The Staging of Sleep Apneics' Sleep: A Comparison of Computerized Analysis with Human Scoring

Computerized sleep staging is maintained to be a possible replacement for human scoring of sleep and is expected to reduce substantially the sleep technologists' time and efforts in scoring sleep into stages and practically to provide paperless polysomnography. So far various computer algorithms have been developed and automatic sleep analyzing systems have been tested mainly on normal human subjects and are alleged to be substantially reliable. However, it still remains to be answered how capable the systems are of reliably diagnosing sleep disordered subjects. The author attempted to review the function of a major automatic sleep analyzer (Oxford Medilog SAC 847 system) in comparison with expert human scoring. In eleven sleep apneic patients, one full night record of nocturnal polysomnography was compared between automatic analysis and human scoring on sleep stages epoch by epoch and on overall sleep architecture including various sleep parameters. The automatic analysis produced fewer stages 1 and REM, and more stage wake. The automatic stager's major difficulty was found to be with identifying wake and REM stages correctly. In conclusion, the present state of sophistication in automatic sleep analysis remains to be tested further in clinical sleep medicine

Time-related Changes in Sleep-Wake Pattern as Correlates of Controlled Shift Work Rotating Directions

In order to elaborate the sleep-wake pattern changes manifested during controlled shift working of counterclockwise and clockwise rotations, eleven subjects were studied. A baseline sleep survey during uncontrolled shift working using a sleep questionnaire revealed that day and night shifts were found to have less total sleep time compared with evening and off duties, with delayed retire time in the evening shifts and advanced rise time in the day shifts. In analyses of data from controlled shift work schedules of opposite directions, difference in rise time appeared to be a crucial factor determining the total sleep time. This finding is compatible with the theory that rise time is one of the most powerful factors in resetting the biological clock. Retire time seemed to be determined more by the subjects' sleep habits and/or the socioenvironmental stimuli. Off-duty allocation was found to be an important variable in sleep-wake pattern modulation in shift working

The Effects of Immobilization Stress on the Synthesis and the Catabolism of Dopamine and Norepinephrine in the Rat Hypothalamus

Immobilization stress was adopted as a prototype stress model for studying the effects of stress on dopaminergic and noradrenergic neuronal activity in the rat hypothalamus. Norepinephrine content was significantly increased after 4 hours of immobilization stress. Also, the turnover rates of both dopamine and norepinephrine were found to be significantly increased after the stress, providing the evidence of increased synthesis rates of both neurotransmitters. These findings were consistent with the increase in plasma corticosterone and catecholamine levels. The activities of tyrosine hydroxylase and dopamine-j1-hydroxylase, the synthesizing enzymes for catecholamines, were significantly increased after the stress, while that of monoamine oxidase, the catabolizing enzyme, did not change to a significant degree at all. Kinetic analysis of tyrosine hydroxylase, the rate-limiting step in catecholamine biosynthesis, revealed that Vmax was significantly increased after the stress without significant change of Km. These findings suggest that dopamine and norepinephrine may playa significant role in mediating stress responses by increasing their neuronal activities

Human Heart Rhythms Synchronize While Co-sleeping

Human physiological systems have a major role in maintenance of internal stability. Previous studies have found that these systems are regulated by various types of interactions associated with physiological homeostasis. However, whether there is any interaction between these systems in different individuals is not well-understood. The aim of this research was to determine whether or not there is any interaction between the physiological systems of independent individuals in an environment where they are connected with one another. We investigated the heart rhythms of co-sleeping individuals and found evidence that in co-sleepers, not only do independent heart rhythms appear in the same relative phase for prolonged periods, but also that their occurrence has a bidirectional causal relationship. Under controlled experimental conditions, this finding may be attributed to weak cardiac vibration delivered from one individual to the other via a mechanical bed connection. Our experimental approach could help in understanding how sharing behaviors or social relationships between individuals are associated with interactions of physiological systems

Comparison of the MicroScan, VITEK 2, and Crystal GP with 16S rRNA sequencing and MicroSeq 500 v2.0 analysis for coagulase-negative Staphylococci

BACKGROUND: Three phenotypic identification systems (MicroScan, VITEK 2, and Crystal GP) were evaluated for their accuracy to identify coagulase-negative staphylococci (CNS). A total of 120 clinical isolates confirmed to be CNS via 16S rRNA sequencing and analysis with the MicroSeq 500 v2.0 database were assessed. RESULTS: The MicroScan, VITEK 2, and Crystal GP systems correctly identified 82.5%, 87.5%, and 67.5% of the isolates, respectively. Misidentification was the main problem in MicroScan (10.8%) and Crystal GP (23.3%) systems, whereas the main problem of VITEK 2 was low-level discrimination (7.5%). CONCLUSION: None of the 3 phenotypic systems tested could accurately and reliably identify CNS at the species level. Further verifications such as biochemical testing or 16S rRNA sequencing together with analysis using a comparable database might be helpful in this regard

정신과질환에서의 Dexamethasone억제검사소견에 관한 연구

83 subjects(20 normal controls, 15 neurotics, 19 major depressives and 29 paranoid schizophrenics) underwent the dexamethasone suppression test(OST) to test the applicability of the test for the diagnosis of major depression. Pre- and post-dexamethasone serum cortisol concentrations were determined in duplicate by radioimmunoassay at 8:00 a.m., 4:00 p.m. and 11:30 p.m. Significantly decreased suppressibility of serum cortisol levels were found in the major depressives at 8:00 a. m. and 4:00 p.m. in the OST and the cortisol suppression index(CSI), compared with those in the normal controls. No significant differences were found in the other comparisons. The nonsuppression rate in the major depressives was 47%. And due to the significant nonsuppression rates(14%-22%) in the other groups, the specificity of the nonsuppression in the OST needs to be further clarified before its significance is established. In the meantime, it is recommended that multiple chronological OSTs be performed during the clinical course and other intervening variables should be considered for meaningful interpretation