Latency Maintenance Research Articles

MiR-190 is upregulated in Epstein–Barr Virus type I latency and modulates cellular mRNAs involved in cell survival and viral reactivation

Epstein–Barr Virus (EBV) is a prevalent human pathogen infecting over 90% of the population. Much of the success of the virus is attributed to its ability to maintain latency. The detailed mechanisms underlying the establishment and maintenance of EBV latency remain poorly understood. A microRNA profiling study revealed differential expression of many cellular miRNAs between types I and III latency cells, suggesting cellular miRNAs may play roles in regulating EBV latency. mir-190 is the most differentially up-regulated miRNA in type I latency cells as compared with type III latency cells and the up-regulation appears to be attributed to EBER RNAs that express in higher levels in type I latency cells than type III cells. With the aide of a lentiviral overexpression system and microarray analysis, several cellular mRNAs are identified as potential targets of mir-190. By targeting TP53INP1, miR-190 enhances cell survival by preventing apoptosis and relieving G0/G1 cell cycle arrest. Additionally, miR-190 down-regulates NR4A3, a cellular immediate-early gene for EBV reactivation, and inhibits the expression of the viral immediate-early gene bzlf1 and viral lytic DNA replication. Taken together, our data revealed a mechanism that EBV utilizes a cellular microRNA to promote host cell survival and prevent virus from entering lytic life cycle for latency maintenance.

MicroRNA miR-BART20-5p Stabilizes Epstein-Barr Virus Latency by Directly Targeting BZLF1 and BRLF1

Epstein-Barr virus (EBV) is a human herpesvirus associated with various tumors. Rather than going through the lytic cycle, EBV maintains latency by limiting the expression of viral genes in tumors. Viral microRNAs (miRNAs) of some herpesviruses have been reported to directly target immediate early genes and suppress lytic induction. In this study, we investigated whether BamHI-A rightward transcript (BART) miRNAs targeted two EBV immediate early genes, BZLF1 and BRLF1. Bioinformatic analysis predicted that 12 different BART miRNAs would target BRLF1. Of these, the results of a luciferase reporter assay indicated that only one interacted with the 3' untranslated region (UTR) of BRLF1: miR-BART20-5p. miR-BART20-5p's effect on gene expression involved two putative seed match sites in the BRLF1 3' UTR, but a mutant version of the miRNA, miR-BART20-5pm, had no effect on expression. As expected from the fact that the entire 3' UTR of BZLF1 resides within the 3' UTR of BRLF1, miR-BART20-5p interacted with the 3' UTR of BZLF1 as well. BZLF1 and BRLF1 mRNA and protein expression was suppressed in cells of an AGS cell line infected with the recombinant Akata strain of EBV (AGS-EBV) transfected with a miR-BART20-5p mimic. The expression of various EBV early proteins was also suppressed by the miR-BART20-5p mimic. In contrast, BZLF1 and BRLF1 expression in AGS-EBV cells transfected with a miR-BART20-5p inhibitor was enhanced. Furthermore, progeny virus production was suppressed by the miR-BART20-5p mimic and enhanced by the miR-BART20-5p inhibitor in AGS-EBV cells induced for the lytic cycle. Our data suggest that miR-BART20-5p plays a key role in latency maintenance in EBV-associated tumors by directly targeting immediate early genes. Herpesviruses maintain latency using various mechanisms and establish lifelong infection in the host. From time to time, herpesviruses are reactivated and express immediate early genes which trigger a lytic cascade, leading to the production of progeny viruses. Recently, some herpesviruses have been shown to use their own microRNAs (miRNAs) to downregulate immediate early genes to inhibit the lytic cycle. This study presents evidence that EBV also downregulates two immediate early genes by miR-BART20-5p to suppress the lytic cycle and progeny virus production. Overall, this is the first study to report the direct regulation of EBV immediate early genes by an EBV miRNA, implying its likely importance in latency maintenance in EBV-associated tumors.

Ovine herpesvirus-2-encoded microRNAs target virus genes involved in virus latency

Herpesviruses encode microRNAs (miRNAs) that target both virus and host genes; however, their role in herpesvirus biology is understood poorly. We identified previously eight miRNAs encoded by ovine herpesvirus-2 (OvHV-2), the causative agent of malignant catarrhal fever (MCF), and have now investigated the role of these miRNAs in regulating expression of OvHV-2 genes that play important roles in virus biology. ORF20 (cell cycle inhibition), ORF50 (reactivation) and ORF73 (latency maintenance) each contain predicted targets for several OvHV-2 miRNAs. Co-transfection of miRNA mimics with luciferase reporter constructs containing the predicted targets showed the 5' UTRs of ORF20 and ORF73 contain functional targets for ovhv-miR-2 and ovhv2-miR-8, respectively, and the 3' UTR of ORF50 contains a functional target for ovhv2-miR-5. Transfection of BJ1035 cells (an OvHV-2-infected bovine T-cell line) with the relevant miRNA mimic resulted in a significant decrease in ORF50 and a smaller but non-significant decrease in ORF20. However, we were unable to demonstrate a decrease in ORF73. MCF is a disease of dysregulated lymphocyte proliferation; miRNA inhibition of ORF20 expression may play a role in this aberrant lymphocyte proliferation. The proteins encoded by ORF50 and ORF73 play opposing roles in latency. It has been hypothesized that miRNA-induced inhibition of virus genes acts to ensure that fluctuations in virus mRNA levels do not result in reactivation under conditions that are unfavourable for viral replication and our data supported this hypothesis.

RNA families in Epstein–Barr virus

Epstein–Barr virus (EBV) is a tumorigenic human γ-herpesvirus, which produces several known structured RNAs with functional importance: two are implicated in latency maintenance and tumorigenic phenotypes, EBER1 and EBER2; a viral small nucleolar RNA (v-snoRNA1) that may generate a small regulatory RNA; and an internal ribosomal entry site in the EBNA1 mRNA. A recent bioinformatics and RNA-Seq study of EBV identified two novel EBV non-coding (nc)RNAs with evolutionary conservation in lymphocryptoviruses and likely functional importance. Both RNAs are transcribed from a repetitive region of the EBV genome (the W repeats) during a highly oncogenic type of viral latency. One novel ncRNA can form a massive (586 nt) hairpin, while the other RNA is generated from a short (81 nt) intron and is found in high abundance in EBV-infected cells.

Architecture and function of metallopeptidase catalytic domains

The cleavage of peptide bonds by metallopeptidases (MPs) is essential for life. These ubiquitous enzymes participate in all major physiological processes, and so their deregulation leads to diseases ranging from cancer and metastasis, inflammation, and microbial infection to neurological insults and cardiovascular disorders. MPs cleave their substrates without a covalent intermediate in a single-step reaction involving a solvent molecule, a general base/acid, and a mono- or dinuclear catalytic metal site. Most monometallic MPs comprise a short metal-binding motif (HEXXH), which includes two metal-binding histidines and a general base/acid glutamate, and they are grouped into the zincin tribe of MPs. The latter divides mainly into the gluzincin and metzincin clans. Metzincins consist of globular ∼ 130-270-residue catalytic domains, which are usually preceded by N-terminal pro-segments, typically required for folding and latency maintenance. The catalytic domains are often followed by C-terminal domains for substrate recognition and other protein-protein interactions, anchoring to membranes, oligomerization, and compartmentalization. Metzincin catalytic domains consist of a structurally conserved N-terminal subdomain spanning a five-stranded β-sheet, a backing helix, and an active-site helix. The latter contains most of the metal-binding motif, which is here characteristically extended to HEXXHXXGXX(H,D). Downstream C-terminal subdomains are generally shorter, differ more among metzincins, and mainly share a conserved loop--the Met-turn--and a C-terminal helix. The accumulated structural data from more than 300 deposited structures of the 12 currently characterized metzincin families reviewed here provide detailed knowledge of the molecular features of their catalytic domains, help in our understanding of their working mechanisms, and form the basis for the design of novel drugs.

Kaposi's Sarcoma-Associated Herpesvirus-Positive Primary Effusion Lymphoma Tumor Formation in NOD/SCID Mice Is Inhibited by Neomycin and Neamine Blocking Angiogenin's Nuclear Translocation

Angiogenin (ANG) is a 14-kDa multifunctional proangiogenic secreted protein whose expression level correlates with the aggressiveness of several tumors. We observed increased ANG expression and secretion in endothelial cells during de novo infection with Kaposi's sarcoma-associated herpesvirus (KSHV), in cells expressing only latency-associated nuclear antigen 1 (LANA-1) protein, and in KSHV latently infected primary effusion lymphoma (PEL) BCBL-1 and BC-3 cells. Inhibition of phospholipase Cγ (PLCγ) mediated ANG's nuclear translocation by neomycin, an aminoglycoside antibiotic (not G418-neomicin), resulted in reduced KSHV latent gene expression, increased lytic gene expression, and increased cell death of KSHV(+) PEL and endothelial cells. ANG detection in significant levels in KS and PEL lesions highlights its importance in KSHV pathogenesis. To assess the in vivo antitumor activity of neomycin and neamine (a nontoxic derivative of neomycin), BCBL-1 cells were injected intraperitoneally into NOD/SCID mice. We observed significant extended survival of mice treated with neomycin or neamine. Markers of lymphoma establishment, such as increases in animal body weight, spleen size, tumor cell spleen infiltration, and ascites volume, were observed in nontreated animals and were significantly diminished by neomycin or neamine treatments. A significant decrease in LANA-1 expression, an increase in lytic gene expression, and an increase in cleaved caspase-3 were also observed in neomycin- or neamine-treated animal ascitic cells. These studies demonstrated that ANG played an essential role in KSHV latency maintenance and BCBL-1 cell survival in vivo, and targeting ANG function by neomycin/neamine to induce the apoptosis of cells latently infected with KSHV is an attractive therapeutic strategy against KSHV-associated malignancies.

A Novel Family of Soluble Minimal Scaffolds Provides Structural Insight into the Catalytic Domains of Integral Membrane Metallopeptidases

In the search for structural models of integral-membrane metallopeptidases (MPs), we discovered three related proteins from thermophilic prokaryotes, which we grouped into a novel family called "minigluzincins." We determined the crystal structures of the zymogens of two of these (Pyrococcus abyssi proabylysin and Methanocaldococcus jannaschii projannalysin), which are soluble and, with ∼100 residues, constitute the shortest structurally characterized MPs to date. Despite relevant sequence and structural similarity, the structures revealed two unique mechanisms of latency maintenance through the C-terminal segments previously unseen in MPs as follows: intramolecular, through an extended tail, in proabylysin, and crosswise intermolecular, through a helix swap, in projannalysin. In addition, structural and sequence comparisons revealed large similarity with MPs of the gluzincin tribe such as thermolysin, leukotriene A4 hydrolase relatives, and cowrins. Noteworthy, gluzincins mostly contain a glutamate as third characteristic zinc ligand, whereas minigluzincins have a histidine. Sequence and structural similarity further allowed us to ascertain that minigluzincins are very similar to the catalytic domains of integral membrane MPs of the MEROPS database families M48 and M56, such as FACE1, HtpX, Oma1, and BlaR1/MecR1, which are provided with trans-membrane helices flanking or inserted into a minigluzincin-like catalytic domain. In a time where structural biochemistry of integral-membrane proteins in general still faces formidable challenges, the minigluzincin soluble minimal scaffold may contribute to our understanding of the working mechanisms of these membrane MPs and to the design of novel inhibitors through structure-aided rational drug design approaches.

A randomized placebo-controlled polysomnographic study of eszopiclone in Japanese patients with primary insomnia

To evaluate the efficacy and dose-response effect of eszopiclone on sleep latency and sleep maintenance in Japanese patients with primary insomnia. In this randomized, double-blind, five-way crossover study, 72 patients received placebo, eszopiclone 1mg, 2mg, and 3mg, and zolpidem 10mg in random order for two consecutive nights with a washout period between treatments. Objective sleep measures from polysomnography (PSG) and subjective patient reports were collected. All active treatments produced significant improvement in objective and subjective sleep latency compared with placebo (P<0.05 for all comparisons); linear dose-response relationships were observed for eszopiclone. PSG-determined wake time after sleep onset (WASO), sleep efficiency, and number of awakenings (NA), and patient-reported measures of WASO, NA, sleep quality, sleep depth, and daytime functioning significantly improved following treatment with eszopiclone 2mg and 3mg and zolpidem 10mg versus placebo (P<0.05). Eszopiclone at all doses increased total sleep time and stage 2 sleep time (P<0.001 for both comparisons), but did not alter REM or slow-wave sleep. Eszopiclone was generally well tolerated; the most frequently reported adverse event was mild dysgeusia. In Japanese patients with primary insomnia, eszopiclone 2mg and 3mg significantly improved PSG-determined and patient-reported sleep latency and sleep maintenance relative to placebo.

The single RBP-Jkappa site within the LANA promoter is crucial for establishing Kaposi's sarcoma-associated herpesvirus latency during primary infection.

Kaposi's sarcoma-associated herpesvirus (KSHV; or human herpesvirus 8 [HHV8]) is implicated in the pathogenesis of many human malignancies including Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). KSHV infection displays two alternative life cycles, referred to as the latent and lytic or productive cycle. Previously, we have reported that the replication and transcription activator (RTA), a major lytic cycle transactivator, contributes to the development of KSHV latency by inducing latency-associated nuclear antigen (LANA) expression during early stages of infection by targeting RBP-Jκ, the master regulator of the Notch signaling pathway. Here, we generated a bacterial artificial chromosome (BAC) KSHV recombinant virus with a deletion of the RBP-Jκ site within the LANA promoter to evaluate the function of the RBP-Jκ cognate site in establishing primary latent infection. The results showed that genetic disruption of the RBP-Jκ binding site within the KSHV LANA promoter led to enhanced expression of the KSHV-encoded immediate early RTA, resulting in an increase in lytic replication during primary infection of human peripheral blood mononuclear cells (PBMCs). This system provides a powerful tool for use in indentifying additional cellular and viral molecules involved in LANA-mediated latency maintenance during the early stages of KSHV infection.

Nonrestorative Sleep: Have We Finally Found It?

Nonrestorative Sleep: Have We Finally Found It?

Automatic slow eye movement (SEM) detection of sleep onset in patients with obstructive sleep apnea syndrome (OSAS): Comparison between multiple sleep latency test (MSLT) and maintenance of wakefulness test (MWT)

Objective To determine whether automatic slow eye movement (SEM) analysis performs comparably to standard sleep onset criteria at the multiple sleep latency test (MSLT) and at the maintenance of wakefulness test (MWT) in patients with obstructive sleep apnea syndrome (OSAS). Methods We compared sleep latencies obtained upon standard analysis of MSLT and MWT recordings with automatically detected SEM latencies in a population of 20 severe OSAS patients that randomly underwent the two tests 1 week apart. Results Eight of 20 OSAS patients had EDS as answered by the Epworth Sleepiness Scale (ESS). Mean SEM latency performed comparably to standard sleep onset in both the MSLT (6.4 ± 5.5 min versus 7.4 ± 5.1 min, p = 0.25) and the MWT (25.2 ± 14.5 min versus 24.4 ± 14.0 min, p = 0.45) settings. Mean SEM latency significantly correlated with the sleep latency at the MSLT ( r = 0.52, p < 0.05) and at the MWT ( r = 0.74, p < 0.001). Finally, the Epworth Sleepiness Scale score correlated with SEM latency at the MWT ( r = −0.62, p < 0.01), but not at the MSLT. Conclusions Automatic SEM detection performed comparably to standard polysomnographic assessment of sleep onset, thus providing a simplified technical requirement for the MSLT and the MWT. Further studies are warranted to evaluate SEM detection of sleep onset in other sleep disorders with excessive daytime sleepiness.

Catalytic Domain Architecture of Metzincin Metalloproteases

Metalloproteases cleave proteins and peptides, and deregulation of their function leads to pathology. An understanding of their structure and mechanisms of action is necessary to the development of strategies for their regulation. Among metallopeptidases are the metzincins, which are mostly multidomain proteins with approximately 130-260-residue globular catalytic domains showing a common core architecture characterized by a long zinc-binding consensus motif, HEXXHXXGXX(H/D), and a methionine-containing Met-turn. Metzincins participate in unspecific protein degradation such as digestion of intake proteins and tissue development, maintenance, and remodeling, but they are also involved in highly specific cleavage events to activate or inactivate themselves or other (pro)enzymes and bioactive peptides. Metzincins are subdivided into families, and seven such families have been analyzed at the structural level: the astacins, ADAMs/adamalysins/reprolysins, serralysins, matrix metalloproteinases, snapalysins, leishmanolysins, and pappalysins. These families are reviewed from a structural point of view.

The role of eszopiclone in the treatment of insomnia

Insomnia is a common and underdiagnosed condition that can result in significant economic and clinical consequences. Despite numerous behavioral and pharmacotherapeutic treatment options available for insomnia, few receive adequate treatment, and sleep maintenance (staying asleep) remains a significant problem. To date, available sedative-hypnotic agents have limitations that have lead to inadequate treatment of insomnia. This review provides an overview of eszopiclone and its role in the treatment of insomnia. Electronic databases (MEDLINE, EMBASE, International Pharmaceutical Abstracts) were searched for applicable primary literature and review articles. Mechanisms of action at the gamma-amino butyric acid (GABA) receptor sites and pharmacologic and pharmacokinetic characteristics are presented. Eszopiclone, a nonbenzodiazepine S-enantiomer of racemic zopiclone, is highlighted as the first sedative-hypnotic agent to be approved by the United States Food and Drug Administration for the treatment of sleep onset latency and sleep maintenance insomnia with no short-term restrictions. Recently, the European Medicines Agency recommended marketing authorization of eszopiclone. Eszopiclone has been shown to be an efficacious and cost-effective option for the treatment of transient and chronic insomnia in adults.

Determinants of the Establishment of Human Immunodeficiency Virus Type 1 Latency

Recent research has emphasized the notion that human immunodeficiency virus type 1 (HIV-1) latency is controlled by a restrictive histone code at, or DNA methylation of, the integrated viral promoter (long terminal repeat [LTR]). The present concept of HIV-1 latency has essentially been patterned from the principles of cellular gene regulation. Here we introduce an experimental system that allows for the qualitative and quantitative kinetic study of latency establishment and maintenance at the population level. In this system, we find no evidence that HIV-1 latency establishment is the consequence of downregulation of initial active infection followed by the establishment of a restrictive histone code at the viral LTR. Latent infection was established following integration of the virus in the absence of viral gene expression (silent integration) and was a function of the NF-kappaB activation level in the host cell at the time of infection. In the absence of a role for epigenetic regulation, we demonstrate that transcriptional interference, a mechanism that has recently been suggested to add to the stabilization of HIV-1 latency, is the primary mechanism to govern latency maintenance. These findings provide direct experimental evidence that the high number of viral integration events (>90%) found in actively expressed genes of CD4(+) memory T cells from highly active antiretroviral therapy-suppressed patients represent indeed latent infection events and that transcriptional interference may be the primary mechanism to control HIV-1 latency in vivo. HIV-1 latency may thus not be governed by the principles of cellular gene regulation, and therapeutic strategies to deplete the pool of latently HIV-1-infected cells should be reconsidered.

Klinische Aspekte der Narkolepsie

The main clinical features of narcolepsy are excessive daytime sleepiness (EDS) and cataplexy. Facultative symptoms are REM sleep-associated sleep paralysis, automatic movements and hypnagogic hallucinations. However, cataplexy characterised by the sudden loss of muscle tone is classified as a REM-sleep symptom. The clinical diagnosis is based on polysomnographic recording of night-time sleep, multiple sleep latency test and maintenance of wakefulness test. Laboratory findings includes specific HLA alleles and decreased level of hypocretin in the cerebrospinal fluid. Therapeutic options are individualised based on the leading symptoms. Stimulants are used to reduce excessive daytime sleepiness while antidepressants are mainly used to treat cataplexy. Gamma-hydroxybutyric acid improves cataplexy but influences also other symptoms. New therapeutic options will be based on the growing knowledge about the biological function of hypocretin.

Multiple Sleep Latency Test and Maintenance of Wakefulness Test

Excessive daytime sleepiness and fatigue are common complaints in the sleep clinic. The objective evaluation and quantification of these symptoms is important for both the diagnosis of underlying health problems and for gauging treatment response. The multiple sleep latency test measures physiologic sleepiness, whereas the maintenance of wakefulness test (MWT) aims to measure manifest sleepiness. Neither test correlates well with subjective measures of sleep such as the Epworth sleepiness scale and the Stanford sleepiness scale. Although in the past methodological testing differences existed, in 2005 updated practice parameters were published, promoting the standardization of testing procedures. In recent years, there has been an effort to document daytime sleepiness when associated with occupational risk. However, these laboratory-based tests may not reflect or predict real-life experience. Normative data for both tests, particularly the MWT, are limited, and are inadequate for the evaluation of pediatric patients, shift workers, and others.

No persistent effect of intravenous immunoglobulins in patients with narcolepsy with cataplexy

We report on four patients with narcolepsy with cataplexy (NC), who were treated with high-dose intravenous immunoglobulins (IVIg). Although in some patients transient effects were seen of both objective (multiple sleep latency test and maintenance of wakefulness test) and subjective symptoms (Epworth Sleepiness Scale and frequency of cataplexy), these effects lasted at the most for a few weeks and did not persist. Our report challenges the recent observations of a favorable and persistent effect of IVIg in NC patients.

P.8.a.020 A valproate-induced encephalopathy without hyperammonemia but with triphasic waves and myoclonus

To evaluate the efficacy and dose–response effect of eszopiclone on sleep latency and sleep maintenance in Japanese patients with primary insomnia.In this randomized, double-blind, five-way crossover study, 72 patients received placebo, eszopiclone 1 mg, 2 mg, and 3 mg, and zolpidem 10 mg in random order for two consecutive nights with a washout period between treatments. Objective sleep measures from polysomnography (PSG) and subjective patient reports were collected.All active treatments produced significant improvement in objective and subjective sleep latency compared with placebo (P < 0.05 for all comparisons); linear dose–response relationships were observed for eszopiclone. PSG-determined wake time after sleep onset (WASO), sleep efficiency, and number of awakenings (NA), and patient-reported measures of WASO, NA, sleep quality, sleep depth, and daytime functioning significantly improved following treatment with eszopiclone 2 mg and 3 mg and zolpidem 10 mg versus placebo (P < 0.05). Eszopiclone at all doses increased total sleep time and stage 2 sleep time (P < 0.001 for both comparisons), but did not alter REM or slow-wave sleep. Eszopiclone was generally well tolerated; the most frequently reported adverse event was mild dysgeusia.In Japanese patients with primary insomnia, eszopiclone 2 mg and 3 mg significantly improved PSG-determined and patient-reported sleep latency and sleep maintenance relative to placebo.

Social system theory as a 'knitting' of structural functionalism: A contribution to the new parsons interpretation

Topic of the article is problem how to understand Parsons’ theory of the social system properly as a product of structural functionalism. In other words question amounts to the method of theory building and thus on the role of main Parsons pattern variables elaborated in the works of Carnegy Project: The Social System (1951), Values, Motives and Structure of Action (1951), and Working Papers in the Theory of Action (1953). Author is about to maintain that crucial conceptual clusters as a basis of Parsons theory building are: under the rubric of theory of action: four pattern variables - universalism-particularism, affectivity-neutrality, performance- quality, specificity-diffuseness; under the rubric of system theory: AGIL scheme - namely adaptation, goal-attainment, integration, and latency or pattern maintenance. Conceptual row needed for synthesis of both is provided with: value-rolenorm- collectivity, along the three general problem of any system: structure and inner dynamic, change and hierarchy and control. Its synthesis is demonstrated on the all three levels of personality system, social system and system of culture. Thus is shortly demonstrated how is possible, on strikingly systematic way to build whole conceptual scheme or Parsons’ system theory. Within this demonstration special attention has been paid to the methodological sense of four pattern variables. Originality of the given interpretation of Parsons is demonstrated: 1) by showing of the methodological role of pattern variables in the theory building; 2) by showing the connection between these variables and four ideal types of action in Max Weber. Thus follows that four variables are very core of Parsons theory of action, and this is demonstrated by the elaborated parallelism between Weber’s and Parsons’ concepts. This insight affords the argument that Parsons theory of action is profoundly Weberian, based on highly original reinterpretation of concepts of action and unique operationalisation on the axis Geselschaft-Gemeinschaft, or modern-premodern society. Whole theory building in The Social System and related works, Working Papers, and Values, Motives and Concept of Action, could be reconstructed as the result of knitting by two rows of categories, on the one side, pattern variables concepts, and on the other side, of AGIL concepts, along the row made of concepts value-role-norm-collectivity. These categorical rows could be conceived as a three knitting-needles for knitting of the whole Parsons’ theory. Therefore, it could be concluded that Parsons theoretical work is highly systematic, coherent and reducible to its basic and simple elements. In addition to this it provides original interpretation of components of modern differentiated society, and as a third, it presents possibility to enrich method of social science that so far was unexploited due to unsound, superficial, unattainable, and ideologically impregnate criticism.

Multiple sleep latency test and maintenance of wakefulness test.

In addition to overnight polysomnography, there are two special tests with which every sleep technologist should be familiar: the multiple sleep latency test and the maintenance of wakefulness test. These two tests classify excessive daytime sleepiness using objective data. The role of the sleep technologist is to understand and perform an accurate test so that sleep clinicians can use that data in diagnosing and treating their patients. This article provides step-by-step directions for performing these tests.