Associations between brain structure and sleep patterns across adolescent development.

STUDY OBJECTIVES: Structural brain maturation and sleep are complex processes that exhibit significant changes over adolescence and are linked to many physical and mental health outcomes. We investigated whether sleep-gray matter relationships are developmentally invariant (i.e. stable across age) or developmentally specific (i.e. only present during discrete time windows) from late childhood through young adulthood. METHODS: We constructed the Neuroimaging and Pediatric Sleep Databank from eight research studies conducted at the University of Pittsburgh (2009-2020). Participants completed a T1-weighted structural MRI scan (sMRI) and 5-7 days of wrist actigraphy to assess naturalistic sleep. The final analytic sample consisted of 225 participants without current psychiatric diagnoses (9-25 years). We extracted cortical thickness and subcortical volumes from sMRI. Sleep patterns (duration, timing, continuity, regularity) were estimated from wrist actigraphy. Using regularized regression, we examined cross-sectional associations between sMRI measures and sleep patterns, as well as the effects of age, sex, and their interaction with sMRI measures on sleep. RESULTS: Shorter sleep duration, later sleep timing, and poorer sleep continuity were associated with thinner cortex and altered subcortical volumes in diverse brain regions across adolescence. In a discrete subset of regions (e.g. posterior cingulate), thinner cortex was associated with these sleep patterns from late childhood through early-to-mid adolescence but not in late adolescence and young adulthood. CONCLUSIONS: In childhood and adolescence, developmentally invariant and developmentally specific associations exist between sleep patterns and gray matter structure, across brain regions linked to sensory, cognitive, and emotional processes. Sleep intervention during specific developmental periods could potentially promote healthier neurodevelopmental outcomes.

Sleep-Wake Differences in Relative Regional Cerebral Metabolic Rate for Glucose among Patients with Insomnia Compared with Good Sleepers.

STUDY OBJECTIVES: The neurobiological mechanisms of insomnia may involve altered patterns of activation across sleep-wake states in brain regions associated with cognition, self-referential processes, affect, and sleep-wake promotion. The objective of this study was to compare relative regional cerebral metabolic rate for glucose (rCMRglc) in these brain regions across wake and nonrapid eye movement (NREM) sleep states in patients with primary insomnia (PI) and good sleeper controls (GS). METHODS: Participants included 44 PI and 40 GS matched for age (mean = 37 y old, range 21-60), sex, and race. We conducted [18F]fluoro-2-deoxy-D-glucose positron emission tomography scans in PI and GS during both morning wakefulness and NREM sleep at night. Repeated measures analysis of variance was used to test for group (PI vs. GS) by state (wake vs. NREM sleep) interactions in relative rCMRglc. RESULTS: Significant group-by-state interactions in relative rCMRglc were found in the precuneus/posterior cingulate cortex, left middle frontal gyrus, left inferior/superior parietal lobules, left lingual/fusiform/occipital gyri, and right lingual gyrus. All clusters were significant at Pcorrected < 0.05. CONCLUSIONS: Insomnia was characterized by regional alterations in relative glucose metabolism across NREM sleep and wakefulness. Significant group-by-state interactions in relative rCMRglc suggest that insomnia is associated with impaired disengagement of brain regions involved in cognition (left frontoparietal), self-referential processes (precuneus/posterior cingulate), and affect (left middle frontal, fusiform/lingual gyri) during NREM sleep, or alternatively, to impaired engagement of these regions during wakefulness.

Bedtime Variability and Metabolic Health in Midlife Women: The SWAN Sleep Study.

STUDY OBJECTIVES: Circadian misalignment, as seen in shift workers, can disrupt metabolic processes. Associations between sleep timing in nonshift workers and metabolic health are unknown. We examined sleep timing and indices of metabolic health in a community sample of midlife women. METHODS: Caucasian (n = 161), African American (n = 121) and Chinese (n = 56) non-shift-working women aged 48-58 y who were not taking insulin-related medications, participated in the Study of Women's Health Across the Nation (SWAN) Sleep Study and were subsequently examined approximately 5.39 (standard deviation = 0.71) y later. Daily diary-reported bedtimes were used to calculate four measures of sleep timing: mean bedtime, bedtime variability, bedtime delay and bedtime advance. Body mass index (BMI) and insulin resistance (homeostatic model assessment-insulin resistance, HOMA-IR) were measured at two time points. Linear regressions evaluated whether sleep timing was associated with BMI and HOMA-IR cross-sectionally and prospectively. RESULTS: In cross-sectional models, greater variability in bedtime and greater bedtime delay were associated with higher HOMA-IR (ß = 0.128; P = 0.007, and ß = 0.110; P = 0.013, respectively) and greater bedtime advance was associated with higher BMI (ß = 0.095; P = 0.047). Prospectively, greater bedtime delay predicted increased HOMA-IR at Time 2 (ß = 0.152; P = 0.003). Results were partially explained by shifted sleep timing on weekends. CONCLUSION: Frequent shifts in sleep timing may be related to metabolic health among non-shift working midlife women. COMMENTARY: A commentary on this article appears in this issue on page 269.

Sleep Concordance in Couples is Associated with Relationship Characteristics.

STUDY OBJECTIVES: Coregulation of biological systems is a defining feature of normative attachment in close adult relationships. Sleep is a shared, intimate biological process between couples; however, sleep is usually examined at the individual level. We examined minute-by-minute concordance in couples' actigraphy-defined sleep-wake patterns, and how attachment style and marital satisfaction relate to concordance. DESIGN: Couples completed measures of avoidant and anxious attachment styles and relationship functioning and wore wrist actigraphs for 10 days. Minute-by-minute concordance of sleep and wake (i.e., the percentage of epochs in which both partners were asleep, or both were awake) was calculated for each sleep period. Mixed modeling was used to account for measurement occasions across time. RESULTS: Percent concordance ranged from 53-88% and was not associated with couples' sleep quality or circadian preference. For wives, neither anxious nor avoidant attachment was associated with sleep-wake concordance. For husbands, anxious attachment style was associated with higher concordance, but was moderated by wives' marital satisfaction. High marital satisfaction in wives was associated with higher concordance, regardless of husbands' attachment style. In couples in which wives reported low satisfaction, concordance was higher when husbands had an anxious attachment style. Avoidant attachment style in husbands was not related to concordance. CONCLUSIONS: Sleep concordance provides a unique measure of couples' cosleep and varies depending on attachment style and relationship satisfaction.

Pentavalent antimonial nephrotoxicity in the rat.

Aspects of the renal function were assessed in rats treated with the pentavalent antimonials Glucantime (Meglumine Antimoniate, Rhodia) or Pentostam (Sodium Stibogluconate, Wellcome). In dose of 30 mg of Sbv (Glucantime or Pentostam) by 100 mg of weight by day for 30 days, renal functional changes were observed consisting of disturbances in urine concentrating capacity. Such disturbances were expressed by significantly low values of urine osmolality as compared to the basal values previous to the drugs. The decrease in urine osmolality was associated to a significant increase in urinary flow and in negative free-water clearance. There was no alteration in osmolar clearance and in fractional excretion of sodium. These observations suggest an interference of the drugs in the action of the antidiuretic hormone. The disturbance in urine concentration was reversible after a seven days period without the drugs administration. No significant histopathological alterations were observed in the kidneys of the rats treated with the drugs. On the other hand, the rats treated with a high dose of Pentostam (200 mg/100 grams of weight/day) showed the functional and the histopathological alterations of the acute tubular necrosis.

Toxoplasma gondii and Coxiella burneti antibodies among Brazilian slaughterhouse employees.

Previous studies have indicated toxoplasmosis and Q fever are potential hazards to persons who handle raw meat or who work in slaughterhouses. The prevalence of antibodies to T. gondii and C. burneti was studied among 144 employees of an abattoir in Belo Horizonte, Brazil, to determine what environmental factors may be associated with the occurrence of these agents among persons who handle meat but who have not reported having toxoplasmosis or Q fever. Seventy-two per cent of the 144 employees were serologically positive to T. gondii and 29% were serologically positive for C. burneti. The highest prevalence of antibodies to T. gondii (92%) occurred among meat inspectors, who also had a geometric mean titer (GMT) of 1400. The prevalence levels of antibodies to T. gondii for employees who handled meat in the deboning and sausage departments were 80% and 79% with GMT's of 412 and 340, respectively. These levels exceeded the antibody prevalences of 60% and 65% and GMT's of 168 and 120 for employees who worked with cattle in the corrals or who worked on the killing floor, respectively. Conversely, the prevalence of antibodies to C. burneti was highest (40%) among employees working in the corrals and who were exposed to dust and hides. A similar prevalence of antibodies to C. burneti was found in employees on the killing floor (36% positive) who were exposed to hides and viscera, but employees handling meat in the deboning or sausage section had prevalence levels of 20% and 14% respectively. Serologic testing of zebu cattle processed at the abattoir indicated that 10% of 124 tested had antibodies to T. gondii and 29% of 156 tested had antibodies to C. burneti. These levels in cattle are probably adequate to expose (and infect) persons who process meat daily. Continuous daily exposures to chronically infected cattle may result in sporadic undiagnosed illnesses or seroconversions from subclinical infections.