Hypersynchronous delta waves and somnambulism: brain topography and effect of sleep deprivation

STUDY OBJECTIVES: Hypersynchronous delta activity (HSD) is usually described as several continuous high-voltage delta waves (> or = 150 microV) in the sleep electroencephalogram of somnambulistic patients. However, studies have yielded varied and contradictory results. The goal of the present study was to evaluate HSD over different electroencephalographic derivations during the non-rapid eye movement (NREM) sleep of somnambulistic patients and controls during normal sleep and following 38 hours of sleep deprivation, as well as prior to sleepwalking episodes. DESIGN: N/A. SETTING: Sleep disorders clinic. PATIENTS: Ten adult sleepwalkers and 10 sex- and age-matched control subjects were investigated polysomnographically during a baseline night and following 38 hours of sleep deprivation. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: During normal sleep, sleepwalkers had a significantly higher ratio of HSD over the time spent in stage 2, 3 and 4 on frontal and central derivations when compared with controls. Sleep deprivation resulted in a significant increase in the ratio of the time in HSD over the time in stage 4 on the frontal lead in both groups and on the central lead in controls. There was no evidence for a temporal accumulation of HSD prior to the episodes. CONCLUSIONS: HSD shows a clear frontocentral gradient across all subjects during both baseline and recovery sleep and has relatively low specificity for the diagnosis of NREM parasomnias. Increases in HSD after sleep deprivation may reflect an enhancement of the homeostatic process underlying sleep regulation.     

Variety and intensity of emotions in nightmares and bad dreams

Nightmares are usually defined as frightening dreams that awaken the sleeper. This study uses the waking criterion to distinguish between nightmares and bad dreams and investigated the variety and intensity of emotions reported in each form of disturbing dream. Ninety participants recorded their dreams for 4 consecutive weeks and, for each dream recalled, noted the emotions present and their intensities on a 9-point scale. Thirty-six participants reported at least one nightmare and one bad dream over the 4 weeks covered by the log, while 29 reported having had at least one bad dream but no nightmares. Nightmares were rated as being significantly (p < 0.001) more intense than bad dreams. Thirty percent of nightmares and 51% of bad dreams contained primary emotions other than fear. The findings support the claim that awakening can serve as an indirect measure of nightmare intensity and raise important implications for the operational definition of nightmares.     

Genetically modified dendritic cells prime autoreactive T cells through a pathway independent of CD40L and interleukin 12: implications for cancer vaccines

Genetic immunization through ex vivo transduction of dendritic cells has been suggested as an effective approach to enhance antitumor immunity by activating both CD4+ and CD8+ T cells. Immunizing mice with dendritic cells transduced with an adenovirus expressing the human melanoma antigen glycoprotein 100 (DCAdhgp100) as a cancer vaccine, we demonstrated complete protective immunity and a potent CTL response against melanomas expressing murine glycoprotein 100 in a CD4+ cell-dependent manner. Surprisingly, however, effective tumor rejection was not the result of cooperation between CD4+ and CD8+ T cells. Protective immunity was completely lost when CD4+ cells were depleted immediately before tumor challenge, whereas it was unaffected by removal of CD8+ cells, establishing a principal role for CD4+ cells in the effector phase of tumor rejection. Neither protective immunity nor CTL generation in this model required interleukin 12, in spite of high levels of IFN-gamma secretion by tumor-reactive T cells. Most notably, the DCAdhgp100 vaccine could elicit protective antitumor CD4+ cells in the absence of CD40 ligand, although it does not bypass the need for CD40-mediated signals to generate melanoma-reactive CTLs. Thus, in contrast to the current thinking that the optimal cancer vaccine should include determinants for both CD4+ and CD8+ cells, the potency of the DCAdhgp100 vaccine appears to be a result of its ability to directly prime autoreactive CD4+ cells through a process that does not require interleukin 12 and CD40 signals.     

A Caenorhabditis elegans model of the myosin heavy chain IIa E706K [corrected] mutation

Mutations in myosin heavy chain (MyHC) genes recently have been shown to be associated with various forms of congenital myopathies: myosin myopathies. The MyHC IIa E706K mutation is associated with congenital joint contractures, early-onset muscle weakness, and progressive course with moderate to severe muscle weakness later in life. To study the pathogenicity of this MyHC mutation, we investigated the effect of the corresponding mutation (E710K) in the major MyHC isoform (MyHC B) of the body wall muscle of the nematode Caenorhabditis elegans. Worms with null mutations in the MyHC B gene (unc-54) are severely paralyzed and depleted of thick filaments in the body wall muscle sarcomeres. unc-54 null mutants with extrachromosomal arrays of a gene construct including the entire wild-type unc-54 gene were partially rescued as determined by a motility assay and by morphological analysis of the body wall muscle. Analysis of unc-54 null mutants with extrachromosomal arrays of the unc-54 gene with the E710K mutation were severely paralyzed but showed formation of thick filaments in the body wall muscle. We conclude that the MyHC E706K (E710K in C. elegans) mutation is pathogenic and that the effect is primarily functional rather than structural because thick filaments are formed. The C. elegans model may be useful to study suspected pathogenic mutations in MyHC genes associated with human muscle diseases.     

A public health intervention at the time of a case of rabies in Quebec

BACKGROUND: In the fall of 2000, a nine-year-old child living in Montreal (Québec) died of rabies encephalitis. Cases of human rabies had not been reported in Canada for 15 years. The molecular characterization of viral nucleic acid implicated the Ln/Ps variant associated with the silver-haired bat and the eastern pipistrelle. This article describes and analyzes the intervention carried out by public health. INTERVENTION AND DISCUSSION: The investigation revealed that contact with the bat must have occurred while the child was sleeping. Following the search for close contacts of the reference case, rabies postexposure prophylaxis (RPEP) was recommended to 59 people (3 household contacts, 12 playmates and 44 health care workers). Discussion with other public health departments in the province was important because of the media coverage of this case, which led to a considerable increase in the number of reported exposures to bats and in RPEP administration. CONCLUSION: Lessons learned from this event are that rapid and coordinated action with all stakeholders is essential to the success of this type of public health intervention and that the population must be informed of the risk of rabies transmission from bats.     

Role of dopamine D3 receptors in thermoregulation: a reappraisal

Dopamine agonist-induced hypothermia has been proposed to be mediated by the D3 receptor (D3R), as it is elicited by (+)7-OH-DPAT and antagonized by S 14297, two putative D3R-preferential ligands. Here we show, however, that S 14297 is a full and partial agonist at D3R and D2R, respectively. Hypothermia was induced in rats by agonists with potencies correlated with their D3R and D2R functional potencies, and was reversed by antagonists, with a rank order of potency typical of the D2R. Moreover, BP 897, a highly potent and selective but partial D3R agonist was inactive in producing hypothermia or reversing (+)7-OH-DPAT-induced hypothermia. (+)7-OH-DPAT was as potent and efficient in inducing hypothermia in wild-type as in D3R-deficient mice. Hence, our results suggest that hypothermia does not result from a selective stimulation of the D3R.     

Quantitative measurement of anti-ErbB-2 antibody by flow cytometry and ELISA.

To establish standard methods for measuring anti-ErbB-2 antibody, a flow cytometric and an enzyme-linked immunosorbent assay (ELISA) were developed and compared. In the flow cytometric assay, the antibody was measured by binding to human breast cancer cell line SKBR3 and the result expressed as mean channel fluorescence (MCF). In ELISA, the antibody was measured by binding to a recombinant, secreted human ErbB-2 containing the N-terminal 505 amino acids of ErbB-2 fused to myc and His tags (secE2/myc/His or secE2) and the result expressed as O.D.(405). A mouse anti-human ErbB-2 mAb 9G6 was used as the standard. Using flow cytometry, MCF of 9G6 binding increased with linearity between 0.6 and 10 microg/ml. Using ELISA, O.D.(405) increased with linearity between 0.015 and 1 microg/ml, indicating greater sensitivity of ELISA. The titer of an immune mouse serum was determined to be 400 and 8000 with flow cytometric and ELISA assay, respectively, consistent with the assay sensitivity. Based on standard curves generated with 9G6, antibody concentration in the same serum sample was calculated to be approximately 230 microg/ml by ELISA and approximately 270 microg/ml by flow cytometry. Therefore, excellent concordance in antibody concentration was obtained with different assays using linear regression and properly diluted samples. This concordance was verified with multiple serum samples.     

Human and pig SRY 5' flanking sequences can direct reporter transgene expression to the genital ridge and to migrating neural crest cells.

Mechanisms for sex determination vary greatly between animal groups, and include chromosome dosage and haploid-diploid mechanisms as seen in insects, temperature and environmental cues as seen in fish and reptiles, and gene-based mechanisms as seen in birds and mammals. In eutherian mammals, sex determination is genetic, and SRY is the Y chromosome located gene representing the dominant testes determining factor. How SRY took over this function from ancestral mechanisms is not known, nor is it known what those ancestral mechanisms were. What is known is that SRY is haploid and thus poorly protected from mutations, and consequently is poorly conserved between mammalian species. To functionally compare SRY promoter sequences, we have generated transgenic mice with fluorescent reporter genes under the control of various lengths of human and pig SRY 5' flanking sequences. Human SRY 5' flanking sequences (5 Kb) supported reporter transgene expression within the genital ridge of male embryos at the time of sex determination and also supported expression within migrating truncal neural crest cells of both male and female embryos. The 4.6 Kb of pig SRY 5' flanking sequences supported reporter transgene expression within the male genital ridge but not within the neural crest; however, 2.6 Kb and 1.6 Kb of pig SRY 5' flanking sequences retained male genital ridge expression and now supported extensive expression within cells of the neural crest in embryos of both sexes. When 2 Kb of mouse SRY 5' flanking sequences (-3 to -1 Kb) were placed in front of the 1.6 Kb of pig SRY 5' flanking sequences and this transgene was introduced into mice, reporter transgene expression within the male genital ridge was retained but neural crest expression was lost. These observations suggest that SRY 5' flanking sequences from at least two mammalian species contain elements that can support transgene expression within cells of the migrating neural crest and that additional SRY 5' flanking sequences can extinguish this expression.     

Quantification of human immunodeficiency virus type 1 RNA from dried plasma spots collected on filter paper.

To assess dried plasma spots (DPSs) as a source of material for virus quantification, human immunodeficiency virus type 1 (HIV-1) RNA levels were quantified in matched DPS and liquid plasma samples from 73 infected patients, including 5 neonates and 4 adult patients with acute HIV-1 infection. Quantifications were performed by commercially available assays (NASBA [nucleic acid sequence-based amplification] or Amplicor, or both). There was a strong correlation between HIV-1 RNA levels in plasma and DPSs. More importantly, there was no decline in HIV-1 RNA levels in DPSs stored for as long as 2 weeks at 20 degrees C. Similarly, storage of DPSs for 3 days at 37 degrees C resulted in no decrease in viral RNA levels. For patients with primary infection, the DPS method allowed for the measurement of RNA levels in plasma during the initial spike in the level of viremia and in the subsequent period of suppressed viral replication. DPS quantification was equally informative in the neonatal setting, with all five newborns showing HIV-1 RNA loads of greater than 4.991 log10 copies/ml. We conclude that the viral RNA levels in DPSs are equivalent to those measured in fresh-frozen plasma. The ease and economy of DPS sampling, the minute volumes required, and the unexpected stability of dried RNA suggest that the use of DPSs will be particularly valuable for small-volume neonatal samples and large, population-based studies in which cold storage and transportation present special problems, as is often the case in developing countries. The ability to measure viral changes during primary infection suggests that the method will be useful for assessing vaccine efficacy in large field trials.