A simple chromatographic technique for the estimation of urinary levels of normetadrenaline and metadrenaline

A simple, but effective, procedure is described for the concurrent estimation of normetadrenaline (NMA) and metadrenaline (MA) in urine. The 3-methoxycatecholamines are adsorbed by a cation exchange resin, desorbed, separated by paper chromatography, and finally estimated spectrophotometrically after oxidation to vanillin. The mean (+/- 2 standards deviations) urinary outputs of NMA and MA from 123 normals (80 males, 43 females) in 24 hours was 2.15 +/- 1.04 and 1.79 +/- 0.96 mu mol respectively. There was no significant difference in the 24-hour urinary outputs of NMA between the male and female groups. However, the output of MA from the males was significantly higher than that from the females.

Auditory dysfunction in Friedreich ataxia: result of spiral ganglion degeneration

We performed behavioral audiometric tests and brainstem auditory evoked potentials in four patients with Friedreich ataxia. None of the patients had symptomatic hearing difficulties. Results of the audiometric tests pointed to a disorder of the eighth nerve. In none of the patients could we elicit normal-appearing waves of the brainstem auditory evoked potentials. These abnormalities could be attributed to degeneration of spiral ganglion neurons. Our patients had useful and functional hearing despite very abnormal brainstem auditory evoked potentials.

A simple chromatographic procedure for the concurrent estimation of urinary 4-hydroxy-3-methoxymandelic acid (HMMA) and homovanillic acid (HVA) using a scanning technique

A rapid and simple procedure is described for the concurrent determination of 4-hydroxy-3-methoxymandelic acid (HMMA) and homovanillic acid (HVA). The acids are separated by chromatography and estimated by a scanning technique. The urinary output of HMMA and HVA over 24 h from 123 normals (80 males, 43 females) gave mean values of 3.3 +/- 0.94 and 4.9 +/- 1.3 mg, respectively. There was no significant difference in the 24 hour urinary output of HMMA and HVA between the male and femal groups.

Comparisons of the distribution of nucleotides and common sequences in deoxyribonucleic acid from selected bacteriophages

Results from comparisons of deoxyribonucleic acid (DNA) from several classes of bacteriophages suggest that most phage chromosomes contain either a homogeneous distribution of nucleotides or are made up of a few, rather large segments of different quanine plus cytosine (G + C) contents which are internally homogeneous. Among those temperate phages tested, most contained segmented DNA. Comparisons of sequence similarities among segments from lambdoid phage DNA species revealed the following order in relatedness to lambda: 82 (and 434) > 21 > 424 > phi80. Most common sequences are found in the highest G + C segments, which in lambda contain head and tail genes. Hybridization tests with lambda and 186 or P2 DNA species verified that the lambdoids and 186 and P2 belong to two distinct groups. There are fewer homologous sequences between the DNA species of coliphages lambda and P2 or 186 than there are between the DNA species of coliphage lambda and salmonella phage P22.