Breathing at low lung volumes and chest strapping: a comparison of lung mechanics

In six normal subjects forced expiratory flow rates increased progressively with increasing degrees of chest strapping. In nine normal subjects forced expiratory flow rates increased with the time spent breathing with expiratory reserve volume 0.5 liters above residual volume, the increase being significant by 30 s (P less than 0.01), and flow rates were still increasing at 2 min, the longest time the subjects could breathe at this lung volume. The increase in flow after low lung volume breathing (LLVB) was similar to that produced by strapping. The effect of LLVB was diminished by the inhalation of the atropinelike drug ipratropium. Quasistatic recoil pressures were higher following strapping and LLVB than on partial or maximal expiration, but the rise in recoil pressure was insufficient to account for all the observed increased in maximum flow. We suggest that the effects of chest strapping are due to LLVB and that both cause bronchodilatation.     

Multichannel software event counter for the MC6809

Software can provide a cheap means of counting low-frequency events such as egg laying. A counting technique and driver program for this example are described.     

The roles of CD8 in cytotoxic T lymphocyte function

The CD8 glycoprotein of cytotoxic T cells is both an adhesion protein and a cosignalling receptor. These functions are regulated by signals from the T-cell antigen receptor complex (TCR-CD3), and CD8 acts to couple TCR occupancy to second messenger pathways. Here Anne O'Rourke and Matthew Mescher examine the roles of CD8 in activating the adhesion and signalling cascade initiated by antigen binding.     

Combined effect of gamma radiation and heating on the destruction of Listeria monocytogenes and Salmonella typhimurium in cook-chill roast beef and gravy

The effect of heating alone (60, 65 or 70 degrees C), heating after irradiation (0.8 kGy) and heating after irradiation and storage for 14 days at 2-3 degrees C on the destruction of Listeria monocytogenes and Salmonella typhimurium in artifically inoculated minced cook-chill roast beef and gravy was investigated. Inoculated minced roast beef samples (5 g) were heated in Stomacher bags completely immersed in a water bath at each of the test temperatures. Survivors were enumerated and D and z values were determined for each of the pathogens. Observed thermal D values for two strains of L. monocytogenes at 60, 65 and 70 degrees C in the absence of pre-irradiation were 90.0-97.5 s, 34.0-53.0 s and 22.4-28.0 s, respectively, whereas thermal D values after pre-irradiation were 44.0-46.4 s, 15.3-16.8 s and 5.5-7.8 s at 60, 65 and 70 degrees C, respectively. This reduction in D values provides evidence for radiation-induced heat-sensitisation in L. monocytogenes. There was some evidence of heat-sensitisation of S. typhimurium at 60 degrees C, but not at either 65 or 70 degrees C. The z value also decreased as a consequence of pre-irradiation to a dose of 0.8 kGy (11.0-12.7 degrees C). The radiation-induced heat-sensitivity in L. monocytogenes was found to persist for up to 2 weeks storage at 2-3 degrees C prior to heating. As cook-chill products are intended to be reheated prior to consumption the results of the present study suggest that any L. monocytogenes present in a cook-chill product would be more easily killed during reheating if it were to be treated with a low dose of gamma radiation during manufacture.     

Gastric carcinoma

Gastric cancer continues to be a major global health problem. In the American College of Surgeons Patient Care study on gastric cancer, 5-year disease-specific survival was 26%, with an overall survival of 14%. Improvements in survival will require both earlier diagnosis and new therapeutic strategies. The ability of surgical oncologists to understand the natural history of the disease, accurately define its extent, and provide the most effective treatment places them in a key position to see that improvements in outcome are brought about expeditiously.     

A role for N-methyl-D-aspartate receptors in the regulation of synaptogenesis and expression of the polysialylated form of the neural cell adhesion molecule in the developing striatum

Striatal development proceeds during a protracted postnatal period in rats. In the dorsolateral striatum, the number of asymmetric synapses, formed mostly by glutamatergic afferents innervating the dendritic spines of medium-sized striatal neurons, increases during the 3rd postnatal week and then rapidly declines before reaching adult levels. The polysialylated form of the neural cell adhesion molecule (PSA-NCAM), which is widely expressed along neuronal membranes early in development, becomes progressively localized to synapses, and is no longer detectable in remaining synapses after synaptic pruning has occurred. Administration of MK-801, an antagonist of N-methyl-D-aspartate receptors, on day 20, either peripherally or locally into the striatum, decreases asymmetric synapse number by 30% and totally abolishes immunolabelling for PSA-NCAM in the dorsolateral striatum.