[Sleep in patients of a memory clinic : Clinical characteristics of the discrepancy between subjective and objective assessment]

BACKGROUND

Dementia is often accompanied by sleep disturbances, whereby the diagnostics with subjective procedures and objective methods can produce discrepant results. The frequency and clinical characteristics of patients, whose subjective sleep efficiency was unimpaired and was in contrast to an objectively conspicuous sleep efficiency in the sense of an overestimation, were investigated in a memory consultation.

METHODS

On 2 consecutive days, patients underwent guideline-oriented diagnostics for dementia (including mini-mental status examination, MMSE and clinical dementia rating, CDR), supplemented by a subjective (Pittsburgh sleep quality index, PSQI) and objective (overnight actigraphy) sleep assessment. Overestimation of sleep efficiency was defined as a subjective sleep efficiency (SSE) of ≥85% with an actigraphic sleep efficiency (ASE) of <85%.

RESULTS

Of 45 patients (74.4 ± 7.8 years; 26 f/19 m; CDR < 1: n = 16, CDR = 1: n = 28; diagnostic groups according to ICD-10: F0: n = 39, F3: n = 5, Z03.x: n = 1) 10 showed an overestimation of sleep efficiency, who showed a lower MMSE score and a higher proportion of patients with a dementia syndrome (CDR = 1) when compared with the other three groups of SSE and ASE ≥85% (n = 17), SSE and ASE <85% (n = 9) and SSE <85% with ASE ≥85% (n = 9). Binary regression showed that MMSE remained an important predictor for overestimation of sleep efficiency.

CONCLUSION

Cognitive deficits in memory clinic patients appear to contribute to a poorer perception and/or an underreporting of objectively disturbed sleep. This could promote false negative subjective screening results in a diagnostic process in which a comprehensive sleep assessment is not routinely considered.

Computer Technology Training in the Workplace: A Longitudinal Investigation of the Effect of Mood

How does a person's mood during technology training influence motivation, intentions, and, ultimately, usage of the new technology? Do these mood effects dissipate or are they sustainable over time? A repeated-measures field study (n = 316) investigated the effect of mood on employee motivation and intentions toward using a specific computer technology at two points in time: immediately after training and 6 weeks after training. Actual usage behavior was assessed for 12 weeks after training. Each individual was assigned to one of three mood treatments: positive, negative, or control. Results indicated that there were only short-term boosts in intrinsic motivation and intention to use the technology among individuals in the positive mood intervention. However, a long-term lowering of intrinsic motivation and intention was observed among those in the negative mood condition. Copyright 1999 Academic Press.

Changes in superoxide dismutase, catalase, and the glutathione cycle during induced myeloid differentiation

The human promyelocytic leukemia cell line HL-60 undergoes induced myeloid differentiation, with acquisition of most polymorphonuclear leukocyte (PMN) functions, including generation of toxic oxygen species. We examined the concurrent changes in the cellular detoxifying defenses against superoxide and H2O2: superoxide dismutase, catalase, and the glutathione cycle. During induced differentiation, total superoxide dismutase activity declined to a level slightly more than 2-fold that of PMN, largely due to a decrease in Mn-superoxide dismutase; CuZn-superoxide dismutase showed virtually no change. Catalase activity declined only slightly (but significantly) to a level 1.3 that of PMN. GSH peroxidase activity fell and then rose back to its original level, remaining throughout differentiation more than 10-fold higher than activity in PMN. GSSG reductase activity declined to a level of 73% that of uninduced cells but twice that of PMN. GSH and GSSG contents both decreased, reaching equivalence to those of PMN. Concurrently, the ability of the cells to generate H2O2 increased 11-fold, a change similar to that previously reported for superoxide production. Thus, there is a paradoxical inverse relationship between the development of active oxygen generation and scavenging systems during myeloid differentiation in HL-60 cells.

Chediak-Higashi syndrome: studies in long-term bone marrow culture

The granulocyte defects of Chediak-Higashi syndrome (CHS) include neutropenia, characteristic giant lysosomal granule morphology, and functionally abnormal cell motility, degranulation, and bacterial killing. Findings of elevated levels of adenosine 3', 5' cyclic monophosphate nucleotide (cAMP) and of concanavalin A (Con A) capping have suggested a pathogenic role of a cyclic-nucleotide-related defect in microtubule polymerization, but not all patients exhibit these abnormalities. In order to test which defects derive from the cells' genetic program and which from the host environment, we examined granulocytes produced by CHS bone marrow progenitors in long-term in vitro bone marrow cultures. These cells exhibited the characteristic giant-granule morphology and defective cell motility of CHS. However, culture-derived CHS granulocytes had normal cAMP contents and normal spontaneous capping of Con A. Granulopoiesis diminished dramatically after five weeks in culture, with accompanying autophagocytosis by mononuclear phagocytes. In mixing experiments, the phenotype of the mature granulocytes corresponded to the genotype of the hematopoietic component of the culture rather than the stroma. These results indicate that the hallmark giant-granule morphology and cell motility defect of CHS are expressions of the genetic program of the hematopoietic cells. However the abnormalities in resting cyclic nucleotide levels and in Con-A capping may be secondary manifestations of the disease and are not essential to the pathogenesis of the chemotactic defect.

Development of the superoxide-generating system during differentiation of the HL-60 human promyelocytic leukemia cell line

Utilizing the induced differentiation of HL-60 promyelocytic leukemia cells as a model of myeloid maturation, we examined the development of the superoxide-generating system, focusing on NADPH oxidase activity, membrane depolarization, and cytochrome b content. NADPH oxidase activity, measured as NADPH-dependent superoxide production, increased with both spontaneous and N,N-dimethylformamide-induced differentiation. Activity in particulate fractions from induced HL-60 cells and human peripheral blood polymorphonuclear leukocytes was proportional to their relative rates of superoxide production, but activity from uninduced cells was surprisingly high: one-third that from induced cells, despite only 7% their rate of superoxide generation. NADPH oxidase activities in phagocytic vesicles from induced HL-60 cells and polymorphonuclear leukocytes were equal, indicating the equivalence of the enzyme system in active portions of their cell membranes. Separation by centrifugal elutriation of the HL-60 cell population into fractions of varying maturity confirmed the relationship of NADPH oxidase activity to advancing differentiation in both dimethylformamide-induced and spontaneously maturing cells. Membrane potential change, an early event related to activation of the oxidase, was followed by 3,3'-dipropylthiodicarbocyanine dye fluorescence. The depolarization response increased dramatically in both magnitude and initial rate of change during differentiation. The cells' cytochrome b content increased 3-fold with induction of differentiation, in proportion to the change in NADPH oxidase activity.