Human nocturnal blood melatonin and liver acetylation status

Chronotypology and melatonin alterations in minimal hepatic encephalopathy

Background

"Minimal (subclinical) hepatic encephalopathy" is a term that describes impairment of every day life activities in cirrhosis patients without clinical neurologic abnormalities. Melatonin diurnal pattern disruption and metabolic changes due to liver insufficiency can affect the human biologic clock. Our study was conducted to measure plasma melatonin levels in an attempt to correlate plasma melatonin abnormalities with liver insufficiency severity, and describe chronotypology in cirrhosis patients with minimal encephalopathy.

Methods

Twenty-six cirrhotic patients enrolled in the study and thirteen patients without liver or central nervous system disease served as controls. All patients had full clinical and biochemical evaluation, chronotypology analysis, neurological evaluation, melatonin profile and quality of life assessment.

Results

Cirrhotic patients with minimal encephalopathy exhibit melatonin secretion abnormalities. Cirrhosis patients with more severe hepatic insufficiency (Child-Pugh score > 5) had significantly (p < 0.04) lower evening melatonin levels compared to patients with less severe insufficiency (Child-Pugh score = 5).

Chronotypology analysis revealed Morning Type pattern in 88% of cirrhosis patients.

Discussion

The presence of abnormal plasma melatonin levels before the onset of clinical hepatic encephalopathy, and the finding that patients with more severe cirrhosis have lower evening melatonin levels are the most important findings of this study. Despite these melatonin abnormalities, chronotypology revealed Morning Type pattern in 23 of 26 cirrhosis patients. We believe these findings are important and deserve further study.

Conclusion

Melatonin abnormalities occur in cirrhosis patients without clinical encephalopathy, are related to liver insufficiency severity, may influence chronotypology patterns, and certainly deserve further investigation.

Allele NAT2*5 determines resistance to bronchial asthma in children

NAT2*5 allele was found in 54.8% healthy children and 35.9% children with bronchial asthma, i.e. the risk of bronchial asthma was considerably lower in individuals carrying NAT2*5 allele. NAT2*5 allele manifests itself in both homo- and heterozygous states.

Estimation of time of death by quantification of melatonin in corpses

A method for the estimation of time of death (TOD), was evaluated by measuring the melatonin (MT) content of pineal bodies (PBs), sera and urine samples from 85 cadavers. A total of 44 cadavers were investigated in Sapporo (geographical coordinates N 43 degrees 4', E 141 degrees 21') and 41 in Tokyo (N 35 degrees 39', E 139 degrees 44'). MT contents were measured by radioimmunoassay (RIA) in 75 PBs, 27 sera and 14 urine samples. Exponential differences of pineal MT content were recognized between peaks in nighttime and nadirs in daytime, ranging from 0.099 to 63.2 ng/PB. Circadian rhythms were also observed for the concentrations of MT in serum (11-205 pg/ml), and in urine (7.5-137.5 pg/ml). Consequently, criteria for the TOD estimation are proposed as follows. 1) Pineal MT contents--(1) 0-0.2 ng/PB: TOD 1100-1700 hours, (2) 0.2-0.3 ng/PB: TOD 0700-2000 hours, (3) 0.3-1 ng/PB: inconclusive, (4) 1-4 ng/PB: TOD 1600-1000 hours, (5) 4-8 ng/PB: TOD 2000-0800 hours, (6) over 8 ng/PB: TOD 2000-0500 hours, 2) Serum MT concentration--(1) 0-100 pg/ml: inconclusive, (2) over 100 pg/ml: TOD 2200-0100 hours, and 3) Urinary MT concentration--(1) 0-35 pg/ml: inconclusive, (2) over 35 pg/ml: TOD 1800-0600 hours. The range of the estimation can be limited by a combination of these 3 criteria. The present method can be combined with other methods for estimating the TOD to decrease the range.