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Biomedical subjects

K Schuster

Publications and source records attributed to K Schuster.

At least 19 recordsLinked to original sources
PubMed2000

Frequency and duration of inattentive behavior after traumatic brain injury: effects of distraction, task, and practice.

Traumatic brain injury (TBI) is associated with impairments of attention, most typically measured through tests of information processing, or by subjective symptom endorsement by patients, families, and clinicians. We have previously shown increased rates of off-task behavior among patients with TBI versus controls as defined by videotaped records of independent work in distracting environments. In this research, we report on a more detailed method of coding such videotaped records which allows measurement of the precise number of off-task behaviors, their durations, and their relationship to distracting events. Using this method, we studied 20 patients with recent moderate-to-severe TBI and 20 demographically comparable controls as they performed independent work tasks while being subjected to controlled distracting events. This research confirms that patients are markedly less attentive than controls both in the presence of distractions and in their absence, that distractions have an influence on off-task behavior in both groups, and that the disruptive impact of distractors wanes relatively quickly for controls but not for patients. The duration of distraction produced by various classes of distracting events appeared similar for patients and controls, although the power to detect differences in behavioral duration between groups was limited. The pattern of inattentiveness among patients showed minimal relationship to measures of injury severity within this sample.

Adolescent↗
PubMed2000

Effect of carnitine on muscular glutamate uptake and intramuscular glutathione in malignant diseases.

Abnormally low intramuscular glutamate and glutathione (GSH) levels and/or a decreased muscular uptake of glutamate by the skeletal muscle tissue have previously been found in malignant diseases and simian immunodeficiency virus (SIV) infection and may contribute to the development of cachexia. We tested the hypothesis that an impaired mitochondrial energy metabolism may compromise the Na+-dependent glutamate transport. A randomized double-blind clinical trial was designed to study the effects of L-carnitine, i.e. an agent known to enhance mitochondrial integrity and function, on the glutamate transport and plasma glutamate level of cancer patients. The effect of carnitine on the intramuscular glutamate and GSH levels was examined in complementary experiments with tumour-bearing mice. In the mice, L-carnitine treatment ameliorated indeed the tumour-induced decrease in muscular glutamate and GSH levels and the increase in plasma glutamate levels. The carnitine-treated group in the randomized clinical study showed also a significant decrease in the plasma glutamate levels but only a moderate and statistically not significant increase in the relative glutamate uptake in the lower extremities. Further studies may be warranted to determine the effect of L-carnitine on the intramuscular GSH levels in cancer patients.

Adult↗
PubMed1999

HLA-DR expression in acute pancreatitis.

OBJECTIVE: To investigate the role of the monocyte/macrophage system in acute pancreatitis DESIGN: Prospective clinical study SETTING: University clinic, Germany SUBJECT: 37 consecutive patients who presented with acute pancreatitis. MAIN OUTCOME MEASURE: Correlation between function of monocytes measured by HLA-DR expression and outcome RESULTS: Patients were divided into three groups according to outcome: those with severe pancreatitis who died (n = 10), those with severe pancreatitis who survived (n = 15), and those with mild pancreatitis who survived (n = 12). There was a clear and significant difference between those with severe and those with mild disease. HLA-DR expression was initially depressed in both groups, but after the third day of treatment it started to recover significantly in those with mild disease (p < 0.05). The difference was also significant from day 7 onwards between those with severe disease who died and those with severe disease who survived (p < 0.05). CONCLUSION: Monocyte function as measured by HLA-DR expression (CD14+DR+) is reduced in patients with acute pancreatitis and does not recover in patients who are going to die (median < 20 relative antigen density units; RU).

Adult↗
PubMed1998

Nitric oxide used to test pulmonary gas exchange in rabbits.

To evaluate whether nitric oxide (NO) is an appropriate test gas for assessing pulmonary gas exchange, we determined the rates of disappearance from the alveolar space (lambda) of NO and singly and doubly 18O-labelled carbon dioxide (C16O18O, C18O2) by performing single-breath manoeuvres on seven artificially ventilated rabbits. By exploiting unique features of both isotopic species and by analysing pulmonary gas transport and lambda values with a commonly used model, we found that diffusion forms 98+/-6% (mean +/- SD) of the overall resistance to alveolar-capillary NO transfer. This means that measurements of pulmonary NO uptake reveal the entire diffusive properties of the alveolar-capillary membrane, because the extremely fast binding of NO to haemoglobin negates the "reactive" component within red blood cells of pulmonary capillaries.

Animals↗
PubMed1998

Role of reaction resistance in limiting carbon monoxide uptake in rabbit lungs.

The contribution of reaction resistance to overall resistance to pulmonary carbon monoxide (CO) uptake [DLCO/(ThetaCO . Vc), where DLCO is lung CO diffusing capacity, ThetaCO is CO uptake conductance of erythrocytes, and Vc is pulmonary capillary blood volume] was determined in 10 anesthetized, paralyzed, and artificially ventilated rabbits. On the basis of the classical double-reciprocal equation of F. G. W. Roughton and R. E. Forster (J. Appl. Physiol. 11: 290-302, 1957), DLCO/(ThetaCO . Vc) was obtained by solving the relation DLCO/(ThetaCO . Vc) = 1 - 2/(DLNO/DLCO), where DLNO/DLCO represents the ratio between the respective single-breath diffusing capacities (DL) of nitric oxide (NO) and CO pulmonary capillary blood. The lungs of eight rabbits were inflated, starting from residual volume, by using 55 ml of indicator gas mixture (0.2% CO and 0.05% NO in nitrogen). DL values were calculated by taking the end-tidal partial pressures of CO and NO as analyzed by using a respiratory mass spectrometer. The overall value was DLCO/(ThetaCO . Vc) = 0.4 +/- 0.025 (mean +/- SD). Because of the use of O2-free indicator gas mixtures, the end-tidal O2 partial pressures were approximately 21 Torr. In one other rabbit, the application of 0.2% CO and 0.001% NO yielded DLCO/(ThetaCO . Vc) = 0.39; in the tenth rabbit, however, inspiratory volume was varied, and an identical value was found at functional residual capacity. We conclude that the contribution of reaction resistance to overall resistance to pulmonary CO uptake is independent of the inspiratory NO concentration used, including, with respect to the pertinent literature, the conclusion that in rabbits, dogs, and humans this contribution amounts to 40% when determined at functional residual capacity.

Animals↗
PubMed1997

In vitro cytokine secretion and maturation phenotype of lymphoma-associated splenic macrophages.

In this study, cytokine secretion capacity and maturation phenotype of human lymphoma-associated splenic macrophages (LASM) were evaluated in a long-term culture. Sixteen spleens from malignant lymphoma patients and five control spleens were investigated. Splenic macrophages (SM) were isolated by teflon adherence and cultured for 6-48 days. Secretion of IL-1 alpha, IL-6 and TNF alpha was measured by ELISA following maximal stimulation with LPS and IFN-gamma, and cytokine mRNA expression was detected by in situ hybridization. Immunohistochemical expression of maturation-associated antigens was evaluated semiquantitatively. Cytokine secretion capacity was significantly altered in LASM which exhibited reduced TNF alpha and IL-6, but elevated IL-1 alpha secretion when compared to control SM. Alterations of cytokine secretion capacity were associated with a modification of LASM maturation phenotype, showing impaired expression of early and chronic/late inflammatory markers. These findings obtained from a long-term culture model suggest that malignant lymphomas induce lasting modifications of cytokine secretion and maturation patterns in LASM.

Adult↗
PubMed1997

Healthcare re-visits the commissary concept.

Commissary production can cost more in the early stages because of investments in equipment and training. But these systems often deliver improved quality, better control, greater efficiency and more meals per man hour.

Capital Financing↗
PubMed1997

Trocar incision and closure: daily problems in laparoscopic procedures--a new technical aspect.

A mini-laparotomy as described by Hasson was used in a modified way in 1,500 laparoscopic procedures. In comparison with the insertion of a Veress needle, we find the open approach to be a safer and quicker technique to obtain the pneumoperitoneum. A new technique for closure of the trocar incision is described. The technique is recommended due to its easy and safe approach requiring no additional special equipment.

Humans↗