The Repeated Bout Effect: Does Evidence for a Crossover Effect Exist?

Individuals undergoing an unaccustomed exercise bout incorporating a high degree of eccentric muscle contractions commonly experience delayed onset muscle soreness. The damage manifests itself via tenderness, loss of strength, swelling, elevated muscle enzyme activity and loss of flexibility. Following an initial "damage bout," a repeated bout results in reduced symptoms. This protective effect is known as the repeated bout effect (RBE) and can last up to 24 weeks between bouts. The mechanism for this RBE is unclear and both central and local mechanisms have been suggested. In an attempt to test the central hypothesis, 12 subjects (mean age = 22.5± 4yrs, ht = 167±9cm, mass = 71.5±13.5kg) underwent an exercise protocol whereby one leg was exercised eccentrically and following complete recovery; the contralateral leg was exercised in the same manner. Subjects were required to step on and off a 46-cm step for 20 minutes at a cadence of 15 steps/minute. One leg was used to go up the step (concentric) while the opposite was used to go down (eccentric). Approximately two weeks later and following complete recovery, the protocol was repeated with the concentrically exercise leg now performing the eccentric contraction. Data analyses indicate that muscle damage was induced during both trials on the eccentrically exercised leg as evidenced by a change in tenderness (bout 1 P < 0.05: bout 2 P < 0.01), pain scores (bout 1 P < 0.0001; bout 2 P < 0.01), and strength loss (bout 1 P = 0.001; bout 2 P = 0.001) over the four day follow up period. No tenderness was evident on the concentrically exercised limbs when compared to baseline (Bout 1: P =0.13, Bout 2: P = .06). Pain was significantly lower in bout two versus bout one (P< 0.04), however, we attribute this to a tolerance effect. Neither strength loss nor tenderness were significantly different between bouts. In the current study, damage was induced in both bouts in the eccentrically exercised limbs. This preliminary data does not provide evidence for a central mechanism in that an initial bout of eccentric exercise using one limb did not provide protection against damage from a repeated bout with the contralateral limb two weeks later.Key words: Eccentric, exercise, muscle damage, protection, contralateral     

Twenty-four-hour automated blood pressure monitoring as a predictor of preeclampsia

OBJECTIVE: The purpose of this study was to determine the predictive ability of parameters of 24-hour ambulatory blood pressure monitoring for the development of preeclampsia or gestational hypertension in women who are already considered at risk for these disorders. STUDY DESIGN: One hundred twenty-two pregnant women who were considered high risk for the development of preeclampsia underwent 24-hour ambulatory blood pressure monitoring between 18 and 30 weeks gestation, while their condition was normotensive according to routine mercury sphygmomanometry. One hundred sixty-four healthy primigravid women who were considered at usual risk for preeclampsia underwent the same tests as a parallel study. Routine blood pressure, awake and sleep average blood pressure, and 24-hour mean average blood pressure were entered into multiple logistic regression as predictors of either preeclampsia or gestational hypertension; significant variables were then tested by a series of receiver operator curves. RESULTS: Eight percent of usual risk and 45% of high risk women experienced the development of preeclampsia or gestational hypertension. In both groups, the average routine mercury blood pressure and awake, sleeping, and 24-hour ambulatory blood pressure monitoring-derived blood pressure were significantly higher in women who later experienced the development of preeclampsia or gestational hypertension. In usual risk women, 24-hour systolic blood pressure of >or=115 mm Hg and sleeping systolic blood pressure of >or=106 mm Hg were predictive of later preeclampsia or gestational hypertension, but sensitivities were low (77% and 54%, respectively). In high risk women, sleeping diastolic blood pressure of >or=62 mm Hg and sleeping mean arterial pressure of >or=79 mm Hg were predictive of preeclampsia or gestational hypertension, but again sensitivities were low (70% and 65%, respectively). CONCLUSION: Awake and sleeping blood pressure are higher in midpregnancy in women who later experience the development of preeclampsia or gestational hypertension. Twenty-four-hour ambulatory blood pressure monitoring provides a noninvasive method of selecting some of these women, but this test has a sensitivity no better than that of other predictive tests, even in women at high risk for preeclampsia.     

Patient satisfaction with chronic pain management

BACKGROUND: This article describes the use of focus groups in research, including the advantages and disadvantages of using this type of research methodology. Using an example of a focus group of patients who experienced chronic pain, the authors discuss the planning, organisation, conduct and analysis of focus groups. CONCLUSION: Focus groups enabled an exploration of the topics in-depth including obtaining insight from a patient's perspective of the management of their chronic pain. It was important and of value to take into account the experiences and expectations of health service delivery from a consumer's perspective.     

A prospectively randomized double-blind study on the effect of initial graft tension on knee stability after anterior cruciate ligament reconstruction

BACKGROUND: No consensus exists on the amount of tension that should be applied to anterior cruciate ligament grafts to best facilitate graft incorporation and re-create normal knee mechanics. HYPOTHESIS: Differences in initial graft tension will affect postoperative knee stability. STUDY DESIGN: Prospective, randomized, double-blind clinical trial. METHODS: Forty-nine patients undergoing bone-patellar tendon-bone autograft anterior cruciate ligament reconstruction by a single surgeon were randomized into high-tension (n = 27) and low-tension (n = 22) groups. Grafts were set at 90 N or 45 N. Arthrometric measurements (KT-1000 arthrometer manual maximum) of anterior tibial displacement and knee range of motion were made before surgery and at 1 week and an average of 20 months after surgery. Knee outcome scores were collected before and after surgery, and a single-leg hop test was also performed at final follow-up. RESULTS: After anterior cruciate ligament reconstruction, anterior tibial displacement was significantly greater in the patients in the low-tension group (P < .05). The side-to-side difference in anterior tibial displacement in the high-tension and low-tension groups was 1.1 +/- 1.7 mm versus 2.4 +/- 2.4 mm 1 week after surgery and 2.2 +/- 1.6 mm versus 3.0 +/- 2.2 mm at follow-up. Five patients had abnormal anterior tibial displacement (>5 mm side-to-side difference), and all were in the low-tension group (P <.05). Knee outcome scores improved with surgery (P <.01), with similar results for low-tension and high-tension groups. Hop test deficits were not different between groups. CONCLUSIONS: Initial graft tension affects the restoration of knee stability. A graft tension of 45 N was not sufficient for restoring knee stability.     

Direct restorative materials use in Australia in 2002

BACKGROUND: This study aimed to determine the reasons for dentists' choice of materials, in particular amalgam and resin composite, in Australia. METHOD: A questionnaire was developed to elicit this information. The names and addresses of 1000 dentists in Australia were selected at random. The questionnaire was mailed to these dentists with an explanatory letter and reply-paid envelope. RESULTS: A total of 560 replies were received. Regarding choice of material, 99 per cent of respondents cited clinical indication as an influencing factor, although patients' aesthetic demands (99 per cent of respondents), patients' wish (96 per cent), patients' financial situation (82 per cent), and lecturers' suggestions (72 per cent) were also reported to influence respondents' choice of materials. Twelve per cent of respondents used composite 'always', 29 per cent 'often', 32 per cent 'sometimes', 23 per cent 'seldom' and 4 per cent 'never' in extensive load-bearing cavities in molar teeth. For composite restorations in posterior teeth, 84 per cent 'always', 'often' or 'sometimes' used the total etch technique, 84 per cent used a thick glass-ionomer layer and 36 per cent never used rubber dam. Fifty-nine per cent of respondents reported a decreased use of amalgam over the previous five years. Sixty-eight per cent of respondents agreed with the statement 'discontinuation of amalgam restricts a dentist's ability to adequately treat patients'. Seventy-five per cent considered that the growth in the use of composites increased the total cost of oral health care. CONCLUSIONS: Of the respondents from Australia 73 per cent place large composite restorations in molar teeth and their choice of material is influenced greatly by clinical indications, and patients' aesthetic demands.     

Severe agitation among ventilated medical intensive care unit patients: frequency,characteristics and outcomes

Objective To determine the frequency, characteristics and outcomes of severe agitation among ventilated medical intensive care unit (MICU) patients.Design Prospective cohort study.Setting Eighteen-bed MICU in 964-bed tertiary care center.Patients All ventilated patients, aged 18 years or older and admitted for more than 24 h between January 1, 2001 and May 8, 2001.Interventions None.Measurements Data were collected daily by concurrent chart abstractions. Variables included sociodemographic, clinical, laboratory, pharmacologic and non-pharmacologic interventions, ventilator settings and adverse events. Severe agitation, the main outcome variable, was defined as two or more Motor Activity Assessment Scale (MAAS) scores above 4 in a 24-h period and sedative and/or narcotic doses above the established sedation and analgesia protocol or a combination of two or more sedatives.Results Twenty-three (16.1%) of 143 enrolled patients exhibited severe agitation. Agitated patients were younger (hazard ratio [HR] 1.32), more likely to be admitted from an outside hospital ICU (HR 2.48), had lower pH (HR 1.55) and PaO₂/FIO₂ less than 200 mmHg (HR 2.59). Agitated patients had longer MICU stays (median 12 versus 5 days, p<0.0001) and more ventilator days (median 14 versus 6, p<0.0001). Agitated patients were more likely to self-extubate (26% versus 6%, p=0.002). Benzodiazepines, narcotics and neuromuscular blocking agents were administered more frequently and at higher doses, but haloperidol was not.Conclusion Severe agitation occurs commonly in critically ill patients and is associated with adverse events including longer ICU stays, duration of mechanical ventilation and self-extubation.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00134-004-2193-9This research was partially supported by Nursing Education and Research Fund. Presented in part at the 2002 Annual Meeting of Society of Critical Care Medicine, San Diego, California.     

Choroidal neovascularization after laser in situ keratomileusis in a patient with low myopia

We report a case of choroidal neovascularization after laser in situ keratomileusis in a 37-year-old man with low myopia.     

The GABA transporter GAT1 and the MAGUK protein Pals1: interaction, uptake modulation, and coexpression in the brain

GABAergic signaling in the CNS is terminated in part through uptake of GABA by GABA transporters. We used the yeast two-hybrid system to identify proteins that associate with the carboxy-terminus of the neuronal GABA transporter GAT1. We found an interaction between GAT1 and the MAGUK protein Pals1. When coexpressed in COS-7 cells, Pals1 co-immunoprecipitates with GAT1. We demonstrate cellular coexpression of GAT1 and Pals1 in the mouse hippocampus and striatum. Functionally, coexpression of GAT1 and Pals1 in COS-7 cells increases [3H]-GABA uptake by GAT1. The mechanism underlying increased uptake is increased levels of GAT1 protein. We hypothesize that Pals1 contributes to the stability of the GAT1, thus promoting the expression level of the transporter protein. In the CNS, Pals1 may stabilize GAT1 at appropriate levels in specific GABAergic neurons.     

Gastroenteric fistula complicating percutaneous endoscopic gastrostomy

Background

Gastroenteric fistula occurs in 2% to 3% of patients undergoing percutaneous endoscopic gastrostomy (PEG). The authors identified 12 children with this major complication.

Methods

A retrospective case note review was performed.

Results

Over a 5-year period, the complication rate for gastroenteric fistula was 3.5% (12 of 343 procedures). Presentation ranged from 1 day to 25 months post-PEG insertion. Eight patients presented with acute intestinal obstruction. The gastroenteric fistulous tract involved the posterior wall of the stomach in all cases. The plain abdominal x-ray was useful in establishing the diagnosis of the gastroenteric fistula.

Conclusions

Patients with gastroenteric fistula as a complication of PEG insertion can remain asymptomatic for prolonged periods. It often is difficult to make the diagnosis. A plain abdominal x-ray is a useful diagnostic modality.     

Transcutaneous magnetic stimulation of the quadriceps via the femoral nerve

We investigated the efficacy of different frequencies and intensities of magnetic stimulation for activating the quadriceps muscles; a painless method for stimulating the quadriceps would be useful in the rehabilitation of patients who have difficulty in voluntarily activating their muscles after injury or surgery. Eleven subjects underwent magnetic stimulation of the femoral nerve over a range of frequencies and intensities using a MagStim Rapid magnetic stimulator. Magnetic stimulation at 30 Hz at 80% of the power output of the stimulator used was capable of generating 72% of quadriceps maximal voluntary contraction torque. Subjects reported little or no pain during the procedure. Magnetic stimulation of the femoral nerve is a well-tolerated way to activate the quadriceps muscles.