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J Radke

Publications and source records attributed to J Radke.

At least 55 records · Page 3Linked to original sources
PubMed1996

Dopamine-somatostatin interactions in the rat striatum: an in vivo microdialysis study.

Dopamine-somatostatin interactions were investigated in the rat striatum using in vivo microdialysis. Somatostatin-14 and somatostatin-28 (10(-4), 10(-5), 10(-6) M) were infused, and the levels of dopamine and its metabolites DOPAC and HVA were assessed using high pressure liquid chromatography with electrochemical detection. Somatostatin-14 was more effective than somatostatin-28 in producing a dose-dependent increase in dopamine levels with no significant alterations in the levels of the metabolites. To assess the effect of dopamine on somatostatinergic neurons, dopaminergic agents were administered and somatostatin levels measured using a radioimmunoassay. The nonselective agonist apomorphine was administered subcutaneously (0.00, 0.05, 0.10, 0.50, 1.00 mg/kg) or directly infused (10(-4), 10(-5) M) in the striatum. The selective D1 and D2 dopamine antagonists SCH23390 and sulpiride, respectively, were also infused at concentrations of 10(-4) and 10(-5) M. None of these agents elicited any significant changes in the somatostatin release in the striatum, while altering dopamine release. This study provides for the first time evidence regarding dopamine-somatostatin interactions in the awake and freely moving animal. The results confirm that somatostatin modulates the function of dopaminergic neurons in the striatum and provide new evidence that somatostatin-14 may differentially regulate dopamine release. Furthermore, our findings suggest that dopamine does not play a major role in the regulation of somatostatin neurons.

Animals↗
PubMed1996

[The perioperative use of recombinant erythropoietin (rhEPO) in Jehovah's witnesses].

UNLABELLED: Erythropoietin, the hematopoietic growth factor, is synthesised in the kidneys and liver and regulates red blood cell production. Within the last few years, recombinant DNA technology has produced synthetic erythropoietin (rhEPO). Some patients, especially Jehovah's Witnesses, will not accept blood transfusion. The perioperative administration of rhEPO increases the patients' hematocrit (HCt) to a higher than physiological level. METHODS AND RESULTS: We report a case of a 66-year-old female Jehovah's Witness who refused blood transfusions and responded favourably to rhEPO treatment. A total hip arthroplasty was planned. A pretreatment hemoglobin level (Hb) of 13.7 g/dl and HCt of 43% were documented. After preoperative subcutaneous application of 5000 I.E. rhEPO three times per week and daily oral substitution of 300 mg ferrous sulfate over a period of 3 weeks, the Hb increased to 15.5 g/dl and the HCt to 49%. The operation was carried out after the ninth application of rhEPO. Postoperatively, the Hb concentration was 11.8 g/dl and the HCt 35%. Therefore, postoperative administration of rhEPO was not considered indicated. No side effects of rhEPO application were noted. The patient left hospital on the 10th postoperative day. CONCLUSIONS: The case report describes perioperative management using human rhEPO in Jehovah's Witnesses. Treatment with rhEPO increases preoperative Hb levels to a point making it possible to compensate for operative blood loss. RhEPO combined with daily iron substitution may be useful in patients who refuse transfusion based on religious convictions.

Aged↗
PubMed1996

-Cytokine level in malignant ascites and peripheral blood of patients with advanced ovarian carcinoma-.

The concentrations of various cytokines were examined by ELISA in blood and in ascites from 14 patients with advanced ovarian cancer (stage IV). The control group consisted of 6 patients with benign gynaecological disorders. Compared with patients with benign gynaecological disorders, ascites and/or plasma of patients with ovarian cancer showed significantly higher levels of IL-6, IL-8, IL-10, TNF-alpha, and sIL-2R. There were no increases of IL-1 alpha, IL-1 beta, IL-2, IFN-gamma, and sCD14 levels. The possible pathogenetic significance of cytokines in ovarian cancer is discussed.

Adult↗
PubMed1995

[Anesthesiologic problems in polytrauma patients].

The anaesthesiological problems concerning the primary care of multiple trauma patients are diverse. In addition to the specific anaesthesiological tasks such as protection of the vital functions by ventilation and volume replacement, the anaesthetist has further responsibilities. Often he has to coordinate primary diagnostics and care. He has charge of effective analgetic therapy, too. Taking all this into account, the specific and general duties require an anaesthetist with wide clinical experience in dealing with multiple trauma patients.

Analgesia↗
PubMed1995

[Interactions between renal and general hemodynamics in fentanyl, droperidol, ketamine, thiopental and in peridural anesthesia--animal studies].

The main focus of this paper is to show regulative interactions between cardiac index (CI) and renal blood flow (RBF) with various intravenous anaesthetics under steady state conditions. Several experimental series were carried out on dogs with the following anaesthetic doses (as given per hour and per kilogram body weight-h-1 x kg-1): fentanyl 50 micrograms, ketamine 4 and 10 mg, and thiopentone 10 and 20 mg. The basic anaesthesia used was halothane (0.7 vol.%) in N2O/O2 (ratio about 3:1), because renal function, renal autoregulation and responsiveness to renally effective drugs remain nearly unaltered by this anaesthetic procedure. The experimental set-up allowed separate evaluation of effects caused by basic anaesthesia, by intravenous anaesthetic under examination or by the combination of both. All physiological parameters, such as blood gas parameters, plasma electrolytes and intravasal volume were kept in normal range throughout the experiments. Under all anaesthetics studied, RBF reflects the situation of general metabolism especially of cardiac output, as long as sympathetic innervation of the kidneys remains unaltered. Especially the relationship between RBF and CI corresponds with regulative effects in situations without anaesthesia. Within the blood pressure range of autoregulation RBF is greater under ketamine than normal and smaller under fentanyl and etomidate, whereas all other anaesthetics applied show no effect on RBF. Functional "denervation" of the kidney by means of epidural anaesthesia is capable of terminating those effects caused centrally by opioids and transmitted by sympathetic nerves. Diuresis is increased by thiopentone and by ketamine, whereas fentanyl reduces it. The activity of the plasma renin level does not correspond with the degree of renal vascular resistance. The effect of each anaesthetic drug on RBF has principally to be taken as regulative adaptation to altered circulatory conditions. Increasing plasma renin levels are mainly a compensatory reaction following a decline in arterial blood pressure due to anaesthesia induced sympathicolysis. With regard to renal function, the additional use of epidural anaesthesia (functional "denervation" of the kidney) can be recommended especially for highly invasive surgical procedures to antagonize reduction of RBF, which is often induced sympathetically by pain or by commonly used anaesthetic drugs.

Anesthesia, Epidural↗
PubMed1994

[Effect of granulocyte colony stimulating factor (G-CSF) on peripheral blood leukocytes and lymphocytes in patients with chemotherapy-induced leukopenia].

In patients with extensive chemotherapy, G-CSF abrogated leukopenia following administration of cytotoxic agents. Six women with ovarian cancer and chemotherapy-induced leukopenia received 300 micrograms Filgrastrim (r-metHuG-CSF, Neupogen 30; AMGEN, Germany) daily for 10 days. Leukocytes and lymphocyte subsets of peripheral blood were determined before, throughout and after subcutaneous injections of G-CSF by flow cytometry using monoclonal antibodies to CD3, CD4, CD8, CD14, CD16/56, CD19 and CD45. It could be observed that not only neutrophils (23 fold) but also lymphocytes (6 fold) and monocytes (10 fold) showed a dramatic increase in cell counts throughout and after G-CSF administration. This is in contrast to previous reports, where only effects on neutrophils were described. In spite of the increase in lymphocytes the relative percentage of CD3+, CD19+, CD3-CD16/CD56+, CD3+, CD8+ and CD3+ CD4+ lymphocyte subsets did not change throughout and after therapy, except for an increased expression of HLA-DR on CD3+ lymphocytes.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

[Leukocyte and lymphocyte populations in peripheral blood and malignant ascites in patients with ovarian carcinoma].

Ascites and peripheral blood of 12 patients with advanced ovarian cancer (stage IV) have been investigated by two-color flow cytometry for leukocytes and lymphocyte subsets with monoclonal antibodies, against CD3, CD4, CD8, CD14, CD16/56, CD19, CD25, CD45, CD57, and HLA-DR. Ascites compared with blood showed a significant raise of CD3-positive lymphocytes (80 +/- 14% vs. 69 +/- 8%) and a significant reduction of CD57-positive lymphocytes (13.6 +/- 13% vs 24 +/- 21%). There was an increased expression of HLA-DR on CD3-positive lymphocytes in malignant ascites. The results are discussed with regard to a supposedly defective local immune defense against the tumor.

Antibodies, Monoclonal↗
PubMed1993

High-dose intravenous magnesium sulfate in the management of life-threatening status asthmaticus.

In severe status asthmaticus basic medical treatment often fails to improve the patient's condition. Mechanical ventilation in this situation is associated with a high incidence of serious complications. After the bronchodilating effect of moderate-dose magnesium sulfate in asthmatic patients had been demonstrated in previous studies we treated five mechanically ventilated patients with refractory status asthmaticus successfully with high dosages of MgSO4 IV (10-20 g within 1 h depending on the bronchodilating effect). MgSO4 resulted in a significant decrease of peak airway pressure (43.0 +/- 6.8 to 32.0 +/- 8.0 cmH2O) and inspiratory flow resistance (22.7 +/- 7.0 to 11.9 +/- 6.0 cmH2O.l-1.s-1) within 1 h. The resulting serum magnesium levels after one hour were up to threefold of the normal serum levels. Although a maintainance dose of 0.4 g/h had been administered continuously during the following 24 h serum magnesium decreased towards normal values within this time. The only relevant side-effect was a mild to moderate arterial hypotension in two of the five patients during the high dose administration period of MgSO4 which responded readily to dopamine treatment.

Adult↗
PubMed1992

The influence of isoflurane on peri-operative endocrine and metabolic stress responses.

Trauma and surgery profoundly affect the circulating concentrations of metabolites and so-called stress hormones, and may thereby directly or indirectly influence recovery. This stress response on the other hand is subject to modification by the anaesthetics employed. We investigated the effects of isoflurane on selected stress parameters in 10 patients undergoing major abdominal surgery and compared them to those in 10 patients receiving halothane. Plasma levels of adrenaline, noradrenaline, cortisol, ACTH, and beta-endorphin, as well as glucose, non-esterified fatty acids (NEFA), and lactate were determined during a pre-operative anaesthesia period as well as intra- and post-operatively. The levels of all parameters remained stable or decreased during the pre-operative anaesthesia period. They increased intra- and/or post-operatively, reaching peak values in the recovery period. Although the changes in both groups were basically similar, we observed lower serum concentrations of cortisol and lactate in the isoflurane group. We conclude that isoflurane and halothane have similar effects on peri-operative changes of endocrine and metabolic parameters, and that neither can effectively block the stress response to major surgery. We found no firm evidence for a stimulatory effect of isoflurane on the parameters studied.

Adrenocorticotropic Hormone↗
PubMed1992

[Analgesia and sedation in intensive care patients].

Analgesia and sedation with the associated reduction of undesired vegetative reactions are important components in the therapeutic regimen of intensive care patients. None of the sedative drugs available can fulfil every one of the criteria expected of an "ideal" sedative. Four commonly used drug combinations have been established as standards: 1. opioid and neuroleptic, 2. opioid and benzodiazepine, 3. ketamine and benzodiazepine, and 4. opioid and propofol. In everyday use one must take not only the specific side-effects of a drug into consideration but also its pharmacokinetic properties. These are often markedly altered in critically ill patients who have impaired functions of vital organs. The pharmacokinetics of a drug is affected by disturbed renal or hepatic function, interactions with other drugs, altered protein binding and the induction or inhibition of metabolic enzymes. The best method of drug administration is by motor-driven pump, with which large fluctuations of the dosage can be avoided. Constant ratios of drug combinations are not recommended, since the pharmacokinetics of each drug is affected to a different degree in the critically ill patient. Withdrawal symptoms, can occur for example after prolonged administration of benzodiazepines, can often be avoided by slowly reducing the dose or by switching to a short-acting substance. In some patients (e.g. those with a history of alcohol abuse) a massive increase of the drug dose is not indicated when the effect is not adequate. Instead, an entirely different substance should be employed and the administration of less frequently used drugs should be considered. Despite detailed knowledge of the altered pharmacokinetics in critically ill patients, the drugs should be dosed as dictated by the situation, true to the anaesthesiologists' adage: "Dosage according to effect!"

Analgesics↗
PubMed1992

[Endotracheal suctioning using a 24-hour continuous system. Can costs and waste products be reduced?].

Suctioning of the airways is often required in critically ill, intubated, or tracheotomised patients. In addition to the primary cost of these disposable materials, expenditures for waste disposal and environmental problems due to plastics should also be considered. In this study, the primary costs and amount of waste products of the closed suction system "Trach Care" were compared with a conventional disposable system. Other advantages and disadvantages of a closed suction system are discussed. METHODS. In this prospective, randomised investigation, both the open disposable suction system and the closed Trach Care system were used, in 60 patients (30 in each group) who were intubated for 1 week or more. During the first 7 days, we counted the number of times endotracheal suctioning was performed and measured the time it took. The costs of purchasing the systems, amounts of waste products, and costs of disposal were compared. RESULTS. The frequency of endotracheal suctioning was quite different from patient to patient and varied from 6 to 41 times per day. On average it was necessary 15 times per day per patient in both groups. Using the disposable system, a mean time of 3.5 min was measured in contrast to 2.5 min with the closed system. The costs of purchase were much lower with the disposable system taking into account all materials needed (17.36 DM vs 53.36 DM per day), whereas the weight of litter produced by the closed system was lower (429 g vs 745 g per day), the costs of disposal being accordingly different. During endotracheal suctioning O2 desaturation was not observed with the closed system, whereas in patients with acute respiratory failure O2 saturation fell rapidly from 90% to as far as 70% when a disposable system was used. CONCLUSION. The closed Trach Care suction system is more expensive to acquire, but may reduce the risk of exogenous nosocomial pneumonias as disconnections from the ventilator are minimised. The workload, weight of waste products, and costs of disposal are lower using the Trach Care system. From the physician's viewpoint, the main advantage of the Trach Care system becomes evident in patients with acute respiratory failure and patients with elevated intracranial pressure. In these cases, we now favor the Trach Care system as a matter of principle.

Anesthesiology↗
PubMed1991

[Gas embolism with cardiac arrest during hysteroscopy. A case report on 3 patients].

Hysteroscopy and laparoscopy are relatively non-invasive methods routinely employed in the investigation of infertility. The danger of air embolism during these procedures was recognized early, and carbon dioxide was substituted for air since it is more readily soluble in blood. In this report we describe 3 cases of circulatory collapse and cardiac arrest in healthy young women during routine hysteroscopy (out of a total of 62 patients during the period 1989-1990) which were most probably caused by massive carbon dioxide embolism. Premedication was with oral diazepam 10 mg. Anesthesia was induced with 0.1 mg fentanyl, 2.5 mg droperidol and 100 mg methohexital (100 mg propofol in one case). Intubation was facilitated with 2 mg pancuronium and 50-100mg succinylcholine. Anesthesia was maintained with nitrous oxide 66% and halothane. Ventilation was controlled with a tidal volume of 10 ml per kilogram body weight at a rate of 10 per minute. Monitoring included ECG, automated non-invasive blood pressure, capnometry, pulse oximetry and body temperature. Anesthesia was uneventful prior to insufflation. In each case the signs and symptoms began approximately 5-8 minutes after the start of insufflation and consisted of an initial tachycardia rapidly followed by ventricular dysrhythmias, bradycardia and cardiac arrest. The end-tidal CO2 decreased during the tachycardic phase and prior to asystole. The patients were cyanotic with engorged jugular veins. Resuscitation with closed chest heart massage and intravenous epinephrine or orciprenaline was successful in every case. The typical "mill wheel phenomenon" of gas embolism was audible on auscultation after heart activity had returned, but disappeared after about 5 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Haemodynamic and endocrine effects of deliberate hypotension with magnesium sulphate for cerebral-aneurysm surgery.

Deliberate hypotension is widely used during cerebral-artery aneurysm surgery to facilitate clipping and to prevent rupture. A large number of drugs are commonly employed to achieve hypotension, but all have their specific drawbacks. We investigated the effects of magnesium-sulphate-induced hypotension on haemodynamics, as well as on plasma catecholamine and renin concentrations in 11 patients undergoing cerebral-aneurysm surgery. Magnesium sulphate lowered blood pressure by reducing systemic vascular resistance. There was no reflex tachycardia or rebound hypertension, and cardiac output was not decreased. Plasma renin activity increased during hypotension but the inhibitory effects of magnesium on angiotensin converting enzyme prevented angiotensin-II-associated hypertension. Plasma catecholamine concentrations increased moderately during hypotension. Renal perfusion was not impaired since diuresis remained constant or even improved during and after hypotension. Magnesium sulphate in high doses has major drawbacks, however, among which are enhanced neuromuscular blockade and delayed return of consciousness. Although the haemodynamic effects of magnesium sulphate during hypotension appear to be beneficial, these side-effects might limits its usefulness, particularly in neurosurgery. More research must be conducted before magnesium sulphate can be considered a routine method.

Adult↗
PubMed1991

[The ozone layer and its modification by N2O and inhalation anesthetics].

As a result of human activities the ozone layer in the stratosphere, which is necessary for life on earth, has changed. The main causes of ozone destruction are chlorofluorcarbons (CFCs) 11 and 12. Recently, caring anesthetists have wondered if and to what degree N2O and popular potent inhalation anesthetics may also contribute to ozone loss. Having consulted the literature, we attempt to answer that question. The ozone-destroying N2O is chiefly produced by burning fossil elements and nitrogenous fertilizing used in agriculture; the share of medically used N2O lies below 2%. Halothane, enflurane, and isoflurane are halogenated anesthetics that contain ozone-destroying halogens (bromine, chlorine, fluorine) to different extents. Complicated experimental calculations for these volatile anesthetics result in a potential for ozone destruction of 0.36 for halothane and 0.02 for enflurane and isoflurane if the potential for ozone destruction by CFCs is set at 1.0. The lifespan of the inhalation anesthetics in the troposphere is with less than 3 years, dramatically less than that of CFCs (70-140 years). The two most important CFCs, 11 and 12, are considered to be currently produced in a quantity of about 800,000 tons per year. On the other hand, the worldwide production of inhalation anesthetics is said to be only 2,000 tons. In view of the experimental calculations and the low worldwide production, the small greenhouse effect, the shorter lifespan in the troposphere, and the low potential for ozone destruction, the negative effects of medically used N2O and inhalation anesthetics on the ozone layer seem negligible. All in all, the inhalation anesthetics are considered to be responsible for only 0.0005% of the ozone destruction at present.

Air Pollutants↗
PubMed1991

[Deterioration of pulmonary gas exchange caused by PEEP in a pulmonary vascular shunt (Rendu-Osler-Weber syndrome)].

A 25-year-old patient with headache was admitted to the neurology department. Computerized tomography revealed an intracerebral abscess of unknown origin, which was removed by craniotomy. After an uneventful operation and anesthetic low arterial oxygen tensions were noted that did not respond to increased FiO2. Angiography revealed a pulmonary arteriovenous (a-v) fistula (angioma), which was responsible for the right-left shunt. A Swan-Ganz catheter was inserted and the effects of varying levels of PEEP on the magnitude of the shunt during spontaneous breathing of 100% oxygen were determined. At zero PEEP the arterial pO2 was 211 mm Hg (AaDO2 470 mm Hg). 5 mbar PEEP caused the arterial pO2 to fall to 118 mm Hg (AaDO2 563 mm Hg). Increasing PEEP to 15 mbar caused a further decrease in arterial pO2 to 72 mm Hg (AaDO2 603 mm Hg), which resulted in arterial desaturation. The arterial pCO2 remained constant. At a virtually constant cardiac output the shunt volume increased from 23% at zero PEEP to 30% at a PEEP of 15 mbar--a relative increase of 30%. Elevating the intrathoracic pressure presumably caused redistribution of the pulmonary perfusion toward the shunt vessels, probably because the vascular resistance increased more rapidly in the normal vasculature than in the angioma. The therapeutic consequences were to reduce the PEEP and avoid mechanical ventilation. Pulmonary a-v-fistulas are not uncommonly associated with brain abscesses, probably because the normal filter function of the pulmonary vascular bed is disrupted. Therapy consists either in resecting the afflicted lung segment or in transvenous occlusion of the fistula with a silicon ballon.

Adult↗
PubMed1990

[Control of the placement of a central venous catheter using Doppler ultrasound].

Precise placement of central venous catheters is necessary to prevent complications and assure proper functioning. Chest X-ray is the current standard method of locating the catheter tip. This is usually not feasible in the operating room setting, particularly after the induction of anesthesia. Intravascular ECG registration using the catheter as a lead and identification of intra-atrial P-waves has been suggested as an alternative. In the present study we evaluated the use of Doppler sonography as a noninvasive method of locating the catheter tip and detecting faulty placement. Two hundred patients scheduled for insertion of a central venous catheter took part in this study. The catheters were inserted via standard routes (internal or external jugular vein, basilar or cephalic vein). A Doppler sonographic device with a 2 mHz probe was used (Parke Electronics 915L). The probe was applied to the right sternal border and affixed at the position where the characteristic venous flow sound was most distinct. The signals were displayed visually, subjected to spectral analysis, and also recorded for later evaluation. A rapid injection of 2-5 ml isotonic saline causes turbulences which can readily be heard and recognized without special training. The position of every catheter was later confirmed by radiography, and in 159 patients the intraatrial ECG method was subjected to direct comparison with the sonographic method. The turbulences due to the injected fluid were found to cause an increased amplitude at frequencies above 350 Hz. If the catheter tip was positioned correctly there was no discernable time lag between the start of the injection and perception of turbulences.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization, Central Venous↗
PubMed1989

[Hemodynamic effects of the benzodiazepine antagonist flumazenil following laparotomy under total intravenous anesthesia using midazolam].

Inhalational anesthetic agents, particularly nitrous oxide, are potentially hazardous to both the patient and operating room personnel. Recent efforts have been directed towards the development of intravenous anesthetic techniques using combinations of a hypnotic with an analgesic. The hypnotic used in such a combination should have a short elimination half-life, little or no influence on hemodynamics, and no side effects. Benzodiazepines are likely candidates for total intravenous anesthesia (TIVA) since they combine hemodynamic stability and paucity of unwanted effects with the ability to induce amnesia for the entire perioperative period. They do have long elimination half-lives; even midazolam, the shortest-acting benzodiazepine, has a half-life of 2 to 3 h. This disadvantage might be counteracted by the use of flumazenil, the recently introduced, specifically acting benzodiazepine antagonist. The aim of this study was to determine the effects of rapid awakening following flumazenil after major abdominal surgery with benzodiazepine-fentanyl TIVA. Six patients (4 male, 2 female) scheduled for elective laparotomies participated in this pilot study. The average duration of surgery was 2.2 +/- 0.9 h. The patients were given 2 mg flunitrazepam p.o. the evening before surgery and 1 h before being brought to the operating room. Baseline pre-induction values were obtained 15 min after inserting catheters and attaching the EEG electrodes. Fentanyl (0.005 mg/kg) was given as a bolus injection followed by a rapid midazolam infusion. The infusion rate was calculated using the method of Wagner et. al. from the data of Lauven et al. to give plasma concentrations of 500 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗