Impact of Sudden Rule Changes on Player Injuries and Performance: Insights from Australian Football

This study investigated the effects of reduced quarter time due to COVID-19 pandemic rule changes, on running performance and injuries in Australian Football. Microsensor data for eight matches performed by the same 17 players were compared between the 2019 (standard) and 2020 (COVID-19) seasons using linear and generalised mixed models. Injury rates were assessed in 34 players across the full 2019 season, and 32 players across the full 2020 season. The total distance (ES = 1.28 [0.55 to 2.02]), high-speed (>18 km/h) (ES = 0.44 [-0.24 to 1.12]) and very highspeed (>24 km/h) (ES = 0.27 [-0.41 to 0.94]) distances, PlayerLoad™ (ES = 0.96 [0.25 to 1.67]), high-intensity efforts (ES = 0.48 [-0.20 to 1.16]), and accelerations (ES = 0.33 [-0.34 to 1.01]) were smaller (p ≤ 0.01) for the 2020 than the 2019 season. Expressed relative to playing time, distance (ES=-0.38 [-1.06 to 0.30]), PlayerLoad™ (ES = -0.27 [-0.94 to 0.41]), and acceleration efforts (ES = -0.50 [-1.18 to 0.18]) were greater (p < 0.05) for the 2020 than the 2019 season. No significant differences in maximum ball-in-play periods nor the difference between the 1^st and 4^th quarters were evident. Injury rates remained similar between 2019 (3.36 per game) and 2020 (3.55 per game). However, the proportion of injuries that led to lost time (missed games) was greater for the 2020 (38%) than 2019 season (24%). The changes in the rules had a profound impact on player performance and increased the likelihood of time loss injuries. Key points

• Rule changes had predominantly a small effect on running performance
• Rule changes had no effect upon the decrement of running performance
• Rule changes had no effect on injury rates
• Rule changes increased the severity of injuries

Key words: COVID-19 pandemic, playing rules, athletic performance, global positioning systems, locomotion, match analysis     

Impact of COVID-19 on the Volume of Acute Stroke Admissions: A Nationwide Survey in Japan

This study aimed to measure the impact of the COVID-19 pandemic on the volumes of annual stroke admissions compared with those before the pandemic in Japan. We conducted an observational, retrospective nationwide survey across 542 primary stroke centers in Japan. The annual admission volumes for acute stroke within 7 days from onset between 2019 as the pre-pandemic period and 2020 as the pandemic period were compared as a whole and separately by months during which the epidemic was serious and prefectures of high numbers of infected persons. The number of stroke patients declined from 182,660 in 2019 to 178,083 in 2020, with a reduction rate of 2.51% (95% confidence interval [CI], 2.58%-2.44%). The reduction rates were 1.92% (95% CI, 1.85%-2.00%; 127,979-125,522) for ischemic stroke, 3.88% (95% CI, 3.70%-4.07%, 41,906-40,278) for intracerebral hemorrhage, and 4.58% (95% CI, 4.23%-4.95%; 13,020-12,424) for subarachnoid hemorrhage. The admission volume declined by 5.60% (95% CI, 5.46%-5.74%) during the 7 months of 2020 when the epidemic was serious, whereas it increased in the remaining 5 months (2.01%; 95% CI, 1.91%-2.11%). The annual decline in the admission volume was predominant in the five prefectures with the largest numbers of infected people per million population (4.72%; 95% CI, 4.53%-4.92%). In conclusion, the acute stroke admission volume declined by 2.51% in 2020 relative to 2019 in Japan, especially during the months of high infection, and in highly infected prefectures. Overwhelmed healthcare systems and infection control practices may have been associated with the decline in the stroke admission volume during the COVID-19 pandemic.     

Progressive outer retinal necrosis in a patient with nephrotic syndrome

Progressive outer retinal necrosis syndrome (PORN) is a variant of necrotizing herpetic retinopathy and the majority of the described cases were related to acquired immunodeficiency syndrome. We present a patient who is HIV negative with nephrotic syndrome and prednisolone use for 4 months who showed clinical features of PORN. Low CD4 counts and lymphocytopenia suggested immunosuppression. In the left eye, tractional retinal detachment at the posterior pole followed by incomplete posterior vitreous detachment developed. In addition to intravenous administration of acyclovir, vitreous surgeries including stripping of the posterior hyaloid and silicone-oil tamponade were successfully performed to repair the retinal detachment in the left eye and to prevent it in the right eye.     

Properties of Corneas Reconstructed with Cultured Human Corneal Endothelial Cells and Human Corneal Stroma

Purpose

To examine the properties of corneas tissue-engineered with cultured human corneal endothelial cells (HCEC) and human corneal stroma.

Methods

Primary HCEC cultures were established from endothelial cell layer explants and propagated on culture dishes coated with bovine corneal endothelial extracellular matrix. A cell suspension of HCEC at the fifth passage was transferred onto human corneal stroma deprived of endothelial cells, and the corneas were gently centrifuged to enhance cell attachment. The cell density of the tissue-engineered corneas was examined after staining with alizarin red and trypan blue. The tissue-engineered corneas were histologically examined by light and electron microscopy. The pump function of the tissue-engineered corneas was measured using an Ussing chamber.

Results

The mean endothelial cell density of four tissue-engineered corneas was 2380 ± 264 cells/mm² (mean ± SD). HCEC on the tissue-engineered corneas had a morphology similar to HCEC in vivo. The pump function parameters of the tissue-engineered corneas were 55%–75% of those of normal corneas.

Conclusions

HCEC on the tissue-engineered corneas have morphology and cellular density similar to HCEC in vivo, whereas the pump function of the tissue-engineered corneas was lower than in normal corneas. Jpn J Ophthalmol 2005;49:448–452 © Japanese Ophthalmological Society 2005     

Beta-hydroxybutyrate,a cerebral function improving agent,protects rat brain against ischemic damage caused by permanent and transient focal cerebral ischemia

In our previous study, beta-hydroxybutyrate (BHB) was found to prolong survival time and to inhibit cerebral edema by improving energy metabolism in the hypoxia, anoxia and global cerebral ischemia models. In this study, the cerebroprotective effect of BHB was examined in rats with permanent (p)-occlusion and transient (t)-occlusion of middle cerebral artery (MCA). BHB (30 mg x kg(-1) x h(-1) was continuously administered through the femoral vein. In rats with p-MCA occlusion, BHB significantly reduced infarct area at 24 h after the occlusion, but not at 72 h after the occlusion. In rats with 2-h t-MCA occlusion followed by 22-h reperfusion, BHB significantly reduced cerebral infarct area, edema formation, lipid peroxidation and neurological deficits. Moreover, in the t-MCA occlusion model, delayed administration of BHB started at 1 h after the initiation of the MCA occlusion also significantly reduced cerebral infarct area. Taking together the results obtained in our previous study into account, these results indicate that BHB decreased cerebral edema formation and infarct area by improving of the cerebral energy metabolism during ischemia and by inhibition of lipid peroxidation after reperfusion.     

Left Ventricular Abnormality and Covert Atrial Fibrillation in Embolic Stroke of Undetermined Source

Aims: The relationship between left ventricular (LV) function and AF detection in embolic stroke of undetermined source (ESUS) patients with insertable cardiac monitors (ICMs) remains unclear. We investigated the association between LV function and AF detection in patients with ESUS after ICMs implantation. Methods: We enrolled patients with ESUS who underwent ICMs implantation from September 2016 to September 2020 using a single-center, prospective registry. LV systolic and diastolic functions were assessed on precordial echocardiography by LV fractional shortening (LVFS) and average E/e’, respectively. Associations between characteristics of LV function and detection of AF by ICMs were analyzed. Results: Participants comprised 101 patients (median age, 74 years; male, 62%). During a median follow-up period of 442 days (interquartile range (IQR), 202–770 days), AF was detected in 24 patients (24%). Median duration from ICMs implantation to AF detection was 71 days (IQR, 13–150 days). When LVFS and E/e’ were dichotomized by cutoff value, each of low LVFS (＜35.5%; adjusted hazard ratio (HR), 4.77; 95% confidence interval (CI), 1.77–12.9) and high E/e’ (≥ 8.65; adjusted HR, 4.56; 95%CI, 1.17–17.7) were independently associated with AF detection after adjusting for age and sex. When patients were divided into four groups according to dichotomized LVFS and E/e’, the combination of low LVFS and high E/e’ was independently associated with AF. Conclusions: In patients with ESUS after ICMs implantation, the LV characteristics of low LVFS and high E/e’ were associated with AF detection.     

Mediastinal Cystic Parathyroid Adenoma Diagnosed by Somatostatin Receptor Scintigraphy

A 71-year-old man complained of nausea and loss of appetite for eight months prior to admission. He was transported to a hospital with disorientation and diagnosed with primary hyperparathyroidism by laboratory examinations. However, ultrasonography, computed tomography, and technetium-99m labeled methoxyisobutyl isonitrile (^99mTc-MIBI) with single-photon emission computed tomography did not yield definite results. In contrast, somatostatin receptor scintigraphy successfully identified the lesion responsible for the over-secretion of parathyroid hormone within the middle mediastinum. The tumor was successfully resected by surgery, and a histopathological analysis confirmed the parathyroid adenoma nature of the tumor.