Effect of adaptation to continuous stress on the contractile function and electric stability of the heart

In the time course of 15-day stress of moderate intensity, rat experiments indicated that following a day there developed a complex of changes typical of acute stressor syndrome. Five days of post-stress , the stress-related cardiac syndrome ceased, bradycardia developed, the contractile function was limited, and the fibrillation threshold returned to the control values, which was shown to be associated with activation of the cholinergic stress-limiting system. Fifteen days later there was normalization of heart rate and cardiac contractility, the fibrillation threshold remained at the baseline level.     

Chest wall kinematics and respiratory muscle action in ankylosing spondylitis patients.

No direct measurements of the pressures produced by the ribcage muscles, the diaphragm and the abdominal muscles during hyperventilation have been reported in patients with ankylosing spondylitis. Based on recent evidence indicating that abdominal muscles are important contributors to stimulation of ventilation, it was hypothesised that, in ankylosing spondylitis patients with limited ribcage expansion, a respiratory centre strategy to help the diaphragm function may involve coordinated action of this muscle with abdominal muscles. In order to validate this hypothesis, the chest wall response to a hypercapnic/hyperoxic rebreathing test was assessed in six ankylosing spondylitis patients and seven controls by combined analysis of: 1) chest wall kinematics, using optoelectronic plethysmography, this system is accurate in partitioning chest wall expansion into the contributions of the ribcage and the abdomen; and 2) respiratory muscle pressures, oesophageal, gastric and transdiaphragmatic (Pdi); the pressure/volume relaxation characteristics of both the ribcage and the abdomen allowed assessment of the peak pressure of both inspiratory and expiratory ribcage muscles, and of the abdominal muscles. During rebreathing, chest wall expansion increased to a similar extent in patients to that in controls; however, the abdominal component increased more and the ribcage component less in patients. Peak inspiratory ribcage, but not abdominal, muscle pressure was significantly lower in patients than in controls. End-inspiratory Pdi increased similarly in both groups, whereas inspiratory swings in Pdi increased significantly only in patients. No pressure or volume signals correlated with disease severity. The diaphragm and abdominal muscles help to expand the chest wall in ankylosing spondylitis patients, regardless of the severity of their disease. This finding supports the starting hypothesis that a coordinated response of respiratory muscle activity optimises the efficiency of the thoracoabdominal compartment in conditions of limited ribcage expansion.     

Computer simulation of the occlusal anatomy of the first mandibular molar after varying the determinants of mandibular movement in the CICERO CAD/CAM system

Static and dynamic occlusal interferences often occur in restorations. The CICERO CAD/CAM technique was used to control the occlusal dimensions of all‐ceramic restorations by setting the variables which determine the mandibular contact movements. The anatomy of the occlusal form of the (pre)molar teeth is influenced by the setting of the sagittal and transversal determinants of mandibular contact movements. In this study the variation in occlusal morphology of a high‐ and low‐limit setting of six variables was compared with an averaged setting. The settings (high, low and averaged, respectively) of the mandibular movement: the sagittal condylar (60°, 0°, 30°) and the incisal guide angle (60°, 0°, 30°) as well as the long centric articulation (1·2 mm, 0 mm, 0·6 mm) influence mainly the antero‐posterior direction, whereas the settings of Bennett movement (laterotrusion: 30°, 0°, 15°), Bennett side shift (laterotranslation: 1, 0, 0·5 mm) and the wide centric (lateral intercuspal contact area: 0·6, 0, 0·3 mm) will mainly influence the transversal direction of the mandibular movement. The influence of the variation of settings on ‘dynamic’ crown morphology as compared with the static crown morphology was studied by comparison of mesio‐distal and bucco‐lingual sections at the same occlusal position of the first lower molar design. Furthermore, the amount of material needed for the correction of the ‘static’ crown to avoid interferences in dynamic conditions was calculated. It appeared that most correction was needed for the ipsilateral settings: Bennett side shift (1·0 mm), Bennett movement (30°) and the Sag. Condylar guidance (0°) as well as the Incisal angle (0°), which could be studied in the bucco‐lingual sections. Also the Bennett side shift on the contra‐lateral side influenced the occlusal contour strongly, which could be seen in the mesio‐distal section. It was concluded that simulation of the influence of several types of determinants of mandibular movement on the three‐dimensional occlusal anatomy can be studied using the CICERO‐CAD/CAM technique. The ipsi‐ and contralateral Bennett side shift variation influenced the occlusal anatomy more than other variables.     

Best evidence in anesthetic practice

Question  

In postoperative non-ventilated patients, what is the efficacy and harm of pharmacological interventions in treating postoperative shivering?     

Screening of male patients with autosomal recessive Duchenne dystrophy through dystrophin and DNA studies

Previously we estimated that about 2.5-4% of isolated male patients diagnosed as Duchenne dystrophy (DMD) may have the autosomal recessive form (AR-DMD). Such cases can be distinguished from X-linked DMD through the analysis of dystrophin. Fifty DMD patients from 47 families were investigated for dystrophin and DNA deletions. Based on our results, we estimate that the frequency of AR-DMD may be about 8-12% among male patients diagnosed as DMD in whom X-linked inheritance could not be confirmed through pedigree data, serum enzymes in female relatives or DNA studies. Such an estimate must be confirmed in a larger sample; however, it shows the importance of assessing dystrophin in all patients diagnosed as DMD in whom X-linked inheritance cannot be proved, since the distinction between these 2 forms has implications for genetic counseling.     

Intravenous drug abuse and Type 1 diabetes: financial and healthcare implications.

AIMS: To determine the morbidity, mortality and healthcare costs of intravenous drug-abusing patients with Type 1 diabetes (IVDA-DM), who are admitted to hospital. METHODS: Retrospective case note analysis of admissions, complications and cost estimation over a 6-year period. Each drug-abusing patient (IVDA-DM) (n = 9) was compared with two controls (n = 18) with Type 1 diabetes but without a history of intravenous drug abuse (DM-controls). Admissions were also analysed for patients with intravenous drug abuse, but without Type 1 diabetes (IVDA-controls) (n = 198). Admissions were at a University teaching hospital in Liverpool, UK. DM-controls were drawn from a population attending diabetes outpatient clinics between 1997 and 2002 at the same hospital. The main outcome measures were: the duration and healthcare costs of hospital admissions per year, outpatient attendances per year, glycated haemoglobin (HbA(1c)), weight, micro- and macrovascular complications and mortality. RESULTS: Multiple admissions, mainly related to ketoacidosis, led to marked differences in mean (95% CI) inpatient days per year per patient [IVDA-DM 28.1 (13.6-42.7) vs. DM-control 1.1 (0.2-1.9); P < 0.0001], mean inpatient days per year per patient in critical care bed (IVDA-DM 1.7 (-0.7-4.2) vs. DM-control 0; P < 0.02) and mean costs of admission, per patient per year (pound sterling 7320 vs. pound sterling 230). The IVDA-DM group frequently omitted insulin, were underweight, failed to attend as outpatients and five had died by the end of 2002. The IVDA-controls spent considerably less time in hospital [3.4 (2.8-3.9) days per patient per year]. CONCLUSION: IVDA-DM patients have higher rates of diabetes complications, are admitted more frequently and have a high mortality compared with DM and IVDA-controls. The cost of inpatient care of this small group of patients was considerable.