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Biomedical subjects

J E Daniels

Publications and source records attributed to J E Daniels.

3 recordsLinked to original sources
PubMed1999

Do plasma melatonin concentrations decline with age?

PURPOSE: Numerous reports that secretion of the putative sleep-promoting hormone melatonin declines with age have led to suggestions that melatonin replacement therapy be used to treat sleep problems in older patients. We sought to reassess whether the endogenous circadian rhythm of plasma melatonin concentration changes with age in healthy drug-free adults. METHODS: We analyzed the amplitude of plasma melatonin profiles during a constant routine in 34 healthy drug-free older subjects (20 women and 14 men, aged 65 to 81 years) and compared them with 98 healthy drug-free young men (aged 18 to 30 years). RESULTS: We could detect no significant difference between a healthy and drug-free group of older men and women as compared to one of young men in the endogenous circadian amplitude of the plasma melatonin rhythm, as described by mean 24-hour average melatonin concentration (70 pmol/liter vs 73 pmol/liter, P = 0.97), or the duration (9.3 hours vs 9.1 hours, P = 0.43), mean (162 pmol/liter vs 161 pmol/liter, P = 0.63), or integrated area (85,800 pmol x min/liter vs 86,700 pmol x min/liter, P = 0.66) of the nocturnal peak of plasma melatonin. CONCLUSION: These results do not support the hypothesis that reduction of plasma melatonin concentration is a general characteristic of healthy aging. Should melatonin replacement therapy or melatonin supplementation prove to be clinically useful, we recommend that an assessment of endogenous melatonin be carried out before such treatment is used in older patients.

Adult↗
PubMed1999

Association between stress and glycemic control in adults with type 1 (insulin-dependent) diabetes.

OBJECTIVE: To examine the relationship between stressful life events and alterations in glycemic control in adults with diabetes. RESEARCH DESIGN AND METHODS: The occurrence of stressful experiences was recorded using the life Events and Difficulties Schedule of Brown and Harris in 55 adults with type 1 diabetes. The two most recent measures of glycemic control (HbA1c) were obtained from medical records, with poor glycemic control defined by the sample median (> or =7.7%). RESULTS: Subjects whose control deteriorated over time or who remained in poor glycemic control were significantly more likely to report severe personal stressors (SPS) in the month before HbA1c measurement, compared with subjects whose control remained fair or whose control improved (43 and 25% vs. 7 and 0%; P = 0.000). Subjects whose control remained fair or whose control improved were significantly more likely to report only positive life events during the same time period (80 and 11% vs. 0 and 0%, respectively; P = 0.000). Multiple regression analysis demonstrated that SPS, sex, and lack of further education were all significantly associated with either remaining in poor control or deterioration of control. CONCLUSIONS: The study has shown that recent severe stressors are associated with poorer glycemic control. Positive life events were associated with fair or improved glycemic control. This study has its limitations, and future studies should be prospective in design. While it is not always possible to avoid stress, learning to recognize and cope with stressors may help individuals with diabetes maintain good glycemic control and improve overall quality of life.

Adult↗