Acute Kidney Injury Following Pediatric Liver Transplant.

OBJECTIVE: To determine the incidence, severity, and risk factors of postoperative acute kidney injury in pediatric liver transplant patients with and without inborn errors of metabolism. DESIGN: Retrospective cohort study. SETTING: Single-center PICU. PATIENTS: All children less than or equal to 18 years old who received a liver transplant between January 2009 and July 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Following exclusion criteria there were 92 transplant encounters. After excluding patients who received combined kidney-liver transplantation, acute kidney injury occurred in 57% of patients (N = 49), with 25.6% (N = 22) stage 1, 15.1% (N = 13) stage 2, and 16.3% (N = 14) stage 3. In an adjusted analysis, metabolic indication for transplant was not significantly associated with presence of acute kidney injury (p = 0.45). For the subset of patients without inborn errors of metabolism, the odds of having acute kidney injury was 1.50 (95% CI: 1.00-2.26) for each 1-unit increase in preoperative INR after adjusting for the covariates of age, preoperative albumin, CMV status of donor, and preoperative creatinine. In the full cohort, as well as the sample of children without inborn errors of metabolism, presence of acute kidney injury was associated with longer total hospital stay as well as number of ICU days. CONCLUSIONS: Acute kidney injury in the early postoperative period is common in pediatric liver transplant patients (57%), 31.4% of whom had severe disease. In patients without inborn errors of metabolism, each unit increase in preoperative INR suggests a higher risk of acute kidney injury after adjusting for covariates including preoperative creatinine. This finding suggests an association between the severity of preoperative synthetic liver function and the risk of developing postoperative acute kidney injury which requires further investigation.

The Effect of the Coronavirus-2019 Pandemic on Pediatric Critical Care Fellowship Training.

Objective: To assess the impact of the coronavirus-2019 (COVID-19) pandemic on pediatric critical care medicine (PCCM) fellowship training through a cross-sectional survey of both program directors (PDs) and fellows. Design: Cross-sectional internet-based survey. Setting: Accreditation Council for Graduate Medical Education (ACGME)-accredited PCCM fellowship programs in the United States. Subjects: PCCM PDs and fellows. Results: A total of 34 PDs and 92 fellows responded to the national survey (rate of 47% and 17%, respectively). The majority (69%) of respondents agreed that medical education has been negatively impacted by the COVID-19 pandemic. When PDs were surveyed, 91% noted a significant decrease in the patient census since March 2020, with 59% citing a >15% decrease. Further, 65% reported trainees had less procedural experience. All respondents reported that education was at least in part provided through virtual learning platforms, with nearly half having exclusive remote learning without in-person sessions. Fifty percent of PDs and 62% of fellows reported decreased learner engagement during virtual didactics when compared to in-person education. The majority of PDs reported specific decreases in simulation, procedural skills training, and ultrasound training. Few PDs (15%) and fellows (13-16%) reported redeployment to adult patient care, with northeastern programs having the highest rates. In univariate analyses, decreased PDs confidence in trainee procedural skills was associated with reported decreases in number of procedures performed (P = .0006) and number of procedural skills didactic sessions (P = .0245). Change in the unit census was associated with less PDs confidence in fellows' medical knowledge (P = .0004), fellows' management skills (P = .0232), and fellows' procedural skills (P = .0003), with larger decreases in patient census correlating with larger decreases in confidence. Conclusions: The COVID-19 pandemic has significantly impacted the education and clinical training of PCCM fellows. More knowledge on this topic can assist PDs in curriculum changes for the future to address any gaps in learning that have occurred.

Heparin-binding EGF-like growth factor (HB-EGF) antisense oligonucleotide protected against hyperlipidemia-associated atherosclerosis.

BACKGROUND AND AIMS: Heparin-binding EGF-like growth factor (HB-EGF) is a representative EGF family member that interacts with EGFR under diverse stress environment. Previously, we reported that the HB-EGF-targeting using antisense oligonucleotide (ASO) effectively suppressed an aortic aneurysm in the vessel wall and circulatory lipid levels. In this study, we further examined the effects of the HB-EGF ASO administration on the development of hyperlipidemia-associated atherosclerosis using an atherogenic mouse model. METHODS AND RESULTS: The male and female LDLR deficient mice under Western diet containing 21% fat and 0.2% cholesterol content were cotreated with control and HB-EGF ASOs for 12 weeks. We observed that the HB-EGF ASO administration effectively downregulated circulatory VLDL- and LDL-associated lipid levels in circulation; concordantly, the HB-EGF targeting effectively suppressed the development of atherosclerosis in the aorta. An EGFR blocker BIBX1382 administration suppressed the hepatic TG secretion rate, suggesting a positive role of the HB-EGF signaling for the hepatic VLDL production. We newly observed that there was a significant improvement of the insulin sensitivity by the HB-EGF ASO administration in a mouse model under the Western diet as demonstrated by the improvement of the glucose and insulin tolerances. CONCLUSION: The HB-EGF ASO administration effectively downregulated circulatory lipid levels by suppressing hepatic VLDL production rate, which leads to effective protection against atherosclerosis in the vascular wall.

Genome-wide association mapping of natural variation in odour-guided behaviour in Drosophila.

A defining goal in the field of behavioural genetics is to identify the key genes or genetic networks that shape behaviour. A corollary to this goal is the goal of identifying genetic variants that are responsible for variation in the behaviour. These goals are achieved by measuring behavioural responses to controlled stimuli, in the present case the responses of Drosophila melanogaster to olfactory stimuli. We used a high-throughput behavioural assay system to test a panel of 157 Drosophila inbred lines derived from a natural population for both temporal and spatial dynamics of odour-guided behaviour. We observed significant variation in response to the odourant 2,3-butanedione, a volatile compound present in fermenting fruit. The recent whole genome sequencing of these inbred lines allowed us to then perform genome-wide association analyses in order to identify genetic polymorphisms underlying variation in responses. These analyses revealed numerous single nucleotide polymorphisms associated with variation in responses. Among the candidate genes identified were both novel and previously identified olfaction-related genes. Further, gene network analyses suggest that genes influencing variation in odour-guided behaviour are enriched for functions involving neural processing and that these genes form a pleiotropic interaction network. We examined several of these candidate genes that were highly connected in the protein- and genetic interaction networks using RNA interference. Our results showed that subtle changes influencing nervous system function can result in marked differences in behaviour.

Short-term anorexigenic effects of central neuropeptide VF are associated with hypothalamic changes in chicks.

The present study was designed to measure food and water intake, changes in hypothalamic chemistry, and other behaviour modifications after central injection of neuropeptide (NP) VF in broiler type chicks. In Experiment 1, chicks responded to central NPVF with a reduction in food intake for up to 90 min post injection. Water intake was unaffected. In Experiment 2, NPVF exerted a less potent and shorter duration of attenuated food intake than did the structurally related NPFF. In Experiment 3, 16.0 nmol NPVF reversed the prolactin-releasing peptide induced orexigenic effect. In Experiment 4, central NPVF treatment was associated with decreased c-Fos immunoreactivity in the lateral hypothalamus, whereas c-Fos immunoreactivity in the dorsomedial nucleus, infundibular nucleus (homologue to the mammalian arcuate nucleus) and ventromedial nucleus was increased. In Experiment 5, behaviours unrelated to ingestion including sit, stand, deep rest and locomotion were affected by central NPVF injection. Some of these behaviours are incompatible with ingestion and may contribute to hypothalamic associated perception of satiety after central NPVF. In conclusion, NVPF is a short-term regulator of appetite and its effects are associated with hypothalamic and behaviour changes in chicks.

NFATc3 regulates BK channel function in murine urinary bladder smooth muscle.

The nuclear factor of activated T-cells (NFAT) is a Ca(2+)-dependent transcription factor that has been reported to regulate the expression of smooth muscle contractile proteins and ion channels. Here we report that large conductance Ca(2+)-sensitive potassium (BK) channels and voltage-gated K(+) (K(V)) channels may be regulatory targets of NFATc3 in urinary bladder smooth muscle (UBSM). UBSM myocytes from NFATc3-null mice displayed a reduction in iberiotoxin (IBTX)-sensitive BK currents, a decrease in mRNA for the pore-forming alpha-subunit of the BK channel, and a reduction in BK channel density compared with myocytes from wild-type mice. Tetraethylammonium chloride-sensitive K(V) currents were elevated in UBSM myocytes from NFATc3-null mice, as was mRNA for the Shab family member K(V)2.1. Despite K(V) current upregulation, bladder strips from NFATc3-null mice displayed an elevated contractile response to electrical field stimulation relative to strips from wild-type mice, but this difference was abrogated in the presence of the BK channel blocker IBTX. These results support a role for the transcription factor NFATc3 in regulating UBSM contractility, primarily through an NFATc3-dependent increase in BK channel activity.

Resistance training alters cytokine gene expression in skeletal muscle of adults with type 2 diabetes.

Resistance training results in muscle hypertrophy and improves glycemic control in patients with type 2 diabetes. Whether resistance training modulates inflammation in muscles of diabetic patients remains unknown. We examined the expression of genes encoding the cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and transforming growth factor-beta1 (TGF-beta1) as well as the pan-leukocyte marker CD18. Thirty men and women (67+/-7 years) were randomized to either 16 weeks of resistance training and usual diabetes care (EX) or to usual diabetes care only (CON). Muscle biopsies were obtained from the vastus lateralis muscle prior to the 16-week intervention, and 72 h following the maximal strength test post-intervention. Fiber cross-sectional area (CSA) was determined following ATPase staining. Cytokine and CD18 transcript levels were assessed by real-time PCR. Resistance training increased CSA of type I and II fibers (both P <0.05) and IL-1beta transcript levels (P = 0.05). TNF-alpha (P<0.05) and TGF-beta1 transcripts (P<0.05) increased over time in the EX group, but these increases did not differ from those in the CON group. In both groups, the increase in CD18 transcripts remained minimal. The two groups differ by the relationship between changes in CD18 and changes in cytokine transcripts, suggesting that resistance training affects the source of cytokines in muscle. Our studies establish that resistance training in older adults with type 2 diabetes results in muscle fiber hypertrophy, despite a greater accumulation of inflammatory cytokine transcripts in muscle.

Characterization and comparison of the chromatographic performance of conventional, polar-embedded, and polar-endcapped reversed-phase liquid chromatography stationary phases.

We have evaluated and compared the performance of several conventional C18 phases with those possessing either a polar-endcapping group or a polar-embedded group within the primary alkyl ligand and found distinct differences in the chromatographic behavior among the three groups, as well as a high degree of variability within each group. The trend is for the polar-endcapped phases to display similar hydrophobic retention characteristics as the conventional C18 columns, but to express higher hydrogen bonding capacities and silanol activity. The polar-embedded phases displayed the opposite behavior, with a greatly reduced hydrophobic nature compared to the conventional and polar-endcapped C18 phases, and also a very much reduced silanol activity. Most interestingly, it appears that ionic or dipole interactions play a significant role in the overall retention behavior of the polar-embedded phases towards basic and acidic analytes.

The efficacy of home based progressive strength training in older adults with knee osteoarthritis: a randomized controlled trial.

OBJECTIVE: To test the effects of a high intensity home-based progressive strength training program on the clinical signs and symptoms of osteoarthritis (OA) of the knee. METHODS: Forty-six community dwelling patients, aged 55 years or older with knee pain and radiographic evidence of knee OA, were randomized to a 4 month home based progressive strength training program or a nutrition education program (attention control). Thirty-eight patients completed the trial with an adherence of 84% to the intervention and 65% to the attention control. The primary outcome was the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index pain and physical function subscales. Secondary outcomes included clinical knee examination, muscle strength, physical performance measures, and questionnaires to measure quality of life variables. RESULTS: Patients in the strength training group who completed the trial had a 71% improvement in knee extension strength in the leg reported as most painful versus a 3% improvement in the control group (p < 0.01). In a modified intent to treat analysis, self-reported pain improved by 36% and physical function by 38% in the strength training group versus 11 and 21%, respectively, in the control group (p = 0.01 for between group comparison). In addition, those patients in the strength training group who completed the trial had a 43% mean reduction in pain (p = 0.01 vs controls), a 44% mean improvement in self-reported physical function (p < 0.01 vs controls), and improvements in physical performance, quality of life, and self-efficacy when compared to the control group. CONCLUSION: High intensity, home based strength training can produce substantial improvements in strength, pain, physical function and quality of life in patients with knee OA.

Freeze tolerance in the gray treefrog: cryoprotectant mobilization and organ dehydration.

Freeze tolerance in the frog Rana sylvatica is supported by nonanticipatory mobilization of cryoprotectant (glucose) and redistribution of organ water. Other freeze-tolerant frogs may manifest these responses but differences exist. For example, the gray treefrog (Hyla versicolor) accumulates mostly glycerol as opposed to glucose. The current study reports additional novel features about cryoprotection in H. versicolor. Frogs were acclimated to low temperature for 12 weeks and frozen for 3 days at -2.4 degrees C. Some frogs were then thawed at 3 degrees C for 4 hr. Calorimetry revealed that frozen frogs had 53.9% +/- 11.1% of their body water in ice, and all frogs recovered following this procedure. Plasma glucose was low prior to the onset of freezing (1.1 +/- 0.9 micromol/ml) and it was 20x higher in postfreeze frogs. Constituting nearly 30% of plasma solute, glycerol was 117.2 +/- 13.6 micromol/ml prior to freezing and it remained equally high in postfreeze frogs. Liver water content was moderately lower in frozen frogs when compared to controls (62.9% +/- 3.7% vs. 68.6% +/- 1.7%), whereas postfreeze frogs excessively hydrated their livers (75.7% +/- 2.1%). Less-pronounced changes were seen in muscle water content. H. versicolor can mobilize its major cryoprotectant, glycerol, in response to extended cold acclimation, which is unique in comparison to other freeze-tolerant frogs, and it experiences only moderate organ dehydration during freezing. This species conforms with other freeze-tolerant frogs, however, by mobilizing glucose as a direct response to tissue freezing.

Etiology and modification of gait instability in older adults: a randomized controlled trial of exercise.

Increased gait instability is common in older adults, even in the absence of overt disease. The goal of the present study was to quantitatively investigate the factors that contribute to gait instability and its potential reversibility in functionally impaired older adults. We studied 67 older men and women with functional impairment before and after they participated in a randomized placebo-controlled, 6-mo multimodal exercise trial. We found that 1) gait instability is multifactorial; 2) stride time variability is strongly associated with functional status and performance-based measures of function that have previously been shown to predict significant clinical outcomes such as morbidity and nursing home admission; 3) neuropsychological status and health-related quality of life play important, independent roles in gait instability; and 4) improvement in physiological capacity is associated with reduced gait instability. Although the etiology of gait instability in older persons with mild-moderate functional impairment is multifactorial, interventions designed to reduce gait instability may be effective in bringing about a more consistent and more stable walking pattern.

Volume-load capacity in fast-gradient liquid chromatography effect of sample solvent composition and injection volume on chromatographic performance.

We studied the effects of sample solvent composition and injection volumes on the chromatographic performance of ODS-bonded silica columns under fast-gradient running conditions. Chromatographic performance is compromised as a function of both sample injection volume and sample solvent strength, with earlier-eluting analytes being much more affected than later-eluting ones. In general, when injecting samples dissolved in a strong solvent, performance was improved by diluting the strong injection solvent and injecting a proportionally larger volume. Volume loading capacity can be increased by using a longer column, or by using a column of equivalent length, but with a larger inner diameter. Data also suggest that sample solvent strength, not viscosity, is responsible for the noted effects.

Down-regulation of Na-K-Cl cotransport by protein kinase C is mediated by protein phosphatase 1 in pigmented ciliary epithelial cells.

The role of protein phosphatases in the regulation of Na-K-Cl cotransport was examined in human pigmented ciliary epithelial (PE) cells. Both a 37 kDa form and a 72 kDa form of protein phosphatase 1 (PP1) could be immunologically detected. The protein phosphatase inhibitor calyculin A stimulated Na-K-Cl cotransport by 89 +/- 12% at 10 n M, whereas okadaic acid had no effect at concentrations less than 100 n M. Calyculin A had no significant effect on either Na-K ATPase or ouabain-insensitive, bumetanide-insensitive 86Rb+uptake. These data suggest that PP1 plays a role in the inhibition of Na-K-Cl cotransport in PE cells. Treatment of cells with phorbol 12-myristate, 13-acetate (PMA), a protein kinase C (PKC) activator caused an 82% inhibition of Na-K-Cl cotransport. When cells were first treated for 5 min with PMA, 10 n M calyculin A stimulated Na-K-Cl cotransport by 53% compared to 101% by calyculin A alone. Treatment of cells with PMA after stimulation of Na-K-Cl cotransport by calyculin A resulted in a prompt 56% drop in cotransport activity. These data suggest that maximal inhibition of Na-K-Cl cotransport by PKC requires PP1 activity, but that a part of PKCs inhibitory effect is independent of PP1. The effect of PKC activation on PP1 was further examined by determining PP1 activity in cells pretreated with PMA. PP1 activity increased 38+/-8% in cells exposed to 1 microM PMA for 5 min. This stimulation was blocked by 100 n M staurosporine or 1 microM bisindolylmaleimide, two PKC inhibitors. An isomer which does not activate PKC (4 alpha phorbol didecanoate), did not stimulate PP1 activity. Thus PKC activation leads to an increase in PP1 activity in PE cells. Pretreatment of cells with the protein kinase A (PKA) inhibitor PHI 14-22 resulted in a partial reduction in calyculin A stimulation of cotransport, suggesting that PP1 and PKA function in a kinase-phosphatase regulatory loop. To determine whether other protein kinases might also be involved, several protein kinase inhibitors were tested, including KT5823 (protein kinase G, type II-specific), KN62 (calmodulin activated kinase-specific) and ML7 (myosin light chain kinase-specific). None prevented activation of Na-K-Cl cotransport by calyculin A, suggesting that these kinases are not involved in the activation of Na-K-Cl cotransport.

Triggering of cryoprotectant synthesis in the woolly bear caterpillar (Pyrrharctia isabella Lepidoptera: Arctiidae).

Isabella tiger moths (Pyrrharctia isabella) overwinter as caterpillars (i.e., woolly bears) that can survive freezing at moderate subzero temperatures. We observed an increase in hemolymph osmolality for field-collected woolly bears during October (325 +/- 47 to 445 +/- 27 mOsmol/liter) and tested the influence of temperature and moisture levels on cryoprotectant production. Laboratory acclimation was done at 5 degrees C in moist conditions and at 25 degrees C acclimation in both dry and moist conditions. Body water contents were diminished by dehydration at 25 degrees C for 4 days (57 +/- 4%). Caterpillars collected in early October did not alter their hemolymph osmolality during cold acclimation, but caterpillars increased by 45% (to 647 +/- 90 mOsmol/liter) after 4 days at 5 degrees C following their collection in late October. Hemolymph composition was markedly changed in caterpillars experiencing dehydration at 25 degrees C (1042 +/- 200 mOsmol/liter; 507 +/- 225 mmol glycerol/liter), whereas caterpillars showed no change in their hemolymph composition when kept moist at 25 degrees C. Our experiments reveal that both dehydration and cold acclimation rapidly induce cryoprotectant synthesis in P. isabella caterpillars. J. Exp. Zool. 286:367-371, 2000.

Freeze tolerance and cryoprotectant mobilization in the gray treefrog (Hyla versicolor).

Interstudy differences have been reported in the cryobiology of Hyla versicolor, especially for southern vs. northern populations, although laboratory conditioning likely was a contributing factor. This study measured freeze tolerance and cryoprotectant levels in H. versicolor from a southern population (Illinois). Frogs fully tolerated freezing at -1.5 and -3.5 degrees C for 24-48 hr but their survival rate declined at -5.5 degrees C (< 50%). Calorimetry revealed that 46% of the body water froze after 24 hr at -1.5 degrees C. Levels of plasma glucose and glycerol were substantially elevated, 14x and 5x respectively, in recently thawed frogs vs. unfrozen frogs. Plasma osmolality correspondingly rose from 242 to 304 mOsmol/L. Three unfrozen frogs had levels of plasma glycerol ranging between 17.1-36.8 mmol/L, suggesting an anticipatory response to freezing, but another three unfrozen frogs had a glycerol level of 1.1 mmol/L. A direct relationship existed between glycerol content and plasma osmolality and an inverse relationship was observed between plasma osmolality and ice content. Glycerol clearly was a major component of cryo-protectant production in these frogs, which was likely essential to their freeze tolerance. The cryobiology of Illinois frogs was only marginally less developed than seen in northern populations of this species.

The effects of progressive resistance training on bone density: a review.

Osteoporosis is a major public health problem that is characterized by low bone mass and increased susceptibility to fractures, primarily of the hip, spine, and wrist. It is estimated to cause 1.5 million fractures annually in the United States in people aged 50 yr and older. Physical activity, particularly weight-bearing exercise, is thought to provide the mechanical stimuli or "loading" important for the maintenance and improvement of bone health, whereas physical inactivity has been implicated in bone loss and its associated health costs. Both aerobic and resistance training exercise can provide weight-bearing stimulus to bone, yet research indicates that resistance training may have a more profound site specific effect than aerobic exercise. Over the past 10 years, nearly two dozen cross-sectional and longitudinal studies have shown a direct and positive relationship between the effects of resistance training and bone density. Conversely, a handful of other studies have reported little or no effect on bone density. However, these results may be partially attributable to the study design, intensity and duration of the exercise protocol, and the bone density measurement techniques used. High-intensity resistance training, in contrast to traditional pharmacological and nutritional approaches for improving bone health in older adults, has the added benefit of influencing multiple risk factors for osteoporosis including improved strength and balance and increased muscle mass.

Retinal location is the key to identifying predators in fiddler crabs (Uca pugilator).

Fiddler crabs (Uca pugilator Bosc; Crustacea, Decapoda) feed and court in open, flat spaces. Their visual system has several putative adaptations to their flat habitat, including the tendency to keep the vertical axis of their eyes perpendicular to the plane of the substratum. It is hypothesized that one of the functions of this behavior is to distinguish accurately predators from conspecifics by aligning the region of the eye sensitive to predators with the region in space in which predators occur. To test this hypothesis, a crab was placed in a glass dish, and a moving stimulus was presented between 20 degrees above and below eye level (horizontal). Stimuli below the crab's horizon hardly ever evoked escape responses, while identical stimuli above the horizon produced escape responses whose frequency varied with the angular size, not the absolute size, of the stimulus. Experiments with artificial horizons showed that it is the position of the stimulus relative to the eye that is important, rather than its position relative to external cues such as the visible horizon, the vertical light gradient or the gravitational horizon. It is concluded that a crab responds to stimuli according to their position relative to its retinal equator. This conclusion is discussed in light of the crabs' natural behavior with respect to supra-horizontal stimuli.

Freeze duration influences postfreeze survival in the frog Rana sylvatica.

Survival, cryoprotection, and the time course for recovery of vital functions were studied in autumn-collected juvenile wood frogs (Rana sylvatica) following freezing at -1.5 degrees C for various periods. Frogs readily tolerated freezing for 3 or 9 d, but only 50% survived a 28-d freezing trial. Generally, the postfreeze return of vital functions (vascular circulation, pulmonary breathing, righting reflex, jumping reflex) occurred later in frogs frozen for longer periods. Augmenting endogenous levels of the cryoprotectant glucose (via injections) prior to freezing substantially increased freeze endurance, as these frogs had excellent survival after remaining frozen for as long as 49 d. The improved freeze endurance of glucose-loaded frogs apparently was not associated with a reduction in ice content but rather may reflect the greater availability of energy substrate needed to support metabolism of frozen ischemic tissues.