The effects of capsaicin upon electrogenic ion transport in rat descending colon

Summary Preparations of rat descending colon mucosa have been used to record changes in short circuit current (SCC) under voltage clamp conditions. When added to the basolateral compartment capsaicin (8-methyl-N-vanillyl-6-nonenamide, 0.1-3 M) caused an initial transient increase in SCC, followed by a more prolonged reduction in SCC, that lasted for 20–30 min.Repeated applications of 3 M capsaicin caused desensitisation of the initial secretory response. The antisecretory effects (i. e. reduction in SCC from the original baseline) remained, although they were significantly reduced. In some preparations described as non-responders, 3 M capsaicin did not elicit a secretory response. No desensitisation of the remaining antisecretory responses was observed in these tissues; in fact these reductions in SCC were consistently larger than those from tissues which responded with a secretory response.Tetrodotoxin (100 nM), hexamethonium (10 M), and yohimbine (50 M) had no significant effect upon either secretory or antisecretory responses. Ruthenium red (10 M) abolished the secretory response to 3 M capsaicin, but had no effect upon the antisecretory responses. Pretreatment of the tissues with 1 M substance P(SP) resulted in significant desensitisation to the peptide and abolished the secretory response to 3 M capsaicin. The antisecretory responses remained, and were significantly larger compared with responses from control tissues. Send offprint requests to H. M. Cox at present address     

Growth hormone responses to acute resistance exercise with vascular restriction in young and old men

ObjectiveResistance exercise (RE) stimulates growth hormone (GH) secretion in a load-dependent manner, with heavier loads producing larger GH responses. However, new research demonstrates that low-load RE performed with blood flow restriction (BFR) produces potent GH responses that are similar to or exceed those produced following high-load RE. We hypothesized that low-load RE with vascular restriction would attenuate the known age-related reduction in GH response to RE.DesignIn a randomized crossover design, ten young (28 ± 7.8 years) and ten older (67.4 ± 4.6 years) men performed bilateral knee extension RE with low-load [20% of one-repetition maximum (1RM)] with BFR and high-load (80% 1RM) without BFR. GH and lactate were measured every 10 minutes throughout a 150-minute testing session (30 minutes prior to and 120 minutes following completion of the exercise); IGF-I was measured at baseline and 60 minutes post-exercise.ResultsArea under the GH curve indicated that both age groups responded similarly to each exercise condition. However, young men had a significantly greater maximal GH response to low-load RE with BFR than the high-load condition without BFR. Additionally, younger men had greater maximal GH concentrations to low-load RE with BFR than older men (p = 0.02). The GH responses were marginally correlated to lactate concentration (r = 0.13, p = 0.002) and IGF-I levels were unchanged with RE.ConclusionsGH responses to low-load RE with vascular restriction are slightly higher than high-load RE without vascular restriction in young men. However, low-load RE with vascular restriction did not attenuate the known age-related reduction in GH response with exercise. These data suggest that while low-load RE with vascular restriction is as effective for inducing a GH response than traditionally-based high-load RE, there is a more potent response in young men.     

Evaluation of changes in the activity of proteolytic enzymes and their inhibitors in the processes that accompany the growth of gastric cancer

Background Many investigators have observed a correlation between the aggressiveness of malignant tumor growth and the levels of cysteine peptidases and their autogenous inhibitors. Cathepsins B and L are activated by pepsin in an acidic pH. This fact encouraged us to measure the activity of these enzymes in tissue samples of gastric cancer.Methods We measured the activities of cathepsins B and L, and their precursors and inhibitors, in homogenates of tissue samples obtained from operations for gastric cancer. We compared the results for the homogenates of tissues from three different sites: the tumor center, the zone of cancer invasion (border of the tumor), and healthy tissue.Results The highest activities of free cysteine peptidases and those in complexes with their inhibitors, as well as their precursors, were observed in the border of the tumor, while the activities in healthy tissue were significantly lower.Conclusion The local activities of cysteine peptidases and their inhibitors reflect the topographical differences between the center of the tumor, the zone of invasion, and healthy tissues in gastric cancer patients. In addition, the results for the pattern of changes in the activity of cysteine peptidases according to the degree of tissue infiltration were not dependent on the method of measurement (colorimetry vs spectrofluorometry).     

Recent trends in tracheal intubation: a retrospective analysis of 97904 cases

We conducted a review of routine anaesthetic audit data collected between April 1995 and December 2001 at Northampton General Hospital. A total of 97 904 anaesthetics were given. The average monthly rate of tracheal intubation fell during the study period from approximately 450 per month to approximately 280 per month. This was largely at the expense of tracheal tubes used during normal working hours, which fell by 40% (from approximately 390 per month to approximately 230 per month). Use outside normal working hours did not change. Of those cases managed in normal working hours with a tracheal tube, the decline in use over time was most obvious in patients of ASA physical status 1-2, and whose surgery was classified as elective or scheduled. The proportion of cases classified as ASA 3-5 or whose surgery was urgent or emergency increased (from 15.5% to 22.3%, and from 7.5% to 15.5%, respectively.) There was considerable variation across surgical specialities, with the greatest decline in tracheal intubation in head and neck surgery. These changes in practice have implications for the teaching of airway management skills.