Meticillin-resistant Staphylococcus aureus colonisation and infection in Thoroughbred racehorses and veterinarians in Japan

Meticillin-resistant Staphylococcus aureus (MRSA) infections have been confirmed in hospitalised Thoroughbred racehorses at the hospitals of two training centres in Japan since 2009. To investigate the source of infection, the authors examined the rate of nasal MRSA colonisation in 600 healthy Thoroughbred racehorses, 53 veterinarians and 16 office staff at the racehorse hospitals of the two training centres. MRSA was not isolated from healthy Thoroughbred racehorses or hospital office staff. However, MRSA was isolated from 16 veterinarians (30.1 per cent), and the colonisation rate was significantly higher in veterinarians than in the office staff of the same hospitals. Also, 10 of the 16 MRSA strains (62.5 per cent) isolated from veterinarians were classified as type II by staphylococcal cassette chromosome mec (SCCmec) typing and ST5 by multilocus sequence typing. Pulsed-field gel electrophoresis analysis demonstrated that these 10 MRSA strains of SCCmec type II and ST5 were genetically identical or very similar to 9 MRSA strains isolated from infected horses hospitalised at these hospitals between 2009 and 2013. These results indicate that SCCmec type II and ST5 MRSA strains were probably transmitted between veterinarians and infected horses.

Zscan4 Is Activated after Telomere Shortening in Mouse Embryonic Stem Cells

ZSCAN4 is a DNA-binding protein that functions for telomere elongation and genomic stability. In vivo, it is specifically expressed at the two-cell stage during mouse development. In vitro, it is transiently expressed in mouse embryonic stem cells (ESCs), only in 5% of the population at one time. Here we attempted to elucidate when, under what circumstances, Zscan4 is activated in ESCs. Using live cell imaging, we monitored the activity of Zscan4 together with the pluripotency marker Rex1. The lengths of the cell cycles in ESCs were diverse. Longer cell cycles were accompanied by shorter telomeres and higher activation of Zscan4. Since activation of Zscan4 is involved in telomere elongation, we speculate that the extended cell cycles accompanied by Zscan4 activation reflect the time for telomere recovery. Rex1 and Zscan4 did not show any correlation. Taken together, we propose that Zscan4 is activated to recover shortened telomeres during extended cell cycles, irrespective of the pluripotent status.

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At longer cell cycles, telomeres are shorter

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Zscan4 is activated when the cell cycles become long

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After the activation of Zscan4, the next cell cycle becomes short

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We propose Zscan4 is activated for telomere maintenance irrespective of pluripotency

A Stepping Stone to Pluripotency

Somatic cells can be reprogrammed into pluripotent stem cells via either expression of transcription factors or addition of small molecule chemicals only. Zhao et al. reveal a unique intermediate state during chemical reprogramming allowing a significant improvement in its efficiency and kinetics.

Sox7 is dispensable for primitive endoderm differentiation from mouse ES cells

Background

Primitive endoderm is a cell lineage segregated from the epiblast in the blastocyst and gives rise to parietal and visceral endoderm. Sox7 is a member of the SoxF gene family that is specifically expressed in primitive endoderm in the late blastocyst, although its function in this cell lineage remains unclear.

Results

Here we characterize the function of Sox7 in primitive endoderm differentiation using mouse embryonic stem (ES) cells as a model system. We show that ectopic expression of Sox7 in ES cells has a marginal effect on triggering differentiation into primitive endoderm-like cells. We also show that targeted disruption of Sox7 in ES cells does not affect differentiation into primitive endoderm cells in embryoid body formation as well as by forced expression of Gata6.

Conclusions

These data indicate that Sox7 function is supplementary and not essential for this differentiation from ES cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12861-015-0079-4) contains supplementary material, which is available to authorized users.

LIF signal in mouse embryonic stem cells

Since the establishment of mouse embryonic stem cells (mESCs) in the 1980s, a number of important notions on the self-renewal of pluripotent stem cells in vitro have been found. In serum containing conventional culture, an exogenous cytokine, leukemia inhibitory factor (LIF), is absolutely essential for the maintenance of pluripotency. In contrast, in serum-free culture with simultaneous inhibition of Map-kinase and Gsk3 (so called 2i-culture), LIF is no longer required. However, recent findings also suggest that LIF may have a role not covered by the 2i for the maintenance of naïve pluripotency. These suggest that LIF functions for the maintenance of naïve pluripotency in a context dependent manner. We summarize how LIF-signal pathway is converged to maintain the naïve state of pluripotency.

Haemostatic management for oral surgery in patients supported with left ventricular assist device--a preliminary retrospective study

We investigated haemostatic management, frequency of postoperative bleeding, and prognosis of patients who had left ventricular assist devices, and who were having oral surgical procedures between April 2002 and March 2014, to identify risk factors for bleeding and find out which were the best methods of haemostasis. Medical records were examined retrospectively and we recorded details of the patients, and frequency of bleeding together with factors associated with it. Twenty-nine patients had 39 oral operations, and there were 17 bleeds (44%). The first procedure for each patient was used for statistical calculations. Duration of bleeding tended to be longer for patients with implantable devices (median (interquartile range, IQR) 12.0 (3-18) days) than for those with extracorporeal devices (median (IQR) 3.0 (1-4) days; p=0.079). There was a significantly greater difference in prothrombin time-international normalised ratio (PT-INR) before and after operation in patients who bled, whose median (range) was 0.85 (0.2-1.81), than in those who did not (median (IQR) 0.16 (-0.09-0.31) (p=0.015). There were moderate correlations with postoperative bleeding were seen for the difference between preoperative and postoperative PT-INR (r=0.479, p=0.012) and PT-INR value when bleeding (r=0.407, p=0.035). In conclusion, postoperative bleeding occurred after oral operations in 17/29 patients with left ventricular assist devices by a median (IQR) of 0.85 (0.2-1.81) of the preoperative value.

Electron-Phonon Coupling in the Bulk of Anatase TiO2 Measured by Resonant Inelastic X-Ray Spectroscopy

We investigate the polaronic ground state of anatase TiO2 by bulk-sensitive resonant inelastic x-ray spectroscopy (RIXS) at the Ti L3 edge. We find that the formation of the polaron cloud involves a single 95 meV phonon along the c axis, in addition to the 108 meV ab-plane mode previously identified by photoemission. The coupling strength to both modes is the same within error bars, and it is unaffected by the carrier density. These data establish RIXS as a directional bulk-sensitive probe of electron-phonon coupling in solids.

Selective elimination of isolectin B4-binding trigeminal neurons enhanced formalin-induced nocifensive behavior in the upper lip of rats and c-Fos expression in the trigeminal subnucleus caudalis

The functional significance of non-peptidergic C-fibers in orofacial pain processing is largely unknown. The present study examined the effects of the selective elimination of isolectin B4 (IB4)-binding (IB4(+)) neurons on formalin-induced face rubbing behavior (FRB) in the upper lip of rats and c-Fos-immunoreactive (c-Fos-IR) cells in the trigeminal subnucleus caudalis (Vc). IB4 conjugated to neurotoxin, saporin (IB4-Sap), blank-saporin (Bl-Sap), or saline (Sal) was injected into the cisterna magna. IB4-Sap treatments significantly decreased IB4(+) terminals in lamina II of Vc and IB4(+) trigeminal ganglia neurons, whereas Sal- and BI-Sap treatments did not. The number of formalin-induced FRB 15-30 min after the formalin injection was significantly higher in IB4-Sap-treated rats than in Sal- or Bl-Sap-treated rats, and was associated with an increase in c-Fos-IR cells. The systemic preadministration of the GABAA antagonist, bicuculline, and agonist, muscimol, had stronger decreasing effects on FRB and c-Fos-IR cells in IB4-Sap-treated rats than the preadministration of Sal, whereas the opposite effects were observed in Sal- and Bl-Sap-treated rats. These results indicate that IB4(+) neurons in the trigeminal nerve play antinociceptive regulatory roles in formalin-induced orofacial pain processing and that GABAA receptor functions at segmental and supratrigeminal sites have complex modulatory influences on antinociceptive roles.

Appropriate sevoflurane concentration to stabilize autonomic activity during intubation with rocuronium in infants: a randomized controlled trial

Background

In infants, sevoflurane is commonly used for induction of anesthesia, following which a muscle relaxant is administered to facilitate tracheal intubation. When rocuronium is used as the muscle relaxant, intubation may be performed before reaching an adequate depth of anesthesia because of its rapid onset. The purpose of this study was to investigate the optimal sevoflurane concentration that would minimize the impact of intubation on hemodynamics and autonomic nervous system (ANS) activity in infants.

Methods

Sixty-one infants aged 1–6 months, undergoing cleft lip repair, were enrolled. Patients were randomly assigned to three end-tidal sevoflurane concentration (E’_Sevo) groups, 3%, 4% and 5%. Anesthesia was induced with 5% sevoflurane with 100% oxygen, and rocuronium (0.6 mg/kg) was administered. The concentration of sevoflurane was adjusted to the predetermined concentration in each group. Mechanical pressure control ventilation via a face mask was commenced. Five minutes after E’_Sevo became stable at the predetermined concentration, tracheal intubation was performed. Immediately after tracheal intubation, ventilation was restarted at the same ventilator settings and continued for 150 seconds. Heart rate (HR) and mean arterial pressure (MAP) were measured 5 times in the 150 seconds after intubation. Normalized units (nu) of high frequency (HF: 0.04-0.15 Hz) and the ratio of low frequency (LF: 0.15-0.4 Hz) to HF components (LF/HF) of HR variability were calculated by MemCalc/Tonam2C™. Normalized units of HF (HFnu) and LF/HF reflect cardiac parasympathetic and sympathetic activity, respectively.

Results

After intubation, HR increased slightly in all groups and MAP increased by 9.2% in the E’_Sevo-3% group. LF/HF increased (p < 0.01) and HFnu decreased (p < 0.01) in all groups 30 seconds after intubation. HFnu was lower (p < 0.001) and LF/HF was higher (p = 0.007) in the E’_Sevo-3% group than in E’_Sevo-5% group. ANS responses to intubation were reduced in a dose-dependent manner.

Conclusions

Sympathomimetic and parasympatholytic responses to intubation in the E’_Sevo-3% group were much greater than those in the E’_Sevo-5% group. During tracheal intubation in infants, 4% or 5% sevoflurane is appropriate for prevention of sympathetic hyperactivation and maintenance of ANS balance as compared to 3% sevoflurane, when a muscle relaxant is co-administered.

Trial registration

The study was registered at UMIN-CTR (UMIN000009933).

Epiblast and primitive endoderm differentiation: fragile specification ensures stable commitment

Specification of the epiblast and primitive endoderm is one of the earliest differentiation steps during embryogenesis. In vitro tracking of pluripotency markers in ESCs suggests that epiblast specification may be plastic; however, live imaging of blastocysts, as detailed in a recent paper from Xenopoulos et al (2015), showed that, unlike in ESCs, fate commitment in vivo is largely irreversible.

Effectiveness of dexmedetomidine for emergence agitation in infants undergoing palatoplasty: a randomized controlled trial

OBJECTIVES

In infants, there is a high incidence of emergence agitation (EA) after sevoflurane (Sev) anesthesia. This study aimed to test the hypothesis that dexmedetomidine (Dex) administration would reduce the incidence and severity of EA after Sev-based anesthesia in infants undergoing palatoplasty.

METHODS

A prospective randomized clinical trial was conducted with 70 patients undergoing palatoplasty, aged 10-14 months. Infants were randomly allocated into two groups: Dex (n=35) and saline (n=35). In the Dex group, Dex (6 μg/kg/h) was administered approximately 10 min before the end of the surgery for 10 min, followed by 0.4 μg/kg/h until 5 min after extubation. In the saline group, an equivalent amount of saline was administered in a similar manner. After the surgery, patients were transferred to the postanesthetic care unit (PACU). The infant's behavior and pain were assessed with scoring system for EA (5-point rating scale) and pain scale (PS; 10-point rating scale), respectively. EA and PS were estimated at six time points (after extubation, leaving the operating room, 0, 30, 60, and 120 min after arrival in PACU).

RESULTS

EA and PS scores were significantly lower in the Dex group than in the saline group from extubation to 120 min after arrival in PACU.

CONCLUSIONS

Dex administration has the advantage of a reduced EA and PS without any adverse effects. Dex provided satisfactory recovery in infants undergoing palatoplasty.

Nr0b1 is a negative regulator of Zscan4c in mouse embryonic stem cells

Nuclear receptor subfamily 0, group B, member 1 (Nr0b1, also known as Dax1) is regarded as an important component of the transcription factor network that governs pluripotency in mouse embryonic stem (ES) cells. Here we generated inducible knockout ES cells for Nr0b1 using the Cre-loxP system and analyzed its precise function. We succeeded in establishing the Nr0b1-null ES cells and confirmed their pluripotency by showing their contribution to chimeric embryos. However, they proliferated slowly with over-expression of 2-cell stage specific transcripts including Zscan4c, which is known to be involved in telomere elongation in ES cells. We revealed that over-expression of Zscan4c prevents normal self-renewal by inducing arrest at G2 phase followed by cell death and that Nr0b1 directly represses the Zscan4c promoter. These data indicated that Nr0b1 is not essential to maintain pluripotency but is involved in the proper activation of 2-cell specific transcripts for self-renewal.

Neural mechanism underlying hyperalgesic response to orofacial pain in Parkinson's disease model rats

To investigate the neural mechanism of pain originating from the orofacial region in PD patients, we used PD model rats produced by unilateral injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. We investigated effects of nigrostriatal lesions on the behavioral response (face rubbing) to formalin injection into the upper lip. We also examined expression of c-Fos and phosphorylated extracellular signal-regulated kinase (pERK) in the trigeminal spinal subnucleus caudalis (Vc) and expression of c-Fos in the periaqueductal gray matter (PAG). Face rubbings following formalin injection showed a biphasic profile, with the first phase for the first 5 min and the second phase from 10 to 90 min. Rats with 6-OHDA lesions showed increased face rubbings in the second phase when formalin was injected ipsilaterally to the lesion, and c-Fos expression in the Vc increased. When formalin was injected contralaterally, face rubbings were reduced in the first phase, however, expression levels of c-Fos and pERK in the Vc were unchanged. No significant difference was found in c-Fos expression in the PAG between 6-OHDA- and saline-injected rats. These results suggest that unilateral dopamine depletion in the nigrostriatal pathway may be involved in hypersensitivity to noxious stimulation delivered to the orofacial region.

The differential activation of intracellular signaling pathways confers the permissiveness of embryonic stem cell derivation from different mouse strains

The requirement of leukemia inhibitory factor (LIF) for the establishment and maintenance of mouse embryonic stem cells (ESCs) depends on the genetic background of the ESC origin. To reveal the molecular basis of the strain-dependent function of LIF, we compared the activation of the intracellular signaling pathways downstream of LIF in ESCs with different genetic backgrounds. We found that the JAK-Stat3 pathway was dominantly activated in ESCs derived from 'permissive' mouse strains (129Sv and C57BL6), whereas the MAP kinase pathway was hyperactivated in ESCs from 'non-permissive' strains (NOD, CBA and FVB). Artificial activation of Stat3 supported stable self-renewal of ESCs from non-permissive strains. These data suggest that the difference in the balance between the two intracellular signaling pathways underlies the differential response to LIF.

Arteriosclerosis can predict hypotension during anesthesia induction in patients 40 years and older

STUDY OBJECTIVES

To identify the factors that predict blood pressure (BP) changes during induction of general anesthesia, and the relationship between the level of arteriosclerosis and BP changes during anesthesia induction.

DESIGN

Prospective, case-control observational study.

SETTINGS

Operating room of a university hospital.

PATIENTS

Seventy-two patients who received general anesthesia for oral and maxillofacial surgery.

MEASUREMENTS

Brachial-ankle pulse wave velocity (baPWV) and central BP were measured. The primary variable was the parameters affecting BP changes during the induction of general anesthesia. For additional analyses, the parameters were compared between high and low PWV groups (1606 cm/s was the cutoff value of baPWV). To measure the relationships between the parameters and BP changes, bivariate and multiple linear regression analyses were performed.

RESULTS

Seventy-two patients (including 41 men) with a mean age of 61.7 years and a median baPWV value of 1606 cm/s were evaluated. Significantly higher values for age, central BP, preoperative systolic BP (SBP), amount of decrease in SBP and diastolic BP, and number of patients with diabetes mellitus (DM) and hypertension were observed in the high PWV group. Multiple linear regression analysis demonstrated that age, baPWV, and DM were factors independently associated with the amount of decrease in SBP.

CONCLUSION

In patients 40 years and older, age, baPWV, and DM are thought to be effective predictors of the amount of decrease in SBP during induction of general anesthesia.

Considerations during intravenous sedation in geriatric dental patients with dementia

OBJECTIVES

We retrospectively assessed the usability and precautions required during intravenous sedation (IVS) for dental treatment in geriatric outpatients with dementia.

MATERIALS AND METHODS

We investigated the intraoperative complications in 65 cases (25 geriatric dental patients with dementia) under IVS, from the standpoint of local anesthesia usage, water usage during treatment, and content of treatment.

RESULTS

Circulatory complications occurred in 46.2 % and respiratory complications in 52.3 % of all cases (n = 65). Bradycardia occurred in 13.8 % and hypotension in 12.3 % of cases in the former, while coughing spells occurred in 41.5 % and snoring in 16.9 % of cases in the latter. Many of the local anesthesia usage cases did not require water usage, such as during tooth extraction (p < 0.0001). Water usage cases, such as for caries treatment, needed longer sedation and treatment times, resulting in more propofol usage (p < 0.001, p < 0.0001, and p < 0.01, respectively). Many coughing spells developed in the water usage cases (p < 0.05). 81.8 % of snoring and 63.3 % of circulatory complications, such as hypotension and bradycardia, developed in the tooth extraction cases (p < 0.05).

CONCLUSIONS

All the scheduled dental treatments in dementia patients were smoothly performed under IVS. However, stringent attention should be paid to the prevention of aspiration of fluids retained in the pharynx, airway obstruction due to therapeutic maneuvers, respiratory inhibition by sedatives, and hemodynamic fluctuations caused by invasive procedures under local anesthesia.

CLINICAL RELEVANCE

In the future, with the growing need for dental procedures in dementia patients, dentists will require training in the general management of such patients.

A prospective, randomized controlled trial of conscious sedation using propofol combined with inhaled nitrous oxide for dental treatment

PURPOSE

Adverse reactions during propofol sedation include a decrease in arterial blood pressure, propofol-induced pain on injection, and airway complications. The purpose of this study was to investigate whether combined use of intravenous propofol and inhaled nitrous oxide could decrease the hypotensive and other adverse effects of propofol.

PATIENTS AND METHODS

We designed and implemented a prospective, randomized controlled trial. Patients undergoing dental procedures requiring intravenous sedation were randomly allocated to 2 groups: group P comprised those receiving sedation with propofol alone, and group N+P comprised those receiving sedation with 40% nitrous oxide inhalation and propofol. During the dental procedures, the sedation level was maintained at an Observer's Assessment of Alertness/Sedation scale score of 4 by adjusting propofol's target plasma concentration. Nitrous oxide inhalation was the predictor variable, whereas the hemodynamic changes, amount and concentration of propofol, and adverse events were the outcome variables.

RESULTS

Eighty-eight patients were successfully analyzed without any complications. The total amount of propofol was significantly less in group N+P (249.8 ± 121.7 mg) than in group P (310.3 ± 122.4 mg) (P = .022), and the mean concentration of propofol was significantly less in group N+P (1.81 ± 0.34 μg/mL) than in group P (2.05 ± 0.44 μg/mL) (P = .006). The mean blood pressure reduction in group N+P (11.0 ± 8.0 mm Hg) was significantly smaller than that in group P (15.8 ± 10.2 mm Hg) (P = .034). Pain associated with the propofol injection and memory of the procedure were less in group N+P (P = .011 and P = .048, respectively). Nitrous oxide did not affect respiratory conditions or recovery characteristics.

CONCLUSIONS

The results of this study suggest that nitrous oxide inhalation combined with propofol sedation attenuates the hypotensive effect and pain associated with propofol injections, along with potentiating the amnesic effect.

Small molecule-directed specification of sclerotome-like chondroprogenitors and induction of a somitic chondrogenesis program from embryonic stem cells

Pluripotent embryonic stem cells (ESCs) generate rostral paraxial mesoderm-like progeny in 5-6 days of differentiation induced by Wnt3a and Noggin (Nog). We report that canonical Wnt signaling introduced either by forced expression of activated β-catenin, or the small-molecule inhibitor of Gsk3, CHIR99021, satisfied the need for Wnt3a signaling, and that the small-molecule inhibitor of BMP type I receptors, LDN193189, was able to replace Nog. Mesodermal progeny generated using such small molecules were chondrogenic in vitro, and expressed trunk paraxial mesoderm markers such as Tcf15 and Meox1, and somite markers such as Uncx, but failed to express sclerotome markers such as Pax1. Induction of the osteochondrogenically committed sclerotome from somite requires sonic hedgehog and Nog. Consistently, Pax1 and Bapx1 expression was induced when the isolated paraxial mesodermal progeny were treated with SAG1 (a hedgehog receptor agonist) and LDN193189, then Sox9 expression was induced, leading to cartilaginous nodules and particles in the presence of BMP, indicative of chondrogenesis via sclerotome specification. By contrast, treatment with TGFβ also supported chondrogenesis and stimulated Sox9 expression, but failed to induce the expression of Pax1 and Bapx1. On ectopic transplantation to immunocompromised mice, the cartilage particles developed under either condition became similarly mineralized and formed pieces of bone with marrow. Thus, the use of small molecules led to the effective generation from ESCs of paraxial mesodermal progeny, and to their further differentiation in vitro through sclerotome specification into growth plate-like chondrocytes, a mechanism resembling in vivo somitic chondrogenesis that is not recapitulated with TGFβ.

The POU-er of gene nomenclature

The pluripotency factor POU5F1 (OCT4) is well known as a key regulator of stem cell fate. Homologues of POU5F1 exist throughout vertebrates, but the evolutionary and functional relationships between the various family members have been unclear. The level to which function has been conserved within this family provides insight into the evolution of early embryonic potency. Here, we seek to clarify the relationship between POU5F1 homologues in the vertebrate lineage, both phylogenetically and functionally. We resolve the confusion over the identity of the zebrafish gene, which was originally named pou2, then changed to pou5f1 and again, more recently, to pou5f3. We argue that the use of correct nomenclature is crucial when discussing the degree to which the networks regulating early embryonic differentiation are conserved.