Electroencephalographic correlates of paced breathing.

Multichannel EEG, respiration, blood pressure and ECG were recorded during paced breathing at five frequencies in 18 subjects in order to elucidate the effects of paced breathing on power changes in alpha, beta and theta bands, and on rhythmical variability of these parameters. Mean power in the beta band and low-frequency beta power variability (0.12-0.04 Hz) increased during paced breathing at frequencies of 0.25 and 0.20 Hz. The total variability of alpha power in the right parietal and occipital electrodes decreased during paced breathing at 0.1 Hz compared with initial rest. The results point to increased cortical excitability during paced breathing at eupnoeic frequencies and to diminished cortical sensitivity to desynchronizing influences during paced breathing at 0.1 Hz.

Headaches in the elderly.

Headache prevalence and etiology vary dramatically with age. The prevalence of primary headache disorders, such as migraine and cluster, declines with age, while the prevalence of secondary headache disorders, such as temporal arteritis and mass lesions, increases. In evaluating elderly patients with new onset of headache, a high index of suspicion for organic disease is required. Headache symptomatology also varies with age. For example, migraine may evolve into a pattern of chronic daily headache, or auras may occur in the absence of headache (late-life migraine accompaniments). A careful longitudinal headache history is therefore important. Headache management is also influenced by age. Elderly people are more susceptible to medication side effects and are often treated with several drugs. Medications may cause headaches and drug interactions may complicate therapy. For these reasons, age of onset and duration of illness are critical headache features that guide the subsequent approach to diagnosis and treatment.

Isolation of the gene encoding the Hin recombinational enhancer binding protein.

In vitro DNA inversion mediated by the protein Hin requires the presence of a recombinational enhancer sequence located in cis relative to the recombination sites and a protein, Fis, which binds to the enhancer. We have cloned and determined the primary sequence of the gene encoding Fis. The deduced amino acid sequence of Fis indicates that the protein is 98 amino acids long and contains a potential helix-turn-helix DNA binding motif at its carboxyl terminus. The gene encoding Fis maps at 72 min on the Escherichia coli chromosome. The construction of mutant strains of E. coli that lack a functional fis gene demonstrates that Fis is not essential for cell growth under laboratory conditions but is required for high rates of Hin-mediated site-specific inversion in vivo.