Generic Dry-Contact Ear-EEG.

Generic dry-contact ear-EEG allows for discreet, user-friendly, unobtrusive, cost-effective and convenient recordings of EEG in real-life settings. In this study we introduce a new generic earpiece design with larger internal ear electrode distances, resulting in an increased spatial coverage compared to previous generic earpiece designs. The signal quality of ear-Fpz, within-ear (the measuring and reference electrode located in the same ear) and cross-ear (the measuring electrodes located in one ear and the reference electrode in the opposite ear) electrode configurations of the developed generic earpiece was evaluated with auditory steady-state responses (ASSR) and compared to dry-contact cEEGrid. Ten subjects with different ear sizes were included. The recordings were performed in a sleep setup, where the subjects were lying on a bed and the effect of sleeping position (back vs. sides) was investigated. We found that the generic earpiece attained statistically significant ASSRs with ear-Fpz, within-ear and cross-ear electrode configurations. However, the dry-contact cEEGrid achieved significantly higher average ASSR signal-to-noise ratio (SNR) compared to the generic earpiece. Additionally, this study showed no significant difference between back and side positions for the ear-EEG.

Auditory Steady-State Responses Across Chirp Repetition Rates For Ear-EEG And Scalp EEG.

Measurement of auditory steady-state responses (ASSR) using ear-EEG potentially enables objective audiometry out of the clinic in the everyday life of hearing aid users. As ear-EEG are measured from electrodes placed within the ear, electrode distances are inherently small and consequently the potential differences, and thereby signal amplitudes, are also small. Because the detection of the ASSR is based on the signalto-noise ratio (SNR), it is of fundamental interest to know the inherent SNR of the ASSR as a function of the stimulus repetition rate. In this study, ASSRs were recorded using both scalp and ear-EEG in response to broadband chirp stimuli with repetition rates from 20 to 95 Hz. The results showed that in general ear-EEG and scalp EEG SNR was on par across repetition rates; an exception to this was at rates around 40 Hz where the SNR was significantly lower for ear-EEG as compared to scalp EEG. For ear-EEG, the ASSR was relatively constant across repetition rates, whereas the noise showed a 1/f characteristic. In consequence, there was a tendency to increased SNR as a function of repetition rate. This suggests that use of relatively high repetition rates may be beneficial in earEEG applications.

Ear-EEG detects ictal and interictal abnormalities in focal and generalized epilepsy - A comparison with scalp EEG monitoring.

OBJECTIVE: Ear-EEG is recording of electroencephalography from a small device in the ear. This is the first study to compare ictal and interictal abnormalities recorded with ear-EEG and simultaneous scalp-EEG in an epilepsy monitoring unit. METHODS: We recorded and compared simultaneous ear-EEG and scalp-EEG from 15 patients with suspected temporal lobe epilepsy. EEGs were compared visually by independent neurophysiologists. Correlation and time-frequency analysis was used to quantify the similarity between ear and scalp electrodes. Spike-averages were used to assess similarity of interictal spikes. RESULTS: There were no differences in sensitivity or specificity for seizure detection. Mean correlation coefficient between ear-EEG and nearest scalp electrode was above 0.6 with a statistically significant decreasing trend with increasing distance away from the ear. Ictal morphology and frequency dynamics can be observed from visual inspection and time-frequency analysis. Spike averages derived from ear-EEG electrodes yield a recognizable spike appearance. CONCLUSIONS: Our results suggest that ear-EEG can reliably detect electroencephalographic patterns associated with focal temporal lobe seizures. Interictal spike morphology from sufficiently large temporal spike sources can be sampled using ear-EEG. SIGNIFICANCE: Ear-EEG is likely to become an important tool in clinical epilepsy monitoring and diagnosis.

The impact of involved node, involved field and mantle field radiotherapy on estimated radiation doses and risk of late effects for pediatric patients with Hodgkin lymphoma.

BACKGROUND: The use of radiotherapy (RT) is debated for pediatric patients with Hodgkin lymphoma (HL) due to the late effects of treatment. Radiation doses to the thyroid, heart, lungs, and breasts are compared with the extensive mantle field (MF), Involved Field RT(IFRT), Modified IFRT (mIFRT), and Involved Node RT (INRT) and the risk of radiation-induced cardiovascular disease, secondary cancers, and the corresponding Life Years Lost (LYL) is estimated with each technique. PROCEDURE: INRT, mIFRT, IFRT, and MF plans (20 and 30 Gy) were simulated for 10 supradiaphragmatic, clinical stage I­II classical HL patients <18 years old, total of 4 x 2 plans for each patient. The lifetime excess risks of cardiac morbidity, cardiac mortality, lung, breast, and thyroid cancer with each technique were estimated. The estimated excess risks attributable to RT were based on HL series with long-term follow-up, treating death from other causes as competing risks. The corresponding LYL were derived from the estimated excess risks. Statistical analyses were performed with repeated measures ANOVA. RESULTS: Both a reduction in field size and in prescribed radiation dose significantly lowered the estimated dose to the heart, lungs, breasts, and thyroid compared to past,extended fields, even for patients with mediastinal disease. This translated into a significantly reduced estimated risk of cardiovascular disease, secondary cancers, and LYL. CONCLUSIONS: Involved Node Radiotherapy should be considered for pediatric patients with Hodgkin lymphoma since it is estimated to substantially lower the risk of severe long-term complications.

A biocompatible micro cell culture chamber (microCCC) for the culturing and on-line monitoring of eukaryote cells.

We have previously shown that a polymeric (PMMA) chip with medium perfusion and integrated heat regulation provides sufficiently precise heat regulation, pH-control and medium exchange to support cell growth for weeks. However, it was unclear how closely the cells cultured in the chip resembled cells cultured in the culture flask. In the current study, gene expression profiles of cells cultured in the chip were compared with gene expression profiles of cells cultured in culture flasks. The results showed that there were only two genes that were differently expressed in cells grown in the cell culture chip compared to cell culture flasks. The cell culture chip could without further modification support cell growth of two other cell lines. Light coming from the microscope lamp during optical recordings of the cells was the only external factor identified, that could have a negative effect on cell survival. Low grade light exposure was however compatible with optical recordings as well as cell viability. These results strongly indicate that a cell culture chip could be constructed that allowed for on-line optical recording of cellular events without affecting the cell culturing condition compared to cell cultured in culture flasks incubated in a dark and CO2 conditioned incubator.

One-step immobilization of aminated and thiolated DNA onto poly(methylmethacrylate) (PMMA) substrates.

Direct immobilisation of modified DNA oligonucleotides (aminated or thiolated) onto a plastic substrate, poly(methylmethacrylate), (PMMA) is described. Using the methyl esters present on non-modified PMMA, it was possible to establish a covalent bond between the electron donor of a DNA probe and the C terminal ester of the PMMA substrate. Since the procedure consists of a single brief wash in isopropanol or ethanol, the procedure is simple and environmentally friendly. The new immobilization strategy was characterized by analysing DNA microarray performance. The new procedure resulted in probe- and hybridization densities that were greater or equivalent to those obtained with commercially available surfaces and other procedures to immobilize DNA onto PMMA. The described chemistry selectively immobilized the DNA via terminal thiol or amine groups indicating that probe orientation could be controlled. Furthermore, the chemical bond between the immobilized DNA and the PMMA could endure repeated heat cycling with only 50% probe loss after 20 cycles, indicating that the chemistry could be used in integrated PCR/microarray devices.

Functionalization of poly(methyl methacrylate) (PMMA) as a substrate for DNA microarrays.

A chemical procedure was developed to functionalize poly(methyl methacrylate) (PMMA) substrates. PMMA is reacted with hexamethylene diamine to yield an aminated surface for immobilizing DNA in microarrays. The density of primary NH2 groups was 0.29 nmol/cm2. The availability of these primary amines was confirmed by the immobilization of DNA probes and hybridization with a complementary DNA strand. The hybridization signal and the hybridization efficiency of the chemically aminated PMMA slides were comparable to the hybridization signal and the hybridization efficiency obtained from differently chemically modified PMMA slides, silanized glass, commercial silylated glass and commercial plastic Euray trade mark slides. Immobilized and hybridized densities of 10 and 0.75 pmol/cm2, respectively, were observed for microarrays on chemically aminated PMMA. The immobilized probes were heat stable since the hybridization performance of microarrays subjected to 20 PCR heat cycles was only reduced by 4%. In conclusion, this new strategy to modify PMMA provides a robust procedure to immobilize DNA, which is a very useful substrate for fabricating single use diagnostics devices with integrated functions, like sample preparation, treatment and detection using microfabrication and microelectronic techniques.

[RTH syndrome--resistance to thyroid hormone syndrome]. / RTH-syndromet--resistance to thyroid hormone syndrome.

The RTH syndrome is an instructive example of a receptor resistance syndrome. A typical case history is reported here. The patient had had symptoms for many years and was first diagnosed as having inappropriate secretion of TSH. Pituitary tumour was excluded. The primary symptom was palpitations and the patient was partially thyroidectomized many years ago on suspicion of thyrotoxicosis. She was then given substitutional Eltroxin, but, because of palpitations, the dose was reduced to almost zero, after which the patient contracted symptoms suggesting myxoedema. The thyroid values could not be used for clinical assessment, however the symptoms of myxoedema disappeared when the Eltroxin dose was increased to 75 micrograms/day. When the dose was increased further the heart symptoms became too troublesome. The patient had no signs of underlying heart disease.

Molecular characterization of a Leishmania donovanii cDNA clone with similarity to human 20S proteasome a-type subunit.

Using plasma from patients infected or previously infected with Leishmania donovanii, we isolated a L. donovanii cDNA clone with similarity to the proteasome a-type subunit from humans and other eukaryotes. The cDNA clone, designated LePa, was DNA sequenced and Northern blot analysis of L. donovanii poly(A(+))mRNA indicated the isolation of a full length cDNA clone with a transcript size of 1.9 kb. The expressed recombinant LePa fusion protein induced proliferation of peripheral blood mononuclear cells in one out of seven patients who had suffered from visceral leishmaniasis. Plasma from 16 out of 25 patients with visceral leishmaniasis and four out of 18 patients with cutaneous leishmaniasis contained IgG antibodies which reacted with the purified LePa fusion protein as evaluated in an ELISA. The LePa DNA sequence was inserted into an eukaryotic expression vector and Balb/c mice were vaccinated. DNA vaccination of Balb/c mice with LePa generated an initial significant reduction in lesion size after challenge.

Modification of T-cell antigenic properties of tetanus toxoid by SDS-PAGE separation. Implications for T-cell blotting.

Using Tetanus Toxoid (TT) as a model antigen the T-cell Blotting method was evaluated. Peripheral blood mononuclear cell (PBMC) cultures were stimulated by blotted nitrocellulose-bound TT or soluble TT. SDS-Poly-Acrylamide-Gel-Electrophoresis separated TT only induced proliferation in 20% of the PBMC cultures whereas proliferation was induced in 79% of the same cultures offered similar treated TT (except for the PAGE separation). When T-cell blotting was performed with TT separated in a SDS-agarose matrix, proliferation was induced in 80% of donors responding to soluble TT. The results show that SDS-PAGE alters the ability of TT to induce T-cell proliferation, possibly due to unpolymerized acrylamide binding to proteins during SDS-PAGE. The use of SDS-PAGE T-cell blotting in the screening for T-cell antigens must therefore be reconsidered. We suggest the use of SDS-Agarose Gel Electrophoresis as an alternative when doing T-cell blots.

Identification of porcine Pneumocystis carinii as a genetically distinct organism by DNA amplification.

DNA was amplified from lung samples from three piglets infected with Pneumocystis carinii, using oligonucleotide primers designed to the P. carinii mitochondrial large subunit ribosomal RNA gene. The nucleotide sequence of the amplification product was determined and indicated lack of sequence variation among these pig-derived P. carinii samples at this locus. The data showed that porcine P. carinii was genetically distinct from P. carinii isolated from other mammalian host species.

Serodiagnosis of cutaneous leishmaniasis: assessment of an enzyme-linked immunosorbent assay using a peptide sequence from gene B protein.

An enzyme-linked immunosorbent assay (ELISA) using a 28 amino acid sequence of the repetitive element of gene B protein (GBP) from Leishmania major was developed for serodiagnosis of cutaneous leishmaniasis (CL). The assay was compared to ELISAs using crude amastigote and promastigote antigens from L. donovani and the major surface glycoprotein (Gp63) from either L. donovani or L. major as a solid-phase ligand. The sensitivity of the assays was tested in 33 patients suffering from CL caused by L. major. The sensitivity of the GBP peptide (GBPP) ELISA was 82%. This was higher than in the assays using crude amastigote (67%) or promastigote (67%) antigens, but the difference was not statistically significant. The sensitivity in the assays using Gp63 from L. donovani (52%) or L. major (39%) was significantly lower than in the assay using GBPP (P = 0.019 and P < 0.001, respectively). Plasma samples from healthy Sudanese individuals living in an area endemic for malaria but free of leish-maniasis were negative in all the assays. Significantly higher levels of antibodies were found in the patients who had suffered from the disease for more than eight weeks than in patients with a shorter clinical history (GBPP ELISA; P = 0.038; amastigote ELISA; P = 0.004; and promastigote ELISA; P = 0.017). In the former group, the sensitivities of the five ELISAs were 100% (GBPP), 87% (amastigote), 93% (promastigote), 67% (L. donovani), and 53% (L. major), respectively.

Pneumocystis carinii from pigs and humans are antigenically distinct.

The antigens of Pneumocystis carinii cysts isolated from pigs and humans were compared by the Western immunoblotting technique. Convalescent pig serum reacted with two antigens (approximately 78 kDa and 32.5 kDa) of porcine P. carinii cysts, whereas convalescent serum from humans did not react with porcine P. carinii cyst antigens. The results indicate that porcine and human P. carinii cysts are antigenically distinct.

Dichotomy of the T cell response to Leishmania antigens in patients suffering from cutaneous leishmaniasis; absence or scarcity of Th1 activity is associated with severe infections.

The T cell response was studied in 25 patients suffering from cutaneous leishmaniasis caused by Leishmania major with severe (n = 10) and mild (n = 15) disease manifestations. Peripheral blood mononuclear cells (PBMC) from the patients were activated by sonicates of Leishmania promastigotes (LMP) and amastigotes (LDA), and the surface protease gp63. The proliferative responses to Leishmania antigens were lower in patients with severe disease than in patients with mild disease (P = 0.01-0.05), and such a difference was not observed in the response to purified protein derivative of tuberculin (PPD) or tetanus toxoid (TT). LMP-induced interferon-gamma (IFN-gamma) production was lower in patients with severe than in patients with mild disease (P < 0.05). When the IL-4 and IFN-gamma responses of each patient were considered, two response patterns were observed in the cultures activated by the Leishmania sonicates. One response pattern was characterized by high production of IFN-gamma without production of IL-4 (a Th1-like pattern), the other was characterized by low IFN-gamma levels which in most cases were associated with IL-4 production (not a Th1-like pattern). These patterns could not be distinguished when the cells from the same donors were stimulated by TT and PPD. The percentages of patients with a Th1-like response pattern after stimulation by LMP in patients with severe and mild disease manifestations were 30% and 80%, respectively. This difference was statistically significant (P = 0.034).

The mu1, mu2, delta, kappa opioid receptor binding profiles of methadone stereoisomers and morphine.

The binding affinities of racemic methadone and its optical isomers R-methadone and S-methadone were evaluated for the opioid receptors mu1, mu2, delta and kappa, in comparison with that of morphine. The analgesic R-methadone had a 10-fold higher affinity for mu1 receptors than S-methadone (IC50 3.0 nM and 26.4 nM, respectively). At the mu2 receptor, the IC50 value of R-methadone was 6.9 nM and 88 nM for S-methadone, respectively. As expected, R-methadone had twice the affinity for mu1 and mu2 receptors than the racemate. All of the compounds tested had low affinity for the delta and kappa receptors. This result suggests that S-methadone does not essentially contribute to opioid effect of racemic methadone. R-methadone has a receptor binding profile which resembles that of morphine.

Morphine pharmacokinetics in premature and mature newborn infants.

The pharmacokinetics of a single dose of morphine was investigated in five term infants (gestational age 37-40 weeks) and eight preterm infants (gestational age 25-32 weeks). In the five term infants, median (range) volume of distribution at steady state (Vd beta) was 1758 (634-2700) ml/kg, plasma clearance (Cl) was 4.73 (1.75-6.61) ml/kg/min and terminal half-life (T1/2) was 224 (107-394) min. In the eight preterm infants, Vd beta was 2366 (1662-2876) ml/kg, Cl was 2.82 (1.88-6.60) ml/kg/min and T1/2 was 556 (248-834) min. No correlation was found between clearance and gestational age, but we found a significant negative correlation between T1/2 and gestational age. We conclude that there is considerable variation in the pharmacokinetic properties of morphine in both term and preterm newborn infants. Because of this variation, careful individual assessment of the clinical effect of therapy with morphine in newborn infants should be exercised.

Dichotomy of the human T cell response to Leishmania antigens. I. Th1-like response to Leishmania major promastigote antigens in individuals recovered from cutaneous leishmaniasis.

The T cell response to antigens from Leishmania major promastigotes was investigated in peripheral blood mononuclear cells from Sudanese individuals with a history of cutaneous leishmaniasis (CL), Sudanese individuals with positive DTH reaction in the leishmanin skin test but with no history of skin lesions, and in Danes without known exposure to Leishmania parasites. Proliferation and production of interferon-gamma (IFN-gamma) and IL-4 in antigen-stimulated cultures was measured. Lymphocytes from individuals with a history of CL proliferated vigorously and produced IFN-gamma after stimulation with either a crude preparation of L. major antigens or the major surface protease gp63. These cultures produced no or only little IL-4. Also cells from leishmanin skin test-positive donors with no history of CL produced IFN-gamma and no IL-4 in response to L. major antigens. Cells from the unexposed Danes were not activated by gp63. The cells from Danish donors produced either IFN-gamma or IL-4, but not both cytokines after incubation with the crude preparation of L. major antigens. The data show that the T cell response to Leishmania antigens in humans who have had uncomplicated CL or subclinical L. major infection is an IFN-gamma-producing Th1-like response.