EEG-microstates in mild memory impairment and Alzheimer's disease: possible association with disturbed information processing

Summary The only available functional neuroimaging methods reaching the time resolution of human information processing are EEG and MEG. Since spectral analysis implies analysis of longer time epochs, the high temporal resolution of EEG is partly lost. By dividing the EEG in the time-domain into segments of similar spatial distribution on the scalp (microstates) it has been possible to assess patterns of neuronal activity representing the information process currently performed by the brain. In the present study alterations of EEG microstates in subjective (n=31) and objective (n=38) memory impairment as well as in probable Alzheimer disease (DAT: n=64) compared to healthy controls (n=21) were investigated. The main findings were reduced segment durations and a more anterior center of gravity of the microstate topography in DAT. With more pronounced cognitive dysfunction larger window sizes were found. Shorter microstates and larger windows reflect more rapidly changing spatial activation patterns, and are interpreted as an impaired capability to establish stable brain states necessary for normal brain function. The anteriorization of the microstates is consistent with results in the frequency domain and may reflect neuropathological changes in DAT.     

An ultrastructural study of the synaptic contacts ofα1-motoneuron axon collaterals. II. Contacts in lamina VII

Horseradish peroxidase (HRP) was injected intracellularly in triceps surae α-motoneurons. The axons and axon collaterals of these neurons were traced light and electron microscopically. Synaptic boutons of collaterals in the ventral part of Rexed's lamina VII were studied ultrastructurally. The boutons exhibited spherical synaptic vesicles and made synaptic contacts with cell bodies and proximal dendrites of neurons assumed to be Renshaw cells and with dendrites of unknown origin. The observations are discussed in relation to earlier qualitative and quantitative studies on the other known synaptic contacts of the α-motor axons, both in the central and peripheral nervous system.     

Placental Transfer of Ampicillin in Man

Abstract: A pharmacokinetic analysis of the foetal/maternal distribution of ampicillin was performed in 25 pregnant women undergoing therapeutic abortion in the middle trimester of pregnancy. The drug was given intravenously before the hysterotomy and the plasma levels were followed during the period up to surgery. When the foetus was removed from the uterus a sample of foetal plasma was taken for ampicillin assay. By means of varying the time between injection and surgery, the ratio between foetal and maternal plasma levels could be determined at various times following the intravenous administration. It was found that the two concentrations became equal after 90 minutes and that the ratio was then steadily increasing for at least 200 minutes. If a two-compartmental pharmacokinetic analysis is made on the basis of the plasma levels in the mother, it shows that a quasi-equilibrium between the central compartment and the tissue compartment is reached already after about 35 minutes following the intravenous injection. Thus, the distribution of ampicillin to the human foetus through the placenta is slower than the distribution of the drug to the maternal tissues. A placental “barrier”seems to exist in the pharmacokinetic sense.     

Temporomandibular disorders in adolescents. Epidemiological and methodological studies and a randomized controlled trial

The aim of the present thesis was to investigate different aspects of temporomandibular disorders (TMD) and pain such as prevalence, diagnostics, and treatment among adolescents. The reliability of a questionnaire and the clinical examination and diagnoses according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were assessed. Overall, we found it possible to assess and diagnose TMD in adolescents in a reliable way. The prevalence of TMD pain, gender differences, and the need for treatment were investigated among 864 adolescents from a Public Dental Service clinic. Seven percent of the subjects received a pain diagnosis according to the RDC/TMD, and the prevalence was higher among girls than boys. More subjects with TMD pain reported school absence and analgesic consumption compared to controls. Approximately every second subject who reported TMD pain also perceived a need for treatment. In an evaluation of psychosocial and dental factors, the following were found to play an important role in adolescents with TMD: stress, somatic complaints, and emotional problems. Three treatment methods were compared in a randomized controlled trial: brief information only, brief information and occlusal appliance, and brief information and relaxation therapy. In the brief information and occlusal appliance group, 60%--significantly more than in the other two groups--experienced a reduction of at least 50% in TMD pain. The influence of somatic and emotional stimuli was evaluated, and we found that adolescents with TMD pain were significantly more sensitive to not only aversive somatic but also pleasant somatic stimuli compared with healthy controls. The results suggest that not only nociceptive but also cognitive processes are implicated in chronic pain states in young TMD subjects. In conclusion, TMD pain is more common in girls than in boys and affects daily life. TMD pain in adolescents can best be improved by traditional treatment with occlusal appliance combined with brief information.     

Temporomandibular disorders in children and adolescents: a survey of dentists' attitudes, routine and experience

The aim of this study was to survey the experience and routine of, attitudes toward, and need for specialist resources in the treatment of temporomandibular disorders (TMD) in children and adolescents among public dentists. A questionnaire study was conducted in three counties in Sweden: Osterg?tland, V?stmanland, and G?teborg. The questionnaire was sent to 286 Public Dental Service dentists. It contained questions on demographic issues, quality assurance, clinical experience and expertise, attitudes, and the need for specialist resources. Eighty-seven per cent (250) of the dentists answered the questionnaire. The dentists in the three areas reported good routine and safety in occlusal splint treatments (74%-81%), occlusal equilibration (28%-55%), jaw exercise (25%-29%), and medication treatments (3%-55%). Good experience concerning diagnostics and therapy decision was reported by 25%-50% of the dentists. A significantly greater portion of the dentists in V?stmanland had attended courses in TMD compared with the two other counties (p = 0.001). Registrations of quality variables such as verbal and/or written case histories with questions on facial pain and tension-type headache (1%-39%) and measurements of jaw openings were performed less frequently in the three counties (0%-5%). Fifty-five per cent of the dentists had a positive attitude toward the care of children and adolescents with TMD. A large need for specialist resources with the possibility to send referrals or to consult was reported by 98%-100% of the respondents, to participate in continuing education by 97%-98%, and to do auscultation by 61%-82%. In conclusion, many of the dentists lacked routines for making diagnoses, deciding therapy, and judging treatment results. Good routines were reported only in occlusal splint therapy. The majority of the dentists had a positive attitude toward the care of children and adolescents with TMD-related symptoms. The majority of the dentists reported a great need for TMD specialists.he     

Tau and Abeta42 in cerebrospinal fluid from healthy adults 21-93 years of age: establishment of reference values

BACKGROUND: Tau protein and the 42-amino acid form of beta-amyloid (Abeta42) measured in cerebrospinal fluid (CSF) have been proposed as potential biochemical diagnostic markers for Alzheimer disease. For the introduction of these assays in clinical practice, adequate reference values are of importance. METHODS: CSF samples were obtained from 231 neurologically and psychiatrically healthy individuals, 21-93 years of age, all with a MiniMental State examination score of 28 or above. Standardized ELISAs were used to measure tau and Abeta42 in CSF. Following IFCC recommendations, we used a rank-based method; the 0.90 and 0.10 fractiles were estimated to establish reference values for CSF-tau and CSF-Abeta42, respectively. Putative confounding factors, such as the influence of the passage of proteins from peripheral blood to CSF, influence of dysfunction of the blood-brain barrier, and freezing and thawing of CSF, were investigated. RESULTS: A correlation with age was found for CSF-tau (r = 0.60; P <0.001). Therefore, separate reference values for different age groups were established for CSF-tau: <300 ng/L in the group 21-50 years of age, <450 ng/L in the group 51-70 years of age, and <500 ng/L in the group 71-93 years of age. CSF-Abeta42 did not correlate with age (r = -0.045), and the reference value was set to >500 ng/L. No correlation was found between blood-brain barrier function and CSF-tau or CSF-Abeta42. CONCLUSIONS: These reference values can be applied when using CSF-tau and CSF-Abeta42 in clinical practice.     

Simple and rapid determination of 5-hydroxyindole-3-acetic acid in urine by direct injection on a liquid chromatographic column

5-Hydroxyindole-3-acetic acid has been determined at normal and increased levels in urine. The urine samples were filtered or centrifuged and then injected into a liquid chromatograph containing a reversed phase column with tributyl phosphate as stationary liquid phase and an aqueous buffer + methanol as eluent. 5-Hydroxyindole-3-acetic acid is detected in the eluate by a fluorometric detector coupled to the outlet of the separation column and the quantitation is performed by measurement of the peak heights of the sample and external standards. The percentage recovery was 97 and the precision 0.01 (sr). The method is suitable for the determination of increased levels of 5-hydroxyindole-3-acetic acid in urine from patients suffering from carcinoid tumours. Indole-3-acetic acid can be determined simultaneously.