Dynamics of ventilation, heart rate, and gas exchange: sinusoidal and impulse work loads in man.

Dynamic characteristics of ventilation, heart rate, and gas exchange in response to sinusoidally varying work loads were analyzed in four male subjects, exercising in the upright position on a bicycle ergometer. Mean work-load and sinusoidal amplitude were about 1.5 and 0.

Studies on the function of two adjacent N6,N6-dimethyladenosines near the 3' end of 16S ribosomal RNA of Escherichia coli. IV. The effect of the methylgroups on ribosomal subunit interaction.

The effect of the presence or absence of the methylgroups of the m2(6)Am2(6)A sequence near the 3' end of 16S rRNA of Escherichia coli on the interaction of the ribosomal subunits has been studied, using wild-type (methylated) and mutant (unmethylated) ribosomes. Subunit exchange experiments and competitive association experiments show a strong preference of the 50S subunit for association with methylated 30S subunits. The results indicate that the equilibrium constant of the reaction 70S in equilibrium with 30S + 50S is dependent on the methylgroups; mutant 30S.

L-2-Hydroxyglutaric aciduria: an inborn error of metabolism?

A 5-year-old boy, excreting large amounts of 2-hydroxyglutaric acid in the urine (3.3-7.6 mmol/l), is described.

The effects of selection for different combinations of weights at two ages on the growth curve of mice.

The weights of mice in lines selected for different combinations of high and low body weights at 5 and at 10 weeks of age were recorded from 3 to 21 weeks of age. The average growth curve for each line was computed using the Gompertz function. The growth curves of lines selected for high or low weight at a single age (ST lines) showed large differences in estimates of mature size and small differences in estimates of maturing rate, i.

Laboratory of Physiological Chemistry, State University Groningen, Netherlands.

To obtain more information about the arrangement of Hind III restriction fragments in the tRNA-rRNA region of the Neurospora crassa mitochondrial (mt) DNA we have cleaved the mtDNA with Hpa I and Hind II. We could construct additional cleavage maps for these enzymes. Hybridization of rRNAs to Hind II fragments confirmed the existence of an intervening region of about 2,300 basepairs in the 24S rRNA (Hahn et al.

Direct and maternal genetic effects on body weight maturing patterns in mice.

Direct and maternal genetic effects were evaluated for maturing patterns of body weight in mice using a crossfostering design. Crossfostering was performed in one group using dams from populations selected for rapid growth rate (M16 and H6) and their reciprocal F1. crosses.

Attempted dietary treatment of a boy with hyperammonemia due to ornithine transferase deficiency.

Dietary treatment of a male patient suffering from the delayed-onset type of OCT deficiency was attempted. Control of the hyperammonemia was attempted by restriction of protein intake, guided by monitoring the plasma ammonia and regular checking of the serum amino acid levels. The influence of supplementary citric acid or lactulose therapy on the plasma ammonia level was investigated and found to be negligible.

The heterogeneity of rat-liver mitochondrial DNA.

Two types of mitochondrial DNA (mtDNA) can be distinquished in an inbred strain of rats of the Wistar type. The population of DNA molecules of the liver of one single rat is homogeneous. This was shown for a number of 100 animals and confirms the data of other investigators.

Methylmalonate excretion in a pregnancy at risk for methylmalonic acidaemia.

In a pregnant woman, who had given birth to a child with methylmalonic acidaemia previously, urinary methylmalonate was measured at various intervals in the second half of the pregnancy. A significant increase was observed towards term. The child proved to be affected.

Gas-liquid chromatographic determination of total inorganic iodine in milk.

Total inorganic iodine in milk is determined by conversion to iodobutanone, which is quantitated by gas-liquid chromatography and electron capture detection. As little as 10 microgram/L can be determined. The thyroid-active iodine content of milk can be determined rapidly with a relative standard deviation of 1.

Some kinetic properites of liver ornithine carbamoyl transferase (OCT) in a patient with OCT deficiency.

Some kinetic properties of liver OCT from a patient with OCT deficiency were studied. Contrary to controls, in which two pH optima were observed (pH 7.7 and pH 8.

Effect of hypothalamic lesions on water metabolism of the toad Bufo marinus.

The rate of cutaneous water uptake after dehydration was significantly depressed in functionally neurohypophysectomized toads (Bufo marinus), which consequently regained weight much more slowly than intact toads when returned to water. Toads bearing hypothalamic lesions were able to develop an antidiuresis when removed from water to a saturated atmosphere, but the antidiuresis was solely glmerular in origin and was established more slowly than in intact animals. The fractional reabsorption of filtrate increased significantly and the relative free water clearance decreased significantly in intact toads after removal from water.

The restriction endonuclease cleavage map of rat liver mitochondrial DNA.

Mitochondrial DNA from rat liver contains six sites for cleavage by the restriction endonucleases Hind III and EcoRI. A large stretch of DNA, comprising about 40% of the mitochondrial genome is not cleaved by either of the enzymes; eight cleavage sites are located on a DNA stretch of 35% of the genome length suggestive of an unequal distribution of the A - T baspairs over the molecule. The number of Hind III and Eco R I fragments is much higher than reported for other mammalian mitochondrial DNAs up to now.