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Biomedical subjects

R D Macdonald

Publications and source records attributed to R D Macdonald.

7 recordsLinked to original sources
PubMed1987

Herpes zoster ophthalmicus with delayed cerebral infarction and meningoencephalitis.

Herpes zoster ophthalmicus can be complicated by a delayed ipsilateral cerebral angiitis which may cause infarction and a smoldering meningoencephalitis. We describe such a case treated successfully with steroids and acyclovir. It is important to consider the diagnosis of this disorder early since therapeutic intervention may prevent an otherwise high morbidity and mortality. Steroids may have to be continued for some time after clinical resolution, using the ESR as a guideline for decreasing dosages.

Acyclovir↗
PubMed1979

The Leboyer method.

The method described is the reception of the newborn on the assumption that the baby is a sensitive, feeling being. The reasons for Leboyer's concept are discussed and the benefits to the parent-child bond are emphasized.

Female↗
PubMed1978

Quantitative analysis of defective interfering particles in infectious pancreatic necrosis virus preparations.

Infectious pancreatic necrosis virus exhibited an interference phenomenon that resulted in the survival of the infected cell with one hit kinetics. The responsible factor was found to co-purify with standard virus through a purification regime that employed two CsCl gradients and a sucrose gradient. This result suggested that a defective interfering (DI) viral particle was involved. It was possible to estimate the number of DI particles by a statistical method using the Poisson distribution that related cell survival to input DI/cell, which indicated that virus samples from dilute passage contained as many DI particles as samples from undiluted passage; this means that multiple undiluted virus passage did not increase the yield of DI particles. In isopycnic CsCl gradient centrifugation, the DI particles were found in a broad band superimposed over the standard virus peak and extending above it, such that the ratio DI/PFU varied from 0.3--20 in different fractions. These centrifugation methods did not completely separate DI particles from standard virus.

Animals↗
PubMed1978

Purification of infectious pancreatic necrosis (IPN) virus and comparison of polypeptide composition of different isolates.

Infectious pancreatic necrosis (IPN) virus was partially purified by freon extraction of infected CHSE-214 cells and concentrated by polyethylene glycol (PEG) precipitation of virus from the medium. Both methods resulted in virus concentrates that could be further purified by two CsCl gradient centrifugations with little loss of infectivity. A Recovery of 80 to 100% of the virus infectivity was obtained and over 100-fold concentration of viral infectivity was achieved by these methods. This purification was used to compare 10 isolates of IPN virus with regard to their physiochemical properties by electron microscopy, buoyant density in CsCl, and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the purified virions. Electron-microscopic observations showed that the virus isolates were identical in that they were isometric, hexagonal in profile, and had a particle diameter of 71 nm. The buoyant densities of the virus isolates in CsCl were found to be 1.33 g/ml. SDS-gel electrophoresis of the virus isolates revealed the presence of three polypeptides of molecular weight 50, 30, and 27 x 10(3) designated as VP50, VP30, and VP27, respectively.

Animals↗
PubMed1977

The structure of infectious pancreatic necrosis virus RNA.

The RNA from infectious pancreatic necrosis virus has been purified and had a sedimentation velocity of 14S on sucrose gradients, a buoyant density of 1-60 g/ml in CS2SO4 and pyrimidine to purine ratios near unity. The RNA had the appearance of a linear double stranded molecule with an average length of 0-92 mum and a standard deviation of 0-07 mum when observed under the electron microscope using the Kleinschmidt protein film technique. This would correspond to a mol. wt. of 2-4 +/- 0-2 X 10(6). The RNase A resistance of IPN virus RNA exhibited a marked salt dependence; it was 92% resistant in 0-1 M-NaCl, but only 9% resistant, or less, in 0-*1 M-NaCl. The RNA was resistant to denaturation by boilding at NaCl concentrations of 0-04 M or higher, but did denature at lower concentrations. Polyacrylamide gel electrophoresis of the RNA indicated that two RNA species were present and the standard deviation of lengths in the electron microscope indicated that they could not differ by more than 4 X 10(5) in mol. wt.

Animals↗