Compared with notifiable disease surveillance, claims-based algorithms estimate higher Lyme disease incidence, but their accuracy is unknown. We applied a previously developed Lyme disease algorithm ...(diagnosis code plus antimicrobial drug prescription dispensing within 30 days) to an administrative claims database in Massachusetts, USA, to identify a Lyme disease cohort during July 2000–June 2019. Clinicians reviewed and adjudicated medical charts from a cohort subset by using national surveillance case definitions. We calculated positive predictive values (PPVs). We identified 12,229 Lyme disease episodes in the claims database and reviewed and adjudicated 128 medical charts. The algorithmʼs PPV for confirmed, probable, or suspected cases was 93.8% (95% CI 88.1%–97.3%); the PPV was 66.4% (95% CI 57.5%–74.5%) for confirmed and probable cases only. In a high incidence setting, a claims-based algorithm identified cases with a high PPV, suggesting it can be used to assess Lyme disease burden and supplement traditional surveillance data.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Systemic pesticides such as neonicotinoids are commonly used on flowering crops visited by pollinators, and their use has been implicated in the decline of insect pollinator populations in Europe and ...North America. Several studies show that neonicotinoids affect navigation and learning in bees but few studies have examined whether these substances influence their basic motor function. Here, we investigated how prolonged exposure to sublethal doses of four neonicotinoid pesticides (imidacloprid, thiamethoxam, clothianidin, dinotefuran) and the plant toxin, nicotine, affect basic motor function and postural control in foraging-age worker honeybees. We used doses of 10 nM for each neonicotinoid: field-relevant doses that we determined to be sublethal and willingly consumed by bees. The neonicotinoids were placed in food solutions given to bees for 24 h. After the exposure period, bees were more likely to lose postural control during the motor function assay and fail to right themselves if exposed to imidacloprid, thiamethoxam, clothianidin. Bees exposed to thiamethoxam and nicotine also spent more time grooming. Other behaviours (walking, sitting and flying) were not significantly affected. Expression of changes in motor function after exposure to imidacloprid was dose-dependent and affected all measured behaviours. Our data illustrate that 24 h exposure to sublethal doses of neonicotinoid pesticides has a subtle influence on bee behaviour that is likely to affect normal function in a field setting.
Reports concerning the effect of endurance exercise on the anabolic response to strength training have been contradictory. This study re-investigated this issue, focusing on training effects on ...indicators of protein synthesis and degradation. Two groups of male subjects performed 7 weeks of resistance exercise alone (R; n = 7) or in combination with preceding endurance exercise, including both continuous and interval cycling (ER; n = 9). Muscle biopsies were taken before and after the training period. Similar increases in leg-press 1 repetition maximum (30%; P<0.05) were observed in both groups, whereas maximal oxygen uptake was elevated (8%; P<0.05) only in the ER group. The ER training enlarged the areas of both type I and type II fibers, whereas the R protocol increased only the type II fibers. The mean fiber area increased by 28% (P<0.05) in the ER group, whereas no significant increase was observed in the R group. Moreover, expression of Akt and mTOR protein was enhanced in the ER group, whereas only the level of mTOR was elevated following R training. Training-induced alterations in the levels of both Akt and mTOR protein were correlated to changes in type I fiber area (r = 0.55-0.61, P<0.05), as well as mean fiber area (r = 0.55-0.61, P<0.05), reflecting the important role played by these proteins in connection with muscle hypertrophy. Both training regimes reduced the level of MAFbx protein (P<0.05) and tended to elevate that of MuRF-1. The present findings indicate that the larger hypertrophy observed in the ER group is due more to pronounced stimulation of anabolic rather than inhibition of catabolic processes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Lyme disease (LD) is the fifth most commonly reported notifiable infectious disease in the United States (US) with approximately 35,000 cases reported in 2019 via public health surveillance. However, ...healthcare claims-based studies estimate that the number of LD cases is >10 times larger than reported through surveillance. To assess the burden of LD using healthcare claims data and the effectiveness of interventions for LD prevention and treatment, it is important to use validated well-performing LD case-finding algorithms ("LD algorithms"). We conducted a systematic literature review to identify LD algorithms used with US healthcare claims data and their validation status. We searched PubMed and Embase for articles published in English since January 1, 2000 (search date: February 20, 2021), using the following search terms: (1) "Lyme disease"; and (2) "claim*" or "administrative* data"; and (3) "United States" or "the US*". We then reviewed the titles, abstracts, full texts, and bibliographies of the articles to select eligible articles, i.e., those describing LD algorithms used with US healthcare claims data. We identified 15 eligible articles. Of these, seven studies used LD algorithms with LD diagnosis codes only, four studies used LD diagnosis codes and antibiotic dispensing records, and the remaining four studies used serologic test order codes in combination with LD diagnosis codes and antibiotics records. Only one of the studies that provided data on algorithm performance: sensitivity 50% and positive predictive value 5%, and this was based on Lyme disease diagnosis code only. US claims-based LD case-finding algorithms have used diverse strategies. Only one algorithm was validated, and its performance was poor. Further studies are warranted to assess performance for different algorithm designs and inform efforts to better assess the true burden of LD.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Ice nucleating particles (INPs) in the Arctic can influence climate
and precipitation in the region; yet our understanding of the concentrations and sources
of INPs in this region remain uncertain. ...In the following, we (1) measured concentrations
of INPs in the immersion mode in the Canadian Arctic marine boundary layer during
summer 2014 on board the CCGS Amundsen, (2) determined ratios of surface areas
of mineral dust aerosol to sea spray aerosol, and (3) investigated the source region of
the INPs using particle dispersion modelling. Average concentrations of INPs at −15,
−20, and −25 ∘C were 0.005, 0.044, and 0.154 L−1,
respectively. These concentrations fall within the range of INP concentrations measured
in other marine environments. For the samples investigated the ratio of mineral dust
surface area to sea spray surface area ranged from 0.03 to 0.09. Based on these ratios
and the ice active surface site densities of mineral dust and sea spray aerosol
determined in previous laboratory studies, our results suggest that mineral dust is a
more important contributor to the INP population than sea spray aerosol for the samples
analysed. Based on particle dispersion modelling, the highest concentrations of INPs were
often associated with lower-latitude source regions such as the Hudson Bay area, eastern
Greenland, or north-western continental Canada. On the other hand, the lowest
concentrations were often associated with regions further north of the sampling sites and
over Baffin Bay. A weak correlation was observed between INP concentrations and the time
the air mass spent over bare land, and a weak negative correlation was observed between
INP concentrations and the time the air mass spent over ice and open water. These
combined results suggest that mineral dust from local sources is an important contributor
to the INP population in the Canadian Arctic marine boundary layer during summer 2014.
Key points
We investigated whether intramuscular temperature affects the acute recovery of exercise performance following fatigue‐induced by endurance exercise.
Mean power output was better preserved ...during an all‐out arm‐cycling exercise following a 2 h recovery period in which the upper arms were warmed to an intramuscular temperature of ̴ 38°C than when they were cooled to as low as 15°C, which suggested that recovery of exercise performance in humans is dependent on muscle temperature.
Mechanisms underlying the temperature‐dependent effect on recovery were studied in intact single mouse muscle fibres where we found that recovery of submaximal force and restoration of fatigue resistance was worsened by cooling (16–26°C) and improved by heating (36°C).
Isolated whole mouse muscle experiments confirmed that cooling impaired muscle glycogen resynthesis.
We conclude that skeletal muscle recovery from fatigue‐induced by endurance exercise is impaired by cooling and improved by heating, due to changes in glycogen resynthesis rate.
Manipulation of muscle temperature is believed to improve post‐exercise recovery, with cooling being especially popular among athletes. However, it is unclear whether such temperature manipulations actually have positive effects. Accordingly, we studied the effect of muscle temperature on the acute recovery of force and fatigue resistance after endurance exercise. One hour of moderate‐intensity arm cycling exercise in humans was followed by 2 h recovery in which the upper arms were either heated to 38°C, not treated (33°C), or cooled to ∼15°C. Fatigue resistance after the recovery period was assessed by performing 3 × 5 min sessions of all‐out arm cycling at physiological temperature for all conditions (i.e. not heated or cooled). Power output during the all‐out exercise was better maintained when muscles were heated during recovery, whereas cooling had the opposite effect. Mechanisms underlying the temperature‐dependent effect on recovery were tested in mouse intact single muscle fibres, which were exposed to ∼12 min of glycogen‐depleting fatiguing stimulation (350 ms tetani given at 10 s interval until force decreased to 30% of the starting force). Fibres were subsequently exposed to the same fatiguing stimulation protocol after 1–2 h of recovery at 16–36°C. Recovery of submaximal force (30 Hz), the tetanic myoplasmic free Ca2+ (measured with the fluorescent indicator indo‐1), and fatigue resistance were all impaired by cooling (16–26°C) and improved by heating (36°C). In addition, glycogen resynthesis was faster at 36°C than 26°C in whole flexor digitorum brevis muscles. We conclude that recovery from exhaustive endurance exercise is accelerated by raising and slowed by lowering muscle temperature.
Key points
We investigated whether intramuscular temperature affects the acute recovery of exercise performance following fatigue‐induced by endurance exercise.
Mean power output was better preserved during an all‐out arm‐cycling exercise following a 2 h recovery period in which the upper arms were warmed to an intramuscular temperature of ̴ 38°C than when they were cooled to as low as 15°C, which suggested that recovery of exercise performance in humans is dependent on muscle temperature.
Mechanisms underlying the temperature‐dependent effect on recovery were studied in intact single mouse muscle fibres where we found that recovery of submaximal force and restoration of fatigue resistance was worsened by cooling (16–26°C) and improved by heating (36°C).
Isolated whole mouse muscle experiments confirmed that cooling impaired muscle glycogen resynthesis.
We conclude that skeletal muscle recovery from fatigue‐induced by endurance exercise is impaired by cooling and improved by heating, due to changes in glycogen resynthesis rate.
ABSTRACT
Intense exercise training is a powerful stimulus that activates mitochondrial biogenesis pathways and thus increases mitochondrial density and oxidative capacity. Moderate levels of reactive ...oxygen species (ROS) during exercise are considered vital in the adaptive response, but high ROS production is a serious threat to cellular homeostasis. Although biochemical markers of the transition from adaptive to maladaptive ROS stress are lacking, it is likely mediated by redox sensitive enzymes involved in oxidative metabolism. One potential enzyme mediating such redox sensitivity is the citric acid cycle enzyme aconitase. In this study, we examined biopsy specimens of vastus lateralis and triceps brachii in healthy volunteers, together with primary human myotubes. An intense exercise regimen inactivated aconitase by 55‐72%, resulting in inhibition of mitochondrial respiration by 50‐65%. In the vastus, the mitochondrial dysfunction was compensated for by a 15‐72% increase in mitochondrial proteins, whereas H2O2 emission was unchanged. In parallel with the inactivation of aconitase, the intermediary metabolite citrate accumulated and played an integral part in cellular protection against oxidative stress. In contrast, the triceps failed to increase mitochondrial density, and citrate did not accumulate. Instead, mitochondrial H2O2 emission was decreased to 40% of the pretraining levels, together with a 6‐fold increase in protein abundance of catalase. In this study, a novel mitochondrial stress response was highlighted where accumulation of citrate acted to preserve the redox status of the cell during periods of intense exercise.—Larsen, F. J., Schiffer, T. A., Ørtenblad, N., Zinner, C., Morales‐Alamo, D., Willis, S. J., Calbet, J. A., Holmberg, H.‐C., Boushel, R. High‐intensity sprint training inhibits mitochondrial respiration through aconitase inactivation. FASEB J. 30, 417‐427 (2016). www.fasebj.org
Purpose
The aim was to compare changes in peripheral and cerebral oxygenation, as well as metabolic and performance responses during conditions of blood flow restriction (BFR, bilateral vascular ...occlusion at 0% vs. 45% of resting pulse elimination pressure) and systemic hypoxia (~ 400 m, F
I
O
2
20.9% vs. ~ 3800 m normobaric hypoxia, F
I
O
2
13.1 ± 0.1%) during repeated sprint tests to exhaustion (RST) between leg- and arm-cycling exercises.
Methods
Seven participants (26.6 ± 2.9 years old; 74.0 ± 13.1 kg; 1.76 ± 0.09 m) performed four sessions of RST (10-s maximal sprints with 20-s recovery until exhaustion) during both leg and arm cycling to measure power output and metabolic equivalents as well as oxygenation (near-infrared spectroscopy) of the muscle tissue and prefrontal cortex.
Results
Mean power output was lower in arms than legs (316 ± 118 vs. 543 ± 127 W;
p
< 0.001) and there were no differences between conditions for a given limb. Arms demonstrated greater changes in concentration of deoxyhemoglobin (∆HHb, − 9.1 ± 6.1 vs. − 6.5 ± 5.6 μm) and total hemoglobin concentration (∆tHb, 15.0 ± 10.8 vs. 11.9 ± 7.9 μm), as well as the absolute maximum tissue saturation index (TSI, 62.0 ± 8.3 vs. 59.3 ± 8.1%) than legs, respectively (
p
< 0.001), demonstrating a greater capacity for oxygen extraction. Further, there were greater changes in tissue blood volume tHb during BFR only compared to all other conditions (
p
< 0.01 for all).
Conclusions
The combination of BFR and/or hypoxia led to increased changes in HHb and tHb likely due to greater vascular resistance, to which arms were more responsive than legs.
Transport of anthropogenic aerosol into the Arctic in the spring
months has the potential to affect regional climate; however, modeling
estimates of the aerosol direct radiative effect (DRE) are ...sensitive to
uncertainties in the mixing state of black carbon (BC). A common approach in
previous modeling studies is to assume an entirely external mixture (all
primarily scattering species are in separate particles from BC) or internal
mixture (all primarily scattering species are mixed in the same particles as
BC). To provide constraints on the size-resolved mixing state of BC, we use
airborne single-particle soot photometer (SP2) and ultrahigh-sensitivity
aerosol spectrometer (UHSAS) measurements from the Alfred Wegener Institute
(AWI) Polar 6 flights from the NETCARE/PAMARCMIP2015 campaign to estimate
coating thickness as a function of refractory BC (rBC) core diameter and
the fraction of particles containing rBC in the springtime Canadian high
Arctic. For rBC core diameters in the range of 140 to 220 nm, we find
average coating thicknesses of approximately 45 to 40 nm, respectively,
resulting in ratios of total particle diameter to rBC core diameters ranging
from 1.6 to 1.4. For total particle diameters ranging from 175 to 730 nm,
rBC-containing particle number fractions range from 16 % to 3 %,
respectively. We combine the observed mixing-state constraints with simulated
size-resolved aerosol mass and number distributions from GEOS-Chem–TOMAS to
estimate the DRE with observed bounds on mixing state as opposed to assuming
an entirely external or internal mixture. We find that the pan-Arctic average
springtime DRE ranges from −1.65 to −1.34 W m−2 when assuming
entirely externally or internally mixed BC. This range in DRE is reduced by
over a factor of 2 (−1.59 to −1.45 W m−2) when using the
observed mixing-state constraints. The difference in DRE between the two
observed mixing-state constraints is due to an underestimation of BC mass
fraction in the springtime Arctic in GEOS-Chem–TOMAS compared to Polar 6
observations. Measurements of mixing state provide important constraints for
model estimates of DRE.
Introduction:
The determination of the optimal occlusion level is a key parameter in blood flow restriction (BFR). This study aimed to compare the effects of elastic (BStrong) vs. nylon (Hokanson) ...BFR cuffs on blood flow in the lower and upper limbs.
Methods:
Eleven healthy participants undertook several BFR sessions with 2 different cuffs of similar width on their lower and upper limbs at different pressures 200, 250, 300, 350, and 400 mmHg for BStrong and 0, 40, and 60% of the arterial occlusion pressure (AOP) for Hokanson. Doppler ultrasound recorded blood flows through the brachial and femoral artery at rest.
Results:
With BStrong, only 350 and 400 mmHg pressures were significantly different from resting values (0% AOP). With Hokanson, both 40% and 60% of the AOP were significantly different from resting values (
p
< 0.05).
Discussion:
While both cuffs elicited BFR, they failed to accurately modulate blood flow. Hokanson is appropriate for research settings while BStrong appears to be a convenient tool for practitioners due to its safety (i.e., the impossibility of completely occluding arteries) and the possibility of exercising freely detached from the pump.
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