Pneumothorax during laparoscopic mobilization of the oesophagus

During laparoscopic dissection of the oesophagus, the left pleura is easily breached, resulting in pneumothorax. This complication has not been widely reported, although it is likely to be common. Management depends on subsequent cardiorespiratory effects, which are variable. Five cases are reported from an initial experience of 190 laparoscopic Nissen fundoplications, illustrating a variety of presentations and management options.     

Abnormal autonomic stress responses in obstructive sleep apnoea are reversed by nasal continuous positive airway pressure

Obstructive sleep apnoea (OSA) is associated with abnormalities in autonomic stress tests, which are tests of cardiovascular response in the autonomic nervous system (ANS). The level of abnormality has been related to the level of overnight arterial oxygen saturation (Sa,O2). We have studied ANS function pre- and post-treatment with nasal continuous positive airway pressure (nCPAP) in six males with moderately severe or severe OSA (apnoea/hypopnoea index (AHI) median 51 (range 14-74 events.h-1 of sleep). Tests consisted of heart rate responses to Valsalva manoeuvre, deep breathing, and change of posture from lying to standing. In addition, systolic blood pressure (SBP) response to standing and diastolic blood pressure (DBP) response to handgrip were studied. Each abnormal test (compared to published normal values) scored +1.0 and each marginal test result (90-95% confidence interval for normals) scored +0.5. A total score was calculated for the five tests performed in the evening and morning (maximum score 10 per patient). Patients had been receiving treatment for more than 1 year (median 471 (389-624) days) and objective compliance was monitored by a clock counter in the nCPAP machines. Five of six patients had regularly used nCPAP (mean 7.8 h.night-1) and all showed a normalization in ANS test score: pre-nCPAP 2 (1-4.5), post-nCPAP 0.2 (0-0.5) (p < 0.05, Wilcoxon signed rank test). One poorly compliant subject (No. 6; nCPAP 3 h.night-1) had a deterioration in ANS test score: 1 pre-nCPAP to 1.5 post-nCPAP. The improvement in ANS test score in the five compliant patients was positively correlated with an improvement in mean Sa,O2 during sleep posttreatment. We conclude that successful treatment of obstructive sleep apnoea leads to normalization of impaired autonomic stress responses.     

Physiological and morphological heterogeneity of dentate gyrus-hilus interneurons in the gerbil hippocampus in vivo

A variety of morphological types of dentate gyrus/hilus interneurons have been described, but little is known about their corresponding physiological characteristics. To address this issue, intracellular responses to current injection and perforant path stimulation were obtained from putative dentate interneurons in anaesthetized adult gerbils. Our sample of interneurons showed heterogeneity in their intrinsic physiological characteristics and spike thresholds to perforant path stimulation, suggesting the existence of distinct physiologically-defined classes. 'Fast-spiking' interneurons had a low threshold to perforant path stimulation, whereas 'slow-spiking' interneurons responded with predominantly inhibitory potentials. In several cases, cells were intracellularly labelled with biocytin for visualization. Interneurons with different physiological traits had distinct morphological features. These results confirm that, as in hippocampus proper, morphologically identifiable interneurons in the dentate hilus show electrophysiological features that are likely to reflect functionally specific roles in informational processing.     

Range of motion and complications after postburn heterotopic bone excision about the elbow

OBJECTIVE: To review the results of surgical management of heterotopic ossification about the elbow in burned patients. DESIGN: Retrospective analysis with long-term patient follow-up. MATERIALS AND METHODS: Eleven patients with 16 elbows requiring surgery were admitted between January 1, 1982 and December 31, 1993. A posterior approach to the elbow with release of the encased ulnar nerve +/- anterior transposition and transolecranon osteotomy to access extensive bone formation in the olecranon fossa was employed. Eight patients (11 elbows) were available for long-term follow-up conducted at mean 50 +/- 13 months after surgery. Long-term follow-up consisted of measurement of range of elbow motion, as well as clinical assessment of ulnar nerve function. MAIN RESULTS: For the 11 elbows examined postoperatively, the mean range of motion preoperatively in flexion-extension was 11 degrees +/- 5 degrees compared to 89 degrees +/- 12 degrees postoperatively (p < 0.001). Three patients with poor long-term results had ankylosis of the joint preoperatively. Of four patients with ulnar nerve paresis preoperatively, none had ulnar nerve dysfunction at follow-up. Of 16 elbows operated on, four (25%) had postoperative complications. Two suffered soft-tissue breakdown with hardware exposure requiring abdominal flap closure, one early failure of olecranon fixation, and one late infected hardware. CONCLUSIONS: Surgery for both limited range of motion as well as ulnar nerve compression is effective in cases of heterotopic ossification about the elbows of burned patients. Early operative intervention is indicated in progressive disease, particularly ulnar nerve palsy, if soft-tissue quality is adequate. Complications with 25% of elbows suggest that use of olecranon osteotomy for joint access may warrant review.     

Massive haemoptysis death and other morbidity associated with high dose rate intraluminal radiotherapy for carcinoma of the bronchus

Fluctuation analysis allows for the determination of mutation rates in cell cultures in vitro. As originally described by Luria and Delbruck and extended by Lea and Coulson and by Capizzi and Jameson, this analysis has been useful in estimating mutation rates in cultured cells where the frequency of mutational events is low. However. in cultures where high mutation rates and multiple independent mutation events occur, leading to the accumulation of many mutant cells, these standard methods may not apply. Here, we present a new method for the estimation of mutation rates based on the assumption that multiple events may contribute to the accumulation of mutant cells. We compared mutation rates determined by Lea and Coulson's and by Capizzi and Jameson's methods with those determined by our method using experimental and stimulated data from our studies of immunoglobulin gene mutation and isotype switching in B lymphocyte cultures. The three methods resulted in very different calculated rates when many mutants were present in the culture, such as when mutation rates were high, while only small differences in calculated rates were found when mutants were rare. Unlike previous fluctuation analysis calculations, our method is applicable for the estimation of both low and high rates.