In this short overview, features of the two suprachiasmatic nucleus (SCN)-independent oscillators are described. One is restricted daily feeding (RF)-associated oscillator and the other is methamphetamine-dependent oscillator. We found that both oscillators have free-running period of circadian range, and express themselves in the special state of energy supply or energy deficiency. The expression of the RF-associated oscillator depends heavily on the catecholaminergic input from the medulla, whereas the methamphetamine-dependent oscillator appears to depend on the sympathomimetic effects of the drug. It is plausible that overt rhythms of both oscillators are complex, mainly because of the interaction of hourglass principle with circadian clock mechanism.

Animals↗

PubMedDate not supplied

Liquid meal attenuates meal anticipation in rat adrenocortical activity.

Effects of dietary consistency were examined on the development and persistence of meal anticipation in adrenocortical activity in rats under restricted daily feeding (RF), in which food supply was restricted to a fixed time of day. Restricted daily solid meal produced the anticipatory hormone peak in 8 days, whereas restricted daily liquid meal produced the peak in 12 days. The developed hormone peak was less prominent by liquid meal than by solid. The anticipatory corticosterone peak developed by solid meal persisted throughout the period examined (3 weeks) after the termination of RF, whereas the peak developed by liquid meal disappeared after the first week. It is concluded that liquid meal attenuates the meal anticipation in the adrenocortical activity in rats under RF.

Adrenal Cortex↗

PubMedDate not supplied

Light and plasma melatonin rhythm in humans.

Plasma melatonin rhythm in humans was investigated: its stability, relationship to the sleep-wake rhythm, and response to light. The so-called day-to-day variation of reference phases of plasma melatonin rhythm was within 1.4 h when blood was sampled at 1-hour intervals. Therefore, a change in phase beyond this value is regarded as a phase shift of melatonin rhythm in individuals. Plasma melatonin rhythm was spontaneously desynchronized from the sleep-wake rhythm and probably regulated by the common circadian pacemaker which drives the rhythm in rectal temperature. When a bright-light pulse was applied, the melatonin rhythm produced a phase shift, but the amount of phase shift seems to be different for the ascending and descending phases of nocturnal melatonin rise. Finally, a partial entrainment was observed in a subject who developed a non-24-hour sleep-wake syndrome later, in which the plasma melatonin rhythm was free-running whereas the sleep-wake rhythm was apparently entrained by a 24-hour day-night alternation. It is concluded that the plasma melatonin rhythm is the best marker of the human circadian pacemaker so far available.

Circadian Rhythm↗

PubMedDate not supplied

Nephrotic syndrome associated with generalized amyloidosis and IgM-monoclonal proteinemia.

A 67-year-old woman was admitted for nephrotic syndrome. In spite of the lack of lymphadenopathy, hepatosplenomegaly and serum hyperviscosity, remarkable monoclonal IgM-proteinemia was demonstrated. Amyloid kidney was shown by renal biopsy. However, in the bone marrow and other organs, neither proliferation nor invasion of monoclonal immunoglobulin-producing cells was revealed by immunohistological investigations of the specimens biopsied or examined at autopsy, excluding Waldenström's macroglobulinemia. Immunosuppressive chemotherapy with cyclophosphamide, vincristine and prednisolone was effective in reducing serum IgM, but could not slow the progression of renal failure. This case suggested the association of generalized amyloidosis with excessive IgM-proteinemia caused by a non-malignant mechanism.

Aged↗

PubMedDate not supplied

Urinary isatin concentrations in patients with Parkinson's disease determined by a newly developed HPLC-UV method.

Isatin, an endogenous monoamine oxidase (MAO) inhibitor, has been found in mammalian tissues. We previously reported that exogenously administered isatin significantly increased acetylcholine (ACh) and dopamine (DA) levels in the rat striatum. In order to elucidate the relationship between isatin and Parkinson's disease, we measured urinary isatin excretions in patients with Parkinson's disease using a newly developed HPLC-UV method. The recovery of this assay was approximately 102.3% at a range from 2 to 50 nmol/ml. The Coefficient of Variance (CV) for the determination at this range was approximately 2.5% for intra-assay and 6.2% for inter-assay, respectively. There was no significant difference in urinary isatin excretion between data from men and women in healthy control. The value in young age group (19-35 years old) was not significantly different compared with that of the older age group (54-84 years old). Urinary isatin levels in patients with Parkinson's disease tended to increase in accordance to the Hoehn and Yahr criteria. This is the first study in which a significant increase in urinary isatin excretion was observed at Stage III, IV and V in patients with Parkinson's disease. Urinary isatin concentrations in drug-treated patients with Parkinson's disease (at Stage I and II) tended to decrease compared with those of patients without medication. These results demonstrated that urinary isatin excretion may serve as an endogenous diagnostic marker for the clinical severity of Parkinson's disease.

Aged↗

PubMedDate not supplied

The metabolism of roxatidine acetate hydrochloride. Liberation of deuterium from the piperidine ring during hydroxylation.

The metabolism of roxatidine acetate hydrochloride (RA), a new histamine-2 receptor antagonist, was studied by GC/MS in rats and dogs in vivo. The co-administration of 14C-RA and RA-d10 labeled with deuterium in the piperidine ring expedited the isolation and identification of 15 urinary metabolites. The major metabolites in both animals were M-1, M-8, M-10, and M-11; M-4 could be found only in the rat. The aromatic and piperidine ring-hydroxylated metabolites were found in small amounts in both species. Following the administration of RA-d10 to rats and dogs, oxygenated metabolites on the piperidine ring, such as M-3 and M-4, were isolated and their analysis indicated the unexpected loss of three or four deuterium atoms from the ring. Also, first and second isotope effects were observed on the conversion rate in vivo and retention time in HPLC, respectively.

Administration, Oral↗