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Biomedical subjects

M Georgieff

Publications and source records attributed to M Georgieff.

At least 199 records · Page 11Linked to original sources

[Fats in parenteral nutrition].

This paper aims at presenting the properties and actions of individual lipids, as determined via various animal experiments, on the organ systems of the area of the splanchnicus and the lung that are of particular relevance for the intensive-care physician, and to derive possible therapeutic options form these data. Although so far no data are available on newly introduced kinds of fat such as fish oil used in parenteral feeding of critically ill patients, it will be the aim of future therapeutic concepts to arrive at optimal combinations for the individual patient of the pharmacological, energetic and essential properties of the individual classes of fatty acids. Structured lipids may possibly be suitable for this task in an ideal manner, the glycerol molecule of which is esterified with linoleic acid as an essential constituent of food, a medium-chain fatty acid as energy carrier, and an omega-3 fatty acid as immunomodulator. The question as to whether such mixtures can eventually be administered in a not too distant future to parenterally fed patients after trauma and during septic condition for their benefit, can be answered only by means of clinical studies that will have to be conducted in years to come.

Animals↗

[Comparison of 5% human albumin and 6% 200/0.5 HES as exclusive colloid components in large surgical interventions].

OBJECTIVE: It was the purpose of the following study to compare effects of 6% hydroxyethyl starch 200/0.5 (HES) and albumin 5% (HA5) on haemostasis, haemodynamics, oncotic function and plasmatic homoeostasis. METHODS: In 2 randomised groups of 20 patients each undergoing large surgery (criteria of exclusion: anaemia, renal, liver, and coagulation disorders, ASA classification > III) we treated up to 1000 ml with colloid solution, from 1000 ml up to 5000 ml with packed red blood cells (PRBC) and colloid solution (1:1) and above 5000 ml with PRBC and fresh frozen plasma (1:1). Group HES received HES and group HA5 albumin as exclusive colloid component and both continuously lactated Ringers' at a rate of 500 ml/h. We measured the parameters before operation, after each 1000 ml colloid up to 3000 ml application and at the end of operation and we registered total blood output/intake. RESULTS: We found comparable amounts of blood loss and blood intake (mean total amount of colloid solution: HES 2044 +/- 579 ml; HA5 2547 +/- 980 ml). We didn't find any differences in haemodynamics nor in haematocrit, platelets or global coagulation parameters which only showed dilutional influences. Differences existed in total serum protein (HES 32.8 +/- 6.5 gr/l; HA5 54 +/- 5.5 gr/l at OP's end); however COP was maintained in both groups during the whole study period at normal ranges. Plasmatic haemostasis showed to a large extent corresponding values. Remarkable was the development of a metabolic acidosis in the HA5 group. CONCLUSION: Regarding total blood output/intake, haemodynamic functions, haematological parameters, coagulation, oncotic function, and plasmatic homoeostasis, HES is a safe colloid if contra-indications are taken into account, capable of replacing albumin 5% entirely as a colloid component of treatment of even large blood losses intraoperatively above the recommended dose of 20 ml/kg BW/d.

Adult↗

[Modification of ventilation and length of stay of traumatized intensive care patients by quality and duration of preclinical management].

AIM: The study aimed at detecting relations between the quality and duration of prehospital care in the case of traumatic patients and the duration of artificial respiration and ICU stay times. DESIGN: 94 traumatic patients, admitted to the intensive care unit, were subdivided into groups according to the type of trauma. The mean time of prehospital care, injury severity score, the Apache II at the admission to the clinic and the discharge to the ICU, intraoperative replacement of blood and clinical care times were calculated. RESULT: In the group of all patients, times of the ICU-stay were correlated to the ISS and the Apache II of the hospital admission. In the group with multiple fractures, a positive correlation to the prehospital care times was found. DISCUSSION: Quality and duration of the prehospital care were identified as factors, influencing the time of the ICU stay. Optimizing these factors will be helpful in respect of economic considerations.

APACHE↗

Influence of phenylephrine bolus administration on left ventricular filling dynamics in patients with coronary artery disease and patients with valvular aortic stenosis.

BACKGROUND: Left ventricular diastolic function is known to be impaired in patients with coronary artery disease and patients with valvular aortic stenosis. Phenylephrine is frequently administered as an intravenous bolus in these patients perioperatively to increase coronary perfusion pressure. Although this is common practice, there is no information about the effect of phenylephrine bolus administration on left ventricular filling dynamics. METHODS: Twenty patients with coronary artery disease (group 1), 15 patients with valvular aortic stenosis (group 2), and 10 subjects without cardiovascular disease (group 3, control) entered the study. Left ventricular filling was evaluated using transesophageal pulsed Doppler echocardiography before and after phenylephrine injection given to patients whose mean blood pressure has decreased by more than 20% (and was not higher than 90 mmHg). We recorded the transmitral blood flow velocity curve and measured peak early and peak atrial flow velocity, acceleration and deceleration time of the early flow velocity peak, and mitral valve diameter. We calculated the ratio of peak early to peak atrial flow velocity (PE/PA), acceleration and deceleration rate of the early flow peak, and peak filling rate. RESULTS: Phenylephrine effectively restored arterial pressure in all three groups. However, in group 1, phenylephrine administration resulted in a reduction of PE/PA, acceleration rate of the early flow peak, and peak filling rate from 1.25 (mean) to 0.75 (P < 0.001), 411 to 276 cm/s2 (P < 0.001), and 439 to 305 ml/s (P < 0.001), respectively. In contrast, in group 2, intravenous phenylephrine increased PE/PA, acceleration rate of the early flow peak, and peak filling rate from 0.76 to 0.97 (P < 0.001), 365 to 503 cm/s2 (P < 0.05), and 321 to 388 ml/s (P < 0.01), respectively. In the control subjects, phenylephrine caused a transient reduction of PE/PA and peak filling rate from 1.71 to 1.39 (P < 0.001) and 618 to 524 ml.s-1 (P < 0.001), respectively. CONCLUSIONS: Phenylephrine bolus administration causes an alteration of left ventricular filling in coronary artery disease patients that seems to be more marked than that seen in normal subjects. In patients with aortic stenosis no deleterious effects were observed in response to phenylephrine.

Adult↗

Performance characteristics of a novel reusable intermediate-volume low-pressure cuffed endotracheal tube.

STUDY OBJECTIVE: To evaluate the performance of the reusable intermediate-volume low-pressure cuffed "Super Safety Yellow" (Willy Rüsch AG, P.O. Box 1620, D-71332 Waiblingen, Germany) endotracheal tube with regard to cuff seal, tube tip position, and incidence of postoperative throat complaints. The "Super Safety Yellow" was compared with the "Super Safety Clear" (W. Rüsch AG), the "lo-pro (Mallinckrodt Laboratories, Cornamady, Athlone County, Ireland), and the "red rubber" (W. Rüsch AG) tubes. METHODS: Two hundred adult patients scheduled for minor surgery under standardized general anaesthesia were allocated to one of these tubes. Past-cuff leakage (indicator; orally instilled 0.2% indigocarmine) as well as intratracheal tube tip position (degree of being centred) were assessed by fibre-optic tracheoscopy. The semi-standardized interviews for the recording of postoperative sore throat were performed in double-blind fashion once a day, starting on the day of operation till p.o. day 3. STATISTICS: chi 2-test; significance: P < 0.05. MAIN RESULTS: A past-cuff leakage was found in three "red rubber" tubes. There were significant differences in tube tip position with the "Super Safety Clear" being best, and the "Super Safety Yellow" being worst centred (P = 0.010). The incidence of postoperative throat complaints showed a nonsignificant tendency in favour of the PVC-tubes. A significant number of such complaints were observed in women (P = 0.0004) and in obese patients (P = 0.011). By contrast, this incidence did not significantly differ with age, tracheal cross-sectional shape, tube tip position, use of atropine, and duration of intubation. CONCLUSION: Although resembling the "red rubber" tube in the incidence of postoperative throat complaints, the "Super Safety Yellow" may be an alternative to the currently used disposable tubes in anaesthesia. Its performance is comparable with regard to cuff seal and intra-cuff pressure. Additionally, it helps in reducing PVC waste and may lessen costs.

Adult↗

Pressure-time product and work of breathing during biphasic continuous positive airway pressure and assisted spontaneous breathing.

The pressure-time product (PTP) and work of breathing (W) were measured in 19 intubated patients during weaning from mechanical ventilation after aortocoronary bypass surgery. The patients were supported by two different ventilatory modes: biphasic continuous positive airway pressure (Biphasic CPAP; a ventilatory mode that permits spontaneous breathing at two different levels of airway pressure during inspiration and during expiration) and pressure-support ventilation (denominated as assisted spontaneous breathing, ASB). Our aim was to compare the energy cost of breathing imposed by both modes. The PTP was obtained by integrating the area enclosed by the esophageal and chest-wall static recoil pressure curves. The W performed by the patient (Wp) was calculated using Campbell's diagram method, based on the esophageal pressure curve and normalized per liter of ventilation. Two comparable support levels, corresponding to a high and a low degree of mechanical support, were studied for each ventilator mode. The levels of support were generally higher than that necessary to overcome inspiratory resistance. We found significantly higher PTP values during biphasic CPAP than during ASB (p < 0.01), whereas the Wp was the same with biphasic CPAP and ASB at both support levels. We conclude that because of the higher PTP values measured during biphasic CPAP, this mode of ventilation appears to have been more exhausting for our patients. The discrepancy between PTP and Wp is probably due to the different mechanisms of support given by the two ventilatory modes and the greater patient effort is related to those respiratory cycles that are not helped by the ventilator and which represent nearly half of the breaths during biphasic.

Aged↗

The effect of ephedrine bolus administration on left ventricular loading and systolic performance during high thoracic epidural anesthesia combined with general anesthesia.

We investigated the effect of ephedrine on left ventricular function in patients without cardiovascular disease under high thoracic epidural anesthesia combined with general anesthesia. Because the epidural block was extended to all cardiac segments, ephedrine was assumed to be deprived of its centrally mediated actions. Left ventricular (LV) function was assessed using transesophageal echocardiography. We measured arterial pressure (AP), heart rate (HR), LV end-systolic and end-diastolic diameter and area (ESA, EDA), wall thickness, and LV ejection time before and after intravenous ephedrine bolus administration. We calculated area ejection fraction (EFA), end-systolic wall stress (ESWS), and mean velocity of circumferential fiber shortening (mVcfc). Ephedrine had a biphasic effect on left ventricular function. It transiently decreased EDA from 18.9 to 16.5 cm2 (mean), whereas EFA and mVcfc were increased from 33% to 49%, and from 1.88 to 2.67 circumferences/s, respectively. During the second phase, ephedrine increased mean arterial pressure (MAP) from a baseline value of 62 to 87 mm Hg, EDA was restored to 19.3 cm2, and EFA and mVcfc remained above baseline (52% and 2.64 circumferences/s, respectively). ESWS was not significantly increased from baseline. We conclude that ephedrine improves left ventricular contractility, even in the presence of high thoracic epidural anesthesia, without causing relevant changes of left ventricular afterload.

Adult↗

Frequency of ventricular fibrillation as a predictor of defibrillation success during cardiac surgery.

The purpose of this study was to record median frequency of ventricular fibrillation (VF) in patients undergoing cardiopulmonary bypass for cardiac surgery, and to assess whether defibrillation success depends upon median VF frequency. Data were collected from 20 patients undergoing aortocoronary bypass grafting. Using computerized fast Fourier transformation of the signal from the electrogram, median VF frequency was assessed from onset of VF until aortic cross-clamping and during the 4-s period immediately before each defibrillation during the reperfusion phase. During VF, when an adequate coronary perfusion was maintained by cardiopulmonary bypass prior to aortic cross-clamping, median VF frequency (5.8 +/- 0.1 Hz to 6.2 +/- 0.1 Hz) remained constant for the entire observation interval (96 +/- 25 s; mean +/- SEM). A total of 42 defibrillations were performed: 22 resulted in supraventricular rhythm, 10 in VF, 6 in asystole, and 4 in electromechanical dissociation (EMD). Median VF frequency before defibrillation resulting in supraventricular rhythm was 4.7 +/- 0.17 Hz. In contrast, median VF frequencies before unsuccessful defibrillation resulting in persistent VF (3.5 +/- 0.28 Hz; P < 0.05), EMD (2.9 +/- 0.15 Hz; P < 0.01), or asystole (2.8 +/- 0.28 Hz; P < 0.01) were significantly lower. Above a threshold of 3.0 Hz, the probability of successful defibrillation increased as median VF frequency increased. The probability of success was 100% at a frequency of > or = 5.5 Hz. We conclude that median VF frequency is a reliable noninvasive variable which can be used to predict defibrillation success during the reperfusion phase after cardiac surgery.

Cardiopulmonary Bypass↗

Mucociliary transport in ICU patients.

OBJECTIVES: The objectives of this study were to determine the bronchial mucus transport velocities in ventilated ICU patients and to study the possible role of impaired mucus transport in the development of retention of secretion and pneumonia. DESIGN: The patients were studied prospectively in a convenience sample trial. SETTING: The study took place at a university hospital. PATIENTS: Thirty-two ventilated patients in a surgical ICU were included in the study. The study was approved by the Ethics Committee of the University of Ulm. INTERVENTIONS: Bronchial mucus transport velocity (BTV) was measured with a small volume of technetium 99m-labeled albumin microspheres within the first 3 days of mechanical ventilation. The radiolabeled bolus was deposited at the distal end of the right and left main bronchus via flexible bronchoscopy. The movement of the microspheres toward the trachea was visualized and recorded using a scintillation camera. After determination of BTV, the patients were examined daily for 4 days to record pulmonary complications (defined as retention of secretion and nosocomial pneumonia). MAIN MEASUREMENTS AND RESULTS: The median BTV in the right primary bronchus was 0.8 mm/min and in the left it was 1.4 mm/min. In nine patients both radioactive drops remained at the application site. In 14 patients, a total of 19 pulmonary complications occurred (10 times retention of secretion, 9 times pneumonia). Patients with pulmonary complications had statistically significant lower BTV compared with patients without pulmonary complications; in the left bronchus 0 (0 to 6.5) mm/min (median with range) vs 3.5 (0 to 10.5) mm/min (p < 0.01) and in the right bronchus 0 (0 to 3.0) mm/min vs 4.7 (0 to 11.7) mm/min (p < 0.01). CONCLUSIONS: Ventilated patients in the ICU frequently have impaired mucus transport, which is associated with the development of retention of secretion and pneumonia.

Adult↗

Right ventricular function during weaning from respirator after coronary artery bypass grafting. Comparison of two different weaning techniques.

The purpose of this investigation was to determine right ventricular function during weaning from controlled ventilation comparing a biphasic positive airway pressure ventilatory support system (BiPAP [Respironics]) with pressure support ventilation (PSV). In 22 patients following coronary artery bypass grafting, both weaning techniques were used in randomized chronological order for 60 min each. Right ventricular end-systolic (RVESV) and end-diastolic volume (RVEDV) and ejection fraction (RVEF) were evaluated using the fast-response Swan-Ganz catheter. In comparison to PSV, the BiPAP system resulted in a significantly higher mean pulmonary artery pressure (20.6 +/- 5.0 vs 19.3 +/- 4.2 mm Hg, p = 0.0158), pulmonary vascular resistance index (206 +/- 55 vs 181 +/- 61 dyn.s.cm-5.m2, p = 0.0355), RVESV (92.2 +/- 36.3 vs 77.2 +/- 30.4 ml, p = 0.0017), and RVEDV (176.4 +/- 48.5 vs 161.8 +/- 43.3 ml, p = 0.0061), while the RVEF was significantly lower (46.0 +/- 11.9 vs 51.8 +/- 12.4 percent, p = 0.0012). No differences in left ventricular function or arterial blood gas analyses were measured during both study periods. In summary, the RV afterload was higher with the BiPAP system compared with PSV which suggested that this was due to differences in the respiratory support between both weaning modes. Because of the Frank-Starling mechanism, this higher afterload did cause a small but significant increase in RV volumes and a significant decrease in RV ejection fraction with the BiPAP system.

Aged↗

[Effect of intravenous glucose versus glucose-xylose (1:1) administration on carbohydrate and lipid metabolism after trauma and during infection].

OBJECTIVE: To detect the effects of glucose-xylitol infusion versus glucose infusion alone on carbohydrate and lipid metabolism in postoperative stress and during sepsis. DESIGN: Prospective randomized study (study I after cardiac surgery) and intraindividual cross-over control study (study II in septic patients), respectively. SETTING: Intensive care unit of a university hospital. PATIENTS: 18 patients after aortocoronary bypass (ACVB) and 5 patients with sepsis. INTERVENTIONS: In study I during the first 24 postoperative hours one group (K I, n = 6) received glucose only (2 mg/kg BW/min), a second group (K II, n = 6) a mixture of glucose and xylitol (1:1; 2 mg/kg BW/min) and a third group (K III, n = 6) a glucose-containing electrolyte solution (0.8 mg/kg BW/min). Glucose, lactate, insulin and free fatty acid concentrations were measured pre- and postoperatively in 6-hour intervals over 36 h. In study II patients were firstly given 4 mg glucose/kg BW/min over 6 h, then infusion was changed to a 1:1 glucose-xylitol mixture (4 mg/kg BW/min) for another 6 h. Hepatic glucose production, palmitate oxidation rates and lactate concentrations were determined at the end of both infusion regimens. RESULTS: Glucose and insulin concentrations were significantly lower in K II and K III than in K I. The highest lactate values were observed 6 h postoperatively in K I. Concentrations of all fatty acids were lower in K I than in K II and K III during the infusion periods. In study II the glucose production and lactate values were significantly reduced during xylitol infusion, whereas palmitate oxidation rates were significantly increased when the infusion regimen changed from glucose to glucose-xylitol mixture. CONCLUSIONS: These data indicate that energetically ineffective high glucose concentrations were avoided and lactate production was diminished by infusion of glucose-xylitol in study I. In addition, xylitol achieved a higher endogenous release and oxidative utilisation of free fatty acids representing important fuel substrates after trauma and during sepsis.

Adult↗

Studies on drug monitoring in thrice and once daily treatment with aminoglycosides.

OBJECTIVES: To investigate at what time the peak level should be determined under conventional thrice daily (t.i.d.) administration of the aminoglycoside netilmicin and to study its serum concentrations under once daily (od) treatment to define the required daily dose and to gain information about convenient drug monitoring. DESIGN: The design of the study was a consecutive sample trial. SETTING: The study took place in a university hospital. PATIENTS: 41 intubated patients of a surgical ICU who received netilmicin as a short-term infusion over 30 min for life-threatening infections were included in the study. INTERVENTIONS: In 21 patients netilmicin was administered t.i.d. The virtual peak levels which had been determined by pharmacokinetic dosage calculation were compared with the serum concentrations obtained directly after the administration as well as after 15, 30, 60 and 180 min. In 20 patients the netilmicin serum concentrations during od treatment were determined directly before and immediately after the application as well as 0.5, 1, 3, 7 and 12 h later. To achieve a virtual peak level of 25 mg/l and a trough level of 0.5 mg/l individual adjustment of the dosage based on pharmacokinetic calculations was performed. MEASUREMENTS AND RESULTS: In t.i.d. treatment the serum concentration measured after 30 min was closest to the virtual peak level; therefore, this is the best time to determine the peak level. In od treatment the required daily dose was 7.86 mg/kg body weight (median) in patients with normal renal function. During od dosing the trough level was extremely important in drug monitoring, whereas determination of the high peak level was of doubtful value. CONCLUSIONS: The peak level should be determined during t.i.d. administration at 30 min. In od treatment the initial daily dose should be 7 mg/kg body weight; in drug monitoring the trough level is very important.

Adolescent↗

Metabolic and haemodynamic effects of dopamine plus domperidone in volunteers.

There are no studies of the relationship between infusion rate of dopamine and the arterial and venous dopamine plasma concentration and the resulting haemodynamic and metabolic effects. Dopamine was administered to seven volunteers using five infusion rates (1, 3, 6, 9, 13 micrograms/kg per minute) in an escalating sequence lasting for 30 min for each step. Since dopamine can cause nausea and vomiting, this relationship was investigated after administration of domperidone for infusion rates above 3 micrograms/kg per minute. Haemodynamic effects were assessed using 2-dimensional echocardiography. During the highest infusion rate the arterial plasma dopamine concentration reached 1,379 +/- 181 nmol/l. There was a linear correlation between the dopamine infusion rate and both the arterial and the venous plasma concentration. There was no significant change in heart rate or diastolic blood pressure. Systolic blood pressure, ejection fraction and cardiac index increased in a dose-dependent manner. Systemic vascular resistance decreased during the two low doses of dopamine and was not different from baseline values during the three high infusion rates. The plasma concentrations of glucose and non-esterified fatty acids increased from 5.3 +/- 0.4 to 0.68 +/- 0.9 nmol/l, and from 360 +/- 119 to 971 +/- 307 mumol/l, respectively, during the 13 micrograms/kg per minute infusion rate. As the plasma noradrenaline concentration increased up to 7.84 +/- 2.46 nmol/l in correlation to the dopamine plasma concentration, an indirect sympathomimetic effect may contribute to the actions of dopamine plasma concentration.

Adult↗

[Preoperative risk factors and intraoperative and postoperative risk management in 11,890 anesthesias. Initial results of a prospective study].

OBJECTIVE: The relation of the frequency and severity of pitfalls, events and complications (PECs) was analysed in respect of preoperative risk factors. The epidemiological data were gathered as a contribution to a current project of the German Society for Anaesthesiology and Intensive Care. METHOD: Preoperative data (age, sex, preexisting diseases, pathological findings, grade of urgency and ASA-class) were integrated in a paper record, as well as the perioperative interventions and directly postoperative events, type of anaesthesia, and kind of operation. The automatically readable paper records were routinely in use for every patient. After control and correction the data were stored in a modern data base. MAIN RESULTS: From October 1, 91 to May 20, 92 11,890 anaesthesias were recorded. 2,959 of them with a total of 4,184 PECs. 2,397 PECs were cardiovascular, 875 respiratory. PECs of grade I (no impact on treatment in the recovery room [RR]) occurred in 14% of patients, grade II (impact on treatment in RR, but no impact on discharge to ward) 7.2%, grade III (prolonged stay in RR or special monitoring in the ward) 2.88%; grade IV (PEC leads to transfer to the ICU) 0.63%, and grade V (PEC leads to disabling damage or death) 0.13%. 13 of 15 patients suffering from PECs grade V were of ASA class 4 or 5. PECs had a certain relation to the ASA-classification of anaesthetic risk. But this relation is quite different in several surgical disciplines. CONCLUSIONS: Preoperatively known risk factors of the patient and the measures taken by specialists of various disciplines contribute to the incidence of PECs. Available data could be processed multicentrally and in standard form for producing prognostic data for risk prediction. Since PECs of grade II or higher are cost- relevant, requiring an interdisciplinary approach, it appears meaningful to base costing on such an interdisciplinary approach in accordance with the requirements of diagnosis and treatment.

Adolescent↗

Effect of phenylephrine bolus administration on global left ventricular function in patients with coronary artery disease and patients with valvular aortic stenosis.

BACKGROUND: Although phenylephrine bolus administration is frequently used to increase coronary perfusion pressure in patients with coronary artery disease or valvular aortic stenosis, there are no data describing its effect on left ventricular function (LVF). METHODS: Twenty patients scheduled for elective coronary artery bypass grafting (group 1) and 18 patients scheduled for elective aortic valve replacement (group 2) entered the study. The effect of phenylephrine was compared with that of norepinephrine in those patients who developed a defined degree of arterial hypotension under general anesthesia. These patients were randomized to receive an initial bolus of either phenylephrine (1 micrograms/kg) or norepinephrine (0.05 micrograms/kg) followed by a bolus of the other drug after arterial pressure and heart rate (HR) had returned to baseline. Transesophageal echocardiography was used to evaluate LVF. Arterial pressure, HR, ejection time, and LV diameter, area, and wall thickness were recorded immediately before and for 3 min after bolus administration. Fractional diameter shortening, fractional area change, mean heart rate corrected velocity of circumferential fiber shortening (mVcfc), and LV meridional end-systolic wall stress (ESWS) were calculated. RESULTS: Both substances effectively restored arterial pressure in both groups. However, in group 1, phenylephrine administration resulted in a reduction of fractional area change from 0.51 (median) to 0.39 (P = 0.0007) and a reduction of mVcfc from 1.16 to 0.61 circ/s (P = 0.0001). End-systolic wall stress increased from 98 to 186 10(3) dyne-cm-2 (P = 0.0001). Administration of norepinephrine to group 1 and administration of either substance to the group 2 patients did not cause any significant changes of LVF. CONCLUSIONS: The results indicate that phenylephrine given as an intravenous bolus to patients with CAD anesthetized with fentanyl causes a transient impairment of LV global function and that phenylephrine bolus administration is well tolerated in patients with valvular aortic stenosis.

Aged↗

Immunomodulating actions of nucleotides: enhancement of immunoglobulin production by human cord blood lymphocytes.

We have shown previously that polynucleotides enhance in vitro antibody and Ig production in response to T-dependent antigens in mice and augment Ig production by adult human peripheral blood mononuclear cells. Herein, we report their effects on umbilical cord blood mononuclear cells (CBMNC) obtained from full-term babies. CBMNC produced much less IgM/IgG and an almost negligible amount of IgA in response to various stimuli compared with adult peripheral blood mononuclear cells. The supplementation of yeast RNA augmented spontaneous and T-dependent IgM (p < 0.01) but not IgG production by CBMNC. This action was largely attributable to polynucleotides, which appeared to exert their actions in a dose-dependent manner at the initial stages of culture. Their actions were dependent upon the presence of T cells, but they also enhanced spontaneous IgM production by CBMNC in the absence of T cells. Preincubation of T cells from CBMNC and peripheral blood mononuclear cells with RNA for 3 h before the culture resulted in enhanced IgM production, independent of the stimulants used. Thus, polynucleotides appear to exert actions on immature human T cells as well as other lineage cells in vitro. Their actions may be dependent on the presence or absence of antigens or other stimuli and the nature of the stimuli (T dependent versus T independent). These findings may further support the potential importance of nucleotides contained in human breast milk.

Adjuvants, Immunologic↗