The influence of passive heat maintenance on lower body power output and repeated sprint performance in professional rugby league players

Objectives: The pre-competition warm-up mediates many temperature related physiological changes which generally lead to an improvement in performance. However, after ceasing exercise body temperature declines rapidly, which reduces some of the benefits of the initial warm-up. We examined the effects of a passive heat maintenance strategy on post-warm-up core temperature (T_core) and performance in professional rugby league players. Design: Twenty professional rugby league players completed this randomised and counter-balanced study. Methods: After a standardised warm-up, players completed a countermovement jump (CMJ) before resting for 15 min wearing normal training attire (control) or wearing a passive heat maintenance jacket (PHM), players then completed another CMJ and a repeated sprint protocol (RSA). T_core was measured at baseline, post-warm-up, pre-RSA and post-RSA. CMJ were analysed for peak power output (PPO), and RSA for fastest, mean and total sprint time. Results: Post-warm-up T_core (mean ± SD; control 37.70 ± 0.28; PHM 37.70 ± 0.27 °C; p = 0.741) and PPO (control 5220 ± 353 vs. PHM 5213 ± 331 W; p = 0.686) were similar between conditions. At pre-RSA, PHM was associated with greater T_core (control 37.14 ± 0.31 vs. PHM 37.51 ± 0.30 °C; p < 0.001) and PPO (control 4868 ± 345 vs. PHM 5056 ± 344 W; p < 0.001) when compared to control. The decline in PPO from post-warm-up to pre-RSA was related to the drop in T_core (r = 0.71; p < 0.001). During the RSA, fastest, mean and total sprint time were all improved under PHM compared to control (p < 0.05). Conclusions: Passive heat maintenance is an effective method of attenuating the post-warm-up decline in T_core and improves PPO and repeated sprint ability in professional rugby league players.     

The effects of PTH,loading and surgical insult on cancellous bone at the bone–implant interface in the rabbit

Enhancing the quantity and quality of cancellous bone with anabolic pharmacologic agents may lead to more successful outcomes of non-cemented joint replacements. Using a novel rabbit model of cancellous bone loading, we examined two specific questions regarding bone formation at the bone–implant interface: (1) does the administration of intermittent PTH, a potent anabolic agent, and mechanical loading individually and combined enhance the peri-implant cancellous bone volume fraction; and, (2) does surgical trauma enhance the anabolic effect of PTH on peri-implant bone volume fraction. In this model, PTH enhanced peri-implant bone volume fraction by 30% in loaded bone, while mechanical loading alone increased bone volume fraction modestly (+ 10%). Combined mechanical loading and PTH treatment had no synergistic effect on any cancellous parameters. However, a strong combined effect was found in bone volume fraction with combined surgery and PTH treatment (+ 34%) compared to intact control limbs. Adaptive changes in the cancellous bone tissue included increased ultimate stress and enhanced remodeling activity. The number of proliferative osteoblasts increased as did their expression of pro-collagen 1 and PTH receptor 1, and the number of TRAP positive osteoclasts also increased. In summary, both loading and intermittent PTH treatment enhanced peri-implant bone volume, and surgery and PTH treatment had a strong combined effect. This finding is of clinical importance since enhancing early osseointegration in the post-surgical period has numerous potential benefits.     

Association of orexin receptor polymorphisms with antipsychotic-induced weight gain

Objectives: Antipsychotic-induced weight gain (AIWG) is a common side effect of treatment with antipsychotics such as clozapine and olanzapine. The orexin gene and its receptors are expressed in the hypothalamus and have been associated with maintenance of energy homeostasis. In this study, we have analysed tagging single nucleotide polymorphisms (SNPs) in orexin receptors 1 and 2 (HCRTR1 and HCRTR2) for association with AIWG. Methods: Schizophrenia or schizoaffective disorder subjects (n?=?218), treated mostly with clozapine and olanzapine for up to 14 weeks, were included. Replication was conducted in a subset of CATIE samples (n?=?122) treated with either olanzapine or risperidone for up to 190 days. Association between SNPs and AIWG was assessed using analysis of covariance (ANCOVA) with baseline weight and duration of treatment as covariates. Results: Several SNPs in HCRTR2 were nominally associated with AIWG in patients of European ancestry treated with either clozapine or olanzapine (P<0.05). In the replication analysis two SNPs rs3134701 (P?=?0.043) and rs12662510 (P?=?0.012) were nominally associated with AIWG. None of the SNPs in HCRTR1 were associated with AIWG. Conclusion: This study provides preliminary evidence supporting the role of HCRTR2 in AIWG. However, these results need to be confirmed in large study samples.     

Characterisation of the cell suspension harvested from the dermal epidermal junction using a ReCell® kit

Background

The use of non-cultured autologous cells to promote wound healing and in reconstructive procedures is increasing. One common method for preparing these cells is the use of the ReCell^® device. However, despite its current clinical use, no characterisation of the cell suspension produced using a ReCell^® device has been published.

Objective

To characterise the ReCell suspension that is applied to wounds for cell type, viability, yield, stability and proliferative potential.

Methods

The ReCell^® device was used to harvest cells from a 2 cm² piece of split-thickness skin isolated using a dermatome. The resulting cell suspension was analysed for cell yield, cell type, viability over time, proliferative potential and reproducibility.

Results

Average viable cell yield was 1.7 × 10⁶/cm² of tissue, with 75.5% of the total cell isolate viable. Total viable cell number was not significantly reduced after 4 h storage at 22 °C or 4 °C, and was stable for 24 h at 4 °C. Proliferative potential was assessed using a colony forming assay, with 0.3% of viable cells isolated forming keratinocyte colonies. Predominantly the suspension contained keratinocytes (64.3 ± 28.8%) and fibroblasts (30.3 ± 14.0%), with a small population of melanocytes also identified (3.5 ± 0.5%). Finally, the supernatant contained low total protein (0.92 mg/ml) and the supernatant had no significant effects on cell viability or growth when applied ex vivo.

Conclusions

These results suggest the ReCell^® device provides a method for the preparation of a cell suspension with high viability and proliferative potential, containing viable melanocytes and no apparent toxic cell debris. Further work on the sustained viability of these cells in vivo, and in particular after application to the wound, will be important to better understand the potential of the ReCell^® device in the clinic.     

Percutaneous fixation of acetabular fractures: computer-assisted determination of safe zones, angles and lengths for screw insertion

Introduction

Percutaneous retrograde screw fixation for acetabular fractures is a demanding procedure due to the complex anatomy of the pelvis and the varying narrow safe bony corridors. Limited information is available on optimal screw placement and the geometry of safe zones for screw insertion in the pelvis.

Methods

Three-dimensional reconstructions of 50 consecutive CT scans of polytrauma patients (35 males, 15 females) were used to introduce three virtual CAD bolts (representing screws) into the anterior column (superior ramus of the pubic bone), posterior column (the ischial bone) and the supraacetabular region, as performed during percutaneous screw fixation. The three-dimensional (3D) position of these screws was evaluated with a computer software (MIMICS) after virtual optimal insertion. The 3D position, the narrowest zone and the distance to the hip joint of the two columns and the supraacetabular region were defined.

Results

The mean maximal screw length for the three virtual screws measured between 107.4 and 148?±?18.7?mm. The narrowest zone of the pelvic bone (superior pubic ramus) had a width of 9.2?±?2.4?mm. The average distances between the bolts and the hip joint were 3.9 and 19.4?±?7.4?mm. For the anterior column (superior pubic ramus) screw, the mean lateral angle to the sagittal midline plane was 39.0?±?3.2° and the mean posterior angle to the transversal midline plane was 15.1?±?4.0°. The mean supraacetabular screw angles measured 22.4?±?3.4° (medial), 35.3?±?4.6° (cranial) and the mean angles for the ischial screw were 12.0?±?5.4° (posterior) and 18.4?±?4.0° (lateral).

Conclusions

The zones for safe screw positioning are very narrow, making percutaneous screw fixation of the acetabulum a challenging procedure. The predefined angles for the most frequently positioned percutaneous screws may aid in preoperative planning, decrease operative and radiation times and help to increase safe insertion of screws.     

The role of shame in distinguishing perpetrators of intimate partner violence in U.S. veterans

Increasing attention is being paid to the fact that exposure to traumatic stressors in military combat may lead to perpetration of intimate partner violence (IPV). Because shame has been identified as a factor in posttraumatic stress disorder (PTSD), the current cross-sectional study examined the relationship in U.S. veterans between IPV and PTSD, depression, guilt, and shame. We hypothesized that shame would be the strongest correlate of perpetration of IPV and that shame would mediate the relationship between PTSD and IPV. Participants were 264 primarily male and Caucasian mixed-era veterans presenting for psychological treatment at a Veterans Affairs hospital. They completed standard measures of depression, PTSD symptoms, shame, and guilt and a local checklist was used to dichotomize the sample regarding IPV. Discriminant analysis indicated that shame contributed most (standardized canonical discriminant function coefficient = .44) to distinguishing perpetrators of IPV. In addition, the results were consistent with shame as a mediator of the relationship between PTSD and IPV. These results are in line with studies indicating that shame is linked to IPV perpetration in nonveteran samples (Harmon, 2002; Rand, 2004; Schibik, 2002) and suggests that shame may be an important aspect of the relationship between PTSD and IPV.     

Carotid endarterectomy in patients with chronic renal insufficiency: a recent series of 184 cases

BACKGROUND: The published results of carotid endarterectomy (CEA) in chronic renal insufficiency (CRI) patients are contradictory, mostly because of the relatively small number of patients in these studies. To better assess the neurologic complications and mortality, we reviewed a recent and substantially larger series of CRI patients who underwent CEAs. METHODS: From March 2000 to March 2003, 675 consecutive primary CEAs were performed in 609 patients (346 men, 57%) under general anesthesia. Asymptomatic carotid artery stenosis accounted for 71% of cases. CRI (serum creatinine level > or = 1.5 mg/dL) was detected in 166 patients (27%) who underwent 184 CEAs. The remaining 443 patients (73%) had 491 CEAs. RESULTS: Patients with CRI were different in age (76 +/- 8 years vs 72 +/- 9 years, P < .001), male gender (73% vs 51%, P < .001), coronary artery disease (50% vs 28%, P < .001), and diabetes mellitus incidence (38% vs 27%, P < .02). No significant difference in stroke rates was observed between the CRI patients and the control group (1.2% vs 0.5%). The mortality rate for CRI patients was 3%, whereas it was 0% for the control group ( P < .002). The 143 CRI patients with serum creatinine levels from 1.5 to 2.9 mg/dL had a 0.7% mortality rate, whereas it was 17% for 23 patients with serum creatinine levels of 3 mg/dL or more ( P < .001). The stroke rate for the former group was 0.7% and 4.3% for the latter group (NS). Asymptomatic (16) and symptomatic (7) patients with serum creatinine levels of 3 mg/dL or more had mortality rates of 13% and 28%, respectively, with P = .6. CONCLUSION: The high mortality rate observed in patients with serum creatinine levels of 3 mg/dL or more after CEA calls for a nonoperative approach in the management of asymptomatic patients.     

Associations among psychosis,mood, anxiety,and posttraumatic stress symptoms: A network analysis

The associations among psychotic experiences (i.e., hallucinations and delusions), trauma exposure, and posttraumatic stress symptoms are complex and multidirectional. Using network analysis to understand how psychotic experiences and symptoms of posttraumatic stress disorder (PTSD) relate to one another may identify new interventional targets to treat comorbidity and its underlying pathological processes. This study aimed to use network analysis to examine the associations among psychotic experiences; negative symptoms of psychosis; and symptoms of PTSD, anxiety, and depression. In this population-based cohort study, 4,472 participants (36.7% male) were assessed for psychotic experiences, negative symptoms of psychosis, PTSD, anxiety, and depression at age 23 (M = 23.86 years, SD = 0.520) or 24 years (M = 24.03, SD = 0.848). Associations among symptoms were assessed via network analysis. Exploratory graph analysis identified three clusters of densely connected symptoms within the overall network: psychotic experiences; PTSD symptoms; and depressive and anxiety symptoms and negative symptoms of psychosis. Psychotic experiences had the strongest associations with other symptoms in the network, and symptoms of anxiety played a key role in bridging psychotic experiences, symptoms of PTSD, and depressive symptoms. Consistent with the stress reactivity and affective models for psychotic experiences, the results suggest that symptoms of anxiety and emotional distress (e.g., hyperarousal, panic) may have a key role in the development and maintenance of psychotic experiences and symptoms of PTSD. Targeting these symptoms may ameliorate symptom burden transdiagnostically.     

Combining automated attenuation-based tube voltage selection and iterative reconstruction: a liver phantom study

Objectives

To determine the value of combined automated attenuation-based tube-potential selection and iterative reconstructions (IRs) for optimising computed tomography (CT) imaging of hypodense liver lesions.

Methods

A liver phantom containing hypodense lesions was imaged by CT with and without automated attenuation-based tube-potential selection (80, 100 and 120 kVp). Acquisitions were reconstructed with filtered back projection (FBP) and sinogram-affirmed IR. Image noise and contrast-to-noise ratio (CNR) were measured. Two readers marked lesion localisation and rated confidence, sharpness, noise and image quality on a five-point scale (1 = worst, 5 = best).

Results

Image noise was lower (31–52 %) and CNR higher (43–102 %) on IR than on FBP images at all tube voltages. On 100-kVp and 80-kVp IR images, confidence and sharpness were higher than on 120-kVp FBP images. Scores for image quality score and noise as well as sensitivity for 100-kVp IR were similar or higher than for 120-kVp FBP and lower for 80-kVp IR. Radiation dose was reduced by 26 % at 100 kVp and 56 % at 80 kVp.

Conclusions

Compared with 120-kVp FBP images, the combination of automated attenuation-based tube-potential selection at 100 kVp and IR provides higher image quality and improved sensitivity for detecting hypodense liver lesions in vitro at a dose reduced by 26 %.

Key Points

? Combining automated tube voltage selection/iterative CT reconstruction improves image quality. ? Attenuation values remain stable on IR compared with FBP images. ? Lesion detection was highest on 100-kVp IR images.