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Biomedical subjects

M R Geier

Publications and source records attributed to M R Geier.

At least 19 recordsLinked to original sources

Prenatal diagnosis of a homologous Robertsonian translocation involving chromosome 15.

We report the prenatal diagnosis of a fetus with a de novo Robertsonian translocation: 45,XY,der(15;15)(q10;q10). Although Robertsonian translocations are common chromosomal rearrangements, those involving homologous chromosomes are infrequent. Since chromosome 15 is imprinted, uniparental disomy (UPD) is a concern when chromosomal rearrangements involving chromosome 15 are identified. In the present case, UPD studies showed normal biparental inheritance. In contrast to the fact that most homologous acrocentric rearrangements are isochromosomes, these results indicate postzygotic formation of a Robertsonian translocation between biparentally inherited chromosomes 15.

Adult↗

Endotoxins in commercial vaccines.

Twenty samples of commercial vaccines intended for administration to humans were assayed for the presence of bacterial endotoxins by using the Limulus amebocyte lysate test. Sixteen of the vaccines contained more than 0.1 ng of endotoxin per ml (which corresponds to 103 bacterial cell wall equivalents per ml in the undiluted vaccines). These results suggest that at some stage of preparation, the vaccines have contained varying amounts of gram-negative bacteria and may indicate the presence of other bacterial products as well. It might be useful to list the level of endotoxins, phage, and other contaminants on each vaccine lot to facilitate studies on any side effects of these contaminants. Selection of vaccine lots with the least endotoxin might reduce some of the adverse effects of vaccinations.

Bacterial Toxins↗

Addition of leucine precursors to the diet of leucine-starved mice.

Leucine-starved mice placed on a diet supplemented with the immediate precursor of leucine, alpha-ketoisocaproic acid, regain lost weight. This weight gain is similar to that observed when the leucine-starved mice are provided with leucine in their diet. Mice on a leucine-free diet supplemented with alpha-ketoisovaleric acid, the first compound in the leucine biosynthetic pathway, continued to lose weight as quickly as mice on leucine-deficient diets.

Animals↗

Galactose utilization in galactosemia.

Cultures of human galactosemic fibroblasts without detectable transferase activity were able to convert [1-(14)C]galactose to (14)CO(2) to the same extent as normal cells, but did so at a significantly slower rate. The utilization of galactose in both normal and galactosemic cells was strongly inhibited by glucose at physiologic concentrations.

Carbon Dioxide↗