed in all preparations. The 1M fraction prevails in DNaseI-sensitive chromatin and the 2M fraction--in the resistant. Chromatin solubilized by MspI restrictase (the active chromatin) contains the 1M and 3M fractions, one solubilized by AluI (inactive)--the 2M fraction. Distribution of the fractions is different in proliferating and quiescent cells.