Airway lesions caused by prolonged intubation with standard and with anatomically shaped tracheal tubes. A post-mortem study

Two groups of patients intubated for long periods were examined post mortem. In Group A (22 patients) the mean duration of intubation was 4.0 days and in Group B (19 patients) 5.7 days. The mean for the two groups was 4.8 days. In Group A a conventional endotracheal tube was used, and in Group B an anatomically shaped tube. Both tubes had cuffs of the intermediate-volume, low-pressure type. The larynx and trachea, from the epiglottis to the bifurcation, were removed in one piece at autopsy and the inner surface was photographed. The photographs were magnified and from these the size and estimated depth of any lesions were recorded. In the arytenoid and tracheal regions no significant difference was found between the two groups. In the cricoid region, on the other hand, the outcome was significantly more favourable following use of the anatomically shaped tube.     

Smoking and caffeine have a synergistic detrimental effect on aortic stiffness and wave reflections

OBJECTIVES: We investigated the acute and chronic combined effect of cigarette smoking and caffeine intake on aortic stiffness and wave reflections. BACKGROUND: We have shown that smoking and caffeine separately increase arterial stiffness. Aortic stiffness and wave reflections are important determinants of the efficient performance of the cardiovascular system and prognosticators of cardiovascular risk. METHODS: The acute effects of smoking (one cigarette), caffeine (200 mg, equivalent to 2 cups of coffee), and smoking plus caffeine were studied in 24 healthy subjects according to a randomized, placebo- and sham procedure-controlled crossover design. The chronic effect of smoking and caffeine was studied in a population study that enrolled 160 healthy subjects. RESULTS: Acute study: there was a significant interaction between caffeine and smoking with regard to pulse-wave velocity (p < 0.01) and augmentation index (p < 0.05). When smoking followed caffeine intake, pulse-wave velocity and augmentation index increased further by 0.52 m/s and 13.4%, respectively, reaching a total of 0.85 m/s and 17.4%, 0.17 m/s and 9.2% in excess of the mere sum of caffeine effect (0.33 m/s and 4%) alone and smoking effect alone (0.35 m/s and 4.2%). Population study: there was a significant interaction of chronic coffee consumption and smoking regarding pulse-wave velocity (p < 0.05) and augmentation index (p = 0.001). CONCLUSIONS: The present study shows, for the first time, that when smoking and caffeine intake are combined, they interact and exert a synergistic, unfavorable effect on aortic stiffness and wave reflections on both an acute and chronic basis.     

Quantifying Cartilage Biomechanical Properties Using a Linearized Frequency-Domain Method

Articular cartilage function relies on its unique mechanical behavior. Cartilage mechanics have been described by several analytic models, whose parameters are usually estimated by fitting their constitutive equations to stress-relaxation data. This procedure can be long and is prone to experimental and fitting errors. Τhis study describes a novel methodology for estimating the biomechanical properties of cartilage samples based on their linearized frequency response, derived by applying a series of small-amplitude harmonic displacements superimposed to a bias strain. The proposed methodology, denoted as linearized frequency-domain method (LFM), was demonstrated by quantifying the effects of collagenase and hyaluronidase on cartilage, where it provided robust cartilage parameter estimates that overall agreed well with estimates obtained by stress-relaxation analysis. LFM was also applied to unveil the strain-dependent nature of porcine cartilage biomechanical parameters. Results showed that increasing the bias strain from 5% to 15% caused a significant decrease in cartilage permeability but did not have significant effect on the compression modulus and the Poisson’s ratio. Apart from cartilage, LFM can potentially quantify the strain-dependent nature of tissues and biomaterials, thereby enhance tissue-level understanding on organ physiology and pathology, lead to better computational tissue models, and guide tissue engineering research.     

Solitary fibrous tumour of the cheek: An unusual presentation of a rare soft tissue tumour

This case report discusses the unusual presentation and ultrasound features of a solitary fibrous tumour of the face. Solitary fibrous tumour is an uncommon form of soft tissue tumour which, although seen predominantly within the lung pleura, can occur throughout the body in sites such as the peritoneum, mediastinum and head and neck. Ultrasound is an excellent imaging modality in the assessment of soft tissue masses in the head and neck. The ultrasound features demonstrated by this example of solitary fibrous tumour are reviewed. This report also highlights that ultrasound alone is ultimately limited in reaching a definitive diagnosis. The roles of other investigations such as ultrasound-guided biopsy and cross-sectional imaging are discussed.     

Beta thalassemia in Melanesia: association with malaria and characterization of a common variant (IVS-1 nt 5 G----C)

Data on the distribution of beta thalassemia among over 6,000 Melanesians reveals a major difference in the carrier rates between populations in the malarious coastal regions of New Guinea and those living in the historically malaria-free Highlands. The island of Maewo in Vanuatu has a particularly high incidence of beta + thalassemia associated with a single restriction enzyme haplotype. Direct cloning into a plasmid vector and sequence analysis demonstrate that the mutation is a G to C transversion at position 5 of intron 1 of the beta- globin gene. Oligonucleotide probe surveys indicate that this variant accounted for all cases of beta thalassemia studied from Maewo. It is also common in coastal Papua New Guinea where haplotype and oligonucleotide probe data suggest that the molecular basis of beta thalassmia is more heterogeneous.     

A comparison of the long-term effects of sotalol and atenolol on QT interval and arrhythmias after myocardial infarction

In order to dissociate the Class III effects of sotalol on QT interval and arrhythmias from those of chronic beta-receptor blockade, we compared the effects of sotalol 160 mg b.d. and atenolol 50 mg b.d. in a double-blind crossover study of 103 patients followed for one year after discharge following acute myocardial infarction. Sotalol caused a highly significant lengthening of the absolute and corrected QT (QTc) interval over atenolol which was apparent by day 6 and persisted unchanged throughout the follow-up period. The increase in QT interval averaged 43 ms (9%). Sotalol blunted the increase in ventricular premature beat frequency on ambulatory monitoring which occurred with atenolol, although direct comparison of arrhythmia frequency between the groups receiving atenolol and sotalol revealed no significant difference. Marked lengthening of QTc interval (greater than 500 ms) was observed on 29 occasions in patients receiving sotalol, most commonly at day 6, but no episodes of polymorphic ventricular tachycardia were recorded. The Class III action of sotalol persists over and above any response to beta-blockade during a one-year follow-up period. In a population with a low incidence of spontaneous arrhythmias, however, there was only a modest difference in antiarrhythmic efficacy between atenolol and sotalol. Episodes of marked lengthening of QT interval induced by sotalol in the absence of other adverse factors need not be arrhythmogenic.     

Significance of serum bilirubin level in response of hepatocellular carcinoma to doxorubicin

To determine which of several clinical and laboratory features could be of significance in the response of hepatocellular carcinoma to doxorubicin we have analysed the frequency of remission in 143 patients treated with this drug. Of those features investigated including age, sex, presence and aetiology of underlying cirrhosis, duration of symptoms, performance grade and liver function tests, a normal serum bilirubin level was shown to be the only one on logistic regression analysis to predict a greater change of response (response rate = 46% with serum bilirubin less than 20 mumol/l and 10% with bilirubin greater than 20 mumol/l). The most likely explanation is that reduction in doxorubicin dosage according to the serum bilirubin level, based on the view that the risk of myelosuppression is thereby lessened, may lead to suboptimal dose administration.