Spectral modulation attenuates molecular, endocrine, and neurobehavioral disruption induced by nocturnal light exposure.

The human eye serves distinctly dual roles in image forming (IF) and non-image-forming (NIF) responses when exposed to light. Whereas IF responses mediate vision, the NIF responses affect various molecular, neuroendocrine, and neurobehavioral variables. NIF responses can have acute and circadian phase-shifting effects on physiological variables. Both the acute and phase-shifting effects induced by photic stimuli demonstrate short-wavelength sensitivity peaking ≈450-480 nm. In the current study, we examined the molecular, neuroendocrine, and neurobehavioral effects of completely filtering (0% transmission) all short wavelengths <480 nm and all short wavelengths <460 nm or partially filtering (~30% transmission) <480 nm from polychromatic white light exposure between 2000 and 0800 in healthy individuals. Filtering short wavelengths <480 nm prevented nocturnal light-induced suppression of melatonin secretion, increased cortisol secretion, and disrupted peripheral clock gene expression. Furthermore, subjective alertness, mood, and errors on an objective vigilance task were significantly less impaired at 0800 by filtering wavelengths <480 nm compared with unfiltered nocturnal light exposure. These changes were not associated with significantly increased sleepiness or fatigue compared with unfiltered light exposure. The changes in molecular, endocrine, and neurobehavioral processes were not significantly improved by completely filtering <460 nm or partially filtering <480 nm compared with unfiltered nocturnal light exposure. Repeated light-dark cycle alterations as in rotating nightshifts can disrupt circadian rhythms and induce health disorders. The current data suggest that spectral modulation may provide an effective method of regulating the effects of light on physiological processes.

Altered sleep architecture and higher incidence of subsyndromal depression in low endogenous melatonin secretors.

Melatonin secretion is synchronized to the sleep/wake cycle and has been suggested to have somnogenic properties. Sleep/wake cycle disruption and alterations in the secretary pattern of melatonin is present in various psychiatric disorders. The objective of this study was to investigate the sleep architecture and the presence of depression in individuals with low endogenous melatonin levels. The study included 16 participants (mean age 30.3 +/- 14.9 years). The first night of testing included psychiatric evaluation followed by melatonin secretion profile evaluation by Dim Light Melatonin Onset test and then standard montage polysomnographic testing. On the second night, only polysomnographic testing was carried out with an imposed sleep period of 8 h. Low endogenous melatonin secretors (LEMS) showed no discernible peaks in melatonin secretion compared to normal secretors (controls). LEMS demonstrated significant alterations in rapid eye movement sleep but not in non-rapid eye movement sleep along with poor sleep initiation and quality compared to controls. 55.6% of the low melatonin secretors group presented with subsyndromal depression. Melatonin has significant bearing on sleep architecture and a lack of melatonin may desynchronize endogenous rhythms allowing subsyndromal depression to manifest.

Congenital dilated cardiomyopathy caused by biallelic mutations in Filamin C.

In the vast majority of pediatric patients with dilated cardiomyopathy, the specific etiology is unknown. Studies on families with dilated cardiomyopathy have exemplified the role of genetic factors in cardiomyopathy etiology. In this study, we applied whole-exome sequencing to members of a non-consanguineous family affected by a previously unreported congenital dilated cardiomyopathy syndrome necessitating early-onset heart transplant. Exome analysis identified compound heterozygous variants in the FLNC gene. Histological analysis of the cardiac muscle demonstrated marked sarcomeric and myofibrillar abnormalities, and immunohistochemical staining demonstrated the presence of Filamin C aggregates in cardiac myocytes. We conclude that biallelic variants in FLNC can cause congenital dilated cardiomyopathy. As the associated clinical features of affected patients are mild, and can be easily overlooked, testing for FLNC should be considered in children presenting with dilated cardiomyopathy.

Shigella bacteremia: a retrospective study.

The aims of this study were to determine the risk factors in, and the clinical and laboratory characterizations of, Shigella bacteremia, as well as the subspecies of Shigella, and the antibiotic susceptibility. A retrospective study of all patients younger than 18 years of age with documented Shigella bacteremia from January 1989 through December 2001 was conducted. Fifteen children with Shigella bacteremia were treated at our center. The mean age (+/- SD) was 20.5 months (+/- 34.2), median 7 months. Thirteen (87%) patients failed to gain weight. The mean duration of diarrhea was 14.7 days. Patients were hospitalized for a mean (+/- SD) of 13.5 days (+/- 9.2). There were no fatalities in our study sample. The vast majority (86.7%) of the Shigella isolates were flexneri. Most isolates were susceptible to ceftriaxone, ciprofloxacine, and gentamicin but resistant to ampicillin and trimethoprim/sulfamethoxazole.

The many faces of Glut1 deficiency syndrome.

Glucose transporter protein type 1 deficiency syndrome is a metabolic disorder manifesting as cognitive impairment, acquired microcephaly, epilepsy, and/or movement disorder caused by mutations in the SLC2A1 gene. We describe a cohort of isolated and familial cases of glucose transporter protein type 1 deficiency syndrome, emphasizing seizure semiology, electroencephalographic (EEG) features, treatment response and mutation pathogenicity. SLC2A1 mutations were detected in 3 sporadic and 4 familial cases. In addition, mutations were identified in 9 clinically unaffected family members in 2 families. The phenotypic spectrum of glucose transporter protein type 1 deficiency is wider than previously recognized, with considerable intra-familial variation. Diagnosis requires either hypoglycorrachia followed by SLC2A1 sequencing or direct gene sequencing. A ketogenic diet should be the first line of treatment, but more flexible diets, like the Atkins modified diet, can also be followed. Carbonic anhydrase inhibitors, such as acetazolamide or zonisamide, can be effective for seizure control.

Tryptophan for the treatment of excessive daytime sleepiness in Prader-Willi syndrome.

An 8-year old girl with Prader-Willi Syndrome presenting with excessive daytime sleepiness improved following treatment with tryptophan; possibly by consolidation of her fragmented sleep. Improvement was recorded on a follow-up sleep study, one year after initiating treatment with tryptophan. We conclude that tryptophan may be an useful medication for excessive sleepiness in children with Prader-Willi Syndrome.

Tryptophan for the Treatment of Excessive Daytime Sleepiness in Prader-Willi Syndrome.

An 8-year old girl with Prader-Willi Syndrome presenting with excessive daytime sleepiness improved following treatment with tryptophan; possibly by consolidation of her fragmented sleep. Improvement was recorded on a follow-up sleep study, one year after initiating treatment with tryptophan. We conclude that tryptophan may be an useful medication for excessive sleepiness in children with Prader-Willi Syndrome.