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Biomedical subjects

B Larsen

Publications and source records attributed to B Larsen.

At least 73 records · Page 4Linked to original sources

[Desflurane and isoflurane. A comparison of recovery and circulatory parameters in surgical interventions].

OBJECTIVES: The new volatile anaesthetic desflurane is characterized by very low blood-gas and tissue-blood partition coefficients, so that rapid induction of anaesthesia and shorter recovery times can be expected. The aim of this investigation was to compare the effects of desflurane and isoflurane on haemodynamics and recovery time when used as part of a balanced anaesthesia technique for elective surgery. METHODS: Fifty patients (18 years and older, ASA status I-III) scheduled for elective surgery (no laparoscopies) of at least 60 min duration were included in this open, randomised, phase-III clinical trial. After oral premedication with midazolam 7.5 mg 45 min before transfer to theatre, anaesthesia was induced with fentanyl 0.1 mg and thiopental 5 mg/kg; succinylcholine or vecuronium facilitated intubation. Desflurane and isoflurane, respectively, were used for maintenance of anaesthesia, both in 50% N2O, with the inspired concentration adapted to the degree of stimulation. All patients were ventilated in a semi-closed system; muscle relaxation was achieved with vecuronium. The electrocardiogram, heart rate (HR), and direct arterial blood pressure (BP) were recorded continuously and anaesthetic gas detection was performed by an infrared absorption technique. With termination of surgery the volatile anaesthetic was discontinued and the following emergence times recorded: spontaneous ventilation (VT > 300 ml), extubation, eye opening, correctly answering the date of birth, arrival in and possible discharge from the post-anaesthesia care unit (PACU). RESULTS: In all, 49 patients were studied at random (desflurane n = 24, isoflurane n = 25). Data of demographics and anaesthetic technique were comparable in both groups (Tables 2 and 3). Anaesthetic elimination (expressed as FA/FAO) was significantly more rapid in the desflurane group 3 min after termination of anaesthesia (Fig. 1). Comparing the emergence times, there was no significant difference between desflurane and isoflurane: in both groups patients opened their eyes 12 min (median time) after termination of the operation (Table 4). Haemodynamics (HR, systolic and diastolic BP) were comparable at intubation, skin incision, end of surgery, extubation, and in the PACU (Fig. 2a, b). In 2 patients a rapid increase in the inspired concentration of desflurane during induction of anaesthesia produced a profound sympathoadrenergic reaction with an excessive increase in BP and HR. Similar reactions in other patients did not occur when the inspired concentration of desflurance was slowly increased. CONCLUSIONS: Despite the physicochemical properties of the new agent, emergence times were similar for desflurane and isoflurane in our study. These results, which are in contrast to those of some other authors, are most probably due to the study design, which included the use of premedicants (midazolam) and a low dose of fentanyl. The reported sympatho-adrenergic reactions after rapid changes in the inspired concentration of desflurane during induction of anaesthesia have been observed by others as well. It seems that this initial cardiovascular stimulation can be avoided by slow increases in desflurane concentration. In summary, desflurane compares to isoflurane in balanced anaesthesia for general surgical procedures with regard to haemodynamics, while the time to awakening is not necessarely reduced.

Adolescent↗

Cardiovascular effects of desflurane and isoflurane in patients with coronary artery disease.

BACKGROUND: Anaesthesia in patients with ischaemic heart disease may cause adverse haemodynamic reactions. This investigation compares the cardiovascular effects of equipotent concentrations of desflurane and isoflurane in 30 patients (ASA III) with coronary artery disease before surgical stimulation. METHODS: After standardised induction of anaesthesia with etomidate, fentanyl and pancuronium and tracheal intubation patients randomly received either desflurane (group I, n = 15) or isoflurane (group II, n = 15) in slowly increasing concentrations. ST-segment analysis and haemodynamic measurements were performed at 0.25, 0.5, 0.75 and 1.0 MAC of desflurane or isoflurane. RESULTS: Cardiac index did not change significantly in the two groups during the administration of the inhalational anaesthetics. Desflurane and isoflurane both caused a dose-dependent significant decrease of mean arterial blood pressure (group I: -16%; group II: -18%). As with isoflurane, the decrease of mean arterial pressure produced by desflurane primarily resulted from a decrease in systemic vascular resistance (group I: -26%, group II: -21%). Central venous pressure was not affected by the two volatile anaesthetics. Pulmonary artery pressure and pulmonary capillary wedge pressure remained unchanged during the administration of isoflurane, but in contrast both parameters significantly increased in patients receiving desflurane (PAP 24%, PCWP 40%). ST-segment analysis provided no signs of myocardial ischaemia. CONCLUSION: The results of this study demonstrate that in patients with coronary artery disease the haemodynamic effects of equipotent concentrations of desflurane and isoflurane are similar except for a significant increase in PAP and PCWP caused by desflurane. Therefore, desflurane should be administered with great caution if it is used as an alternative anaesthetic in patients with ischaemic heart disease.

Adult↗

Characterization of two conformational epitopes of the Chlamydia trachomatis serovar L2 DnaK immunogen.

Chlamydia trachomatis DnaK is an important immunogen in chlamydial infections. DnaK is composed of a conserved N-terminal ATP-binding domain and a variable C-terminal peptide-binding domain. To locate the immunogenic part of C. trachomatis Dnak, we generated monoclonal antibodies (MAbs) against this protein. By use of recombinant DNA techniques, we located the epitopes for two MAbs in the C-terminal variable part. Although the antibodies reacted in an immunoblot assay, it was not possible to map the epitopes completely by use of 16-mer synthetic peptides displaced by one amino acid corresponding to the C-terminal part of C. trachomatis DnaK. To determine the limits of the epitopes, C. trachomatis DnaK and glutatione S-transferase fusion proteins were constructed and affinity purified. The purified DnaK fusion proteins were used for a fluid-phase inhibition enzyme-linked immunosorbent assay with the two antibodies. The epitopes were found not to overlap. To obtain DnaK fragments recognized by the antibodies with the same affinity as native C. trachomatis DnaK, it was necessary to express, respectively, regions of 127 and 77 amino acids. The MAbs described in this study thus recognized conformational epitopes of C. trachomatis DnaK.

Adenosine Triphosphatases↗

Soleus stretch reflex modulation during gait in humans.

1. The modulation of the short-latency stretch reflex during walking at different walking speeds was investigated and compared with the stretch reflex during standing in healthy human subjects. 2. Ankle joint stretches were applied by a system able to rotate the human ankle joint during treadmill walking in any phase of the step cycle. The system consisted of a mechanical joint attached to the subject's ankle joint and connected to a motor placed beside the treadmill by means of bowden wires. The weight of the total system attached to the leg of the subject was 900 g. 3. The short-latency soleus stretch reflex was modulated during a step. In the stance phase, the amplitude equaled that found during standing at matched soleus background electromyogram (EMG). In the transition from stance to swing, the amplitude was 0 in all subjects. In late swing, the stretch reflex amplitude increased to 45 +/- 27% (mean +/- SD) of the maximal amplitude in the stance phase (stretch amplitude 8 degrees, stretch velocity 250 degrees/s). 4. The onset (42 +/- 3.2 ms) and peak latencies (59 +/- 2.5 ms) of the stretch reflex did not depend on the phase in the step cycle at which the reflex was elicited. 5. When the ankle joint is rotated, a change in torque can be measured. The torque measured over the first 35 ms after stretch onset (nonreflex torque) was at a maximum during late stance, when the leg supported a large part of the body's weight, and at a minimum during the swing phase. At heel contact the nonreflex torque was 50% of its maximal value. 6. During the stance phase the maximal EMG stretch reflex had a phase lead of approximately 120 ms with respect to the maximal background EMG and a phase lead of approximately 250 ms with respect to the maximal nonreflex torque. 7. The constant latency of the stretch reflex during a step implied that the ankle extensor muscle spindles are always taut during walking. 8. The relatively high amplitude of the stretch reflex in late swing and at heel contact made it likely that the stretch reflex contributed to the activation of the ankle extensor muscles in early stance phase.

Adult↗

[Transplantation of lung lobe from a mother to a child previously transplanted with her bone marrow].

The lower lobe of the left lung was transplanted from a mother to her child, who previously had received a bone marrow transplant from the mother because of an immune defect. After the bone marrow transplant the child had developed progressive pulmonary fibrosis (obliterative bronchiolitis). The surgical procedure and the early postoperative period has been uncomplicated. Immunosuppression with corticosteroids was only given for a short period, after which no immunosuppressive treatment has been given. The operation and results for both donor and recipient are described. The early results are promising, but rehabilitation is progressing slowly.

Bone Marrow Transplantation↗

[Stellate ganglion block with transcutaneous electric nerve stimulation (TENS): a double-blind study with healthy probands].

OBJECTIVE: Blockade of the stellate ganglion is an established and highly effective diagnostic and therapeutic procedure for management of certain acute and chronic pain syndromes or other disorders. The paratracheal injection of a local anaesthetic is the simplest and most frequently used approach for blocking the cervicothoracic sympathetic nerves (ganglion stellate). However, since serious complications can occur during or following the anterior paratracheal technique including accidental intravenous or intraarterial injection, non-invasive methods for blockade of the stellate ganglion have been suggested. In 1980 Jenkner (15) reported the successful interruption of the sympathetic outflow from the stellate ganglion together with the relief of pain by transcutaneous electrical nerve stimulation (TENS), followed by the development of an "optimal wave form" in 1981 (14). Since we were unable to reproduce Jenkner's results of sympathetic blockade in our patients, this study was designed to investigate the effects of TENS on the sympathetic activity of the stellate ganglion in healthy volunteers. METHODS: 50 healthy volunteers were randomised into two groups (n = 25). In group I the left stellate ganglion was stimulated for 20 min by the mode described by Jenkner (monophasic pulse, small anode, large cathode, frequency 20 Hz), while group II was stimulated by conventional TENS (biphasic pulse, electrodes of identical size, frequency 100 Hz). The method of stimulation was blinded to both the investigator and the subjects investigated. Measurements included cutaneous blood flow of the volar forearm (laser Doppler), skin temperature on two sites of the cheeks (thermistor), pupil diameter and size of the palpebral fissures, sweat production (ninhydrine test) and global sensitivity and pain perception thresholds on both sides (electrical stimulation). Measurements were performed before TENS of the stellate ganglion, after 5, 10, 15 and 20 min of stimulation and 10 min after termination of TENS. Statistical analysis of the obtained data was performed by Friedman-Test and by Mann-Whitney-U-Test. p < 0.05 was assigned statistical significance. MAIN RESULTS: Skin temperature increased in both groups and on both sides by 1.2 degrees C, while skin perfusion rate, pupil size, size of the palpebral fissure and sweat production remained unchanged. Global sensitivity and pain perception thresholds of forehead decreased in both groups and on both sides, while there was no change of both parameters on the hands. CONCLUSION: No signs and symptoms of sympathetic blockade could be demonstrated in any of the groups, neither by TENS of the stellate ganglion as described by Jenkner nor by unspecific TENS. Thus, pain relief by TENS of the stellate ganglion as reported in the literature must involve other mechanisms than sympathetic blockade. In addition, TENS may not replace traditional blockade of the stellate ganglion by local anesthetics, if sympathetic blockade is required for diagnostic and therapeutic purposes.

Adult↗

Biochemical identification of the bovine blood group M' antigen as a major histocompatibility complex class I-like molecule.

Absorption and elution experiments showed that it was impossible to separate antibodies against blood group factor M' from antibodies against bovine lymphocyte antigen (BoLA) A16 in an antiserum showing haemolytic activity against M' as well as lymphocytotoxic activity against BoLA-A16. To elucidate the structural relationship between BoLA-A16 and blood group antigen M', immunoprecipitation experiments on red and white cell lysates isolated from M'-A16 positive and negative cattle were carried out. These results showed that M(r) 44,000 and M(r) 12000 polypeptides can be precipitated from both red and white cells isolated from M'-A16 positive animals, whereas no bands were seen in M'-A16 negative animals in precipitations with the same antibody. Precipitation with a crossreacting human beta 2-microglobulin (beta 2-m) specific antibody confirmed a class-I-like structure associated with beta 2-m on M' positive red cells and the absence of such a structure on M' negative red cells. Sequential precipitations gave analogous results. Proteolytic degradation by papain and V8 protease did not reveal any substantial difference between red and white M'-A16 positive cells, but a slight difference in the pI of the immunoprecipitable components of red and white cells was observed. All together, this indicates that either the blood group antigen M' is the BoLA-A16 class I antigen or M' and BoLA-A16 are two different class I polypeptides with the same relative mass, sharing identical epitopes and both associated with beta 2-m. Comparable results were obtained with M1 and BoLA-A24.

Animals↗

In situ mycotoxin production by Candida albicans in women with vaginitis.

The virulence attributes of Candida albicans in cases of mucocutaneous disease have not been identified. Based on the recent finding that C. albicans is able to produce an immunosuppressive mycotoxin, gliotoxin, we analyzed vaginal samples of 3 women severely symptomatic for vaginal candidiasis and found that they contained significant levels of gliotoxin. Three control women who were not colonized with C. albicans showed no gliotoxin in vaginal samples. These findings raise the possibility that gliotoxin may play a role in the virulence of C. albicans.

Candida albicans↗

One month treatment with the once daily oral beta 2-agonist bambuterol in asthmatic patients.

Bambuterol is a new long-acting oral bronchodilator for once daily use in patients with asthma. It is a prodrug of terbutaline, designed to be slowly metabolized to terbutaline. Results from comparative studies have shown that it has similar clinical efficacy to other oral bronchodilators, but less side-effects. The present study was aimed at verifying the 24 h effect duration of bambuterol, 10 and 20 mg in comparison with placebo during a one month treatment period. The study was conducted as a double-blind, randomized, parallel group placebo-controlled, multicentre trial. It started with a one week run-in period with placebo, when oral bronchodilators were withdrawn. At the end of this reference period, the patients were randomized to one of three treatments: placebo, bambuterol 10 mg, or bambuterol 20 mg, once daily in the evening. The treatment period lasted for 4 weeks. Four hundred and eighty seven patients with a mean age of 45 yrs were included. Mean baseline forced expiratory volume in one second (FEV1) and FEV1% of predicted were 2.05 l and 62%, respectively. Administration of 10 mg bambuterol resulted in a significant 24 h effect duration, expressed as an increase in mean daily morning and evening peak expiratory flow (PEF) (+11 l.min-1, adjusted means) throughout the study, as compared with placebo. Bambuterol, 20 mg, gave a significant 24 h effect duration in both FEV1 and morning and evening PEF as compared with placebo. Furthermore, the adverse events observed during the study were relatively few and mild.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Transplantation of a lobe of lung from mother to child following previous transplantation with maternal bone marrow.

A left lower lobe of the lung was transplanted from a mother to her child, who had previously received a maternal bone marrow transplant for an immune defect. Following the bone marrow transplantation, the child had developed severe pulmonary fibrosis. Surgery and the early postoperative course have been uncomplicated. Immunosuppression with corticosteroids was administered for a short period, after which all immunosuppressive treatment was discontinued. The operation and the outcome are described both in the donor and recipient. Rehabilitation was slow, but one year later the patient is doing well.

Adult↗

Intranasal levocabastine for the treatment of seasonal allergic rhinitis: a multicentre, double-blind, placebo-controlled trial.

In this international, multicentre, randomized, double-blind, parallel-group, placebo-controlled trial 262 patients participated to assess the efficacy and tolerability of levocabastine nasal spray in the treatment of seasonal allergic rhinitis. Patients were randomized to receive either twice daily 0.05% levocabastine or matching placebo nasal spray with a treatment duration of four weeks. Assessments of global therapeutic efficacy favoured levocabastine. At the end of the trial, 55% of levocabastine-treated patients considered therapeutic efficacy to be excellent or good compared to 36% of those who received placebo (p < 0.001). The corresponding values for the investigator assessments were 54% and 37% (p < 0.001), respectively. Analysis of patients' diary data showed significantly lower AUCs for all parameters in the levocabastine group (p < 0.05). Investigator assessments revealed a trend towards a greater reduction in individual symptom severity from baseline in levocabastine-treated patients compared to placebo-treated controls. Adverse experiences were reported by 21% of levocabastine-treated patients and by 19% of those who received placebo, with no statistically significant differences in incidence or type. Headache and local reactions following application were the most frequently reported adverse events. Levocabastine nasal spray appears to be effective and well-tolerated for the treatment of seasonal allergic rhinitis and is an alternative to oral antihistamines.

Administration, Intranasal↗

[A herbal preparation Resium in symptomatic gallstones. A preliminary study of the effect].

Resium, an old Spanish herb, is claimed to remove gallstone symptoms and to dissolve gallstones. Ten patients admitted for cholecystectomy because of intermittent bile cholics participated in a study for six months to evaluate the effects. None had had complications to their gallstone disease, and all had normal liver biochemistry and a normal well-functioning gallbladder before entry into the study. By ultrasonography minor changes in both directions in stone number and volume were seen. Five patients experienced some relief of symptoms, while the rest had unchanged, or worse symptoms. No adverse events to Resium were seen. In conclusion no effect of Resium upon gallstone size and volume was seen. The design of the study does not allow any conclusion about symptomatic effect to be drawn.

Adult↗

Cloning, expression, and purification of a functional nonacetylated mammalian mitochondrial chaperonin 10.

An intact mouse mitochondrial chaperonin 10 has been cloned, sequenced, and overexpressed in Escherichia coli as a fusion protein harboring an oligohistidine tail at its COOH terminus. The latter was added to simplify protein purification. The purified protein is free of contaminating groES from the bacterial host cells. Edman degradation reveals that the initiator Met residue of the recombinant protein is removed in vivo, similar to the authentic chaperonin 10 purified from rat liver mitochondria. However, in contrast to the latter, the amino-terminal Ala residue of the recombinant protein is not acetylated; the molecular mass determined by electrospray ionization mass spectrometry is 12,350.9 +/- 2.6 daltons, in agreement with that predicted for the nonacetylated protein (12,351.2 daltons). Facilitated protein folding experiments with ribulose-biphosphate carboxylase, under "nonpermissive" in vitro conditions, demonstrate that the recombinant protein is fully functional with groEL. Thus, both the initial rates of protein folding and final yields observed with this heterologous combination are virtually identical to those obtained with groEL and groES. More important, like the authentic protein purified from mitochondria, the recombinant mitochondrial chaperonin 10, but not groES, is functionally compatible with the heptameric chaperonin 60 of mammalian mitochondria.

Acetylation↗

[Viral encephalitis after tick bite].

TBE is caused by a Flavivirus and is endemic in certain areas of Central and Eastern Europe, such as Austria, the south of Germany, Hungary, Czechoslovakia, Poland, the former Yugoslavia and SNG and certain areas of Sweden and Finland. Recent developments in the Eastern European countries have made them popular with Danish travellers, who are thus exposed to infection. Until now TBE has been a very rare disease in Denmark. The clinical course is biphasic being preceded by an incubation period of ten days. After the initial phase with uncharacteristic symptoms, a period af about five days follows where the patient has no symptoms. About one-third of the patients develop meningo-encephalitis where paresis can be seen. The course of the disease is often prolonged. The prognosis is good in terms of full recovery and low mortality. The diagnosis is made serologically with haemagglutination-inhibition test or ELISA-technique. Differential diagnosis includes other causes of viral encephalitis and Lyme disease with neurological manifestations, when there is a history of tick-bites. Vaccination provides good protection and is recommended for certain travellers with trips of some duration in endemic areas.

Denmark↗