Reduction of whole PTH/intact PTH ratio as a predictor of bone metabolism in cinacalcet treatment of hemodialysis patients with secondary hyperparathyroidism.

UNLABELLED: In cinacalcet treatment of hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT), not only intact parathyroid hormone (I-PTH), whole PTH (W-PTH), and bone markers, but also W-PTH/I-PTH ratio as proportion of active PTH(1-84) molecules were decreased. Changes in W-PTH/I-PTH ratio significantly correlated and predicted changes in bone marker. INTRODUCTION: Cinacalcet partly suppresses the secretion of PTH by enhancing PTH(1-84) degradation into N-truncated fragments. The objectives of this study is to investigate the significance of the N-truncated PTH/PTH(1-84) ratio for the prediction of the effect of cinacalcet in HD patients. METHODS: Serum parameters were measured during 12 weeks of oral cinacalcet administration at 25 mg daily in 39 HD patients with SHPT. RESULTS: Serum Ca, Pi, W-PTH, I-PTH, and W-PTH/I-PTH ratio all decreased significantly in a time-dependent manner during cinacalcet administration. Serum tartrate-resistant acid phosphatase (TRAP) 5b reflected these changes more precisely than serum N-telopeptide of type-I collagen. At 1 week, changes in I-PTH and W-PTH correlated significantly with those in serum Pi, but not Ca. Changes in serum Pi (but not Ca) and serum W-PTH also correlated significantly with changes in serum TRAP5b at both 4 and 12 weeks, while changes in serum I-PTH correlated significantly with those in serum TRAP5b only at 12 weeks. Changes in the serum W-PTH/I-PTH ratio correlated significantly with those in serum TRAP5b at both 4 and 12 weeks, and changes in serum W-PTH/I-PTH ratio at 4 weeks showed a tendency for a correlation with changes in serum TRAP5b at 12 weeks. HD patients with a reduced W-PTH/I-PTH ratio after 4 weeks had a significantly greater reduction of TRAP5b over 12 weeks. CONCLUSION: W-PTH and the W-PTH/I-PTH ratio allow estimation of the potency of cinacalcet in enhancement of PTH degradation, and thus no less reliable markers than I-PTH for reflecting cinacalcet-induced bone resorption.

Influences of biological rhythms on the effects of psychotropic drugs.

The efficacy of psychotropic drugs varies depending on the time of administration. This phenomenon is observed with antipsychotics, antidepressants, mood stabilizers, benzodiazepines, barbiturates, and psychostimulants. The presence or absence of this phenomenon and the rhythm phase in the efficacy of each drug varies depending on the drug, dose, parameter measured, animal species, and strain. A recent study demonstrating circannual changes in the phases of circadian rhythm of drug efficacy suggests that discrepancies between studies may be considerably explained by the presence of a circannual rhythm. The rhythms in drug effects are suggested not to be due to rhythmic changes in the pharmacokinetics of the drugs but rather to an endogenous rhythm in drug susceptibility resulting from a circadian rhythm in the intracerebral neurotransmission system. The presence of this phenomenon and its law have been demonstrated to a considerable extent in animals, but corresponding clinical reports in humans remain insufficient despite its clinical importance. Further study in humans is certainly warranted.

Double-blind test on the efficacy of methylcobalamin on sleep-wake rhythm disorders.

The therapeutic effect of methylcobalamin (Met-12) on sleep-wake rhythm disorders was examined in a double-blind test. In the test group which was given a large dosage, a higher percentage of improvement was found compared to the control group with a small dosage, although the difference was not significant. The test group inconsistently showed significant improvement in both the sleep-wake cycle parameters and in clinical symptoms. The tendency was for the results to show a beneficial effect of Met-12 on rhythm disorders. However, because the percentage of improvement was low and significant improvement was inconsistent, Met-12 might be considered to have a low therapeutic potency and possible use as a booster for other treatment methods of the disorders.

Atypical depressive symptoms possibly predict responsiveness to phototherapy in seasonal affective disorder.

Phototherapy was administered to 24 depressed patients with seasonal affective disorder (SAD), of which 62%, 24%, and 14%, respectively, showed improvements of greater than or equal to 50%, 25-50%, and less than 25% based on the Hamilton rating scale for depression for SAD (HAMSAD). No patients showed aggravation or side effects. Although the improvement rate in HAMSAD correlated significantly with the pretreatment severity of atypical symptoms of depression, it did not correlate with that of typical symptoms. This suggests that phototherapy is a useful treatment in SAD and that responsiveness to phototherapy in SAD can possibly be predicted by the atypical depressive symptoms before treatment.

Double-blind study of the chronopharmacotherapy of depression.

To investigate the possibility of chronotherapy with antidepressants for patients with depression, we gave single daily doses of clomipramine 150 mg/day to 30 patients with depression at three different times of day, i.e., morning, noon, or before bedtime, using a double-blind method over a 4-week period. Beneficial effects differed according to the administration time of day, with the most effective result being found for the administration at noon. Time-dependent differences in side effects were observed in tremors and dryness of mouth. An additional 10 patients were administered their medications three times a day by traditional, equally divided doses, and the efficacy was inferior than daily single doses at noon. The study results showed the significance of the administration time of day for the benefits and side effects of antidepressant therapy for depression.

Circadian rhythm of brain susceptibility to haloperidol during chronic administration.

Circadian fluctuation has been reported to exist to the effects of haloperidol after acute administration. In an attempt to clarify the viability of chronotherapy with haloperidol, the antiapomorphine effect of haloperidol after chronic administration was investigated in the present paper. Haloperidol was administered once daily at the same time for 21 consecutive days to rats which were kept under 12 hr lighting conditions with light onset at 19:30. Then the chronology of the antiapomorphine effect was investigated. The antiapomorphine effect was significantly stronger in the group treated at 19:30 than that treated at 13:30. These data agreed with the results found after the acute administration of the drug. After chronic administration, no difference was found in the plasma and brain level of haloperidol due to the time of administration. These experimental results seem to suggest that a circadian rhythm in the brain susceptibility to haloperidol exists even during chronic administration.