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Biomedical subjects

B Schultz

Publications and source records attributed to B Schultz.

At least 19 recordsLinked to original sources
PubMed1992

[Reduction of the number of recorded EEG channels for routine monitoring in the intensive care unit].

Monitoring patients in the intensive care unit with the aid of the conventional electroencephalogram employing a large number of recording channels is rather difficult, and can be laborious. This imposes limits on the routine application of this method. To investigate the possibility of developing a new monitoring device for easier application in the ICU, we aimed to establish whether the relevant information provided by a multi-channel EEG could be found in a subgroup of channels, thus reducing the number of channels required. Preferably those channels should be identified for use which are least contaminated by artefacts under routine conditions in the ICU. A total of 150 EEG recordings from the intensive care unit were inspected visually for the presence of artefacts. The derivations C3-P3 and C4-P4 proved to be least contaminated, at 35% and 39%, respectively. In these derivations visual assessment of the EEG was found to be impossible due to artefacts in only 4 and 5%, of all cases, respectively. A data set comprising 52 EEG segments with the fewest possible artefacts, was analysed using time series methods. On the basis of multivariate autoregressive processes, a measure was derived which describes the loss of information associated with a reduction in the number of EEG channels. The computation of the information loss for several channel combinations revealed that the derivations F3-C3, C3-P3 and A1-Cz represent a good compromise between information content, number of channels and frequency of artefacts. Practical experience shows that, at least for the control of sedation, a further reduction to a single channel should be possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Artifacts↗
PubMed1992

Indium-111-leukocyte and gallium-67 imaging in acute sarcoidosis: report of two patients.

Two young women with acute sarcoidosis underwent (111)In-labeled autologous leukocyte imaging because of persistent fevers. Images of one of the women demonstrated faint thoracic lymph node uptake of labeled cells, but no discrete focus suggestive of infection was seen. Images of the second woman were normal. Gallium-67 imaging, performed 48 hr after the leukocyte studies, revealed multiple areas of abnormal radiotracer accumulation corresponding to regions of active sarcoid in both women. These cases suggest that leukocyte imaging is not useful for assessing the extent of disease in patients with sarcoidosis. This technique may be valuable, however, in excluding superimposed infection in these individuals.

Acute Disease↗
PubMed1992

Testing the Gaussianity of the human EEG during anesthesia.

The Gaussian properties of human EEGs, which were measured over various stages of general anesthesia, were tested. The basis of the method was to describe the EEG signals by autoregressive models and to test the normality of the regression residuals with the Shapiro-Wilk statistic. The results show that in general the human EEG during anesthesia can be considered as a realization of a Gaussian stochastic process.

Anesthesia, General↗
PubMed1991

Identification of EEG patterns occurring in anesthesia by means of autoregressive parameters.

In EEG analysis an automatic pattern recognition is of interest. In this paper the usefulness of autoregressive parameters to classify EEG segments recorded during anesthesia is examined. Assuming that the AR parameters are multivariate normally distributed, parametric methods of discriminant analysis can be applied. The results show that AR parameters have high discriminating power and that the lowest error classification rate (smaller than 3%) is obtained by using quadratic discriminant functions. Consequently autoregressive parameters are efficient for classifying EEG segments into general stages of anesthesia.

Adult↗
PubMed1991

[Slowing down of the EEG during hypoventilation in emergence from anesthesia].

Electroencephalographic (EEG) recordings were made using a "Narkograph", which performs an automatic on-line interpretation of electroencephalographic data obtained during anesthesia. The EEG was classified into one of 13 stages from A (awake) to F (very deep narcosis). In 20 of roughly 600 patients EEG changes were observed that could not be explained by the effects of anesthetics. Slowing of the EEG occurred during the transition from controlled to spontaneous ventilation and disappeared after minute ventilation increased. The alterations seen during hypoventilation were similar to the effects of hypoxia described in the literature. During the slowing in the rough EEG, waves appeared that were very regularly formed and corresponded to sharp peaks in the power spectrum. These features are rather atypical of the effects of anesthetics such as thiopental, propofol, halothane, isoflurane, and enflurane and were not observed when patients went back to sleep after extubation. If depth of anesthesia is monitored by EEG recording, clinical circumstances should be taken into account because conditions such as hypoxia may cause alterations of the EEG that bear a resemblance to the effects of anesthetics.

Anesthesia Recovery Period↗
PubMed1990

Airborne asbestos in public buildings.

The U.S. Environmental Protection Agency sampled air in 49 government-owned buildings (six buildings with no asbestos-containing material, six buildings with asbestos-containing material in generally good condition, and 37 buildings with damaged asbestos-containing material). This is the most comprehensive study to date of airborne asbestos levels in U.S. public buildings during normal building activities. The air outside each building was also sampled. Air samples were analyzed by transmission electron microscopy using a direct transfer preparation technique. The results show an increasing trend in average airborne asbestos levels; outdoor levels are lowest and levels in buildings with damaged asbestos-containing material are highest. However, the measured levels and the differences between indoors and outdoors and between building categories are small in absolute magnitude. Comparable studies from Canada and the UK, although differing in their estimated concentrations, also conclude that while airborne asbestos levels may be elevated in buildings that contain asbestos, levels are generally low. This conclusion does not eliminate the possibility of higher airborne asbestos levels during maintenance or renovation that disturbs the asbestos-containing material.

Air Pollutants↗
PubMed1990

[Postoperative ventilation in the "iron lung"].

Postoperative artificial ventilation by using an endotracheal tube may cause a pulmonary infection. A possibly necessary permanent sedation and relaxation may result in an additional danger for the patient. The principle of the "iron lung" represents an alternative to endotracheal artificial respiration, which applies especially to endangered patients who are under postoperative artificial respiration. After an abdominal operation five patients have been extubated and artificially respirated by using the "iron lung" principle while not being able to breath by themselves. The degree of the sedation was monitored both intraoperatively and postoperatively using an automatic EEG classification. The performance spectrum of the respiratory curve enabled very early detection of the onset of spontaneous respiration.

Abdomen↗
PubMed1990

[The effects of ketamine on the electroencephalogram--typical patterns and spectral representations].

In 40 female patients aged between 17 and 79 years, the pre- and intraoperative EEG was recorded and processed by personal computer. For induction of general anesthesia patients received between 2 and 3 mg/kg ketamine i.v. within 30 s. In the phase of diminished ketamine effects enflurane was given in addition. Activity in the theta band was observed in all patients during general anesthesia, and in 30% there were complexes. These complexes differ in their spectral content of burst suppression patterns. Under effect of ketamine nearly all patients showed fast beta waves in the EEG. It is proposed that the spectral domain of EEG evaluations be enhanced to an upper limit of 45 Hz.

Adolescent↗
PubMed1987

Fulminant infections of odontogenic origin.

The dentition is a common source of infection in the head and neck and most odontogenic infections respond uneventfully to proper dental therapy. Some more fulminant odontogenic infections can produce complications including airway obstruction, necrotizing fasciitis, and extension of the infection to the orbits, intracranial structures, and thorax. Six such cases treated by the authors are presented and recommendations for management including aggressive antimicrobial, therapy-based bacteriology and surgical drainage and debridement are made.

Airway Obstruction↗
PubMed1978

Decreased serum complement in the Gardner-Diamond syndrome: immunofluorescent findings and association with angioimmunoblastic lymphadenopathy.

Immunologic and immunofluorescent profiles of two patients with the Gardner-Diamond syndrome are described. During the time ecchymoses were present, both patients had decreased serum complement levels; when the lesions healed, the serum complement level returned to normal. One patient had associated angioimmunoblastic lymphadenopathy and subepidermal deposits of immunoglobulin IgM at the basement membrane of ecchymotic skin. The other patient had a normal immunofluorescent pattern. Both patients had increased B-cell counts. The association of immunologic and immunofluorescent findings in patients with the Gardner-Diamond syndrome is suggestive and deserves further study.

Adult↗
PubMed1978

The response to insulin by adipose tissue of insulin-dependent diabetics in vitro.

Subcutaneous adipose tissue was removed by surgical biopsy from 10 normal subjects and 4 insulin-dependent diabetics under exact intracutaneous anaesthesia. The adipose tissue fragments or isolated fat cells were incubated with a tracer amount of labeled glucose. In the presence of insulin (62.5 muU/ml) the production of carbon dioxide from glucose by adipose tissue fragments of nonobese controls as well as diabetics increased up to 286 +/- 62% and 198 +/- 14.7%, respectively. Furthermore, triglyceride synthesis was raised to 257 +/- 30% and 267 +/- 34%, respectively. There were no differences in the sensitivity of adipose tissue to insulin of healthy volunteers and juvenile diabetics.

Adipose Tissue↗
PubMed1976

[Stimulation of growth hormone and prolactin secretion with TRH in acromegaly (author's transl)].

Inappropriate stimulation of growth hormone (hGH)-secretion with TRH in acromegalic subjects has been shown previously, whereas prolactin (hPRL) secretion was reported to be blunted in active acromegaly. In this study TRH induced hGH and hPRL secretion was investigated in 23 active (mean hGH level: 68.5 +/- 19.9 ng/ml; +/- SE) and 15 inactive acromegalics (mean hGH level: 2.3 +/- 0.4 ng/ml; +/- SE). Fourteen of the active acromegalics showed a significant increase up to more than double of the basal hGH level after 200 mug TRH while in only one of the inactive acromegalics an inappropriate rise of hGH was induced by TRH. Basal hPRL levels were elevated in 9 and within normal range in 14 of the patients with active acromegaly. Except in 3 patients who had normal basal hPRL levels and in one patient with excessively elevated hPRL and hGH levels due to an hPRL and hGH producing adenoma, all patients had normal hPRL responses to TRH. In those with inactive acromegaly, 9 had hPRL levels below normal and only , out of the 15 patients showed a normal rise of hPRL after TRH. The patients who showed no hPRL response to TRH demonstrated also other signs of pituitary insufficiency due to the operative procedure. In contrast to a previous report these findings demonstrate that normal or enhanced hPRL secretion is found in active acromegaly. The inappropriate rise of hGH after TRH is compatible with a loss of specificity of the receptor for GRH of the adenoma cell and can be found also in patients with normal basal hGH levels after treatment suggesting that remaining adenoma tissue is present in the pituitary fossa.

Acromegaly↗