Biomedical subjects

L G Ekman

Publications and source records attributed to L G Ekman.

7 recordsLinked to original sources

PubMed1990

Clinical evaluation of an ensemble-averaging impedance cardiograph for monitoring stroke volume during spontaneous breathing.

Simultaneous determination of stroke volume (SV) with an ensemble-averaging impedance cardiograph (AIGG) and the thermodilution technique (TD) was compared in 10 patients scheduled for major vascular surgery. A small, successive increase in SV was achieved by a step-wise infusion of dextran-70 and elevation of the patient's legs. The patients were allowed to breathe normally during the measurement procedures. There was no difference between the ability of AICG and TD to monitor changes in SV and the correlation coefficient for the measurement of changes in SV by the two methods was 0.88. There was no difference between the reproducibility of AICG- (4.6 ml) and TD- (9.2 ml) determined SV or between the coefficient of variation for AICG (4.8%) and TD (9.9%). The mean difference between AICG- and TD-determined SV at the different measurement points (range 1.3-4.2 ml) was well within acceptable limits. In conclusion, the ensemble-averaging impedance cardiograph described in this study was found to be reliable for monitoring changes in SV during uninterrupted, spontaneous breathing.

Aged↗

PubMed1990

Effects of intravenous terbutaline on maternal circulation and fetal heart activity.

The effects of terbutaline on maternal circulation and fetal heart activity were studied in 15 healthy pregnant women admitted for external cephalic version. The two-step infusion of terbutaline (5-10 micrograms/min) resulted in increases in maternal heart rate (p less than 0.001), cardiac output (p less than 0.001), systolic arterial pressure (p less than 0.001) and pulse pressure (p less than 0.001), while diastolic arterial pressure (p less than 0.001) and total peripheral vascular resistance (p less than 0.001) were reduced. Mean arterial pressure was unchanged after the infusion. Fetal heart activity assessed by cardiotocography showed a gradual increase in baseline fetal heart rate (p less than 0.01) and an increased percentage acceleration time (p less than 0.05). Fetal movements also increased during the infusion (p less than 0.05). The terbutaline infusion had a positive inotropic effect and produced decreased systemic vascular resistance in the pregnant woman, and placental transfer of the drug resulted in increased fetal heart activity. The potential influence of the drug-induced changes in maternal hemodynamics on utero-placental perfusion require further investigation.

Adult↗

PubMed1988

Hemodynamic changes during laparoscopy with positive end-expiratory pressure ventilation.

Hemodynamic measurements were performed in 10 healthy women undergoing elective laparoscopy for the investigation of infertility. A standardized anesthetic technique which included the application of positive end-expiratory pressure (PEEP), 0.49 kPa (3.7 mmHg) was utilized. The following variables were studied: cardiac output, stroke volume and left ventricular ejection time (determined non-invasively with impedance cardiography), heart rate, blood pressure, total peripheral vascular resistance and end-tidal carbon dioxide (ET-CO2). The combination of 25 degrees head-down tilt and PEEP ventilation during laparoscopy was associated with a pressure response that restored arterial pressures to essentially pre-anesthetic levels. Net cardiac effects were small. With this regime low pressure 0.7-1.1 kPa (5-8 mmHg) intra-abdominal insufflation with CO2 was associated with only minor cardiovascular changes. There were no indications that 0.49 kPa PEEP during laparoscopy produced adverse cardiovascular effects. The application of PEEP reduced (P less than 0.001) ET-CO2. There was no net increase in ET-CO2 after CO2-insufflation compared to the measurement after induction of anesthesia. This is in contrast to earlier studies without PEEP where a significant net increase in ET-CO2 was reported after CO2-insufflation.

Adult↗

PubMed1986

Pilot-error accidents: male vs female.

In this study, general aviation accident records from the files of the National Transportation Safety Board (NTSB), have been analysed by gender to observe the number and rate of pilot-error related accidents from 1972 to 1981 inclusive. If both females and males have no difference in performance, then data would have indicated similarities of accident rates and types of injuries. Males had a higher rate of accidents than females, and a higher portion of the male accidents resulted in fatalities or serious injuries than for females. Type of certificate, age, total flight time, flight time in type of aircraft, phase of operation, category of flying, degree of injury, specific cause factors, cause factor miscellaneous acts/conditions were analysed, taking the total number of United States Active Civilian General Aviation Pilots into consideration. The data did indicate a difference in all variables.

Journal Article↗

PubMed1986

Stimulatory effect of interleukin-1 upon hepatic metabolism.

The liver plays an important role in the acute-phase response to sepsis and injury, and host survival often depends upon an adequate hepatic response. Many of the metabolic sequelae to sepsis and injury are mediated by interleukin-1. This study was undertaken to investigate the impact of interleukin-1 upon hepatic metabolism and whether this mediator acted directly upon the liver. Interleukin-1 (5 rabbit pyrogen dose units) was administered to male Fisher F344 rats (175 to 200 g), and hepatocytes were isolated at three time periods; 2 to 4, 6 to 10, and 12 to 14 hours following an intraperitoneal injection. Alanine transport, gluconeogenesis, nonsecretory protein synthesis, and oxygen consumption were measured simultaneously in freshly isolated hepatocytes. Interleukin-1 stimulated initial rates of alanine uptake over a four-minute period. Peak stimulation of gluconeogenesis occurred at six to ten hours (0.52 +/- .14 v 0.08 +/- .01 nmol alanine converted/10(6) cells/min, P less than 0.05); nonsecretory protein synthesis was significantly stimulated at 12 to 14 hours (2.1 +/- .7 v 0.7 +/- 0.1 nmol valine converted/10(6) cells/min, P less than 0.05). These enhanced metabolic processes were associated with an increased oxygen consumption, with peak oxygen utilization occurring at six to ten hours (69 +/- 2 v 25 +/- 7 nmol of oxygen consumed 10(6) cells/min, P less than 0.05). In order to examine if interleukin-1 exerted its effect directly upon the liver, hepatocytes from normal rats were incubated in vitro with this mediator for two hours. Under these experimental conditions, interleukin-1 did not reproduce the stimulatory effect obtained following in vivo administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗

PubMed1985

Elevated energy expenditure in hepatocytes from tumor-bearing rats.

Mechanisms for the development of cancer cachexia are not well defined. Oxygen consumption and the capacity of the host liver to metabolize lactate were studied in isolated hepatocytes from sarcoma-bearing rats (TIH) and pair-fed controls (CH). Basal oxygen consumption (without exogenous substrate) is significantly increased by 65% in the TIH as compared to the CH. The addition of a physiologic concentration of lactate stimulated oxygen consumption over the already stimulated basal state by 13% in the TIH compared to 5% in the CH. When the hepatocytes are incubated with 1.5 mM of [U-14C]lactate, glucose production, lactate oxidation, and entry of lactate carbons into nonsecretory protein are significantly increased in the TIH. Associated with this stimulation is a significant decrease in lactate incorporation into glycogen and lipid in the TIH. This study suggests that the tumor-influenced liver utilizes lactate at an increased rate and its intermediary metabolism is directed toward energy utilization rather than energy storage. The enhanced metabolic processes in the tumor-influenced liver are associated with an increased oxygen consumption which may be a contributory factor to the negative energy balance, a characteristic of cancer cachexia.

Animals↗

PubMed1982

Blood glutathione-peroxidase levels in skin diseases: effect of selenium and vitamin E treatment.

Blood glutathione-peroxidase (GSH-Px) was determined in 61 healthy subjects and 506 patients with various skin disorders. Depressed levels were observed in patients with psoriasis, eczema, atopic dermatitis, vasculitis, mycosis fungoides and dermatitis herpetiformis. Low values of GSH-Px were also found in some patients with pemphigoid, acne conglobata, polymyositis, rheumatoid arthritis, scleroderma and systemic lupus erythematodes. Vegetarian diet, malnutrition and alcohol abuse could possibly account for the low values in some patients. Fifty patients with low GSH-Px levels were treated with tablets containing 0.2 mg selenium as Na2SeO3 and 10 mg tocopheryl succinate. The GSH-Px levels increased slowly within 6-8 weeks of treatment. The clinical effect was encouraging and calls for controlled studies.

Adolescent↗