Identification of a Preliminary Plasma Metabolome-based Biomarker for Circadian Phase in Humans.

Measuring individual circadian phase is important to diagnose and treat circadian rhythm sleep-wake disorders and circadian misalignment, inform chronotherapy, and advance circadian science. Initial findings using blood transcriptomics to predict the circadian phase marker dim-light melatonin onset (DLMO) show promise. Alternatively, there are limited attempts using metabolomics to predict DLMO and no known omics-based biomarkers predict dim-light melatonin offset (DLMOff). We analyzed the human plasma metabolome during adequate and insufficient sleep to predict DLMO and DLMOff using one blood sample. Sixteen (8 male/8 female) healthy participants aged 22.4 ± 4.8 years (mean ± SD) completed an in-laboratory study with 3 baseline days (9 h sleep opportunity/night), followed by a randomized cross-over protocol with 9-h adequate sleep and 5-h insufficient sleep conditions, each lasting 5 days. Blood was collected hourly during the final 24 h of each condition to independently determine DLMO and DLMOff. Blood samples collected every 4 h were analyzed by untargeted metabolomics and were randomly split into training (68%) and test (32%) sets for biomarker analyses. DLMO and DLMOff biomarker models were developed using partial least squares regression in the training set followed by performance assessments using the test set. At baseline, the DLMOff model showed the highest performance (0.91 R2 and 1.1 ± 1.1 h median absolute error ± interquartile range [MdAE ± IQR]), with significantly (p < 0.01) lower prediction error versus the DLMO model. When all conditions (baseline, 9 h, and 5 h) were included in performance analyses, the DLMO (0.60 R2; 2.2 ± 2.8 h MdAE; 44% of the samples with an error under 2 h) and DLMOff (0.62 R2; 1.8 ± 2.6 h MdAE; 51% of the samples with an error under 2 h) models were not statistically different. These findings show promise for metabolomics-based biomarkers of circadian phase and highlight the need to test biomarkers that predict multiple circadian phase markers under different physiological conditions.

Lipid effects of hormone replacement therapy with sequential transdermal 17-beta-estradiol and oral dydrogesterone.

OBJECTIVE: To assess the effects on lipid and lipoprotein levels of a combination therapy of matrix patch and oral sequential dydrogesterone. METHODS: The lipid effects of transdermal estradiol (E2) (80 microg/day continuously) and oral dydrogesterone (10 mg from days 15-28 of each cycle) were assessed in a multicenter, prospective, open, baseline-controlled study. Subjects were 42 healthy, postmenopausal women who had not had hysterectomies. Fasting blood samples were taken at baseline, day 14 of cycle 3 (estrogen alone), and day 25 of cycle 6 (estrogen and progestogen). The main outcome measures were changes from baseline in total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides after six cycles. RESULTS: Thirty-six subjects completed six cycles and in the 28 with complete data, HDL cholesterol increased by 10.6% from 65.25 to 72.2 mg/dL (95% confidence interval [CI] 2.32, 11.58, P = .005) and LDL cholesterol fell by 5.1% from 130.9 to 124.3 mg/dL (95% CI 13.9, 1.16, P = .07). There was a nonsignificant decrease in LDL cholesterol from 130.9 at baseline to 124.3 mg/dL at 6 months and in triglycerides from 110.6 to 107.1 mg/dL. CONCLUSION: Sequential treatment with transdermal E2 and oral dydrogesterone increased HDL cholesterol, without the accompanying increase in triglycerides that occurs with oral estrogen replacement therapy.

20 years of practicing anesthesia in a small hospital.

Anesthesia has developed from being a procedure each doctor performed on his own patients when necessary, to a specialty, sometimes practiced part time by family physicians. Training varies considerably. There have been dramatic changes in the pharmacology. Since there will likely always be a need for part time anesthetists, family physicians who will fill this need must be well prepared for the task. The benefits are a greater understanding of applied pharmacology, and a heightened sense of selection for surgery.