To better define the characteristic clinical features of benign convulsions with mild gastroenteritis, recently recognized as a new entity in Japan, we reviewed all the 10 patients we have seen from 1992 to 1994. The clinical features have been previously reported in the literature to be afebrile generalized tonic-clonic seizures occurring between the first and the fifth sick day of mild gastroenteritis. In our series, four of 10 patients had convulsions before the onset of gastroenteritis. Overall, seizures were mostly brief and often repetitive occurring in cluster (19 seizures/10 episodes). Among these, a prolonged or partial seizure was frequently observed. In six of the 10 patients, the seizure type changed during an episode: from generalized to partial seizures (n = 2), from partial to generalized seizures (n = 2), or from partial to another type of partial seizures (n = 2). None in our series experienced a recurrence episode of afebrile convulsion during follow-up. These findings suggest that benign convulsions with mild gastroenteritis exhibit some variations in their clinical manifestation.

Child, Preschool↗

PubMedDate not supplied

Regulation by guanine nucleotides and cations of melatonin binding sites in the goldfish brain.

Effects of nucleotides and cations on 2-[125I]iodomelatonin binding sites in the goldfish brain were examined. Nucleotides (10(-6)-10(-3) M) dose-dependently inhibited the specific binding with the following order of potency: guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) > GTP = GDP > GMP = ATP > cyclic GMP. Cyclic AMP was ineffective. The treatment of membranes with GTP gamma S induced rapid dissociation of 2-[125I]iodomelatonin from membranes when added at the steady state, increased the Kd and decreased the Bmax values as revealed by saturation analysis, and increased the IC50 value of melatonin to inhibit the specific binding. The treatment decreased the specific binding to membrane preparations obtained from six brain regions as well. Inorganic salts (5-200 mM) dose-dependently inhibited the specific binding with the following order of potency: CaCl2 > MgCl2 > LiCl > NaCl > choline chloride > KCl, except for 5 mM MgCl2, which enhanced the specific binding. Saturation experiments demonstrated that 75 mM CaCl2, 100 mM MgCl2 and 200 mM NaCl increased the Kd and decreased the Bmax while 5 mM MgCl2 increased the Bmax value. These results imply that G protein and physiological concentrations of cations are involved in the regulation of melatonin binding sites in the goldfish brain.

Animals↗

PubMedDate not supplied

Photic and circadian regulations of melatonin rhythms in fishes.

Photic and circadian regulations of melatonin rhythms in the pineal organ and the retina of several teleosts were studied to investigate the regulatory mechanisms of melatonin rhythms in fishes. In the eyecup preparations of the goldfish, Carassius auratus, both time of day and lighting conditions affected melatonin production, with high melatonin production observed only in the dark-treated group incubated during the 'subjective' night. Thus, in the goldfish retina, local photoreceptors and an ocular circadian clock seem to regulate melatonin production, as in the zebrafish retina and in the pineal organ of a number of teleosts, including the goldfish. However, this circadian regulation of melatonin rhythms is not universal among fishes. Although the superfused pineal organ of the masu salmon Oncorhynchus masou secreted melatonin in a rhythmic fashion under light-dark (LD) cycles, the rhythm disappeared under constant darkness (DD), as in the rainbow trout, with a large amount of melatonin released both during the subjective day and the subjective night. These results suggest that all salmonids lack circadian regulation of melatonin rhythms. Furthermore, when ocular melatonin rhythms were compared in two cyprinids, the ugui Tribolodon hakonensis and the oikawa Zacco platypus occupying different ecological niches, ocular melatonin contents exhibited daily variations, with higher values during the dark phase of LD cycles in both species. The rhythmic changes persisted in the ugui under DD, with higher levels at subjective midnight than at subjective midday; however, ocular melatonin levels in the oikawa were consistently high under DD. Thus, the circadian regulation of melatonin rhythms in fishes is influenced not only by phylogeny, but also by the ecological niches of the animals. These results suggest that the physiological functions of melatonin in the circadian and photoperiodic systems differ among fishes.

Animals↗