Dysfunctions of the vestibular organ in patients with migrainous vertigo in the results of objective tests of the equilibrium system.

<b>Introduction:</b> Migrainous vertigo (MV) is one of the most common causes of episodic vertigo. Diagnostic criteria for MV are described in the appendix to the third edition of the International Classification of Headache Disorders (Beta Version). The dysfunction exerts its impact on certain peripheral and central structures within the vestibular system.

Role of the CDC8 gene in the repair of single strand breaks in DNA of the yeast Saccharomyces cerevisiae.

It has been found that the repair of single strand breaks is defective in the DNA replication mutants cdc8-1 and cdc8-3 of Saccharomyces cerevisiae both in permissive (23 degrees C) and restrictive conditions (36 degrees C). In permissive conditions we observed a significant delay in single strand break repair in a diploid strain HB7 (cdc8-1/cdc8-1), as compared with the wild-type strain. Under restrictive conditions no repair was observed, but rather degradation of MMS-damaged DNA occurred.

The effect of DNA replication on mutation of the Saccharomyces cerevisiae CDC8 gene.

Incubation in YPD medium under permissive conditions when DNA replication is going on, strongly stimulates the induction of cdc+ colonies of UV-irradiated cells of yeast strains HB23 (cdc8-1/cdc8-3), HB26 (cdc8-3/cdc8-3) and HB7 (cdc8-1/cdc8-1). Inhibition of DNA replication by hydroxyurea, araCMP, cycloheximide or caffeine or else by incubation in phosphate buffer pH 7.0, abolishes this stimulation.

Induced recombination and reversion of the CDC8 gene in relation to the cell cycle of yeast.

The induction of mitotic recombination in the CDC8 locus was studied in a diploid strain heteroallelic for cdc8 mutations (cdc8-1/cdc8-3); mitotic reversion was studied in strains cdc8-1/cdc8-1 and cdc8-3/cdc8-3. Conversion and reversion did not occur in those cells blocked at the S stage of the cell cycle by exposure to a nonpermissive temperature. In stationary phase cells irradiated just prior to exposure to temperature stress, the induction of recombinants was rather low and the induction of revertants was minimal.

Alkaline elution of yeast DNA: a simple method of detection of DNA single-strand breaks.

A method of analysis has been developed to study the induction and repair of single-strand breaks in yeast DNA by alkaline elution from filters. By this technique sphaeroplasts obtained from yeast cells were lysed on the filters and single-strand DNA fragments selectively eluted by alkaline elution. Three different approaches are proposed: (i) pH step alkaline elution from the filters; (ii) alkaline elution from the filters using one selected level of pH; (iii) alkaline elution from the filter in which fractions were collected directly on Whatman 17 glass filter paper, thus simplifying the procedure.