Racial differences in hemoglobin and plasma volume variation: implications for muscle performance and recovery

Objective: To examine the effect of race differences on sprint performance, Hemoglobin (Hb), Hematocrit (Ht) and plasma volume (PV) variation in response to repeated sprint exercise.

Design: Thirty-six healthy, moderately trained men and women (20.8?±?0.2 year-old) volunteered to participate in this study. They were allocated to one of the four groups according to their gender and race: Black men’s group (BM, n?=?9), White men’s group (WM, n?=?9), Black women’s group (BW, n?=?9) and White women’s group (WW, n?=?9). All participants performed the running-based anaerobic sprint test (RAST), which consists of six?35-m sprints with 10 s of recovery in-between. Six venous blood samples were collected to determine Hb, Ht and PV levels at rest, after warm-up, immediately post- and at 5, 15 and 30 min post-RAST. Blood lactate is also sampled during the 3rd minutes of recovery.

Results: The best running time was significantly shorter (P?=?.002) in BW compared to WW. We have observed significantly higher Hb (P?=?.010) and Ht (P?=?.004) levels in BW compared to WW during the 5th minute of recovery. During RAST, the PV decreased significantly (P?=?.007) in WM only. Black groups had lower (P?<?.05) lactate levels compared to the white subjects. During recovery, PV increase was significantly (P?=?.003) higher in WW compared to BW during the 5th minute of recovery.

Conclusion: This study demonstrated that sprint and repeated sprint performances were different between white and black women. Differences in anaerobic performance between the groups were associated with racial differences in lactate levels and blood count among women’s group during recovery time. Hence, it is important to take into account this race-related difference in hematological parameters in responses to intense efforts.     

Blur adaptation: clinical and refractive considerations

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.     

Retrograde Inversion Stripping as a Complication of the Clarivein? Mechanochemical Venous Ablation Procedure

The endovenous revolution has accelerated the development of new techniques and devices for the treatment of varicose veins. The ClariVein^® mechanochemical ablation device offers tumescentless treatment with a rotating ablation tip that can theoretically become stuck in tissue. We present the first report of retrograde stripping of the small saphenous vein without anaesthesia following attempted use of the ClariVein^® device, without adverse sequelae.     

In-Room Ultraviolet Air Filtration Units Reduce Airborne Particles During Total Joint Arthroplasty

Reducing airborne bioburden in total joint arthroplasty (TJA) is of critical importance. The efficacy of crystalline ultraviolet-C (C-UVC) filtration in reducing bioburden in a dynamic operating room (OR) environment has not been evaluated. We assessed whether C-UVC filtration reduced (i) total particle counts (TPC); (ii) viable particle counts (VPC); and (iii) colony-forming units (CFUs). Fifty primary TJA cases were performed in a positive-pressure OR; 25 cases with the C-UVC unit and 25 cases without. The air was sampled by a particle counter and an impact air sampler to measure particle counts and CFUs, respectively. To compare TPC, VPC, and CFU/m³ between groups, independent t tests and multivariate regression, adjusted for number of OR staff and door openings, were performed. The C-UVC group had significantly lower TPC (2.6 × 10⁶ vs. 4.7 × 10⁶ particles, p = 0.001) and VPC (18,605 vs. 27,516 particles, p = 0.001). There were fewer CFUs in the C-UVC group (10.9 CFU/m³ vs. 13.7 CFU/m³, p = 0.163). Multivariate analysis identified C-UVC filtration as a significant predictor of decreased TPC (β = −0.44, p = 0.002) and VPC (β = −0.47, p = 0.001) after accounting for door openings and number of OR staff. The reduction in CFUs was not significant on multivariate analysis. In this prospective pilot study, a C-UVC air disinfection and recirculation unit led to a significant reduction in both TPC and VPC and a non-significant reduction in CFU. Statement of clinical significance: Further studies are needed to investigate the effects of C-UVC filtration units on surgical-site infection rates. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:431-437, 2020     

What is a safe waiting time for coronary artery bypass surgery?

To determine the factors that influenced doctors' prioritization and decisions on safe waiting time for coronary artery bypass surgery, 50 'paper patients', based on a random sample of cases who actually had surgery, were assessed by 33 clinicians. We used linear regression models to reflect the impact of clinical and non-clinical 'cues' on safe waiting time and priority decisions. The benefits of surgery tended to be over-estimated. For example, the average perceived gain in life expectancy for patients with left main-stem disease was 6.74 years. However, models incorporating only the perceptions of benefit as independent variables (i.e. the anticipated symptom reduction, MI risk reduction and life expectancy extension), had only modest explanatory power (mean R2 was 0.55 for safe waiting time, and 0.56 for priority decisions). Models which incorporated perceptions of benefit and the cases' clinical and non-clinical characteristics had generally much higher explanatory power (mean R2, 0.83 and 0.86, respectively). Lifestyle and demographic variables had much less impact on the doctors' judgements than the major clinical cues of angina severity and left main-stem stenosis. Demographic and lifestyle cues had different impacts on safe waiting time and priority for about 25% of doctors.      

[<Superscript>18</Superscript>F]FDG PET Neuroimaging Predicts Pentylenetetrazole (PTZ) Kindling Outcome in Rats

Purpose

Epileptogenesis, i.e., development of epilepsy, involves a number of processes that alter the brain function in the way that triggers spontaneous seizures. Kindling is one of the most used animal models of temporal lobe epilepsy (TLE) and epileptogenesis, although chemical kindling suffers from high inter-assay success unpredictability. This study was aimed to analyze the eventual regional brain metabolic changes during epileptogenesis in the pentylenetetrazole (PTZ) kindling model in order to obtain a predictive kindling outcome parameter.

Procedures

In vivo longitudinal positron emission tomography (PET) scans with 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) along the PTZ kindling protocol (35 mg/kg intraperitoneally (i.p.), 18 sessions) in adult male rats were performed in order to evaluate the regional brain metabolism.

Results

The half of the PTZ-injected rats reached the kindled state. In addition, a significant decrease of [¹⁸F]FDG uptake at the end of the protocol in most of the brain structures of kindled animals was found, reflecting the characteristic epilepsy-associated hypometabolism. However, PTZ-injected animals but not reaching the kindled state did not show this widespread brain hypometabolism. Retrospective analysis of the data revealed that hippocampal [¹⁸F]FDG uptake normalized to pons turned out to be a predictive index of the kindling outcome. Thus, a 19.06 % reduction (p?=?0.008) of the above parameter was found in positively kindled rats compared to non-kindled ones just after the fifth PTZ session.

Conclusion

Non-invasive PET neuroimaging was a useful tool for discerning epileptogenesis progression in this animal model. Particularly, the [¹⁸F]FDG uptake of the hippocampus proved to be an early predictive parameter to differentiate resistant and non-resistant animals to the PTZ kindling.

     

Inactivation of human immunodeficiency virus by gamma radiation and its effect on plasma and coagulation factors

The inactivation of HIV by gamma-radiation was studied in frozen and liquid plasma; a reduction of the virus titer of 5 to 6 logs was achieved at doses of 5 to 10 Mrad at -80 degrees C and 2.5 Mrad at 15 degrees C. The effect of irradiation on the biologic activity of a number of coagulation factors in plasma and in lyophilized concentrates of factor VIII (FVIII) and prothrombin complex was examined. A recovery of 85 percent of the biologic activity of therapeutic components present in frozen plasma and in lyophilized coagulation factor concentrates was reached at radiation doses as low as 1.5 and 0.5 Mrad, respectively. As derived from the first-order radiation inactivation curves, the radiosensitive target size of HIV was estimated to be 1 to 3 MDa; the target size of FVIII was estimated to be 130 to 160 kDa. Gamma radiation must be disregarded as a method for the sterilization of plasma and plasma-derived products, because of the low reduction of virus infectivity at radiation doses that still give acceptable recovery of biologic activity of plasma components.