A practical technique for disinfecting electrical stimulation apparatuses used in wound treatment.

BACKGROUND AND PURPOSE: Electrical stimulation (ES) is used in wound management. Concerns, however, have been raised about the possible role ES might play in promoting or exacerbating wound infections, especially bacterial infections. The purpose of this study was to address these concerns by evaluating the efficacy of a method for disinfecting ES electrodes used in wound treatment. METHODS: Samples were taken from each wound treated in this study prior to and after ES and from sponges used with the ES electrodes prior to treatment, after treatment, and after 20 minutes of chemical disinfection. The presence and types of bacteria recovered were determined through standard microbiological techniques. RESULTS: In this study of 25 patient samples, large numbers (ie, thousands) of bacteria were recovered from the pretreatment and posttreatment wound samples and from the posttreatment sponges. Following disinfection, however, bacteria were absent from the sponges in 23 of the 25 patient samples. In the remaining 2 samples, no more than two bacterial colonies were recovered after disinfection. CONCLUSION AND DISCUSSION: Immersion of the electrodes and sponges for 20 minutes in the disinfectant resulted in reduction of bacteria to safe, noninfective levels. Disinfection either completely eliminated all bacteria from the sponges (in 92% of the samples) or eliminated nearly all bacteria (in the remaining 8% of the samples), compared with predisinfection samples, which contained very large numbers of bacteria. These results demonstrate that the disinfection method used in this study is efficacious, and it appears to be cost-effective, practical, and safe for clinical use.

The effects of exercise mode, swimming vs. running, upon bone growth in the rapidly growing female rat.

The purpose of this study was to compare the effects of two programs of endurance training, of equal duration and intensity, on bone development in female rats. Thirty-eight female Wistar rats were randomly assigned to one of three groups: run-trained (RUN), swim-trained (SWIM) or control (CON). The RUN group ran at a speed of 27 m/min up an 8 degrees incline. Swim trained animals swam with 2% of body weight attached to their tails. Training sessions were 2 h/day, 5 days/week and were conducted over a 10-week period. Hindlimb and forelimb muscles were removed upon sacrifice and analyzed for citrate synthase (CS) activity, liver (LG) and muscle (MG) glycogen. The parametrial fat pads were removed, digested with collagenase, and 2-deoxy-D-[3H]glucose uptake measured in isolated cells. Bone weight, length, diameter, ponderal index and bone mineral content (BMC) were measured in the femur and humerus of each animal. The LG, MG, fat cell volume, glucose uptake of the adipocyte and adrenal weight data indicate that the training response was identical. The CS activity of the muscles indicated that mechanical and recruitment patterns of the upper and lower body differ and could be responsible for bone development patterns found in this study. Exercise had a minimal effect on bone growth in the run-trained animals but did stimulate development in the swim-trained animals. The humerus of the SWIM was significantly (P < 0.05) heavier, wider and had a greater BMC when compared with those of the RUN and CON rats. The results of this study indicate that the muscular forces applied by the swim training protocol produced greater bone adaptations than the forces applied by a running protocol of equal duration and intensity.

Polymyxin B inhibits stimulation of glucose transport in muscle by hypoxia or contractions.

Glucose transport can be stimulated via two separate pathways in muscle. One is activated by insulin, the other by contractile activity and hypoxia. Polymyxin B, a cationic antibiotic that displaces Ca2+ from anionic phospholipids, is reported to selectively inhibit the stimulation of glucose transport by insulin in muscle. A purpose of the present study was to determine whether the inhibition by polymyxin B is actually restricted to insulin. We found that polymyxin B (250 micrograms/ml) significantly inhibited the stimulation of glucose transport in rat skeletal muscles not only by insulin and vanadate but also by hypoxia, electrical stimulation, and K+. Polymyxin B also decreased the tension developed in response to electrical stimulation or K+. Although polymyxin B inhibited the increase in sugar transport activity induced by insulin and hypoxia, it had no inhibitory effect on sugar transport after it had been stimulated by these agents. These results show that the inhibitory effect of polymyxin B on the stimulation of glucose transport is not specific for insulin action. They suggest that polymyxin B inhibits a step that is common to the two pathways for stimulating glucose transport in skeletal muscle.

Prolonged increase in insulin-stimulated glucose transport in muscle after exercise.

Exercise can induce short-term increases in the sensitivity and responsiveness of skeletal muscle glucose transport to insulin. The purpose of this study was to determine the effect of carbohydrate deprivation on the persistence of increased insulin sensitivity and responsiveness after a bout of exercise. Three hours after a bout of exercise, epitrochlearis muscles from carbohydrate-deprived (fat fed) rats showed a 25% greater increase in 3-O-methylglucose (3-MG) transport in response to a maximal insulin stimulus compared with muscles of nonexercised rats; this increase in insulin responsiveness had reversed 18 h postexercise. Muscles of rats fed carbohydrate showed no increase in insulin responsiveness 3 h after exercise. The effect of 60 microU/ml of insulin on 3-MG transport was approximately twofold greater in muscles studied 3 h after exercise than in nonexercised controls regardless of dietary carbohydrate intake. This increase in insulin sensitivity was lost within 18 h in carbohydrate-fed rats but persisted for at least 48 h in carbohydrate-deprived rats. Muscle glycogen increased approximately 41 mumol/g in the rats fed carbohydrate for 18 h, and only approximately 14.5 mumol/g in the rats fed fat for 48 h, after exercise. The persistent increase in insulin sensitivity after exercise in carbohydrate-deprived rats was unrelated to caloric intake, as muscles of fasted and fat-fed rats behaved similarly.

Reversal of the exercise-induced increase in muscle permeability to glucose.

Exercise is associated with an increase in permeability of muscle to glucose that reverses slowly (h) in fasting rats during recovery. Previous studies showed that carbohydrate feeding speeds and carbohydrate restriction slows reversal of the exercise-induced increase in glucose uptake. This study was designed to evaluate the roles of glucose transport, glycogen synthesis, and protein synthesis in the reversal process in rat epitrochlearis muscle. In contrast to recovery in vivo, when muscles were incubated without insulin in vitro, the exercise-induced increase in muscle permeability to sugar reversed rapidly regardless of whether glucose transport or glycogen synthesis occurred. Inhibition of protein synthesis did not prevent the reversal. Addition of 33% rat serum or a low concentration of insulin to the incubation medium markedly slowed reversal in vitro. We conclude that 1) prolonged persistence of the increased permeability of mammalian muscle to glucose after exercise requires a low concentration of insulin, and 2) reversal of the increase in permeability does not require glucose transport, glycogen synthesis, or protein synthesis.

Influence of selected carbohydrate drinks on cycling performance and glycogen use.

Eight well-trained male cyclists were used to determine the influence of carbohydrate feedings on exercise performance and muscle glycogen use. Two days prior to each trial, the subjects performed a 60-min "depletion ride" at 70% VO2max, which was followed by the ingestion of a high carbohydrate diet (approximately 500 g X -1). During the experimental trials, the men performed 2 h of cycling exercise and consumed 150 ml of 1 of 4 solutions at 24-min intervals. The drinks were: H2O (artificially flavored and sweetened); maltodextrin (5 g X 100 ml-1) and fructose (5 g X 100 ml-1); maltodextrin (7.7 g X 100 ml-1) and high fructose corn syrup (2.3 g X 100 ml-1); maltodextrin (3 g X 100 ml-1 and glucose (2 g X 100 ml-1). The amount of work completed during the four trials was not significantly different. Initial glycogen levels were high, and glycogen values were not significantly different at the beginning of exercise or at 90 min (185.35 +/- 3.26 and 91.93 +/- 3.39, respectively). Blood glucose was greater at 60 min in trial maltodextrin and glucose (5.70 +/- 0.36 mmoles X l-1), maltodextrin and high fructose corn syrup (6.05 +/- 0.54), and maltodextrin and fructose (6.03 +/- 0.42) compared to H2O (4.97 +/- 0.35) (P less than 0.05). Blood glucose remained elevated at 90 min during the maltodextrin and fructose and maltodextrin and high fructose corn syrup trials and at 120 min in the maltodextrin and fructose trial. No differences were observed between trials in blood lactate, serum glycerol, respiratory exchange ratio, or the subjects' perception of effort.(ABSTRACT TRUNCATED AT 250 WORDS)