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Biomedical subjects

R Sandin

Publications and source records attributed to R Sandin.

At least 19 recordsLinked to original sources

Detection of airborne cytomegalovirus in hospital rooms of immunocompromised patients.

Human cytomegalovirus (CMV) is a major pathogen in immunocompromised patients. Transmission in this population is known to occur by fomites, but the potential for airborne spread is unknown. In this study, air from the rooms of two immunosuppressed patients with CMV pneumonia and one patient with latent infection was filtered and examined by a polymerase chain reaction assay. CMV-DNA was easily detected in the rooms of the patients with pneumonia and a weak positive signal was detected in the room of the patient with latent CMV infection. This technique permits the detection of aerosolized CMV-DNA and could possibly be adapted to detect other airborne pathogens.

AIDS-Related Opportunistic Infections

Recall during intermittent propofol anaesthesia.

We discontinued temporarily an infusion of propofol for surgical reasons in 20 patients undergoing incontinence surgery. The patients, who had not received neuromuscular blockers, were allowed to regain consciousness to a level enabling them to cough on command, open their eyes, and identify and verbally confirm a randomly assigned digit shown on paper. Thereafter, 5-14 min after discontinuation of the propofol infusion, anaesthesia was reinstituted. Memory of the request to cough, a standard conversation and the digit shown was tested 1 h after anaesthesia and on the following day. Only 35% of patients were able to recall one or more of the stimuli presented during wakefulness or were even able to recall having been "awake", and there were very few differences in memory on the day after surgery compared with 1 h after anaesthesia. In comparison with corresponding stimuli given before anaesthesia, memory of material learned during wakefulness was significantly impaired (P < 0.0001). Thus patients temporarily capable of cognitive action during propofol anaesthesia may have no subsequent explicit recall of intraoperative events.

Aged

Local anaesthesia and propofol-fentanyl sedation for carotid artery surgery.

BACKGROUND: In patients undergoing carotid artery surgery with local anaesthesia (LA), a sedative/analgesic pharmacological supplement is appropriate in most cases in order to provide comfort. This adjunct should not preclude continuous clinical neurological monitoring. The aim was to investigate if a combination of fentanyl and propofol to supplement LA would provide comfort for the patient, allow continuous clinical neurological monitoring and absence of difficulties for the anaesthetist, and good conditions for surgery, including insertion of a shunt if this should become necessary. METHODS: During a 1-year period low doses of propofol and fentanyl were used to supplement LA in 36 cases of carotid artery surgery in 34 consecutive patients. A shunt was only used if neurological dysfunction occurred. Data on haemodynamics, pulmonary gas exchange, clinical neurological monitoring, and subjective opinions from patients, surgeons and anaesthetists were obtained. Morbidity within 30 days was documented. RESULTS: Conversion to general anaesthesia was undertaken in one patient, previously operated on the same artery, who became unconscious due to a stroke during manipulation of the artery before arteriotomy. No other adverse outcome was found within 30 days. In the remaining 35 cases the procedures were carried out under LA. Stump pressures below 50 mmHg were found in 17/35 cases. Intraoperative neurological dysfunction was detected in 10/35 cases (stump pressures between 23 and 60 mmHg). Shunting was easily performed, and rapidly relieved the neurologic symptoms in all these patients. Intraoperative respiratory and haemodynamic control was satisfactory. Ease of performance, including clinical neurological monitoring, was acknowledged by both anaesthetists and surgeons, and all 33 patients (35 operations) who were accessible for a postoperative interview stated that they would prefer the same regimen in the case of further surgery. CONCLUSION: The number of cases in this open, uncontrolled study does not permit an evaluation of this anaesthetic and sedative technique in terms of neurological and cardiac outcome. Thus, we simply want to inform about our positive experiences regarding patient acceptance and ease of performance in all relevant respects when fentanyl and propofol are used to supplement LA for carotid artery surgery.

Aged

Fasting guidelines in different countries.

Abstention from food and drink prior to anaesthesia remains a cornerstone in safe practice. Despite the lack of scientific support, previous guidelines, similar for fluids and solids, have for more than three decades more often than not recommended "nil by mouth" ("nothing-per-os"; "NPO" in the US) after midnight or a fixed duration of time. Based on an increased number of studies of relevance to the duration of preoperative fasting, reviews on this subject concerning both adults (1) and children (2) and a large number of editorials (3-7), have recently been published. Since there may be a discrepancy between conclusions based on scientific studies and the current routine practice-this presentation is intended to survey the current recommendations in different countries and how they relate to publications on the subject. Opinions are mainly derived from officers of associations linked to The World Federation for Anaesthesiologists (WFSA) and from current literature.

Adult

Prophylactic i.m. ephedrine in bupivacaine spinal anaesthesia.

In a double-blind, placebo-controlled, randomized study, we have investigated the efficacy of i.m. ephedrine in 98 elderly patients undergoing hip arthroplasty under spinal anaesthesia with plain bupivacaine. Fifty patients received ephedrine 0.6 mg kg-1 body weight, deep in the paravertebral muscles immediately after injection of bupivacaine, and 48 received an equal volume of saline. Patients in both groups were given the same volumes of fluid before anaesthesia. Systolic arterial pressure during the first 60 min after anaesthesia remained significantly more stable in the ephedrine-treated group, and there was also a significantly smaller number of patients in this group who had decreases in pressure of more than 30% of pre-block levels, and fewer required rescue i.v. ephedrine. An increase in heart rate or systolic pressure of > or = 20% from baseline was found in two patients in the ephedrine group and in one patient in the placebo group. We conclude that ephedrine 0.6 mg kg-1 body weight administered in the paravertebral muscles immediately after plain bupivacaine spinal anaesthesia is a simple and effective means of reducing the incidence of hypotensive episodes in the elderly patient.

Adult

Expression of A antigens on erythrocytes of weak blood group A subgroups.

Scanning immune electron microscopy using a monoclonal anti-A antibody which reacts with all type A oligosaccharide chains revealed A antigens on less than 5% of Am and Ael cells, some of which showed extremely strong labelling. This explains why Am and Ael cells can absorb significant amounts of anti-A without being agglutinated. A3 may be a heterogeneous subgroup, since A antigens were found on 82 and 58%, respectively, of the cells of 2 A3 individuals. A antigens were found on 75% or more of Ax cells. In many weak A individuals A-positive cells are apparently best detected if an anti-A is used which reacts strongly with other A oligosaccharide chains than type 2. From hyperimmune pregnancy sera Ax, Am and Ael erythrocytes absorbed antibodies which seemed to have other fine specificities than those absorbed by A2 cells. We conclude that weak subgroups of A may deviate from A2 both by number of erythrocytes expressing A antigens and the biochemical nature of the antigens.

ABO Blood-Group System

Activation of complement by an IgG molecule without a genetic hinge.

The hinge region links the two Fab arms to the Fc portion of the IgG molecule. It mediates flexibility to the molecule and serves as a connecting structure between the two heavy chains. In addition it provides space between the Fab and Fc parts. All three properties have been proposed to be important for the ability of IgG to initiate complement activation leading to complement-mediated cell lysis (CML). Here we report the construction of a hinge-deleted mouse-human chimaeric IgG3 molecule with specificity for the hapten NIP (3-iodo-4-hydroxy-5-nitrophenacetyl), HM-1. HM-1 lacks the genetic hinge, but has an introduced cysteine between Ala 231 (EU numbering) and Pro 232 in the lower hinge encoded by the CH2 exon. The introduced cysteine forms a disulphide bond between the two heavy chains of the molecule. In CML, HM-1 shows a greater activity than IgG3 wild type. This is the first time an IgG molecule without a genetic hinge has been found to be active in CML. We conclude that the hinge functioning as a spacer is not a prerequisite for complement activation. Rather, its major role seems to be to connect the heavy chains to each other in the amino-terminal part of CH2. Because HM-1 is expected to have low Fab-Fc flexibility, this molecular feature is probably of no importance for complement activation.

Animals

Human IgG3 can adopt the disulfide bond pattern characteristic for IgG1 without resembling it in complement mediated cell lysis.

In this paper we describe the construction of mouse-human IgG3 mutant antibodies resembling IgG1 in their disulfide bond pattern between the heavy and light chain (H-L) and between the two heavy chains (H-H). The effector functions of these mutant antibodies were compared to normal IgG3 and IgG1. Changing only the disulfide bond pattern between the heavy and light chains did not alter the ability to induce complement mediated cell lysis (CML), regardless of the amount of corresponding antigen that had been introduced to the surface of the target cells. However, alteration of the disulfide bond pattern between the two heavy chains had a large effect on CML due to shortening of the hinge from 62 to 15 amino acids. No difference between the mutants and normal antibodies in antibody-dependent cell-mediated cytotoxicity (ADCC) was observed. This suggests that IgG3 can adopt the H-L disulfide bond pattern of IgG1 without obtaining the CML activity characteristic for IgG1.

Amino Acid Sequence

Delayed presentation of an extradural abscess in a patient with alcohol abuse.

Three cases of extradural abscess with delayed presentation after extradural analgesia have been reported previously. The present report describes a patient with alcohol abuse who was treated for 5 days with extradural injections of bupivacaine for pain from multiple rib fractures. The first symptoms of an extradural abscess developed approximately 11 days after removal of the extradural catheter, and definite diagnosis was delayed a further 7 days.

Abscess

Awareness during total i.v. anaesthesia.

Five cases of awareness have been identified during total i.v. anaesthesia with mechanically controlled ventilation and neuromuscular block. Two of the cases resulted from inability to deliver the target dose of anaesthetics, while the patient's need for anaesthetics was greater than anticipated in three. It is concluded that all cases were caused primarily by lack of experience, and could have been prevented. These five cases occurred in experience from approximately 2500 patients anaesthetized with this technique. Pre-, per- and postoperative data on the most recent 1727 patients have been entered into a database and may serve to provide data on the group of patients in whom the five cases of awareness occurred.

Adult

Renal vascular response to left atrial injection. An experimental study in the pig.

It has previously been shown that a rapid, transient and pronounced reduction in superficial renal cortical blood flow can be elicited by injection of 1 ml of plasma into the left atrium of the anaesthetized pig. This renal vascular response might constitute an important error in measurements of renal blood flow by means of the microsphere technique. In the present study we have investigated total renal (ultrasonic Doppler) and superficial renal cortical (laser Doppler flowmetry) blood flow after left atrial injections of saline and autologous blood. The average reductions in total renal blood flow were 4.7 +/- 2.4% (mean +/- s.d.) and 18.4 +/- 12.5% (mean +/- s.d.) for the blood and saline injections, respectively. The flow reduction was more pronounced in the superficial renal cortex with average reductions of 17.4 +/- 26.0% (mean +/- s.d.) and 59.4 +/- 38.5% (mean +/- s.d.) for blood and saline, respectively (laser Doppler flowmetry). Furthermore, two consecutive injections of microspheres were performed. The results from the second injection were compared with those from the first injection. In the superficial renal cortex the second injection indicated a significant reduction in blood flow and an significantly increased heterogeneity in the blood flow in two different tissue volumes. No corresponding differences were found in the juxtamedullary cortex. These results indicate that the renal vascular response to a left atrial injection is detectable as a reduction in total renal blood flow and is most pronounced in the superficial renal cortex. All these results taken together constitute an important error in measurements of superficial renal cortical blood flow by the microsphere technique.

Animals

Diclofenac for pain relief after arthroscopy: a comparison of early and delayed treatment.

The effect of diclofenac on pain after arthroscopy of the knee joint was investigated in 64 patients. The aim of this double-blind, placebo-controlled, randomised study was to compare administration before surgery with delayed treatment. The effect on postoperative pain was evaluated by means of a Visual Analogue Scale and recording of the need for additional analgesics postoperatively. After surgery, hourly assessments were performed within 6 h after the anaesthetic block (approximately 5 h after start of surgery), and on the morning after surgery. Both treatment with diclofenac before surgery and delayed treatment were superior to placebo concerning pain scores within 6 h after onset of anaesthesia (P < 0.0065 and P < 0.0005, respectively). On the morning after surgery, only delayed treatment was superior to placebo (P < 0.02). No differences in pain scores were evident between the different groups treated with diclofenac. No differences in the need for additional analgesics were found.

Arthroscopy