Rationale and design of a prospective study of the clinical significance of atrial arrhythmias detected by implanted device diagnostics: The TRENDS study

Background: Sustained atrial fibrillation (AF) is a common risk factor for stroke. While intermittent AF also appears to pose a substantial stroke risk, the quantitative relationship between the percentage of time spent in AF and stroke risk is poorly specified and “intermittent” AF is not the same as paroxysmal AF. Improved assessment of the impact of AF burden on stroke risk will allow more targeted and safer use of antithrombotic therapy. Methods and Results: The primary objective of this study is to determine if AT/AF (all device detected atrial tachyarrhythmias, including atrial flutter, atrial fibrillation, and atrial tachycardia) burden over a 30 day period is an independent predictor of the occurrence of ischemic stroke, transient ischemic attack (TIA) and/or systemic embolism in subjects not receiving anticoagulation therapy. TRENDS is a prospective, post-market, non-randomized, multicenter study designed to enroll 3100 subjects who have an independent Class I/II indication for cardiac rhythm device implantation and who have demographic features suggestive of an increased risk for thromboembolic complications related to AT/AF. All implanted devices will have the ability to collect long-term AT/AF burden trending data and will be equivalently programmed to ensure consistent data collection. All subjects will be followed with device interrogations every 3 months and clinic visits every 6 months for 1 year. Subjects with a documented history of AT/AF prior to enrollment and those who develop AT/AF during the 12-month follow-up will be followed until the last subject enrolled in the study has completed their 24-month follow-up. Conclusions: The results of the TRENDS study should help clarify the implications of data retrieved from an implantable device with regard to the risk for thromboembolic complications from atrial arrhythmias, even in the absence of symptoms.     

Discrepancy of left and right hip bone mineral density (BMD) in Thai women: diagnostic agreement and misclassification

Objective

To determine the diagnostic agreement and the degree of misclassification when using data from the left and right hips.

Methods

The cross-sectional study of 1,943 perimenopausal and postmenopausal Thai women, who had bone mineral density (BMD) measurements at the left (non-dominant) and right hips for the screening of low bone mass (LBM) or osteoporosis (OP) in the Department of Radiology, Faculty of Medicine, Chiang Mai University from September 2008 to August 2010 was performed. The kappa statistic was used to assess diagnostic agreement. The prevalence of LBM and OP and the percentage of misclassification were reported.

Results

There was a significant correlation between the left and right BMD values for the femoral neck (FN) (r ²?=?0.83; p?<?0.001) and the total hip (TH) (r ²?=?0.89; p?<?0.001). The diagnostic agreement of the FN and TH regions was significant in all study groups ranging from 0.69 to 0.76 (p?<?0.001). For the final diagnosis, which is based on the least T-score of the FN or TH regions, the diagnostic agreement was 0.73 for all women, 0.77 for perimenopausal women, 0.73 for postmenopausal women, 0.70 for postmenopausal women age less than 65?years and 0.71 for postmenopausal women age greater than or equal to 65?years. The percentage of misclassification for all women was 16.9?%, with 3.3?% being downgraded from normal to LBM and 3.4?% from LBM to OP.

Conclusion

Despite the fact that good diagnostic agreement was demonstrated in this study, a significant number of diagnostic discordance between left and right hips (16.9?%) was also observed. BMD measurements of both hips are recommended for diagnosing LBM and OP in clinical practice.     

A critical review of modern and emerging absorbent dressings used to treat exuding wounds

Wound management has progressed significantly over the last five decades. This emanates from a greater understanding of wound healing, technological progression and improved clinical and scientific research. There are currently a plethora of absorbent dressings on the wound care market which claim to have the ability to manage exudates whilst encouraging healing. However, it is becoming clear, from analysing randomised controlled trials, that some of these absorbent dressings are not meeting their expectations when applied in a clinical setting. Many clinicians now feel that there should be more focus, not only on a dressing's ability to manage exudate efficiently, but on a dressing's ability to proactively encourage healing and thus exudate reduction will ensue. This paper proposes to critically review modern and emerging absorbent wound care dressings used to manage exuding wounds and discuses some advances in this area.     

Endocrinological responses during suckling in Hatano high- and low-avoidance rats

Hatano high-avoidance (HAA) and low-avoidance (LAA) animals were originally selected from Sprague-Dawley rats for good and poor active avoidance learning in a shuttle box. We studied the endocrinological profile in lactating rats to determine the effect of suckling during mid-lactation in HAA and LAA rats. The pups were separated from their mother rats 6 h before the onset of suckling and blood samples were drawn from unanaesthetized mother rats via a jugular cannula at 0, 5 and 15 min after the suckling stimulus and then 15, 45 and 105 min after pups were removed. Plasma concentrations of oxytocin in HAA rats were significantly higher than in LAA rats during the suckling period. Plasma concentrations of prolactin and ACTH in HAA rats were significantly higher than in LAA rats during the suckling period, and at 15 min and 45 min after the pups were removed. However, there were no strain differences in circulating corticosterone between the two lines, indicating that the response of the hypothalamo-pituitary axis to the suckling stimulus was greater in HAA rats than in LAA rats, whereas the ACTH-induced adrenal response of corticosterone release was higher in LAA rats than in HAA rats. Since dopamine from the median eminence inhibits prolactin secretion from the lactotrophs of the anterior pituitary, and tuberoinfundibular dopaminergic neurones are partially regulated by the level of circulating prolactin, we evaluated the activity of tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis. TH, measured by the accumulation of 3,4-dihydroxyphenylalanine, was significantly higher in HAA rats than in LAA rats before the suckling stimulus. After the suckling stimulus, TH activity in HAA rats was significantly lower than before suckling, whereas TH activity in LAA rats was not changed. These findings clearly demonstrated that apparent differences between the two Hatano lines exist in endocrinological profiles during suckling. These strain differences probably originate from neurotransmitter changes, such as dopamine.     

Marked seasonal changes in response to the negative feedback action of estradiol on luteinizing hormone secretion in the female Japanese monkey

The seasonal changes in response to the negative feedback action of estradiol on LH secretion were studied in two groups of ovariectomized Japanese monkeys (Macaca fuscata fuscata; n = 6). Blood samples were collected two to three times a week, and changes in serum concentrations of LH, estradiol, and progesterone were examined. Before ovariectomy (OVX), serum LH was maintained at about 320 pg/ml regardless of the season (breeding season: autumn and winter). After OVX and simultaneous treatment sc with a Silastic implant of estradiol during the first breeding season, serum LH increased rapidly and remained high. As spring arrived, serum LH decreased abruptly and remained low. The removal of implants during the subsequent nonbreeding season resulted in an increase in serum LH similar to that during the previous breeding season after OVX and estradiol treatment. After the reinsertion of implants during the same nonbreeding season, serum LH reverted to previous low levels. As autumn arrived (second breeding season), serum LH rose again and remained high under the presence of implants. In the first subset of animals (n = 3), the implants were left in place until the subsequent mid-nonbreeding season when they were removed, and reinserted during the same non-breeding season. The findings closely corresponded to the previous results. In these animals, the implants were removed during the third breeding season, which resulted in a significant increase in serum LH. The second subset of animals (n = 3) underwent removal of implants during the second breeding season, which resulted in a further increase in serum LH, but the difference was not significant. In both subsets of animals, the timing of the increase and decrease in serum LH under the presence of implants virtually coincided with the onset and end of the breeding season in ovary-intact animals. Serum estradiol after OVX was maintained at levels similar to those in intact animals (80-100 pg/ml) under the presence of implants, but removal of implants resulted in decrease in serum estradiol to around 30 pg/ml within 1 week. Serum progesterone after OVX was maintained at low levels (less than 0.2 ng/ml) regardless of the presence of estradiol implants. These results clearly indicate a marked seasonal difference in serum LH concentrations in ovariectomized monkeys in response to constant serum estradiol. It is suggested that seasonal breeding of the Japanese monkey is governed by biannual changes in the response of the hypothalamo-hypophysial axis to the negative feedback action of estradiol.     

Ovarian and hormonal response of female goats to active immunization against inhibin

This study was conducted to evaluate the effect of active immunization against inhibin on hormonal levels and the ovulation rate in goats. Ten adult Shiba goats (Capra hircus) in two groups were used in this study. The first group was injected with inhibin vaccine (immunized, n=5) and the second group was injected with Freund's adjuvant (control, n=5) followed by three booster injections at 4-week intervals. After the third booster injection, three consecutive periods of oestrus were induced using prostaglandin F(2alpha) at intervals of 11 days. Blood samples were collected at 2-6 h intervals and the ovaries were monitored using B-mode ultrasonography. All inhibin-immunized goats generated antibodies that bound (125)I-labelled bovine inhibin and their FSH concentrations were significantly higher than corresponding values in the control group. Also, inhibin-immunized goats had significantly higher preovulatory oestradiol-17beta (P<0.01) and higher concentrations of progesterone in the luteal phase (P<0.05). Immunization of goats against inhibin resulted in a significant (P<0.01) increase in ovulation rate (control: 1.7+/-0.3 vs immunized: 7.6+/-1.1). These results demonstrate that active immunization against inhibin enhances ovarian follicular development and ovulation rate by promoting an increase in pituitary FSH secretion. Therefore, immunization against inhibin may be a useful alternative to the conventional approach of superovulation in goats.     

The Impact of the Acute Results on the Long—Term Outcome after the Treatment of In—stent Restenosis：A Serial Intravascular Ultrasoun Study

Stenting reduces acute complications and restenosis compared to balloon angioplasty and other devices. However, in- stent restenosis (ISR) is an important clinical problem. The current serial intravascular ultrasound (IVUS)analysis was undertaken to determine whether the acute results obtained during the treatment of ISR influence the long term results and whether this is true for patients treated with and without adjunct brachytherapy.