I.V. PRACTOLOL DURING MICROLARYNGOSCOPY. EFFECT ON ARTERIAL PRESSURE, HEART RATE, BLOOD GLUCOSE AND LIPOLYSIS

Twenty-five patients undergoing microlaryngoscopy were anaesthetizedwith thiopentone and nitrous oxide with suxamethonium as a musclerelaxant. Thirteen received practolol 0.4 mg kg^–1 andatropine 1.5mg i.v. shortly before anaesthesia. During anaesthesiapractolol 0.2 mg kg^–1 was given. Twelve (control) receivedatropine 0.5 mg before anaesthesia. Practolol reduced the frequencyof tachycardia and arrhythmia. The treatment group had a greaterreduction in systolic arterial pressure during induction. Thehypertensive response to laryngoscopy was not significantlyattenuated by practolol. A weak hyperglycaemic response to microlaryngoscopywas not affected, nor was the plasma concentration of glycerol.     

A gonadotrophin-releasing hormone agonist stimulates oxygen consumption and maturation of follicle-enclosed rat oocytes in vitro

Rat oocytes were induced to resume meiosis by incubating isolated preovulatory follicles with LH or a gonadotrophin-releasing hormone (GnRH) agonist. Oocyte maturation was accompanied by a 32% increase in oxygen consumption by the denuded oocyte after incubation with LH and a 67% increase after incubation with the GnRH agoinst.     

Secondary polycythaemia associated with nocturnal apnoea — a relationship not mediated by erythropoietin?

Abstract. A polysomnographic study was undertaken in nine patients with unexplained polycythaemia and nine age- and sex-matched controls. Circulating plasma levels of immunoreactive erythropoietin (IrEPO) were analysed before and after sleep. Seven out of nine polycythaemia patients were found to have sleep-disordered breathing and fulfilled the criteria for the sleep apnoea syndrome. Erythrocyte volume fraction was by definition higher among polycythaemia patients, and showed a weak positive correlation with minimum oxygen saturation during sleep (P < 0.05). However, plasma IrEPO did not differ between the two groups or between morning and evening samples within the respective groups. In a separate study, IrEPO was repeatedly analysed during sleep in a group of six patients with severe obstructive sleep apnoea and six matched controls. No correlation with severity of sleep-disordered breathing was found. None of these patients had polycythaemia, and there was no obvious diurnal variation in IrEPO levels. A nocturnal sleep study may be warranted in patients with unexplained polycythaemia. Obstructive sleep apnoea does not appear to be related to increased IrEPO levels, although polycythaemia has been reported as a relatively common finding in this disease.     

The Adjuvant Action of Cholera Toxin is Associated with an Increased Intestinal Permeability for Luminal Antigens

This study addresses the question of whether cholera toxin (CT) increases gut permeability for molecules greater than 3000 Da and whether such an effect is associated with an adjuvant function by CT on the gut immune response. We found that CT after oral administration gives rise to strikingly increased gut permeability for Dextran (Mw 3000) concomitantly with a strong enhancing effect on the anti-keyhole limpet hemocyanin (KLH) specific immune response in the lamina propria after oral immunization with KLH plus Dextran and CT. In contrast, the B-subunit of the holotoxin, which lacks the adenylate cyclase/cAMP-activating property of CT, failed to increase gut permeability as well as local anti-KLH immune responses. These results might suggest a causal linkage between the ability of CT to increase gut permeability and its adjuvant property on gut mucosal immune responses. In addition this finding supports the notion that the adenylate cyclase/cAMP system plays a regulatory role in gut permeability and is important in enhancing mucosal immune responses. Based on previous studies and the present data we propose that the mechanism for CT's adjuvant function on mucosal immune responses is by affecting antigen-presenting cells, T and B cells in the gut to give a net enhancing effect on the stimulation of local immunity, and that the CT-induced increase in gut permeability might be part of the adjuvant mechanism by facilitating luminal antigens to access the gut mucosal immune system.     

Chlorhexidine solutions in histological and histochemical techniques1

Abstract. Chlorhexidine solutions have been tested to determine their usefulness as media for the transport of biopsy specimens for diagnosis in order to facilitate the use of cold microtome sectioning and enzyme histochemical techniques in routine histopathological diagnostic practice. The drug was chosen for its antibacterial and protein “preserving” capacities. Tissue morphology, chemical components and enzyme activities were found to be retained well in specimens from human gingiva when stored in a cold solution, pH 7.2, containing 2.2 mM chlorhexidine gluconate, 0.19 M cacodylate buffer and 7.5 % polyvinylpyrrolidone. The procedure allowed reliable enzyme activity evaluations to be performed under the light microscope within 48 hours after excision of the tissues. Fresh frozen tissues served as controls. In an additional electron microscopic study, morphology of the cells was found to be reasonably well preserved after transport in the solution.     

A feedback and probing strategy to regulate harvesting from a renewable resource

A strategy is introduced for regulating harvesting when onlyvery limited information about stock size and stock dynamicsis available. The strategy only requires regular observationsof a relative abundance index and only very general assumptionsabout stock dynamics are made. The strategy consists of twoparts: a feedback rule on the relative rate of change of theindex which serves the purpose of stabilizing the stock sizeat some level and a probing component which moves it towardsa more productive level. In general there is a delay betweenthe observation and the control action. By considering a stockwhich is described by a general ordinary differential equationwith delay, the general properties of this rule are discussed,as well as the stability properties. Finally, some deterministicand stochastic simulations are presented.     

METOPROLOL, FENTANYL AND STRESS RESPONSES TO MICROLARYNGOSCOPY: Effects on arterial pressure, heart rate and plasma concentrations of catecholamines, ACTH and cortisol

Forty patients undergoing microlaryngoscopy were anaesthetizedwith thiopentone and nitrous oxide. Twenty patients receivedmetoprolol 200 mg in a slow-release tablet once daily for 4days up to, and including, the morning of operation, and l0mg^–1i.v. shortly before induction of anaesthesia. Theother patients received placebo tablets and physiological salinei. v., instead- Both groups of 20 patients were further subdivided,half of the patients receiving fentanyl 1.0–1.5mg duringanaesthesia, the effect of which was antagonized by naloxoneat the end of the procedure. The other patients received salinei.v. instead of fentanyl or naloxone. Metopropolol decreasedheart rate and the general level of arterial pressure duringanaesthesia, but did not affect the fluctuations in pressure.Arterial plasma noradrenaline concentrations during microlaryngoscopywere enhanced by metoprolol, in comparison with placebo, thereverse being the case for cortisol concentrations. Fentanyldecreased arterial pressure and plasma ACTH and cortisol concentrationsregardless of whether the patient had received metoprolol. Plasmaadrenaline and noradrenaline concentrations were decreased byfentanyl in the patients receiving metoprolol.