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Biomedical subjects

E Meyers

Publications and source records attributed to E Meyers.

At least 19 recordsLinked to original sources

Scanning acoustic microscopy study of titanium-ceramic interface of dental restorations.

Failures that occur in titanium-ceramic restorations are of concern in clinical dentistry. The purpose of this study was to nondestructively characterize the internal cracks and nonadherent defects at the titanium-porcelain interface using scanning acoustic microscopy. Titanium samples coated with porcelain without a bonding agent, with sputter coated palladium or chromium as an oxygen diffusion barrier on the titanium, and with the use of a porcelain bonding agent (control group) were compared. The scanning acoustic microscopy analyses were correlated with four-point bending test results. The group that was initially coated with palladium had fewer interfacial defects and a higher load to failure than the control group, and the group that did not contain the bonding agent had a higher void area and a lower load to failure than the control group. The use of chromium produced no differences from the control group. Samples after a four-point bending test were also analyzed by scanning electron microscopy. The scanning electron microscopy was not able to characterize interfacial defects at the fractured titanium-ceramic interface for some of the samples. The validity of nondestructive analysis at the Ti-ceramic interface using scanning acoustic microscopy was demonstrated in this study.

Chromium↗

Bacillaene, a novel inhibitor of procaryotic protein synthesis produced by Bacillus subtilis: production, taxonomy, isolation, physico-chemical characterization and biological activity.

Bacillaene, a novel polyene antibiotic, was discovered and isolated from fermentation broths of a strain of Bacillus subtilis. The novel antibiotic has a nominal molecular weight of 580 and an empirical formula of C35H48O7. Bacillaene is active against a broad spectrum of bacteria in agar-plate diffusion assays. Studies in vitro indicate that the antibiotic inhibits prokaryotic protein synthesis but not eukaryotic protein synthesis. Cell survival studies performed with strains of Escherichia coli indicate that the antibiotic is a bacteriostatic agent.

Anti-Bacterial Agents↗

Disturbances of magnesium metabolism in the spontaneously hypertensive rat.

Magnesium balance, and plasma and urinary levels, were studied in spontaneously hypertensive (SHR), Wistar Kyoto (WKY) and in Wistar (WI) rats. We found few differences in the measured parameters between WKY and WI rats, but the SHR rat which similarly maintained Mg balance has lower plasma Mg levels and less urinary Mg excretion. These abnormalities could favor establishment or maintenance of hypertension.

Animals↗

Xylocandin: a new complex of antifungal peptides. I. Taxonomy, isolation and biological activity.

Xylocandin is a complex of novel peptides with potent antifungal activity that is produced by Pseudomonas cepacia ATCC 39277. The complex was isolated from the fermentation broth by extraction with butanol-methanol, 9:1, followed by collection of the precipitate formed upon concentration of the solvent extract. Purification was effected by chromatography on reversed phase and size exclusion gels followed by TLC on silica gel. These techniques afforded eight components: A1, A2, B1, B2, C1, C2, D1 and D2. A mixture of the two closely related components, xylocandins A1 and A2, displayed potent anticandidal and antidermatophytic activities in vitro. The activity was diminished by the presence of serum or vaginal washings. No antibacterial activity was demonstrable.

Animals↗

Catacandins, novel anticandidal antibiotics of bacterial origin.

Two novel antibiotics, catacandin A and catacandin B, were isolated from the fermentation broth of the bacterium, Lysobacter gummosus, by extraction and adsorption, reverse-phase and gel filtration chromatography. On the basis of their physico-chemical properties, they are acyltetramic acids that are easily distinguishable from others in this class. Catacandin A and catacandin B possess good anticandidal activity.

Anti-Bacterial Agents↗

[Study of several parameters of magnesium metabolism in spontaneously hypertensive rats].

We have compared a few parameters of magnesium metabolism in spontaneously hypertensive (SHR) and Wistar Kyoto rats (WKY). The results show a decrease of plasma magnesium and urinary magnesium. There is no difference in fecal magnesium and in balance of magnesium. These results have raised a question as to the importance of changes in magnesium metabolism in the mechanism of hypertension.

Animals↗

Effects of nitrous oxide anesthesia on intraocular air volume.

To study the effect of nitrous oxide on the rate of absorption of intraocular air one eye of each of 20 rabbits was injected with 4 ml of air following lensectomy and total vitrectomy. After 24 hours the eyes of the 10 rabbits anesthetized with N2O had absorbed 25% more of the air than the eyes of the 10 rabbits anesthetized without N2O. These results suggest that the use of nitrous oxide for general anesthesia when air must be injected into the eye may be inadvisable.

Absorption↗

Activity of sulfa drugs and dihydrofolate reductase inhibitors against Candida albicans.

Growth of Candida albicans can be inhibited by sulfa drugs which prevent biosynthesis of folic acid. The dihydrofolate reductase (E.C. 1.5.1.3) inhibitors aminopterin and methotrexate also exhibit anticandidal activity, but trimethoprim does not. Kinetic evaluations with C. albicans dihydrofolate reductase indicate that methotrexate and aminopterin are tight-binding inhibitors whereas trimethoprim binds poorly.

Aminopterin↗

Obstetric and psychological effects of psychoprophylactic preparation for childbirth.

Medical records, personal interviews about the childbirth experience, and self-administered attitudinal and socioeconomic data were obtained 1 to 3 days post partum in a large metropolitan hospital, for 249 women, 95 of whom had taken psychoprophylaxis training for childbirth prior to delivery. When controlled by parity, psychoprophylactic preparation was not related to any obstetric differences except for lower levels of anesthesia for both primiparas and multiparas and lower levels of analgesia among multiparas only. Preparation was significantly related to lower levels of pain and higher levels of enjoyment during childbirth, and these psychological benefits did not diminish when controlled for parity, socioeconomic status, and four sets of psychological and attitudinal characteristics.

Adult↗

Ionomycin, a new polyether antibiotic.

Ionomycin, a new polyether antibiotic with a high affinity for calcium ions, is obtained in pure form from fermentation broths of Streptomyces conglobatus sp. nov. Trejo by solvent extraction. It is unique amongst known polyether antibiotics in that it has a UV absorption maximum at 300 nm. thereby distinguishing it from other antibiotics of its class. The Ca salt has the molecular formula C41H70O9Ca. Ionomycin is a narrow spectrum antibiotic being active against Gram-positive bacteria.

Animals↗