bluuebunny/crossref_metadata_2025_split huggingface dataset:
A membrane glucocorticoid receptor mediates the rapid/non‐genomic actions of glucocorticoids in mammalian skeletal muscle fibres
Authors: Pérez María Hernández‐Alcalá , Cormack Jonathan , Mallinson David , Mutungi Gabriel 
Published: July 2013

Key points
Glucocorticoids are stress hormones used in the treatment of many chronic inflammatory diseases including asthma. They exert most of their physiological/pharmacological actions by regulating the activity of genes involved in the inflammatory response. However, they also have rapid/non‐genomic effects whose functions are poorly understood.
In this study we used two widely prescribed glucocorticoids, beclomethasone dipropionate and prednisolone acetate, to investigate whether these hormones have rapid/non‐genomic effects in mammalian skeletal muscles.
Both glucocorticoids increased maximum force in slow‐twitch muscle fibres/cells without significantly affecting that of fast‐twitch muscle fibres.
The increase in force occurred within 10 min and was blocked by an inhibitor of the glucocorticoid receptor and a protein (antibody) that binds the receptor.
These findings suggest that these hormones/drugs have rapid/non‐genomic effects in mammalian skeletal muscles; these effects are mediated by a membrane glucocorticoid receptor and are physiologically/pharmacologically beneficial, especially in slow muscles.
Abstract  Glucocorticoids (GCs) are steroid hormones released from the adrenal gland in response to stress. They are also some of the most potent anti‐inflammatory and immunosuppressive drugs currently in clinical use. They exert most of their physiological and pharmacological actions through the classical/genomic pathway. However, they also have rapid/non‐genomic actions whose physiological and pharmacological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the rapid/non‐genomic effects of two widely prescribed glucocorticoids, beclomethasone dipropionate (BDP) and prednisolone acetate (PDNA), on force production in isolated, intact, mouse skeletal muscle fibre bundles. The results show that the effects of both GCs on maximum isometric force (Po) were fibre‐type dependent. Thus, they increased Po in the slow‐twitch fibre bundles without significantly affecting that of the fast‐twitch fibre bundles. The increase in Po occurred within 10 min and was insensitive to the transcriptional inhibitor actinomycin D. Also, it was maximal at ∼250 nm and was blocked by the glucocorticoid receptor (GCR) inhibitor RU486 and a monoclonal anti‐GCR, suggesting that it was mediated by a membrane (m) GCR. Both muscle fibre types expressed a cytosolic GCR. However, a mGCR was present only in the slow‐twitch fibres. The receptor was more abundant in oxidative than in glycolytic fibres and was confined mainly to the periphery of the fibres where it co‐localised with laminin. From these findings we conclude that the rapid/non‐genomic actions of GCs are mediated by a mGCR and that they are physiologically/therapeutically beneficial, especially in slow‐twitch muscle fibres.
The working stroke of the myosin II motor in muscle is not tightly coupled to release of orthophosphate from its active site
Authors: Caremani Marco , Melli Luca , Dolfi Mario , Lombardi Vincenzo , Linari Marco 
Published: July 2013

Key points
Force and shortening in muscle are caused by ATP‐driven working strokes of myosin II motors, during their cyclic interactions with the actin filament in each half‐sarcomere. Crystallographic studies indicate that the working stroke consists in an interdomain movement of the myosin motor associated with the release of inorganic phosphate (Pi).
Here the coupling of the working stroke with the release of Pi is studied in situ using fast half‐sarcomere mechanics on skinned fibres from rabbit psoas.
The isotonic velocity transient following stepwise force reductions superimposed on isometric contraction measures the mechanical manifestation of the working stroke and its rate of regeneration.
The results indicate that the release of Pi from the catalytic site of an actin‐attached myosin motor can occur at any stage of the working stroke, and a myosin motor uses two consecutive actin monomers to maximize the power during shortening.
Abstract  Skeletal muscle shortens faster against a lower load. This force–velocity relationship is the fundamental determinant of muscle performance in vivo and is due to ATP‐driven working strokes of myosin II motors, during their cyclic interactions with the actin filament in each half‐sarcomere. Crystallographic studies suggest that the working stroke is associated with the release of phosphate (Pi) and consists of 70 deg tilting of a light‐chain domain that connects the catalytic domain of the myosin motor to the myosin tail and filament. However, the coupling of the working stroke with Pi release is still an unsolved question. Using nanometre–microsecond mechanics on skinned muscle fibres, we impose stepwise drops in force on an otherwise isometric contraction and record the isotonic velocity transient, to measure the mechanical manifestation of the working stroke of myosin motors and the rate of its regeneration in relation to the half‐sarcomere load and [Pi]. We show that the rate constant of the working stroke is unaffected by [Pi], while the subsequent transition to steady velocity shortening is accelerated. We propose a new chemo‐mechanical model that reproduces the transient and steady state responses by assuming that: (i) the release of Pi from the catalytic site of a myosin motor can occur at any stage of the working stroke, and (ii) a myosin motor, in an intermediate state of the working stroke, can slip to the next actin monomer during filament sliding. This model explains the efficient action of muscle molecular motors working as an ensemble in the half‐sarcomere.
Intrauterine inflammation alters fetal cardiopulmonary and cerebral haemodynamics in sheep
Authors: Galinsky Robert , Hooper Stuart B. , Polglase Graeme R. , Moss Timothy J. M. 
Published: July 2013

Key points
Intrauterine inflammation impairs fetal pulmonary vascular development and increases cerebral metabolism in fetal sheep. Whether these structural and metabolic changes have functional consequences for fetal cardiopulmonary and cerebral haemodynamics is presently unknown.
We demonstrated that intra‐amniotic administration of lipopolysaccharide increased fetal pulmonary vascular resistance, and reduced pulmonary blood flow and carotid arterial oxygen content in the fetus and caused a transient increase in fetal cerebral blood flow. These effects occurred over a time course consistent with previously observed effects on pulmonary vascular development and cerebral metabolism.
Our data suggest that pathophysiological changes in cardiopulmonary and cerebral haemodynamics observed in fetuses exposed to intrauterine inflammation may be present and detectable in human pregnancies, offering potential for detecting fetuses affected by intrauterine inflammation.
Abstract  Intrauterine inflammation impairs fetal pulmonary vascular development and increases cerebral metabolic rate in fetal sheep. We hypothesized that these structural and metabolic effects of intrauterine inflammation would be accompanied by reduced fetal pulmonary blood flow and increased cerebral perfusion. Fetal sheep were instrumented at 112 days of gestation (term is 147 days) for measurement of cardiopulmonary and cerebral haemodynamics. At 118 days ewes were randomly assigned to receive intra‐amniotic lipopolysaccharide (LPS, 20 mg from Escherichia coli; n= 7) or saline (control, 4 ml; n= 6). Fetal haemodynamic data were recorded continually from 1 h before intra‐amniotic LPS or saline, until 144 h after. Fetal arterial blood was sampled before, and periodically after, intra‐amniotic LPS or saline. End‐diastolic and mean pulmonary blood flows were significantly lower than control from 48 and 96 h after LPS exposure, respectively, until the end of the experiment. Carotid blood flow was transiently increased at 96 and 120 h after LPS exposure. Carotid arterial oxygen content was lower than control from 48 h after intra‐amniotic LPS. Fetal arterial lactate concentration was higher than control between 4 and 12 h after intra‐amniotic LPS. Experimental intrauterine inflammation reduces pulmonary blood flow in fetal sheep, over a time course consistent with impaired pulmonary vascular development. Increased carotid blood flow after LPS administration may reflect an inflammation‐induced increase in cerebral metabolic demand.
Contraction‐induced lipolysis is not impaired by inhibition of hormone‐sensitive lipase in skeletal muscle
Authors: Alsted Thomas J. , Ploug Thorkil , Prats Clara , Serup Annette K. , Høeg Louise , Schjerling Peter , Holm Cecilia , Zimmermann Robert , Fledelius Christian , Galbo Henrik , Kiens Bente 
Published: July 2013

Key points
In skeletal muscle hormone‐sensitive lipase (HSL) is considered the only enzyme responsible for breakdown of intramyocellular triacylglycerol (IMTG) during contractions. This notion is based on indirect measures in which important cellular events are not taken into account.
Using two histochemical techniques to measure breakdown of IMTG during contractions in isolated skeletal muscles we found that IMTG was decreased (1) in rat muscles during acute pharmacological blockade of HSL, and (2) in muscles of HSL knockout mice.
We demonstrated that adipose triglyceride lipase (ATGL) and HSL collectively account for at least 98% of the total TG lipase activity in mouse muscle, and other TG lipases accordingly seem of negligible importance for breakdown of IMTG.
In conclusion, breakdown of IMTG occurs in the contracting muscle in the absence of HSL activity. Our data suggest that ATGL is activated during contractions and plays a major role in breakdown of IMTG.
Abstract  In skeletal muscle hormone‐sensitive lipase (HSL) has long been accepted to be the principal enzyme responsible for lipolysis of intramyocellular triacylglycerol (IMTG) during contractions. However, this notion is based on in vitro lipase activity data, which may not reflect the in vivo lipolytic activity. We investigated lipolysis of IMTG in soleus muscles electrically stimulated to contract ex vivo during acute pharmacological inhibition of HSL in rat muscles and in muscles from HSL knockout (HSL‐KO) mice. Measurements of IMTG are complicated by the presence of adipocytes located between the muscle fibres. To circumvent the problem with this contamination we analysed intramyocellular lipid droplet content histochemically. At maximal inhibition of HSL in rat muscles, contraction‐induced breakdown of IMTG was identical to that seen in control muscles (P < 0.001). In response to contractions IMTG staining decreased significantly in both HSL‐KO and WT muscles (P < 0.05). In vitro TG hydrolase activity data revealed that adipose triglyceride lipase (ATGL) and HSL collectively account for ∼98% of the TG hydrolase activity in mouse skeletal muscle, other TG lipases accordingly being of negligible importance for lipolysis of IMTG. The present study is the first to demonstrate that contraction‐induced lipolysis of IMTG occurs in the absence of HSL activity in rat and mouse skeletal muscle. Furthermore, the results suggest that ATGL is activated and plays a major role in lipolysis of IMTG during muscle contractions.
Genetic Characterization and Emergence of the Metallo-β-Lactamase GIM-1 in Pseudomonas spp. and Enterobacteriaceae during a Long-Term Outbreak
Authors: Wendel Andreas F. , Brodner Alexander H. B. , Wydra Stephan , Ressina Sofija , Henrich Birgit , Pfeffer Klaus , Toleman Mark A. , MacKenzie Colin R. 
Published: July 2013

ABSTRACT

Since the first isolation in 2002, the metallo-β-lactamase GIM-1 has not been detected outside Germany. The data presented here, for 50 clinical
bla
GIM-1
-positive isolates, including
Pseudomonas
spp. and
Enterobacteriaceae
(
Enterobacter cloacae
,
Klebsiella oxytoca
,
Serratia marcescens
,
Escherichia coli
, and
Citrobacter freundii
), collected between 2007 and 2012 at the original site in an ongoing outbreak, demonstrate a diverse genetic background and dissemination of the gene conferring resistance to enteric bacteria.
Adjunctive
N
-Acetyl-
l
-Cysteine in Treatment of Murine Pneumococcal Meningitis
Authors: Högen Tobias , Demel Cornelia , Giese Armin , Angele Barbara , Pfister Hans-Walter , Koedel Uwe , Klein Matthias 
Published: July 2013

ABSTRACT

Despite antibiotic therapy, acute and long-term complications are still frequent in pneumococcal meningitis. One important trigger of these complications is oxidative stress, and adjunctive antioxidant treatment with
N
-acetyl-
l
-cysteine was suggested to be protective in experimental pneumococcal meningitis. However, studies of effects on neurological long-term sequelae are limited. Here, we investigated the impact of adjunctive
N
-acetyl-
l
-cysteine on long-term neurological deficits in a mouse model of meningitis. C57BL/6 mice were intracisternally infected with
Streptococcus pneumoniae
. Eighteen hours after infection, mice were treated with a combination of ceftriaxone and placebo or ceftriaxone and
N
-acetyl-
l
-cysteine, respectively. Two weeks after infection, neurologic deficits were assessed using a clinical score, an open field test (explorative activity), a t-maze test (memory function), and auditory brain stem responses (hearing loss). Furthermore, cochlear histomorphological correlates of hearing loss were assessed. Adjunctive
N
-acetyl-
l
-cysteine reduced hearing loss after pneumococcal meningitis, but the effect was minor. There was no significant benefit of adjunctive
N
-acetyl-
l
-cysteine treatment in regard to other long-term complications of pneumococcal meningitis. Cochlear morphological correlates of meningitis-associated hearing loss were not reduced by adjunctive
N
-acetyl-
l
-cysteine. In conclusion, adjunctive therapy with
N
-acetyl-
l
-cysteine at a dosage of 300 mg/kg of body weight intraperitoneally for 4 days reduced hearing loss but not other neurologic deficits after pneumococcal meningitis in mice. These results make a clinical therapeutic benefit of
N
-acetyl-
l
-cysteine in the treatment of patients with pneumococcal meningitis questionable.
Interaction of Silver Nanoparticles with Serum Proteins Affects Their Antimicrobial Activity
In Vivo
Authors: Gnanadhas Divya Prakash , Ben Thomas Midhun , Thomas Rony , Raichur Ashok M. , Chakravortty Dipshikha 
Published: July 2013

ABSTRACT

The emergence of multidrug-resistant bacteria is a global threat for human society. There exist recorded data that silver was used as an antimicrobial agent by the ancient Greeks and Romans during the 8th century. Silver nanoparticles (AgNPs) are of potential interest because of their effective antibacterial and antiviral activities, with minimal cytotoxic effects on the cells. However, very few reports have shown the usage of AgNPs for antibacterial therapy
in vivo
. In this study, we deciphered the importance of the chosen methods for synthesis and capping of AgNPs for their improved activity
in vivo
. The interaction of AgNPs with serum albumin has a significant effect on their antibacterial activity. It was observed that uncapped AgNPs exhibited no antibacterial activity in the presence of serum proteins, due to the interaction with bovine serum albumin (BSA), which was confirmed by UV-Vis spectroscopy. However, capped AgNPs [with citrate or poly(vinylpyrrolidone)] exhibited antibacterial properties due to minimized interactions with serum proteins. The damage in the bacterial membrane was assessed by flow cytometry, which also showed that only capped AgNPs exhibited antibacterial properties, even in the presence of BSA. In order to understand the
in vivo
relevance of the antibacterial activities of different AgNPs, a murine salmonellosis model was used. It was conclusively proved that AgNPs capped with citrate or PVP exhibited significant antibacterial activities
in vivo
against
Salmonella
infection compared to uncapped AgNPs. These results clearly demonstrate the importance of capping agents and the synthesis method for AgNPs in their use as antimicrobial agents for therapeutic purposes.
Improvement of the Pharmacokinetics and
In Vivo
Antibacterial Efficacy of a Novel Type IIa Topoisomerase Inhibitor by Formulation in Liposomes
Authors: Shapiro Adam B. , Newman Joseph , Goteti Kosalaram , Beaudoin Marie-Eve , Harrison Rane , Hopkins Sussie , Agrawal Nikunj , Rivin Olga 
Published: July 2013

ABSTRACT

Several useful properties of liposome-based formulations of various existing antibacterial drugs have been reported. These properties include lower MICs, improved pharmacokinetics, lower toxicity, selective distribution to infected tissues, and enhanced
in vivo
efficacy. Here we report
in vivo
studies of a liposomal formulation of a member of a novel class of antibacterial type II topoisomerase inhibitors, others of which have progressed to early phases of clinical trials. The free (i.e., nonliposomal) compound has broad-spectrum MICs but suboptimal pharmacokinetics in rats and mice, characterized by a high volume of distribution and rapid clearance. The liposomal formulation of the compound had essentially unchanged MICs but greatly reduced volume of distribution and clearance in rats and mice. In an
in vivo
mouse model of
Staphylococcus aureus
infection of one thigh, the liposomal compound localized preferentially to the infected thigh, whereas the free compound showed no preference for the infected versus the uninfected thigh. Most importantly, the liposomal compound had enhanced efficacy at clearing the infection compared with the free compound. Delivery of this class of compounds as liposomal formulations may offer clinical advantages compared with free compounds.
Genomic Characterization of Ciprofloxacin Resistance in a Laboratory-Derived Mutant and a Clinical Isolate of Streptococcus pneumoniae
Authors: Lupien Andréanne , Billal Dewan S. , Fani Fereshteh , Soualhine Hafid , Zhanel George G. , Leprohon Philippe , Ouellette Marc 
Published: July 2013

ABSTRACT

The broad-spectrum fluoroquinolone ciprofloxacin is a bactericidal antibiotic targeting DNA topoisomerase IV and DNA gyrase encoded by the
parC
and
gyrA
genes. Resistance to ciprofloxacin in
Streptococcus pneumoniae
mainly occurs through the acquisition of mutations in the quinolone resistance-determining region (QRDR) of the ParC and GyrA targets. A role in low-level ciprofloxacin resistance has also been attributed to efflux systems. To look into ciprofloxacin resistance at a genome-wide scale and to discover additional mutations implicated in resistance, we performed whole-genome sequencing of an
S. pneumoniae
isolate selected for resistance to ciprofloxacin
in vitro
(128 μg/ml) and of a clinical isolate displaying low-level ciprofloxacin resistance (2 μg/ml). Gene disruption and DNA transformation experiments with PCR fragments harboring the mutations identified in the
in vitro
S. pneumoniae
mutant revealed that resistance is mainly due to QRDR mutations in
parC
and
gyrA
and to the overexpression of the ABC transporters PatA and PatB. In contrast, no QRDR mutations were identified in the genome of the
S. pneumoniae
clinical isolate with low-level resistance to ciprofloxacin. Assays performed in the presence of the efflux pump inhibitor reserpine suggested that resistance is likely mediated by efflux. Interestingly, the genome sequence of this clinical isolate also revealed mutations in the coding region of
patA
and
patB
that we implicated in resistance. Finally, a mutation in the NAD(P)H-dependent glycerol-3-phosphate dehydrogenase identified in the
S. pneumoniae
clinical strain was shown to protect against ciprofloxacin-mediated reactive oxygen species.
Candida tropicalis Antifungal Cross-Resistance Is Related to Different Azole Target (Erg11p) Modifications
Authors: Forastiero A. , Mesa-Arango A. C. , Alastruey-Izquierdo A. , Alcazar-Fuoli L. , Bernal-Martinez L. , Pelaez T. , Lopez J. F. , Grimalt J. O. , Gomez-Lopez A. , Cuesta I. , Zaragoza O. , Mellado E. 
Published: July 2013

ABSTRACT

Candida tropicalis
ranks between third and fourth among
Candida
species most commonly isolated from clinical specimens. Invasive candidiasis and candidemia are treated with amphotericin B or echinocandins as first-line therapy, with extended-spectrum triazoles as acceptable alternatives.
Candida tropicalis
is usually susceptible to all antifungal agents, although several azole drug-resistant clinical isolates are being reported. However,
C. tropicalis
resistant to amphotericin B is uncommon, and only a few strains have reliably demonstrated a high level of resistance to this agent. The resistance mechanisms operating in
C. tropicalis
strains isolated from clinical samples showing resistance to azole drugs alone or with amphotericin B cross-resistance were elucidated. Antifungal drug resistance was related to mutations of the azole target (Erg11p) with or without alterations of the ergosterol biosynthesis pathway. The antifungal drug resistance shown
in vitro
correlated very well with the results obtained
in vivo
using the model host
Galleria mellonella
. Using this panel of strains, the
G. mellonella
model system was validated as a simple, nonmammalian minihost model that can be used to study
in vitro-in vivo
correlation of antifungals in
C. tropicalis
. The development in
C. tropicalis
of antifungal drug resistance with different mechanisms during antifungal treatment has potential clinical impact and deserves specific prospective studies.
Pharmacokinetics and Absorption of Paromomycin and Gentamicin from Topical Creams Used To Treat Cutaneous Leishmaniasis
Authors: Ravis William R. , Llanos-Cuentas Alejandro , Sosa Nestor , Kreishman-Deitrick Mara , Kopydlowski Karen M. , Nielsen Carl , Smith Kirsten S. , Smith Philip L. , Ransom Janet H. , Lin Yuh-Jing , Grogl Max 
Published: July 2013

ABSTRACT

This study evaluated the pharmacokinetics of topical creams containing 15% paromomycin (“paromomycin alone”) and 15% paromomycin plus 0.5% gentamicin (WR 279,396) in patients with cutaneous leishmaniasis. The investigational creams were applied topically to all lesions once daily for 20 days. Plasma samples were analyzed for simultaneous quantitation of paromomycin and gentamicin isomers and total gentamicin. Pharmacokinetic parameters for gentamicin could not be calculated because detectable levels were rarely evident. After one application, the paromomycin area under the concentration-time curve from 0 to 24 h (AUC
0–24
) was 2,180 ± 2,621 ng · h/ml (mean ± standard deviation [SD]) for the paromomycin-alone group and 975.6 ± 1,078 ng · h/ml for the WR 279,396 group. After 20 days of application, the paromomycin AUC
0–24
and maximum concentration of drug (
C
max
) were 5 to 6 times greater than those on day 1 for both treatment groups. For the paromomycin-alone group, the AUC
0–24
was 8,575 ± 7,268 ng · h/ml and the
C
max
was 1,000 ± 750 ng/ml, compared with 6,037 ± 3,956 ng · h/ml and 660 ± 486 ng/ml for the WR 279,396 group, respectively. Possibly due to large intersubject variability, no differences (
P
≥ 0.05) in the AUC
0–24
or
C
max
were noted between treatment or between sites on day 1 or 20. The percentage of dose absorbed on day 20 was 12.0% ± 6.26% and 9.68% ± 6.05% for paromomycin alone and WR 279,396, respectively. Paromomycin concentrations in plasma after 20 days of application were 5 to 9% of those after intramuscular administration of 15 mg/kg of body weight/day to adults for the systemic treatment of visceral leishmaniasis. Effective topical treatment of cutaneous leishmaniasis appears to be possible with limited paromomycin and gentamicin systemic absorption, thus avoiding drug accumulation and toxicity. (The work described here has been registered at
ClinicalTrials.gov
under registration no. NCT01032382 and NCT01083576.)