Distribution of extracellular matrix components and their receptors in human lymphoid tissue and B-cell non-Hodgkin lymphomas

In this study the distribution patterns of various extracellular matrix components and their receptors (i.e. β1 integrins) in B-cell non-Hodgkin lymphomas were examined and compared to those in reactive lymphoid tissue. Neoplastic follicles within follicular lymphomas showed similar patterns to that observed in reactive follicles, which appeared to be strongly associated with the presence of follicular dendritic cells. Diffuse lymphomas of low and intermediate malignancy grade revealed features comparable to those of interfollicular areas of reactive lymphoid tissue, irrespective to which compartment the tumour cells were related. Highly malignant lymphomas, however, displayed unique extracellular matrix configurations, resulting from active matrix degradation by macrophages; this may support rapid tumour growth. Extranodal lymphomas showed virtually the same matrix patterns as their nodal counterparts, suggesting that (malignant) lymphoid cells generate (at least partly) their own specific microenvironment. In reactive lymphoid tissue β1 integrins were mainly found on resident cells and except for α4, α5 (and β1) the lymphoid cells expressed very little, if any, β1 integrins. In comparison, expression of these integrins on lymphoma cells was reduced (follicular lymphomas) or could not be detected at all (diffusely growing lymphomas); this might contribute to the growth pattern and metastatic properties of the tumours.     

Risk factors for myocardial infarction during coronary artery bypass graft surgery

Patients with a particular thrombotic profile may be at greaterrisk of myocardial infarction during coronary artery bypassgraft surgery. The thrombotic profile of 50 patients admitted to hospital withstable angina pectoris was determined prior to haemodynamicinvestigation. ECG results and determination of cardiac enzymesshowed that 12 patients had suffered a perioperative myocardialinfarction. These patients had a higher mean atheroscleroticscore (42.1 ± 10.5 vs 32.9 ± 13, P<0.02), alonger aortic cross clamp time (59 ± 15.2 vs 45.7 ±16.3 min, P < 0.05), lower serum levels of protein C (101.2±26vs 124.7+ 31.4%, P<0.05) and tissue plasminogen activator(322 ± 580 vs 2307±2830 IU ml^–1, P<0.01). There were no differences between the two groups in Jenkin'scoronary score, the number and type of grafts, ejection fraction,left ventricular end-diastolic pressure, lipid profile or levelsof markers of platelet release. In addition to a more severe distal coronary atheroma and alonger aortic cross-clamp time, patients with impaired endothelialfibrinolytic activity appeared to be at greater risk of myocardialinfarction during coronary artery bypass graft surgery.     

Performance of the Airtraq™ laryngoscope after failed conventional tracheal intubation: a case series

Background: The Airtraq^™, a new disposable indirect laryngoscope, was evaluated in patients with difficult intubation.
Methods: The Airtraq^™ was used in 47 patients with predicted or unpredicted difficult intubation after failed orotracheal intubation performed by two senior anaesthesiologists with the Macintosh laryngoscope.
Results: Tracheal intubation with Airtraq^™ was successful in 36 patients (80%). The Cormack and Lehane score was IIb–III in 35 patients, and IV in 12 patients, with the Macintosh laryngoscope, while Cormack and Lehane score was I–IIa in 40 patients, IIb–III in three and IV in four with Airtraq^™. A gum elastic bougie was used to facilitate tracheal access in one-third (11/36) of the cases. Orotracheal intubation was not possible with Airtraq^™ in nine cases, five of whom had a pharyngeal, laryngeal or basal lingual tumour.
Conclusion: In patients with difficult airway, following failed conventional orotracheal intubation, Airtraq^™ allows securing the airway in 80% of cases mainly by improving glottis view. However, the Airtraq^™ does not guarantee successful intubation in all instances, especially in case of laryngeal and/or pharyngeal obstruction.     

CLONIDINE DECREASES POSTOPERATIVE OXYGEN CONSUMPTION IN PATIENTS RECOVERING FROM GENERAL ANAESTHESIA

Twenty ASA I patients, undergoing thyroid surgery were allocatedrandomly to receive at the end of surgery either an isotonicsaline solution or clonidine 2 fig kg^–1 i.v. administeredover 20 min. Oxygen consumption (VO2) and carbon dioxide production(VCO2) were measured during recovery in patients breathing spontaneouslywith a head canopy system. Clonidine was found to attenuatethe increase in Vo2 and Vco2 associated with recovery from anaesthesia.The effect of clonidine was associated with a reduction in shivering.Sedative and analgesic properties of clonidine may also contributeto the reduction in metabolic demand during recovery from anaesthesia.     

Mode Switch Despite Undersensing of Atrial Fibrillation in ODD Pacing

Mode switching algorithms are commonly used to protect the ventricles against high rates induced by atrial tachycardia. In the case of atrial fibrillation (AF), the response of these algorithms depends on the quality of atrial sensing. The Chorum 7234 DDDR pacemaker uses a new mode switching algorithm, based on a statistical analysis of the atrial rhythm. It includes two criteria of diagnosis: "high" if more than 28 of 32 cycles are abnormally accelerated; and "low" if more than 36 of 64 cycles are abnormally accelerated. Methods: From a taped database of electrophysiological studies, episodes of AF lasting more than 2 minutes were selected. A tape recorder replayed the atrial signals into an external Chorum device. Each episode was replayed eight times with a programmed atrial sensitivity increasing from 0.4 –2.0 mV. For each criterion of diagnosis and each programmed sensitivity, the percentage of atrial sensing, the time to switching, and the mean ventricular rate were measured. Ten episodes of AF from 10 patients (9 men and 1 woman; ages 62 ± 16 years) were included: 1.95 ± 0.97 mV and 196 ± 64 ms. The sensitivity of the algorithm to diagnose atrial tachycardia reached 100%, for an atrial sensitivity set between 0.4 and 1.0 mV. The mean percentages of atrial sensed events were 74%± 18% and 46%± 9% for the "high" and "low" criteria, respectively. The mean diagnostic times were 28 ± 26 seconds and 68 ± 27 seconds, respectively. Sensing of < 23% of AF events resulted in failure to diagnose the arrhythmias by both algorithms. In the event of diagnostic failure, the mean ventricular pacing rate was 79 ± 9 ppm. Conclusion: Up to an atrial sensitivity of 1 mV, 100% of AF episodes were diagnosed. The Chorum mode switching algorithms are 100% reliable if > 45% of the AF waves are sensed. In the event of switching failure, the ventricle is protected by an average rate remaining below 80 ppm. (PACE 1996;     

Circadian Variations in Minute Ventilation Can Be Reproduced by a Pacemaker Sensor

Special software allowing the memorization of 24-hour minute ventilation can be loaded into the memoiy of the Chorus RM, a DDDR pacemaker driven by minute ventilation. This feature was tested in the postimplant period in 13 patients. Measurements of minute ventiiation, respiratory rate, and respiratory amplitude were analyzed according to prospectively defined diurnal and nocturnal time periods. Minute ventilation decreased by 39% (P < 0.001) from the diurnal to the nocturnal phase, while respiratory rate and amplitude decreased by 18% and 28%, respectively (P < 0.001 each). Thus, minute ventilation allowed discrimination between sleep and waking hours. This information could be utilized to modulate the backup rate of the pacemaker.