Ultrasound-guided vs. palpation-guided techniques for radial arterial catheterisation in infants: A randomised controlled trial.

BACKGROUND: The usefulness of ultrasound-guided techniques for radial arterial catheterisation has been well identified; however, its usefulness has not been completely evaluated in infants under 12 months of age, who are generally considered the most difficult group for arterial catheterisation. OBJECTIVE: We evaluated whether ultrasound guidance would improve success rates and reduce the number of attempts at radial arterial catheterisation in infants. DESIGN: A randomised, controlled and patient-blinded study. SETTING: Single-centre trial, study period from June 2016 to February 2017. PATIENTS: Seventy-four infants undergoing elective cardiac surgery. INTERVENTION: Patients were allocated randomly into either ultrasound-guided group (group US) or palpation-guided group (group P) (each n=37) according to the technique applied for radial arterial catheterisation. All arterial catheterisations were performed by one of two experienced anaesthesiologists based on group assignment and were recorded on video. MAIN OUTCOME MEASURES: The primary endpoint was the first-pass success. The number of attempts and total duration of the procedure until successful catheterisation were also analysed. RESULTS: The first-pass success rate was significantly higher in the group US than in the group P (68 vs. 38%, P = 0.019). In addition, fewer attempts were needed for successful catheterisation in the group US than in the group P (median 1 [IQR 1 to 2] vs. 2 [1 to 4], P = 0.023). However, the median [IQR] procedural time (s) until successful catheterisation in the two groups was not significantly different (102 [49 to 394] vs. 218 [73 to 600], P = 0.054). CONCLUSION: The current study demonstrated that the ultrasound-guided technique for radial arterial catheterisation in infants effectively improved first-pass success rate and also reduced the number of attempts required. TRIAL REGISTRATION: ClinicalTrials.gov NCT02795468.

Physiological-based pharmacokinetic modeling of endotoxin in the rat.

We have previously measured the distribution and pharmacokinetics of biosynthetically radiolabeled endotoxin of Salmonella typhimurium following intraperitoneal (IP) dosing (200 µg/kg) in Sprague-Dawley rats. In our experiments, the fatty acid residues were labeled with (3)H and the glucosamine residues were labeled with (14)C. To predict the dynamics of endotoxin exposure, we developed a physiological-based pharmacokinetic model using our measured distribution results. The model was validated with published low-dose (30 µg/kg) IP exposure results in rats. Endotoxin pharmacokinetics depended on dose and route. At high IP doses, absorption was followed by biphasic decay over 48 h in plasma. There were tissue accumulations of the fatty acid and glucosamine residues in various target organs, including the brain. We also found that the glucosamine and fatty acid components separated in vivo about 3 h after IP injection. At the lower IP dose, a smaller fraction of the dose was distributed to the tissues, with most of the dose remaining in the blood. Each component had its own dynamic behavior and target tissue distribution in the rat. The fatty acid components tended to remain in the brain stem, caudate nucleus, cerebellum, frontal cortex, hippocampus, and hypothalamus. Other organs (spleen, kidney, meninges, and choroid plexus) had similar biphasic distribution. The liver had the unique accumulation of both glucosamine and fatty acid residues.

Distribution and pharmacokinetics of double-radiolabeled endotoxin in the rat brain and peripheral organs.

The endotoxin, lipopolysaccharide (LPS), of Salmonella typhimurium was biosynthetically labeled with (3)H and (14)C incorporated into the fatty acyl chains and glucosamine residues, respectively. The radio-labeled LPS was isolated from the bacteria and then injected into Sprague-Dawley rats. The distribution of (14)C and (3)H-LPS in plasma and other organs was determined following intraperitoneal (IP) doses of (14)C and (3)H-LPS (200 µg/kg). Plasma concentrations of both fatty acyl chains and glucosamine residues were biphasic, with a relatively rapid decay followed by a slow decline for 48 h. Similar biphasic results were found in the peripheral organs (kidney and heart) and brain barrier tissues (meninges and choroid plexus). In other brain tissues (brain stem, caudate nucleus, hypothalamus, frontal cortex, cerebellum and hippocampus), the glucosamine residue was biphasic, whereas the fatty acyl chains showed accumulation. Highest concentrations of LPS were found in the plasma, spleen and the liver. In addition, in the liver, sustained elevations of (14)C-glucosamine and (3)H-fatty acyl chains were observed. This indicates LPS accumulation in the liver. By contrast, the spleen showed biphasic decay of glucosamine residues and accumulation of fatty acyl chains. In the brain barrier tissues, peak LPS concentrations were significantly reduced (about 70%) and were further reduced (about 95%) in other brain tissues. The high elevation of LPS in the spleen is considered indicative of an immune response. Our findings highlight the potential significant role of lipid A as shown with the sustained elevation of (3)H-fatty acyl chains in the brain.

Free fatty acids profile of the fetal brain and the plasma, liver, brain and kidneys of pregnant rats treated with sodium arsenite at mid-organogenesis.

Free fatty acids (FFAs) are known to be markers of cellular membrane degradation through lipid peroxidation and are substrates for the production of reactive oxygen species (ROS). Oxidative stress, due to overproduction of ROS, may facilitate cellular insult by various toxicants. The ability of the rat conceptus to respond to toxic stress may be critical for normal development. In this study, the effects of the environmental toxicant sodium arsenite (NaAsO2) on FFAs were investigated after administering a single oral dose, in water and in a lipid medium, to pregnant rats on gestational day (GD) 10, a time point at mid-organogenesis. NaAsO2 was administered in deionized water (AsH2O) or in half and half dairy cream (AsHH) at a dose of 41 mg sodium arsenite (NaAsO2)/kg body weight. Control animals were treated with either dairy cream (HH) or deionized water (H2O). The animals were sacrificed on GD 20. The fetal brain and the maternal liver, brain, plasma and kidneys were harvested. The FFAs were extracted and analyzed by gas chromatography. In the liver, there was an increase of myristic acid (1200%), myristoleic acid (174%), palmitic acid (47%), elaidic acid (456%), oleic acid (165%) and docosahexaenoic acid (224%) in the AsH2O group as compared to the AsHH group. Oleic acid and arachidonic acid were increased by 192% and 900%, respectively, in the AsH2O group as compared to the H2O group, and myristic acid was decreased by 90% in the AsHH group as compared to the HH group. In the maternal brain, myristoleic acid was decreased by 91% in the AsH2O group as compared to the H2O group, and DHA increased by 148% in the AsHH group as compared to the HH group. In the fetal brain, myristic and stearic acids were decreased by 87% and 89%, respectively, in the AsH2O group as compared to the AsHH group. Myristic, stearic and arachidonic acids were increased by 411%, 265%, and 144%, respectively, in the AsHH group as compared to the HH group. There was no effect on the fatty acids concentrations in the kidney or plasma as compared to controls. This study shows that NaAsO2 produced a differential effect on the fatty acid profiles in rats. Further investigation is needed to elucidate the role of fatty acids in differential signaling and regulation by either the palmitoylation or myristoylation process of cellular functions in these target organs.

The differential JunB responses to inhibition of succinate dehydrogenase in rat hippocampus and liver.

The inhibitor of mitochondrial enzyme succinate dehydrogenase, 3-nitropropionic acid (3-NPA), induces cellular energy deficit followed by oxidative stress, secondary excitotoxicity and neuronal degeneration. The fast activation of Jun and Fos proteins and other proteins encoding inducible transcription factors (ITFs) occurs in most tissues upon exposure to a variety of stressors including exposure to mitochondrial inhibitors. However, the consequences of this activation can differ dramatically in different organs. For example, while activation of the same ITFs may lead to apoptosis and necrosis in neurons it may stimulate liver regeneration. Here, we report the alterations in mRNAs levels of c-Fos, JunB, and Krox20 proteins induced in the rat brain and liver by the acute exposure to 3-NPA at 30 mg/kg, s.c. While the increase of c-fos transcripts was observed in both the hippocampus and liver, the junb transcript increased in the hippocampus but decreased in the liver. No changes were observed in krox-20 mRNA in the hippocampus. Interestingly, there was a large variation in krox-20 mRNA levels in the liver among animals within the same experimental group. In conclusion, out of the three ITFs transcripts examined here junb may activate different pathways depending on the tissue as indicated by differential responses to mitochondrial inhibition in the hippocampus and liver.

Hepatotoxicity of androstenedione in pregnant rats.

Androstenedione, a naturally occurring steroid hormone, is a dietary supplement used to enhance athletic performance. Little is known, however, about the safety of its use by young adults including women of child bearing age. To test the possible hepatotoxic effects of androstenedione use, this study was undertaken using a rat model. Pregnant rats (six rats/dose) were exposed to androstenedione in corn oil by gastric intubation at 0, 5, 30 or 60 mg/kg body weight/day beginning 2 weeks before mating and continuing through gestation day 19. On gestation day 20, blood and livers were collected from the pregnant rats for analysis of hepatotoxicity endpoints: serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), glutathione (GSH) and glutathione S-transferase (GST), total microsomal P450, nuclear DNA damage and lipid peroxidation. Under these experimental conditions, no significant differences were observed in any of these biomarkers over the concentration range examined.

Validation of an in vitro model for assessment of androstenedione hepatotoxicity using the rat liver cell line clone-9.

Androstenedione, a naturally occurring steroid hormone, has been used to enhance athletic performance. Little is known, however, about its hepatotoxicity. Clone-9 cells, a non-transformed epithelial cell line that was originally isolated from normal liver of a 4-week old Sprague-Dawley rat, were used as an in vitro model to assess the hepatotoxic potential of androstenedione. The cultures were treated with androstenedione for 24 h at 37 degrees C in 5% CO(2) at concentrations of 0-100 microg ml(-1). After the treatment period, the cells and the culture supernatants were assayed for markers of cytotoxicity which included: release of liver enzymes, cell viability, cellular double-stranded DNA content, oxidative stress, steatosis, cellular ATP content, caspase-3 activity, the mitochondrial permeability transition and induction of cytochrome P450 activity. Significant concentration-dependent differences from control were observed in some endpoints at medium concentrations of 10 microg ml(-1) and above. These in vitro findings were compared with comparable endpoints obtained from an in vivo study of androstenedione toxicity in female Sprague-Dawley rats. Of the eight endpoints that could be compared between the two studies, only three (lipid accumulation, ATP depletion and P450 activity) appeared to be concordant. This suggests that, under the experimental conditions used, the clone-9 cells were not a good model for androstenedione hepatotoxicity.

A dynamic simulation of bisphenol A dosimetry in neuroendocrine organs.

Bisphenol A (BPA) is a known xenoestrogen with similar properties to 17beta-estradiol. BPA and estrogen are hydrophobic compounds, and this affects the pharmacokinetics of both compounds in mammals. In a previous study we measured the distribution of BPA in female F344 rats exposed to oral doses of 0.1, 10 and 100 mg/kg. The results showed distribution to target neuroendocrine organs at all doses tested. Using these results, we developed a pharmacokinetic model to predict the dynamic uptake and excretion of BPA by various routes of exposure (po, iv, sc, ip). The model was able to simulate the entire time course (48 h) following various routes of exposure in rats over the dose ranges tested. The model indicated that the ultimate tissue uptake of BPA was established by the rapid initial transfer of free BPA into tissues. After free BPA enters the systemic circulation, metabolism and excretion reactions cause a relatively short duration and rapid decline. This period is followed by a slower long-term decline characteristic of BPA's biphasic pharmacokinetics. Plasma protein and tissue binding reactions established the long-term half-life of BPA in the body. Route differences in tissue uptake were directly related to the competition between transfer and binding reactions during the absorption phase.

Exercise, Body Weight, and Amenorrhea in Professional Ballet Dancers.

In brief Thirty-two professional female ballet dancers were studied by means of a gynecological questionnaire to determine the prevalence of menstrual dysfunction. Thirty-seven percent had a history of amenorrhea (p <.01 compared with controls). Forty-seven percent had a history of menstrual dysfunction manifested by delayed menarche, amenorrhea, or oligomenorrhea (p <.001 compared with controls). Menstrual dysfunction was related to both strenuous physical exercise and diminished body weight, and it was reversible, often disappearing with significant weight gain or intervals of less intense exercise. Thirteen women had pituitary hormone levels measured before and after exercise, and both were within the normal range.

Determination of the rat tissue partitioning of endotoxin in vitro for physiologically-based pharmacokinetic (PBPK) modeling.

The biosynthetically double-labeled lipopolysaccharide (LPS), containing (3)H-labeled on the fatty acyl-chains and (14)C-labeled on the glucosamine of Salmonella enterica serotype typhimurium, was isolated from bacteria grown in proteose peptone-beef extract (PPBE) medium in the presence of labeled precursors; 133 micro Ci/ml of [2-(3)H] acetate sodium salt and 0.167 micro Ci/ml of N-acetyl[D-1-(14)C]glucosamine. The LPS was extracted from the bacteria with 90% phenol/chloroform/petroleum ether, purified and stored in 0.1% (v/v) triethylamine/10 mM Tris HCl at -70 degrees C. Tissue slices and portions of the meninges were prepared and incubated in artificial cerebrospinal fluid (CSF) or Krebs phosphate buffer (Krebs) containing 150 ng/ml LPS with [(3)H] LPS (0.004 micro Ci/ml, sp. act. 28 micro Ci/mg LPS). The tissues were incubated under 95% oxygen/5% carbon dioxide at 37 degrees C with constant agitation until steady-state uptake was reached (60 min). At the end of the incubation period, tissues were processed for radioactivity measurement. The rat tissue partitioning of LPS in artificial CSF for brain and Krebs for other organs was measured by using the ratio of tissue to medium at the steady state in vitro. The following results were obtained from the study: Heart, 0.15; liver, 0.19; spleen, 0.12; kidney, 0.18; stomach, 0.17; small intestine, 0.18; brain stem, 0.10; cerebellum, 0.11; meninges, 0.77; hippocampus, 0.12; hypothalamus, 0.12; frontal cortex, 0.09 and caudate nucleus, 0.10. This information, along with plasma or blood/buffer partition coefficients, is a requisite for constructing a physiologically-based pharmacokinetic (PBPK) model of endotoxins for quantitative risk assessment.