High-tech children. Interfacing EMS providers with children in the community.
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Apnea↗
Biomedical subjects
B Diehl
Publications and source records attributed to B Diehl.
Measurement of temporal asymmetries of glucose consumption using linear profiles: reproducibility and comparison with visual analysis.
AIM: One approach to regionally analyze temporal glucose consumption consists in drawing linear profiles over the maximal values measured in the temporal cortical ribbon. The aim of our study was to test the reproducibility of this method and to compare its diagnostic performance to that of visual analysis in patients with complex partial seizures (CPS). METHODS: Regional cerebral glucose consumption (rCMRGIc) was measured interictally in 25 CPS patients and 10 controls using F-18-deoxyglucose and the positron emission tomography (PET) camera ECAT EXACT 47. The PET scans were visually analyzed for the occurrence of unilateral temporal hypometabolism. Furthermore, rCMRGIc was quantified on six contiguous coronal planes by manually tracing maximal values of temporal glucose consumption, thus creating line profiles of temporal glucose consumption for each side. Indices of asymmetry (ASY) were then calculated from these line profiles in four temporal regions and compared to the corresponding 95% confidence intervals of the control data. All analyses were performed by two observers independently from each other and without knowledge of the clinical findings. RESULTS: The agreement between the two observers with regard to focus lateralization was 96% (kappa = 0.93) on visual analysis and 100% (kappa = 1) on quantitative analysis. There was an excellent agreement with regard to focus lateralization between visual and quantitative evaluation (kappa = 0.8). CONCLUSION: Quantitation of local temporal rCMRGIc by using linear profile analysis is highly reproducible; for the lateralization of epileptogenic foci, however, this method does not possess significant advantages over the visual evaluation of the scans.
Adult↗
PET and SPECT in medically non-refractory complex partial seizures. Temporal asymmetries of glucose consumption, benzodiazepine receptor density, and blood flow.
AIM: In contrast to medically refractory complex partial seizures (CPS), only limited knowledge exists on cerebral perfusion and metabolism in medically non-refractory CPS. The aim of this study was to investigate the frequency of temporal asymmetries in regional cerebral glucose consumption (rCMRGlc), regional cerebral blood flow (rCBF), and regional cerebral benzodiazepine receptor density (BRD) in this group of patients. METHODS: The study included 49 patients with medically non-refractory cryptogenic CPS (age: 36.0 +/- 16.1 years). rCMRGlc was studied with F-18-FDG-PET (FDG), rCBF with Tc-99m-ECD-SPECT (ECD), and BRD with l-123-iomazenil-SPECT (IMZ). All studies were performed interictally and within four weeks in each patient. Duration of epilepsy ranged from 0.1 to 42 years (median 4.0 years). SPECT was performed with the triple-headed SPECT camera Multispect 3, PET with the PET camera ECAT EXACT 47. Using linear profiles, glucose consumption, as well as uptake of ECD and IMZ, were measured in four temporal regions of interest (ROIs), and asymmetry indices were calculated (ASY). The results were compared to 95% confidence intervals determined in control subjects. RESULTS: Thirty-five of the 49 (71%) patients had at least one significantly elevated ASY; temporal rCMRGlc was asymmetrical in 41% of the patients, temporal BRD in 29%, and temporal rCBF in 24%. One patient had an asymmetry of all three variables, two of temporal rCMRGlc and BRD, three of temporal rCMRGlc and rCBF, and another four of rCBF and BRD. Fourteen patients had an isolated temporal asymmetry in rCMRGlc, seven in BRD, and four in rCBF. A discrepancy in lateralization between the three modalities was not observed. CONCLUSION: The majority of patients with medically non-refractory CPS have focal abnormalities of blood flow and metabolism in their temporal lobe. In this group of patients, FDG-PET demonstrates abnormalities with the highest frequency of the three modalities studied, followed by IMZ-SPECT, and ECD-SPECT.
Adolescent↗
Spontaneous oscillations in cerebral blood flow velocities in middle cerebral arteries in control subjects and patients with epilepsy.
BACKGROUND AND PURPOSE: Cardiac arrhythmias mediated by the sympathetic nervous system have been implicated in sudden, unexplained deaths in patients with epilepsy. Cerebral blood flow velocities (CBFV) as measured by transcranial Doppler are characterized by slow spontaneous oscillations in part attributed to changes in sympathetic activity (M waves, 3 to 9 cycles per minute) and to discharges of monoaminergic neurons in the brain stem (B waves, 0.5 to 2 cycles per minute). This study was designed to compare spontaneous fluctuations of CBFV in patients with epilepsy with those in normal control subjects. METHODS: Simultaneous registrations of scalp electroencephalograms, with electrodes placed according to the 10-20 System, and transcranial Doppler recordings of both middle cerebral arteries were performed in 27 patients (9 with primary generalized epilepsy, 18 with focal epilepsy). Data analysis of CBFV was based on the envelope curves of the Doppler spectrum. A fast Fourier transformation over the 20-minute CBFV curve was performed, and the amplitudes of B and M waves were calculated and compared with those in 20 normal, age-matched control subjects. RESULTS: While the amplitudes of the B waves in both groups were similar, patients with epilepsy showed significantly increased M waves. Patients with focal epilepsy did not present asymmetries between the normal hemisphere and the side of the epileptic focus with respect to both M and B waves. CONCLUSIONS: Enhanced M waves in epileptic patients may reflect increased sympathetic activity even in the absence of seizures. This study provides further evidence for an autonomic dysfunction as a possible mechanism for sudden unexplained death in patients with epilepsy.
Adult↗
Persistent unihemispheric perceptual impairments in humans following focal seizures.
Perception has been linked to a highly coordinated activation of cortical regions whose functional organization and performance is subject to plastic changes. We tested whether chronic repetitive disturbances of the brain by focal epileptic activity have a long-standing detrimental effect on the perceptual performance in the affected hemisphere. Nine patients were examined who had a history of complex partial seizures but no structural cerebral damage on magnetic resonance imaging and no evidence of ongoing epileptic activity on scalp electroencephalography and who had clinically been without seizures for at least 3 days. The side of primary epileptic involvement was determined by seizure semiology (n = 2), focal electroencephalographic slowing (n = 3) or focal abnormality during single photon emission topography (SPECT) (n = 4). The computer controlled psychometric assessment of the somesthetic frequency discrimination revealed that the perception in the hand corresponding to the affected hemisphere was impaired relative to the contralateral hand (P < 0.01), and to the performance of a group of normal controls (P < 0.01). We conclude that mechanisms related to focal epileptic activity can result in regional perceptual decrements even when there is no clinical or surface-electroencephalographic evidence of epileptic discharges. This in turn suggests that somatosensory testing may be of help in localizing, or at least lateralizing an epileptic focus.
Adult↗
Reduced GABAA receptor density contralateral to a potentially epileptogenic MRI abnormality in a patient with complex partial seizures.
Imaging cerebral GABAA receptor density (GRD) with single-photon emission tomography (SPET) and iodine-123 iomazenil is highly accurate in lateralizing epileptogenic foci in patients with complex partial seizures of temporal origin. Limited knowledge exists on how iomazenil SPET compares with magnetic resonance imaging (MRI) in this regard. We present a patient with complex partial seizures in whom MRI had identified an arachnoid cyst anterior to the tip of the left temporal lobe. Contralaterally to this structural abnormality, interictal electroencephalography (EEG) performed after sleep deprivation disclosed an intermittent frontotemporal dysrhythmic focus with slow and sharp waves. On iomazenil SPET images GRD was significantly reduced in the right temporal lobe and thus contralaterally to the MRI abnormality, but ipsilaterally to the pathological EEG findings. These data suggest that iomazenil SPET may significantly contribute to the presurgical evaluation of epileptic patients even when MRI identifies potentially epileptogenic structural lesions.
Adult↗
Variability of Doppler microembolic signal counts in patients with prosthetic cardiac valves.
BACKGROUND AND PURPOSE: The purpose of this study was the evaluation of intraobserver, interobserver, and intrasubject variability in the Doppler detection of microembolic signals in patients with mechanical prosthetic valves. Simultaneously, the feasibility of automated embolus detection by means of a neuronal network was investigated. METHODS: From 25 patients with mechanical prosthetic heart valves, single transcranial Doppler monitoring sessions of 30 minutes' duration were recorded on videotape, randomized, and subsequently analyzed by eight independent trained observers from three centers. Three observers evaluated these tapes on three separate occasions, blinded to their previous results. An additional 48 patients with prosthetic heart valves were repetitively monitored with transcranial Doppler ultrasonography for 30 minutes three times within 1 year to examine the long-term variability in the occurrence of microembolic signals. Finally, in an effort to assess the short-term intrasubject variability, 20 patients were examined for 90 minutes, and the results of the three 30-minute periods were compared. The interobserver, intraobserver, and intrasubject (both short- and long-term) variability was evaluated. RESULTS: No significant differences in microembolic signal counts were found among the different observers, between the human observers and the neuronal network, or among the three separate evaluations of stored data by the same observer. The same was true for repeat examinations of the same patient (P > .05, Student's two-paired t test and Friedman's test). CONCLUSIONS: The detection of microembolic signals in patients with prosthetic cardiac valves is a reproducible technique. The reliable performance of the neuronal network argues for a broader use of this device. The intrasubject stability of the microembolic rate over 1 year supports the concept that the underlying emboligenic process is associated with intrinsic mechanical properties of the valve implant and not due to a thromboembolic process in the heart.
Cerebral Arteries↗
A double-blind comparison of amitriptylinoxide versus doxepine in the treatment of severe depression.
In a double-blind parallel group study the efficacy and safety of amitriptylinoxide were evaluated vs. doxepine in the treatment of in-patients with severe depression. Two groups of 22 patients each received amitriptylinoxide and doxepine respectively at a daily dosage of 120-360 mg for a period of 4 weeks. The total score on the Hamilton Depression Scale (HAMD) was reduced with amitriptylinoxide on an average from 28 +/- 5 before treatment to 12 +/- 8 at the end of treatment, with doxepine from 29 +/- 8 to 13 +/- 11. Of the amitriptylinoxide-treated patients, 12 showed a more than 50% reduction in this score compared with 15 under doxepine. The difference was not statistically significant. Twenty patients in each group experienced adverse drug reactions, the percentage of anticholinergic side effects being equal in the two groups.
Adult↗
The influence of mechanical stimuli and of acetylsalicylic acid on the discharges of slowly conducting afferent units from normal and inflamed muscle in the rat.
In anaesthetized rats, the influence of an experimental inflammation and of acetylsalicylic acid (ASA) on the discharge properties of muscle receptors with slowly conducting afferent fibres was studied using a single-fibre recording technique. Following the induction of a myositis with carrageenan, the proportion of units having background activity and the frequency of the background discharge were significantly increased. The latter change was particularly prominent in high-threshold mechanosensitive (HTM) units. There was evidence for an inflammation-induced lowering of mechanical threshold in HTM units, but the change was not statistically significant. Administration of ASA intravenously led to a decrease in the frequency of background discharge in some units while others were unaffected, although they appeared to be sensitized by the inflammation. If one assumes that at least some of the HTM receptors fulfil nociceptive functions, the results suggest that the pain and tenderness of an inflamed muscle is largely due to a sensitization and hence increased activity of nociceptive muscle receptors. The sensitization is only partially abolished by ASA.
Action Potentials↗
An educational program for school nurses caring for the pediatric client with a tracheostomy. Training the school nurse to care for a child re-entering the public education system with a tracheostomy.
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Child↗
Spontaneous oscillations in cerebral blood flow velocity in normal humans and in patients with carotid artery disease.
Spontaneous oscillations in cerebral blood flow velocity (CBFV) in normals and in patients with stenoses or occlusions of the internal cerebral artery were measured using transcranial Doppler sonography. In normal subjects, large oscillations of up to +/- 30% from the mean CBFV were found with low frequencies between 0.4 and 9 cycles/min. No correlations between CBFV oscillations and systemic circulatory parameters were detected. In patients with carotid artery obstructions the CBFV oscillations were significantly reduced in the middle cerebral artery ipsilaterally to a hemodynamically significant lesion, but not contralaterally. Our results support the hypothesis that spontaneous oscillations (B-waves) of small pial vessels are responsible for the CBFV fluctuations.
Adult↗
Histological and neurophysiological changes induced by carrageenan in skeletal muscle of cat and rat.
Infiltration of the rat gastrocnemius-soleus (GS) muscle with carrageenan induced a myositis which was characterized histologically by an accumulation of polymorphonuclear leukocytes around capillaries and small arterioles. In chloralose-anaesthetized cats having an inflamed GS-muscle, the discharge behaviour of single muscle receptors with group III and IV afferent fibres was recorded. Concerning background activity, only group III receptors showed a significant increase, whereas a significant lowering in mechanical threshold was present only among group IV receptors. Both high- and low-threshold mechanosensitive receptors showed signs of a sensitization. In contrast to group IV receptors in the cat, rat group IV receptors showed a significantly higher level of background activity in inflamed muscle but no increased responsiveness to mechanical stimuli. Acetylsalicylic acid (ASA) influenced only some of the receptors in the inflamed tissue. Leukotriene D4 did not act as a sensitizing substance but depressed the activity of group IV muscle receptors.
Animals↗
Cerebral blood flow in autogenic training and hypnosis.
In 12 healthy volunteers with at least an experience of six months in autogenic training (AT), the cerebral blood flow (CBF) was measured at rest, in AT and in hypnosis (H). The results were correlated with individual test profiles. The cortical flow pattern at rest of our AT trained volunteers did not show the hyperfrontality which is described in the literature. This may be interpreted as an effect of better and habitualized relaxation in long trained AT practitioners. This flow pattern corresponds to the low grades of neuroticism and aggressivity found in the tests. Furthermore an activation in central cortical areas and a deactivation in regions which are associated with acoustic and autonomous functions occur. Possible explanations for these phenomena as well as for the relatively low perfusion of the left hemisphere at rest and activation in AT are discussed. The global rise of CBF in H may be an activation effect caused by resistance against the hypnotizer: the deeper the trance, the smaller the CBF increase in the motor cortical area needed for maintaining catalepsy of the right arm and in temporal cortical fields processing acoustic inputs.
Adult↗
Single base-pair mutations in centromere element III cause aberrant chromosome segregation in Saccharomyces cerevisiae.
In this paper we show that a 211-base pair segment of CEN3 DNA is sufficient to confer wild-type centromere function in the yeast Saccharomyces cerevisiae. We used site-directed mutagenesis of the 211-base pair fragment to examine the sequence-specific functional requirements of a conserved 11-base pair segment of centromere DNA, element III (5'-TGATTTATCCGAA-3'). Element III is the most highly conserved of the centromeric DNA sequences, differing by only a single adenine X thymine base pair among the four centromere DNAs sequenced thus far. All of the element III sequences contain specific cytosine X guanine base pairs, including a 5'-CCG-3' arrangement, which we targeted for single cytosine-to-thymine mutations by using sodium bisulfite. The effects of element III mutations on plasmid and chromosome segregation were determined by mitotic stability assays. Conversion of CCG to CTG completely abolished centromere function both in plasmids and in chromosome III, whereas conversion of CCG to TCG decreased plasmid and chromosome stability moderately. The other two guanine X cytosine base pairs in element III could be independently converted to adenine X thymine base pairs without affecting plasmid or chromosome stability. We concluded that while some specific nucleotides within the conserved element III sequence are essential for proper centromere function, other conserved nucleotides can be changed.
Base Composition↗
[Changes in the historiography of medicine and the sciences in their social context. 75th anniversary of the Karl Sudhoff Institute, Leipzig].
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Academies and Institutes↗
Studies on the lissamine green distribution in three model rat tumors.
In order to gain knowledge on the extent of distribution of chemotherapeutical agents through the blood systems of various tumors, we studied as an indicator the lissamine green concentrations in various tumor segments after different exposure times. As model tumors we used the autochthonic benzpyrene fibrosarcoma and the transplantable tumors Walker and Yoshida in Sprague-Dawley rats. Remarkable differences in the providing blood vessel were observed.
Animals↗
Experimental investigations on the influence upon the chemical carcinogenesis. IInd communication: studies with 3,4-benzopyrene.
After subcutaneous application of 0.5 mg 3,4-benzopyrene (BP) to Sprague-Dawley-rats on the 2nd day of life, 50% of the animals developed local fibrosarcomas after 250 +/- 70 days. Additional treatment with immunostimulating (BCG, albumin, vitamin A-acid) or immunodepressive agents (hydrocortisone, cyclophosphamide, methotrexat) which was started 6 days after birth and maintained throughout life, did not influence carcinogenesis with respect to tumor incidences and induction periods of tumors.
Animals↗
Experimental investigations on the influence upon the chemical carcinogenesis. IIIrd communication: studies with 1,2-dimethylhydrazine.
After ten times monthly, subcutaneous, injections of 30 mg/kg 1,2-dimethylhydrazine (DMH) to Sprague-Dawley-rats, malignant tumors were found in approximately 90% of the animals after a mean induction period of approximately 330 days. Injections were started on the 2nd day of life and maintained during 10 months. 72% of the tumors induced were formed in the colon, 17% were squamous cell carcinomas of the ear duct, adenosarcomas of the kidney and hepatocellular carcinomas were found in 13 and 11% of the animals, respectively. Additional treatment with immunodepressive (cyclophosphamide, methotrexat, hydrocortisone) and immunostimulating substances (BCG, albumin, vitamin A-acid) as well as an enzyme-stimulating agent (Luminal) did not alter incidences and induction periods of tumors. After application of a vegetarian diet, the rate of liver and kidney tumors was diminished significantly and induction periods of intestinal and ear duct tumors increased.
Animals↗