STUDY OBJECTIVES The Oxford Sleep Resistance Test (OSLER) is an objective vigilance test based on... more STUDY OBJECTIVES The Oxford Sleep Resistance Test (OSLER) is an objective vigilance test based on behavior. It is a modified version of the maintenance of wakefulness test (MWT) and considered less burdensome and less expensive than MWT. Although professional drivers with obstructive sleep apnea in Europe must be assessed for their ability to maintain adequate wakefulness on a yearly basis, OSLER results are usually normal in this population. In this retrospective observational study, we searched for predictive factors of abnormal OSLER sleep latency. METHODS We included 1071 OSLER results of patients with obstructive sleep apnea (95% male, aged 21-74 years). Mean sleep latency < 40 minutes was considered abnormal. RESULTS Sleep latency was abnormal in 12.0% of tests. Participants at risk for abnormal test results self-reported as sleepy, depressed, on sick leave, unemployed, or retired or considered themselves unable to work. In a logistic regression model, the self-reported view on work capacity was the most important predictor of abnormal OSLER sleep latency (odds ratio 3.5). Ongoing sick leave was also an important predictor for abnormal test results. CONCLUSIONS A self-reported good ability to work predicts that a patient with sleep apnea can maintain wakefulness in a vigilance test. This may help in reducing the increasing challenge with frequent tests.
ABSTRACT Both gamma-aminobutyric acid (GABA)(C) receptor subunit mRNA and protein are expressed i... more ABSTRACT Both gamma-aminobutyric acid (GABA)(C) receptor subunit mRNA and protein are expressed in the stratum pyramidale in the CA1 area of the adult rat hippocampus, but so far no conclusive evidence about functional hippocampal GABA(C) receptors has been presented. Here, the contribution of GABA(C) receptors to stimulus-evoked postsynaptic potentials was studied in the hippocampal CA1 area with extracellular and intracellular recordings at the age range of 21-47 postnatal days. Activation of GABA(C) receptors with the specific agonist cis-4-aminocrotonic acid (CACA) suppressed postsynaptic excitability and increased the membrane conductance. The GABA(C) receptor antagonist 1,2,5,6-tetrahydropyridine-4-ylmethylphosphinic acid (TPMPA), but not the GABA(A) receptor antagonist bicuculline, inhibited the effects of CACA. GABA-mediated long-lasting depolarizing responses evoked by high-frequency stimulation of local inhibitory interneurons in the CA1 area in the presence of ionotropic glutamate receptor and GABA(B) receptor blockers were prolonged by TPMPA, indicating that GABA(C) receptors are activated under these conditions. For weaker stimulation, the effect of TPMPA was enhanced after GABA uptake was inhibited. Our data demonstrate that GABA(C) receptors can be activated by endogenous synaptic transmitter release following strong stimulation or under conditions of reduced GABA uptake. The lack of GABA(C) receptor activation by less intensive stimulation under control conditions suggests that these receptors are extrasynaptic and activated via spillover of synaptically released GABA.
GABAC receptors are thought to be homo‐ or heteropentamers composed of ρ1, ρ2 and ρ3 subunits. Pr... more GABAC receptors are thought to be homo‐ or heteropentamers composed of ρ1, ρ2 and ρ3 subunits. Previous work on rat ρ2 subunits expressed in Xenopus oocytes has suggested that they do not form functional homo‐oligomeric GABAC receptors, but do combine with ρ1 or ρ3 subunits to form hetero‐oligomers. These findings are difficult to interpret because both human and mouse ρ2 subunits do form functional homo‐oligomeric receptors. Also, many regions of the rat brain express solely ρ2 subunit transcripts which, according to presently available evidence, would not result in expression of functional GABAC receptors. We show here that homomeric rat ρ2 receptors can be expressed in HEK 293 cells. Homo‐oligomeric rat ρ2 receptors expressed in mammalian cells matured slowly and displayed small but detectable GABA‐induced currents with slow kinetics. Rat ρ2 receptors also had a decreased sensitivity to picrotoxin and a marked sensitivity to the GABAC receptor agonist cis‐aminocrotonic acid. Our results demonstrate for the first time the expression of functional homomeric rat ρ2 receptors, and suggest that ρ2 subunits may contribute to brain function, including in areas not expressing other ρ subunits.
Journal of Sleep Disorders: Treatment and Care, 2019
Background: Home sleep apnea tests are economical but their technical failure rate is higher than... more Background: Home sleep apnea tests are economical but their technical failure rate is higher than with in-lab studies. We aimed to predict factors related to failures. Methods: Altogether, 1,055 consecutive respiratory polygraphy recordings for subjects aged 16-90 years (38% female) were included. The sleep nurses were asked to predict the success of the upcoming recording according to their experienced perception. The recording was considered successful if the main recorded parameters (nasal flow, thoracic and abdominal movements, blood oxygen saturation, snoring, and posture) were intelligible during ≥80% of the night. Results: Defects due to a recording device caused a failure rate of 4.4%, and those recordings were excluded from further analyses. Subject-related reasons caused a failure rate of 10.4% (i.e. 70% of all failures). There were no statistically significant differences in the failure rate regarding gender, age, education level, ESS, smoking habits, BMI, comorbidities, ...
STUDY OBJECTIVES The Oxford Sleep Resistance Test (OSLER) is an objective vigilance test based on... more STUDY OBJECTIVES The Oxford Sleep Resistance Test (OSLER) is an objective vigilance test based on behavior. It is a modified version of the maintenance of wakefulness test (MWT) and considered less burdensome and less expensive than MWT. Although professional drivers with obstructive sleep apnea in Europe must be assessed for their ability to maintain adequate wakefulness on a yearly basis, OSLER results are usually normal in this population. In this retrospective observational study, we searched for predictive factors of abnormal OSLER sleep latency. METHODS We included 1071 OSLER results of patients with obstructive sleep apnea (95% male, aged 21-74 years). Mean sleep latency < 40 minutes was considered abnormal. RESULTS Sleep latency was abnormal in 12.0% of tests. Participants at risk for abnormal test results self-reported as sleepy, depressed, on sick leave, unemployed, or retired or considered themselves unable to work. In a logistic regression model, the self-reported view on work capacity was the most important predictor of abnormal OSLER sleep latency (odds ratio 3.5). Ongoing sick leave was also an important predictor for abnormal test results. CONCLUSIONS A self-reported good ability to work predicts that a patient with sleep apnea can maintain wakefulness in a vigilance test. This may help in reducing the increasing challenge with frequent tests.
ABSTRACT Both gamma-aminobutyric acid (GABA)(C) receptor subunit mRNA and protein are expressed i... more ABSTRACT Both gamma-aminobutyric acid (GABA)(C) receptor subunit mRNA and protein are expressed in the stratum pyramidale in the CA1 area of the adult rat hippocampus, but so far no conclusive evidence about functional hippocampal GABA(C) receptors has been presented. Here, the contribution of GABA(C) receptors to stimulus-evoked postsynaptic potentials was studied in the hippocampal CA1 area with extracellular and intracellular recordings at the age range of 21-47 postnatal days. Activation of GABA(C) receptors with the specific agonist cis-4-aminocrotonic acid (CACA) suppressed postsynaptic excitability and increased the membrane conductance. The GABA(C) receptor antagonist 1,2,5,6-tetrahydropyridine-4-ylmethylphosphinic acid (TPMPA), but not the GABA(A) receptor antagonist bicuculline, inhibited the effects of CACA. GABA-mediated long-lasting depolarizing responses evoked by high-frequency stimulation of local inhibitory interneurons in the CA1 area in the presence of ionotropic glutamate receptor and GABA(B) receptor blockers were prolonged by TPMPA, indicating that GABA(C) receptors are activated under these conditions. For weaker stimulation, the effect of TPMPA was enhanced after GABA uptake was inhibited. Our data demonstrate that GABA(C) receptors can be activated by endogenous synaptic transmitter release following strong stimulation or under conditions of reduced GABA uptake. The lack of GABA(C) receptor activation by less intensive stimulation under control conditions suggests that these receptors are extrasynaptic and activated via spillover of synaptically released GABA.
GABAC receptors are thought to be homo‐ or heteropentamers composed of ρ1, ρ2 and ρ3 subunits. Pr... more GABAC receptors are thought to be homo‐ or heteropentamers composed of ρ1, ρ2 and ρ3 subunits. Previous work on rat ρ2 subunits expressed in Xenopus oocytes has suggested that they do not form functional homo‐oligomeric GABAC receptors, but do combine with ρ1 or ρ3 subunits to form hetero‐oligomers. These findings are difficult to interpret because both human and mouse ρ2 subunits do form functional homo‐oligomeric receptors. Also, many regions of the rat brain express solely ρ2 subunit transcripts which, according to presently available evidence, would not result in expression of functional GABAC receptors. We show here that homomeric rat ρ2 receptors can be expressed in HEK 293 cells. Homo‐oligomeric rat ρ2 receptors expressed in mammalian cells matured slowly and displayed small but detectable GABA‐induced currents with slow kinetics. Rat ρ2 receptors also had a decreased sensitivity to picrotoxin and a marked sensitivity to the GABAC receptor agonist cis‐aminocrotonic acid. Our results demonstrate for the first time the expression of functional homomeric rat ρ2 receptors, and suggest that ρ2 subunits may contribute to brain function, including in areas not expressing other ρ subunits.
Journal of Sleep Disorders: Treatment and Care, 2019
Background: Home sleep apnea tests are economical but their technical failure rate is higher than... more Background: Home sleep apnea tests are economical but their technical failure rate is higher than with in-lab studies. We aimed to predict factors related to failures. Methods: Altogether, 1,055 consecutive respiratory polygraphy recordings for subjects aged 16-90 years (38% female) were included. The sleep nurses were asked to predict the success of the upcoming recording according to their experienced perception. The recording was considered successful if the main recorded parameters (nasal flow, thoracic and abdominal movements, blood oxygen saturation, snoring, and posture) were intelligible during ≥80% of the night. Results: Defects due to a recording device caused a failure rate of 4.4%, and those recordings were excluded from further analyses. Subject-related reasons caused a failure rate of 10.4% (i.e. 70% of all failures). There were no statistically significant differences in the failure rate regarding gender, age, education level, ESS, smoking habits, BMI, comorbidities, ...
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Papers by Anniina Alakuijala