Leptospiral lipopolysaccharide dampens inflammation through upregulation of autophagy adaptor p62 and NRF2 signaling in macrophages

Leptospira interrogans are pathogenic bacteria responsible for leptospirosis, a worldwide zoonosis. All vertebrates can be infected, and some species like humans are susceptible to the disease whereas rodents such as mice are resistant and become asymptomatic renal carriers. Leptospires are stealth bacteria that are known to escape several immune recognition pathways and resist killing mechanisms. We recently published that leptospires may survive intracellularly in and exit macrophages, avoiding xenophagy, a pathogen-targeting form of autophagy. Interestingly, the latter is one of the antimicrobial mechanisms often highjacked by bacteria to evade the host immune response. In this study we explored whether leptospires subvert the key molecular players of autophagy to facilitate infection. We showed in macrophages that leptospires triggered a specific accumulation of autophagy-adaptor p62 in puncta-like structures, without altering autophagic flux. We demonstrated that Leptospira-induced p62 accumulation is a passive mechanism depending on the leptospiral virulence factor LPS signaling via TLR4/TLR2. p62 is a central pleiotropic protein, also mediating cell stress and death, via the translocation of transcription factors. We demonstrated that Leptospira-driven accumulation of p62 induced the translocation of transcription factor NRF2, a key player in the anti-oxidant response. However, NRF2 translocation upon Leptospira infection did not result as expected in antioxydant response, but dampened the production of inflammatory mediators such as iNOS/NO, TNF and IL6. Overall, these findings highlight a novel passive bacterial mechanism linked to LPS and p62/NRF2 signaling that decreases inflammation and contributes to the stealthiness of leptospires.

Leptospira interrogans Prevents Macrophage Cell Death and Pyroptotic IL-1β Release through Its Atypical Lipopolysaccharide

Leptospira interrogans are bacteria that can infect all vertebrates and are responsible for leptospirosis, a neglected zoonosis. Some hosts, such as humans, are susceptible to the disease, whereas mice are resistant and get chronically colonized. Although leptospires escape recognition by some immune receptors, they activate the NOD-like receptor pyrin 3-inflammasome and trigger IL-1β secretion. Classically, IL-1β secretion is associated with lytic inflammatory cell death called pyroptosis, resulting from cytosolic LPS binding to inflammatory caspases, such as caspase 11. Interestingly, we showed that L. interrogans and Leptospira biflexa do not trigger cell death in either murine, human, hamster, or bovine macrophages, escaping both pyroptosis and apoptosis. We showed, in murine cells, that the mild IL-1β secretion induced by leptospires occurred through nonlytic caspase 8-dependent gasdermin D pore formation and not through activation of caspase 11/noncanonical inflammasome. Strikingly, we demonstrated a potent antagonistic effect of pathogenic L. interrogans and their atypical LPS on spontaneous and Escherichia coli LPS-induced cell death. Indeed, LPS of L. interrogans efficiently prevents caspase 11 dimerization and subsequent massive gasdermin D cleavage. Finally, we showed that pyroptosis escape by leptospires prevents massive IL-1β release, and we consistently found no major role of IL-1R in controlling experimental leptospirosis in vivo. Overall, to our knowledge, our findings described a novel mechanism by which leptospires dampen inflammation, thus potentially contributing to their stealthiness.

Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication

Leptospira interrogans are pathogenic bacteria responsible for leptospirosis, a zoonosis impacting 1 million people per year worldwide. Leptospires can infect all vertebrates, but not all hosts develop similar symptoms. Human and cattle may suffer from mild to acute illnesses and are therefore considered as sensitive to leptospirosis. In contrast, mice and rats remain asymptomatic upon infection, although they get chronically colonized in their kidneys. Upon infection, leptospires are stealth pathogens that partially escape the recognition by the host innate immune system. Although leptospires are mainly extracellular bacteria, it was suggested that they could also replicate within macrophages. However, contradictory data in the current literature led us to reevaluate these findings. Using a gentamicin–protection assay coupled to high-content (HC) microscopy, we observed that leptospires were internalized in vivo upon peritoneal infection of C57BL/6J mice. Additionally, three different serotypes of pathogenic L. interrogans and the saprophytic L. biflexa actively infected both human (PMA differentiated) THP1 and mouse RAW264.7 macrophage cell lines. Next, we assessed the intracellular fate of leptospires using bioluminescent strains, and we observed a drastic reduction in the leptospiral intracellular load between 3 h and 6 h post-infection, suggesting that leptospires do not replicate within these cells. Surprisingly, the classical macrophage microbicidal mechanisms (phagocytosis, autophagy, TLR–mediated ROS, and RNS production) were not responsible for the observed decrease. Finally, we demonstrated that the reduction in the intracellular load was associated with an increase of the bacteria in the supernatant, suggesting that leptospires exit both human and murine macrophages. Overall, our study reevaluated the intracellular fate of leptospires and favors an active entrance followed by a rapid exit, suggesting that leptospires do not have an intracellular lifestyle in macrophages.

Secretory Phospholipase A2 Digital Expression Analysis in Colon Adenocarcinoma

BACKGROUND/AIM

Phospholipases A2 represent a family of enzymes that regulate the metabolism of phospholipids by hydrolyzing them into fatty acids. Secretory phospholipase A2 (SPLA2) catalyzes the calcium-dependent 2-acyl groups hydrolysis to produce 3-sn-phosphoglycerides. This study aimed to investigate SPLA2 expression in colon adenocarcinoma (CA).

MATERIALS AND METHODS

Thirty (n=30) formalin-fixed, paraffin-embedded primary CA tissue sections were used and analyzed. Immunohistochemistry was performed using an anti-SPLA2 antibody. Digital image analysis was also implemented for evaluating objectively the corresponding protein expression levels.

RESULTS

Increased SPLA2 protein expression (high & moderate immunostaining levels) was observed in 23/30 (76.6%) cases, whereas 7/30 (23.4%) CA tissues demonstrated low protein levels. High expression levels were detected in 9/30 (30%) cases. SPLA2 overall expression was strongly associated with tumor diameter (p=0.004), whereas other statistically significant associations were not observed (stage: p=0.971, inflammatory infiltration: p=0.795; carcinoma location: p=0.340; differentiation grade: p=0.748; sex: p=0.369; ulceration: p=0.433).

CONCLUSION

SPLA2 over-expression is observed in significant subsets of CAs correlating with advanced tumor growth progression (increased diameter). SPLA2 seems to influence endogenous cell responses by its crucial enzymatic activity and can potentially be a biomarker for monitoring CA patients.

Impact of peroxiredoxin-6 expression on colon adenocarcinoma

PURPOSE

Peroxiredoxins (Prdxs) represent a family of proteins that act as antioxidant enzymes and are involved in a variety of metabolic functions including mainly the intracellular hydrogen peroxide (H2O2) levels reduction. Especially, Prdx-6 protein encoded by the PRDX6 gene (1q25.1) regulates also phospholipid modifications and induces response to oxidative stress and injuries. Our aim was to investigate the expression of Prdx-6 in colon adenocarcinoma (CA).

METHODS

A series of 30 formalin-fixed, paraffin-embedded primary CAs tissue sections were used and analyzed. Immunohistochemistry was performed using an anti-Prdx-6 antibody. Digital image analysis was also implemented for evaluating objectively the protein expression levels on the corresponding stained cells.

RESULTS

Prdx-6 protein overexpression (increased immunostaining levels) was observed in 12/30 (40%) cases, whereas 18/30 (60%) CA tissues demonstrated low to moderate protein levels, respectively. Prdx-6 overall expression was strongly associated with the stage of the examined tumors (p=0.011), whereas other statistical significances were not assessed (inflammatory infiltration: p=0.364; carcinoma location: p=0.93; differentiation grade: p=0.517; tumor diameter: p=0.983; ulceration: p=0.622).

CONCLUSIONS

Prdx-6 overexpression is observed in a significant subset of CAs correlating with aggressive biological behavior (advanced stage). Prdx-6 is a crucial enzyme for oxidative stress/injury endogenous cell response and should be an interesting agent as a biomarker and potential therapeutic target.

Phospholipases A2 as biomarkers in ARDS

Acute respiratory distress syndrome (ARDS) is a multifactorial life-threatening lung injury, characterized by diffuse lung inflammation and increased alveolocapillary barrier permeability. The different stages of ARDS have distinctive biochemical and clinical profiles. Despite the progress of our understanding on ARDS pathobiology, the mechanisms underlying its pathogenesis are still obscure. Herein, we review the existing literature about the implications of phospholipases 2 (PLA2s), a large family of enzymes that catalyze the hydrolysis of fatty acids at the sn-2 position of glycerophospholipids, in ARDS-related pathology. We emphasize on the versatile way of participation of different PLA2s isoforms in the distinct ARDS subgroup phenotypes by either potentiating lung inflammation and damage or by preserving the normal lung. Current research supports that PLA2s are associated with the progression and the outcome of ARDS. We herein discuss the transcellular communication of PLA2s through secreted extracellular vesicles and suggest it as a new mechanism of PLA2s involvement in ARDS. Thus, the elucidation of the spatiotemporal features of PLA2s expression may give new insights and provide valuable information about the risk of an individual to develop ARDS or advance to more severe stages, and potentially identify PLA2 isoforms as biomarkers and target for pharmacological intervention.

Secretory Phospholipase A2-IIA Protein and mRNA Pools in Extracellular Vesicles of Bronchoalveolar Lavage Fluid from Patients with Early Acute Respiratory Distress Syndrome: A New Perception in the Dissemination of Inflammation?

Secretory phospholipase-IIA A₂ (sPLA₂-IIA) is expressed in a variety of cell types under inflammatory conditions. Its presence in the bronchoalveolar lavage (BAL) fluid of patients with acute respiratory distress syndrome (ARDS) is associated with the severity of the injury. Exosomal type extracellular vesicles, (EVs), are recognized to perform intercellular communication. They may alter the immune status of recipient target cells through cargo shuttling. In this work, we characterized the exosomal type EVs isolated from BAL fluid of patients with early and late ARDS as compared to control/non-ARDS patients, through morphological (confocal and electron microscopy) and biochemical (dynamic light scattering, qRT-PCR, immunoblotting) approaches. We provide evidence for the presence of an sPLA₂-IIA-carrying EV pool that coprecipitates with exosomes in the BAL fluid of patients with ARDS. PLA2G2A mRNA was present in all the samples, although more prominently expressed in early ARDS. However, the protein was found only in EVs from early phase ARDS. Under both forms, sPLA₂-IIA might be involved in inflammatory responses of recipient lung cells during ARDS. The perception of the association of sPLA₂-IIA to the early diagnosis of ARDS or even with a mechanism of development and propagation of lung inflammation can help in the adoption of appropriate and innovative therapeutic strategies.

Colonization and Infection With Extensively Drug Resistant Gram-Negative Bacteria in Liver Transplant Recipients

BACKGROUND

Infections due to extensively drug resistant Gram-negative bacteria (GNB) after solid organ transplantation are increasing in prevalence and are associated with high morbidity and mortality. Surveillance culture (SC) seems to be an important tool for extensively drug resistant GNB control. The aim of this study was to evaluate colonization rates and subsequent infections by XDR-GNB in liver transplant recipients.

MATERIAL AND METHODS

This was a prospective cohort study in patients who underwent liver transplantation (LT) between January 2016 and January 2018. Data on demographics, extensively drug resistant colonization, and 3-month clinical outcomes were obtained. Colonization was defined as a positive surveillance culture (SC-perirectal) immediately before transplantation, once weekly after LT, and after intensive care unit discharge, with emphasis to carbapenem-resistant Gram-negative bacteria (CR-GNB).

RESULTS

Forty-four patients who underwent LT were included in the study. Ten patients (22.72%) were colonized with CR-GNB prior to transplantation, and 7/10 (70%) developed infection due to the same pathogen (5 patients bloodstream infections, 2 patients pneumonia) during the study period. Intensive care unit length of stay was significantly longer in colonized with CR-GNB patients (P < .05). Mortality rate was higher in colonized patients (30%) than in noncolonized (11.76%) (P = .2).

CONCLUSION

Our study results suggest an overall 70% risk of CR-GNB infection among colonized patients. Given the high mortality rate and the difficulty in treating these infections, further research to investigate and develop strategies to eliminate the colonization is needed.

Perioperative Chemoprophylaxis οr Treatment for Extensively Drug Resistant Gram-Negative Bacteria in Patients Undergoing Liver Transplantation Based on Preoperative Donor/Recipient Surveillance Cultures: A Prospective Study

INTRODUCTION

The importance of preoperative donor/recipient colonization or donor infection by extensively drug-resistant Gram-negative bacteria (XDR-GNB) and its relation to serious post-transplantation infection pathogenicity in liver transplantation (LT) patients has not been clarified.

AIM

Prevention of postoperative infection due to XDR-GNB with the appropriate perioperative chemoprophylaxis or treatment based on preoperative donor/recipient surveillance cultures in LT patients, as well as their outcome.

MATERIALS AND METHOD

Twenty-six patients (20 male, 6 female) were studied (average preoperative Model for End-Stage Liver Disease score ≈15, range: 8-29) from January 2017 to January 2018. In all patients, blood, urine, and bronchial secretions culture samples as well as a rectal colonization culture were taken pre- and postoperatively, once weekly after LT, and after intensive care unit discharge. Recipients with positive XDR-GNB colonization and patients receiving a transplant from a donor with an XDR-GNB positive culture or colonization received the appropriate chemoprophylaxis one half hour preoperatively according to culture results. De-escalation of the antibiotic regimen was done in 2 to 5 days based on the colonization/culture results of the donor and recipient and their clinical condition. Evaluation for serious infection was done at 1 week and at 28 days for outcome results.

RESULTS

Fourteen out of 26 recipients (53.8%) were positive for XDR-GNB colonization preoperative, with 2/14 (14.28%) presenting serious infection due to the same pathogen. Intensive care unit length of stay was significantly longer in colonized with XDR-GNB patients (P < .0001). The outcome of colonized patients was 6/14 (42.8%) expired, but only in 2/14 (14.2%) was mortality attributable to infection.

CONCLUSION

Administering appropriate perioperative chemoprophylaxis and treatment may limit the frequency of XDR-GNB infections and intensive care unit length of stay and may improve the outcome in LT recipients.

The involvement of phosphorylation of myosin phosphatase targeting subunit 1 (MYPT1) and MYPT1 isoform expression in NO/cGMP mediated differential vasoregulation of cerebral arteries compared to systemic arteries

AIM

Constitutive release of NO blunts intrinsic and stimulated contractile activity in cerebral arteries (CA). Here, we explored whether phosphorylation and expression levels of the PKG-sensitive, leucine zipper positive (LZ⁺ ) splice variants of the regulatory subunit of myosin phosphatase (MYPT1) are involved and whether its expression is associated with higher cGMP sensitivity.

METHODS

Vascular contractility was investigated by wire myography. Phosphorylation of MYPT1 was determined by Western blotting.

RESULTS

Constitutive phosphorylation of MYPT1-T696 and T853 was lower and that of S695 and S668 was higher in cerebral arteries from the circulus arteriosus (CA-w) than in femoral arteries (FA), while total MYPT1 expression was not different. In CA-w but not in FA, L-NAME lowered phosphorylation of S695/S668 and increased phosphorylation of T696/T853 and of MLC₂₀ -S19, plus basal tone. The increase in basal tone was attenuated in CA-w and basilar arteries (BA) from heterozygous MYPT1-T696A/+ mice. Compared to FA, expression of the LZ⁺ -isoform was ~2-fold higher in CA-w coincident with a higher sensitivity to DEA-NONOate, cinaciguat and Y27632 in BA and 8-Br-cGMP (1 μmol/L) in pre-constricted (pCa 6.1) α-toxin permeabilized CAs. In contrast, 6-Bnz-cAMP (10 μmol/L) relaxed BA and FA similarly by ~80%.

CONCLUSION

Our results indicate that (i) regulation of the intrinsic contractile activity in CA involves phosphorylation of MYPT1 at T696 and S695/S668, (ii) the higher NO/cGMP/PKG sensitivity of CAs can be ascribed to the higher expression level of the LZ⁺ -MYPT1 isoform and (iii) relaxation by cAMP/PKA pathway is less dependent on the expression level of the LZ⁺ splice variants of MYPT1.

Tigecycline for treatment of carbapenem-resistant Klebsiella pneumoniae infections after liver transplantation in the intensive care unit: a 3-year study

BACKGROUND

This 3-year prospective, observational, single-center study was undertaken to describe prescription, microbiology findings, tolerance, and efficacy of tigecycline for carbapenem-resistant Klebsiella pneumoniae (CRKP) infections after liver transplantation in the intensive care unit (ICU).

METHODS

All patients after liver transplantation treated with tigecycline for ≥3 days for CRKP infections in our ICU from January 1, 2010, to December 31, 2012, were studied. Patient characteristics, indication of treatment, bacteriology, and ICU mortality were collected. The main end points were clinical and microbiologic efficacy and tolerance of tigecycline.

RESULTS

Over the study period, 8 men and 2 women (18 CRKP isolates), aged 54.3 ± 7.7 years, were included in the study. Acute Physiology and Chronic Health Evaluation and Sequential Organ Failure Assessment scores on ICU admission were 13.7 ± 2.7 and 10 ± 2.2, respectively. In 7 isolates, tigecycline was prescribed for CRKP blood stream infection (BSI), in 6 for complicated intra-abdominal infection (IAI), in 2 for ventilator-associated pneumonia (VAP), in 2 for surgical site infection, and in 1 for urinary tract infection. In 4 cases, tigecycline was prescribed for secondary BSI followed by VAP and/or IAI. All isolates were susceptible to tigecycline, 83.4% to colistin, 44.5% to gentamicin, and 27.8% to amikacin. In 2 patients, tigecycline was prescribed as monotherapy. Three patients had clinical failure. The microbiologic response rate was 70%. Superinfection was detected in 5 patients, and Pseudomonas aeruginosa was the most frequently isolated pathogen. Tigecycline was generally well tolerated. The ICU mortality rate was 60% with attributable mortality rate 30%.

CONCLUSIONS

Our pilot study suggests that tigecycline shows a good safety and tolerance profile in patients with CRKP infections in the ICU after orthotopic liver transplantation. Limited therapeutic options for such infections leave physicians no choice but to use tigecycline for off-label indications such as urinary tract and blood stream infections.

Comparison of RIFLE and AKIN criteria in the evaluation of the frequency of acute kidney injury in post-liver transplantation patients

BACKGROUND

Acute renal dysfunction is presented quite often after orthotopic liver transplantation (LT), with a reported incidence of 12-64%. The "RIFLE" criteria were introduced in 2004 for the definition of acute kidney injury (AKI) in critically ill patients, and a revised definition was proposed in 2007 by the Acute Kidney Injury Network (AKIN), introducing the AKIN criteria. The aim of this study was to record the incidence of AKI in patients after LT by both classifications and to evaluate their prognostic value on mortality.

METHODS

We retrospectively evaluated the records of patients with LT over 2 years (2011-2012) and recorded the incidence of AKI as defined by the RIFLE and AKIN criteria. Preoperative and admission severity of disease scores, duration of mechanical ventilation, intensive care unit length of stay, and 30- and 180-day survivals were also recorded.

RESULTS

Seventy-one patients were included, with an average age of 51.78 ± 10.3 years. The incidence of AKI according to the RIFLE criteria was 39.43% (Risk, 12.7%; Injury, 12.7%; Failure, 14.1%), whereas according to the AKIN criteria it was 52.1% (stage I, 22.5%; stage II, 7%; stage II 22.55%). AKI, regardless of the classification used, was related to the Model for End-Stage Liver Disease score, the volume of transfusions, the duration of mechanical ventilation, and survival. The presence of AKI was related to higher mortality, which rose proportionally with the severity of AKI as defined by the stages of either the RIFLE or the AKIN criteria.

CONCLUSIONS

AKI classifications according to the RIFLE and AKIN criteria are useful tools in the recognition and classification of the severity of renal dysfunction in patients after LT, because they are associated with higher mortality, which rises proportionally with the severity of renal disease.

Serum pregnancy-associated plasma protein-A in the three trimesters of pregnancy: effects of maternal characteristics and medical history

OBJECTIVE

To define the contribution of maternal variables which influence the measured level of maternal serum pregnancy-associated plasma protein-A (PAPP-A) in screening for pregnancy complications.

METHODS

Maternal characteristics and medical history were recorded and serum PAPP-A was measured in women with a singleton pregnancy attending for three routine hospital visits at 11 + 0 to 13 + 6, 19 + 0 to 24 + 6 and 30 + 0 to 34 + 6 weeks' gestation. For pregnancies delivering phenotypically normal live births or stillbirths ≥ 24 weeks' gestation, variables from maternal demographic characteristics and medical history that are important in the prediction of PAPP-A were determined from a linear mixed-effects multiple regression.

RESULTS

Serum PAPP-A was measured in 94,966 cases in the first trimester, 7785 in the second trimester and 8286 in the third trimester. Significant independent contributions to serum PAPP-A were provided by gestational age, maternal weight, height, racial origin, cigarette smoking, diabetes mellitus, method of conception, previous pregnancy with or without pre-eclampsia (PE) and birth-weight Z-score of the neonate in the previous pregnancy. The effects of some variables were similar and those for others differed in the three different trimesters. Random-effects multiple regression analysis was used to define the contribution of maternal variables that influence the measured level of serum PAPP-A and express the values as multiples of the median (MoMs). The model was shown to provide an adequate fit of MoM values for all covariates, both in pregnancies that developed PE and in those without this pregnancy complication.

CONCLUSIONS

A model was fitted to express the measured serum PAPP-A across the three trimesters of pregnancy as MoMs, after adjusting for variables from maternal characteristics and medical history that affect this measurement.

Serum free β-human chorionic gonadotropin in the three trimesters of pregnancy: effects of maternal characteristics and medical history

OBJECTIVE

To define the contribution of maternal variables which influence the measured level of maternal serum free β-human chorionic gonadotropin (β-hCG) in screening for pregnancy complications.

METHODS

Maternal characteristics and medical history were recorded and serum free β-hCG was measured in women with a singleton pregnancy attending for three routine hospital visits at 11 + 0 to 13 + 6, 19 + 0 to 24 + 6 and 30 + 0 to 34 + 6 weeks' gestation. For pregnancies delivering phenotypically normal live births or stillbirths ≥ 24 weeks' gestation, variables from maternal demographic characteristics and medical history that are important in the prediction of free β-hCG were determined from a linear mixed-effects multiple regression.

RESULTS

Serum free β-hCG was measured in 94 985 cases in the first trimester, 7879 in the second trimester and 8424 in the third trimester. Significant independent contributions to serum free β-hCG were provided by gestational age, maternal weight, age and racial origin, cigarette smoking, method of conception, diabetes mellitus and family history of pre-eclampsia (PE) in the mother of the patient. The effects of some variables were similar and those for others differed in each trimester. Random-effects multiple regression analysis was used to define the contribution of maternal variables that influence the measured level of serum free β-hCG and express the values as multiples of the median (MoMs). The model was shown to provide an adequate fit of MoM values for all covariates both in pregnancies that developed PE and in those without this pregnancy complication.

CONCLUSIONS

A model was fitted to express measured serum free β-hCG across the three trimesters of pregnancy as MoMs after adjusting for variables from maternal characteristics and medical history that affect this measurement.

Differential effects of RGK proteins on L-type channel function in adult mouse skeletal muscle

Work in heterologous systems has revealed that members of the Rad, Rem, Rem2, Gem/Kir (RGK) family of small GTP-binding proteins profoundly inhibit L-type Ca(2+) channels via three mechanisms: 1), reduction of membrane expression; 2), immobilization of the voltage-sensors; and 3), reduction of Po without impaired voltage-sensor movement. However, the question of which mode is the critical one for inhibition of L-type channels in their native environments persists. To address this conundrum in skeletal muscle, we overexpressed Rad and Rem in flexor digitorum brevis (FDB) fibers via in vivo electroporation and examined the abilities of these two RGK isoforms to modulate the L-type Ca(2+) channel (CaV1.1). We found that Rad and Rem both potently inhibit L-type current in FDB fibers. However, intramembrane charge movement was only reduced in fibers transfected with Rad; charge movement for Rem-expressing fibers was virtually identical to charge movement observed in naïve fibers. This result indicated that Rem supports inhibition solely through a mechanism that allows for translocation of CaV1.1's voltage-sensors, whereas Rad utilizes at least one mode that limits voltage-sensor movement. Because Rad and Rem differ significantly only in their amino-termini, we constructed Rad-Rem chimeras to probe the structural basis for the distinct specificities of Rad- and Rem-mediated inhibition. Using this approach, a chimera composed of the amino-terminus of Rem and the core/carboxyl-terminus of Rad inhibited L-type current without reducing charge movement. Conversely, a chimera having the amino-terminus of Rad fused to the core/carboxyl-terminus of Rem inhibited L-type current with a concurrent reduction in charge movement. Thus, we have identified the amino-termini of Rad and Rem as the structural elements dictating the specific modes of inhibition of CaV1.1.

The effect of Antithrombin-III on routine hematological and biochemical parameters in an experimental animal model of skeletal muscle ischemia-reperfusion injury

BACKGROUND

Antithrombin III (AT-III) has been shown to attenuate the local and systemic harmful effects of skeletal muscle ischemia-reperfusion (I-R) injury. The aim of the present study was to monitor the fluctuation of routine hematological and biochemical parameters in an experimental animal model of tourniquet-induced skeletal muscle I-R injury and to investigate how these are influenced by the protective administration of AT-III.

METHODS

Sixty male Wistar rats were submitted to a 6-hour, tourniquet-induced, complete ischemia of the right hind-limb. Animals were divided into those receiving AT-III (dose, 250 IU/kg) 30 minutes before the reperfusion (group A, n=30) and those receiving placebo (group B, n =30). Another 10 animals were sham-operated (group C). White blood cell (WBC) and platelet (PLT) count, aspartate and alanine aminotransferases (AST and ALT), alkaline phosphatase (ALP), and γ-glutamyl transferase (γ-GT) were estimated in blood samples taken from the inferior vena cava at 3 different time points post-reperfusion (at baseline, at 30 minutes and at 4 hours) and groups A and B were compared using the Mann-Whitney U test.

RESULTS

There were no statistically significant differences between the AT-III and the placebo groups at 0, 30 minutes and 4 hours with regard to the WBC, ALT and γ-GT levels, however, there was a significant decrease of AST levels 4 hours post-reperfusion in the AT-III group compared to the placebo group (p=0.002). An increased PLT count and ALP levels 30 minutes post-reperfusion were also noted in the AT-III group compared to placebo (p<0.001; and p=0.001, respectively).

CONCLUSIONS

Of the routine hematological and biochemical parameters tested, AST was found to be significantly suppressed at 4 hours in the AT-III-treated animals, suggesting a possible beneficial effect of AT-III in mouse skeletal muscle I-R injury. The effect of AT-III on PLTs and ALP levels merits further investigation. Hippokratia 2014; 18 (3): 234-239.

Potent inhibition of L-type Ca2+ currents by a Rad variant associated with congestive heart failure

Ca(2+) influx via L-type voltage-gated Ca(2+) channels supports the plateau phase of ventricular action potentials and is the trigger for excitation-contraction (EC) coupling in the myocardium. Rad, a member of the RGK (Rem, Rem2, Rad, Gem/Kir) family of monomeric G proteins, regulates ventricular action potential duration and EC coupling gain through its ability to inhibit cardiac L-type channel activity. In this study, we have investigated the potential dysfunction of a naturally occurring Rad variant (Q66P) that has been associated with congestive heart failure in humans. Specifically, we have tested whether Rad Q66P limits, or even eliminates, the inhibitory actions of Rad on CaV1.2 and CaV1.3, the two L-type channel isoforms known to be expressed in the heart. We have found that mouse Rad Q65P (the murine equivalent of human Rad Q66P) inhibits L-type currents conducted by CaV1.2 or CaV1.3 channels as potently as wild-type Rad (>95% inhibition of both channels). In addition, Rad Q65P attenuates the gating movement of both channels as effectively as wild-type Rad, indicating that the Q65P substitution does not differentially impair any of the three described modes of L-type channel inhibition by RGK proteins. Thus, we conclude that if Rad Q66P contributes to cardiomyopathy, it does so via a mechanism that is not related to its ability to inhibit L-type channel-dependent processes per se. However, our results do not rule out the possibility that decreased expression, mistargeting or altered regulation of Rad Q66P may reduce the RGK protein's efficacy in vivo.

Infections related to renal transplantation requiring intensive care admission: a 20-year study

INTRODUCTION

The aim of this study was to evaluate infection complications as the reason for intensive care unit (ICU) admission among transplant recipients.

METHODS

We studied all renal transplant recipients with infectious complications admitted to our ICU from 1992 to 2012:44.3% of all renal transplant recipients admitted to ICU. The epidemiology and prognosis of infectious complications requiring ICU admission were evaluated with analysis of mortality factors.

RESULTS

The 22 men and 5 women included in this study showed a mean age of 42.7 ± 12.3 years. The Acute Physiologic and Chronic Health Evaluation II and Seguential Organ Failure Assessment scores on ICU admission were 20 ± 4.6 and 8.6 ± 3.9, respectively. The main infections complications requiring ICU admission were cytomegalovirus pneumonia (n = 15) and aspergillus pneumonia (n = 4). Sixteen patients required hemodialysis and 14, catecholamine support upon ICU admission owing to septic shock. The mortality rate among study patients was 62.9%, versus 26.5% for noninfectious renal transplant recipients requiring ICU admissions. Catecholamine support at ICU admission was independently related to mortality.

CONCLUSION

The mortality rate of renal transplant recipients admitted to ICU owing infection complications was higher than that of noninfected renal transplant patients. These data suggest that infections and septic shock in renal transplant recipients requiring ICU admission worsen their outcome significantly.

Infections after orthotopic liver transplantation in the intensive care unit

PURPOSE

The purpose of the study was to assess the characteristics and risk factors of infections in the early period after orthopic liver transplantation (OLT) among adult patients.

MATERIAL AND METHODS

We studied 75 patients who underwent OLT over 3 years from 2008 to 2010. We recorded all infections that developed during hospitalization in the intensive care unit (ICU) their outcomes, and the possible risk factors.

RESULTS

During the study period in 80 OLT we recorded 19 bloodstream infections (47.5%), 7 ventilator-associated pneumonias (VAP; 17.5%), and 14 intra-abdominal infections (35%). Among the 40 isolated microbes, 72.5% were Gram negative, 25% were Gram positive, and 2.5% were fungi. The median time to developing the infection was 4.95 days (range 2-10). Patients with infections showed longer durations of mechanical ventilation, longer lengths of ICU stay, and lower 1-year survivals.

Operative treatment of gynaecologic diseases in puberty: seven years of experience

PURPOSE OF INVESTIGATION

The aim of this study is to present the incidence and surgical management of gynaecologic pathology in adolescence in the 1st Obstetrics and Gynecology Department of Aristotle University of Thessaloniki.

METHODS

After a retrospective review of the medical records of over a seven year period (2004-2011), 32 adolescent patients with reported surgical gynaecologic procedures were identified and analysed.

RESULTS

Fourteen out of the 16 adolescents with ovarian masses (eight neoplastic and eight non-neoplastic) were treated by laparoscopy. Congenital anomalies were diagnosed in seven patients and only one of them was treated by laparotomy. The rest were surgically treated for uterine leiomyoma (1), ectopic pregnancy (2), pelvic abscess (1), mesosalpingeal cysts (2), mesenterian cyst (1) and investigation of chronic pelvic pain.

DISCUSSION

Although benign ovarian cysts and congenital anomalies represent the major indication for operative treatment of gynaecologic diseases in puberty, laparoscopy and/or hysteroscopy should be the gold standard procedure after careful preoperative investigation.

Reduced metaboreflex control of blood pressure during exercise in individuals with intellectual disability: a possible contributor to exercise intolerance

The aim was to investigate the hemodynamic responses to isometric handgrip exercise (HG) and examine the role of the muscle metaboreflex in the exercise pressor response in individuals with intellectual disability (IID) and non-disabled control subjects. Eleven males with mild-moderate intellectual disabilities and eleven non-disabled males performed a testing protocol involving 3-min periods of baseline, HG exercise (at 30% MVC), circulatory occlusion, and recovery. The same protocol was repeated without occlusion. At baseline, no differences were detected between groups in beat-to-beat mean arterial pressure (MAP), heart rate (HR), stroke volume, and peripheral resistance. IID were able to sustain an exercise MAP response at comparable levels to the control group exerting similar peripheral resistance; however, IID exhibited a blunted chronotropic response to HG and a diminished exercise vagal withdrawal compared to controls. During occlusion, IID exhibited a lower pressor response than their control peers, associated with a lower increase in peripheral resistance during this task. In conclusion, although intellectual disabilities can be the consequence of many different genes, IID share common deficits in the chronotropic response to exercise and a blunted metaboreflex-induced pressor response.

Epithelial splenic cysts and life-threatening splenic rupture

BACKGROUND/AIM

Primary splenic cysts are relatively uncommon and in the majority of cases are classified as epithelial cysts which are more frequent in young patients. Most of them are asymptomatic, and they are found incidentally during imaging techniques or laparotomy. We report two rare cases of patients with epithelial splenic cysts as an incidental finding during emergency laparotomy for splenic rupture.

MATERIALS AND METHOD

The first patient was a 70-year-old man who presented with symptoms of acute abdomen after intensive cough during an episode of asthma. Emergency laparotomy findings were splenic rupture and intraperitoneal haemorrhage. A splenectomy was performed and the histological examination showed a ruptured spleen with an epithelial cyst. The second patient was a 19-year-old man who was transferred to the Emergency Department in hypovolemic shock due to intraperitoneal bleeding after a blunt abdominal injury. During laparotomy a splenic rupture was found, and an epithelial cyst.

CONCLUSION

Epithelial splenic cysts are a rare entity and they can be an incidental finding during the surgical treatment of a spleen rupture and haemoperitoneum. These cysts may be a predisposing factor to splenic rupture in cases of increased intraabdominal pressure or blunt abdominal trauma.

Primary inflammation of an epiploic appendix of the ascending colon. Is atypical presentation a reason for emergency laparotomy?

Right lower quadrant pain is a very common symptom in everyday clinical practice, and of variable etiology. In patients arriving in the emergency room with sudden-onset right lower quadrant pain, the commonest cause is acute appendicitis. Primary epiploic appendagitis, a rare entity, with a clinical presentation similar to other causes of acute abdomen, and one that subsides spontaneously, can constitute a problem in differential diagnosis, because it is a condition best treated conservatively. The exact diagnosis is a prerequisite for conservative treatment. We present the case of a 62 year old woman with primary epiploic appendagitis of the ascending colon that presented as acute abdomen, who underwent an exploratory laparotomy with the preoperative diagnosis of acute appendicitis.

The Use of a New Wound Alginogel for the Treatment of Partial-thickness Hand Burns

 The following retrospective analysis reports on patients with partial-thickness wounds admitted to the burn unit of the General Hospital of Athens who were treated with a new alginogel and were later compared to the burn center's standard treatment.

METHODS

Patient information from January-December 2008 was analyzed for the number of days until healing and wound bacterial loads. Wound healing was characterized as a quick onset of epithelialization and low occurrence of inflammation.

RESULTS

A limited number of wounds (15%) were found to be positive for wound swabs and accordingly few signs of inflammation were reported. The organisms that were retrieved from the alginogel treated wounds were Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, and Acinetobacter baumanii.

CONCLUSION

These data are discussed and compared with the experience of the burn unit and its standard treatment. .

Mixed tumor of the vagina: sonographic and magnetic resonance imaging findings

Mixed tumor of the vagina is a rare benign neoplasm that is composed of epithelial and mesenchymal cells. The majority of tumors are asymptomatic and simple tumor excision is curative. We report a case with pathological confirmation that was seen in a 42-year-old woman. On ultrasound examination the lesion appeared as an ovoid hypoechoic mass, 2.0 x 2.7 cm in size, arising from the lower third of the vagina. The lesion was well defined, solid and showed diffuse hypervascularity on color flow images. Magnetic resonance imaging of the pelvis showed a well-circumscribed ovoid mass (2.0 x 2.5 cm) on the left lateral vaginal wall. On T2-weighted images the mass appeared as a homogeneous hyperintense lesion, while on T1-weighted images it was difficult to discern the mass from the vaginal wall. After intravenous administration of gadolinium the mass showed progressively increasing homogeneous enhancement. The lesion was excised without complication and there was no evidence of recurrence at the 10-month follow-up.

In French children, primary gastritis is more frequent than Helicobacter pylori gastritis

The aim of this study was to analyze the histological characteristics according to the updated Sydney classification (intensity of gastritis, degree of activity, gastric atrophy, intestinal metaplasia, and Helicobacter pylori) in symptomatic children referred for upper gastrointestinal endoscopy. A 4-year retrospective descriptive study was carried out in 619 children (282 females and 337 males), median age 3.75 years (15 days to 17.3 years) referred for endoscopy. Six gastric biopsies were done (three antrum and three corpus) for histological analysis (n = 4), direct examination and H. pylori culture (n = 2). H. pylori status was considered positive if at least two out of three tests were positive and negative if all three tests were negative. The results showed that only 66 children (10.66%) were H. pylori positive. Histological antral and corpus gastritis was detected in, respectively, 53.95% and 59.12% of all cases, most of them of mild grade 1. Antral and corpus activity was grade 1 in 18.57% and 20.03% of cases. H. pylori-positive versus H. pylori-negative children did differ in terms of moderate and marked histological gastritis and grade 2 or 3 activities. One girl had moderate gastric atrophy and another one moderate intestinal metaplasia, both being H. pylori negative. The findings indicate that primary antrum and corpus gastritis is 5.3 and 6.9 times, respectively, more frequent than H. pylori gastritis in French children, with usually mild histological gastritis and activity. Gastric atrophy and intestinal metaplasia are rare.

Directional Persistence in the Rewarded Alternation Model of Obsessive-compulsive Disorder is Responsive to both Dopaminergic and Serotonergic Manipulations

Rationale:

In the rewarded alternation model of obsessive compulsive disorder (OCD), the serotonin agonist m-chlorophenylpiperazine (mCPP) increases persistent behaviour, while chronic pretreatment with selective serotonin reuptake inhibitor (SSRI-fluoxetine) but not benzodiazepine or desipramine abolishes mCPP effects. However, we noted that acute SSRI administration also causes transient persistence increases, counteracted by mCPP pretreatment.

Objectives:

This study

a.

Methods:

In both experiments, baseline and drug testing was carried out under daily T-maze alternation training.

Exp.1:

Matched group (n=8) pairs of rats received one of the following 20-day pretreatments (daily intraperitoneal administration):

1.

One group per pretreatment then received a 4-day challenge with high-dose fluoxetine (10mg/kg), the other with high-dose mCPP (2.5mg/kg).

Exp.2:

One group (n=12) of rats received 20-day treatment with saline, another with quinpirole (0.5 mg/kg).

Results:

Exp.1:

Saline and low-dose mCPP- or fluoxetine-pretreated animals showed significant persistence increases under both challenges, while combined low-dose fluoxetine+mCPP pretreatment afforded full protection from either challenge.

Exp.2:

Quinpirole significantly increased directional persistence after 13 administration days.

Conclusions:

These results establish the sensitivity of the rewarded alternation OCD model to D2,3receptor activation, thereby extending its profile of pharmacological isomorphism with OCD. Furthermore, they suggest a common mechanism of action of an SSRI and a serotonin agonist in the control of directional persistence.

an Investigation of 5-ht2 Involvement in the Acute Behavioural Effects of Fluoxetine and MCPP in an Animal Model of OCD

Background:

We reported that the non-specific 5HT agonist m-chlorophenylpiperazine (mCPP) and the SSRI fluoxetine (FLX) both cause acute persistence increases in the rewarded alternation (RA) model of OCD. Chronic pretreatment with either substance or their combined subclinical doses protects from this ‘pathogenic’ effect, so mCPP and fluoxetine exhibit cross-tolerance and synergy.

Aims:

Using specific 5HT2A and 5HT2C receptor antagonists we investigated whether these receptors participate in a common mechanism of action mediating the acute mCPP/fluoxetine effect in our model.

Methods:

Naïve, male Wistars were used. Drugs used (intraperitoneally): FLX (10mg/kg), mCPP (2.5mg/kg), M100907 (5HT2A antagonist, 0.03mg/kg), SB242084 (5HT2C antagonist, 0.5mg/kg), vehicle. Experiments included a drug-free training/baseline phase in T-maze RA (group-matching for spontaneous persistence: SP).

Experiment 1: Effects of M100907, SB242084, vehicle were assessed on 3 matched low SP and 3 high SP groups.

Experiment 2: the acute effect of FLX, mCPP and saline were examined on RA in 3 SP-matched groups.

Experiment 3: Effects of Vehicle+FLX, M100900+FLX, SB242084+FLX and Vehicle were examined on RA, in 4 SP-matched groups.

Experiment 4: Correspondingly for mCPP.

Results:

Experiment 1: Neither M100907 nor SB242084 affected high or low SP.

Experiment 2 replicated the pathogenic effects of FLX/mCPP.

Experiment 3: Neither M100907 nor SB242084 affected the pathogenic effect of FLX.

Experiment 4: in contrast, SB242084 (but not M100907) significantly reduced the pathogenic mCPP effect.

Conclusions:

The acute pathogenic action of mCPP, but not of FLX, involves 5HT2C but not 5HT2A receptors. the similar acute action of mCPP and FLX on persistence cannot be attributed to 5HT2 mediation.

[Case reports of operative management of very large, benign phylloid tumors--is a safety margin necessary?]

The phylloid tumor (PT, formerly called cystosarcoma phylloides) is a rare neoplasia of the female breast. Usually the PT is treated with breast-conserving surgery. In spite of progress in early diagnosis, PTs recur frequently--independently of tumor's degree of malignancy. Especially in cases of malignant PT, complete resection with tumor-free margins is seen as the only predictive marker for tumor recurrence or metastases. Benign PT is also often resected with wide tumor-free margins. Because of the tumor's occasionally enormous dimensions, this therapy concept makes breast-conserving surgery almost impossible. A simple enucleation of benign PT is an option to facilitate the preservation of breast tissue and a cosmetically satisfactory breast reconstruction. In the case of particularly large benign PT, enucleation even without wide margins prevents tumor recurrence.

Cytolytic and Cytotoxic Activity of a Human Natural Killer Cell Line Genetically Modified to Specifically Recognize HER-2/neu Overexpressing Tumor Cells

NK92 cells genetically engineered to recognize the HER-2/neu oncoprotein have been previously reported to lyse HER-2/neu positive tumor cell lines through direct cell to cell contact. In the present study we have transduced NK92 cells with a chimeric receptor gene composed of the HER-/neu specific scFv (FRP5) antibody fragment, joined to the peptide CD8 hinge region and the signaling CD3 zeta chain. NK92 cells expressing this chimeric receptor (NK92.HER-2/neu/zeta) specifically recognized and lysed HER-2/neu overexpressing tumor cell lines both in vitro and in preclinical tumor models in vivo. More important we demonstrate that NK92.HER-2/neu/zeta cells constitutively secrete high levels of soluble scFv which mediate strong tumor cytostatic effects by directly binding on cell surface HER-2/neu. Our data uncover an additional mechanism through which NK92.HER-2/neu/zeta cells mediate antitumor effects and further support their use in cell based therapeutics for the treatment of HER-2/neu expressing cancers.

Trichoblastic carcinoma of the pinna. A rare case

Adnexal tumors of the hair follicle can be regarded as lesions that show similar differentiation to one or more portions of the hair follicle. Trichoblastic carcinoma is a rare malignant adnexal tumor, which usually occurs on the scalp. There have been reported cases with regional lymph node metastasis. We report a case of a 65 years old man with a painless irregular mass of the posterior surface of the right pinna, which was slowly growing over a 5-year period. He had a history of a similar lesion on the same site, which was removed 8 years before he presented to us. We excised the lesion and the defect was covered with an advancing flap. Because of the histology result the patient was re-operated and reviewed for over 3 years and there wasn't any sign of recurrence.

Surfactant administration in severe inhalation injury: case report

Inhalation injury is one of the main causes of death in patients with severe burns. Administration of exogenous surfactant appears promising for the treatment of acute respiratory failure. We report our clinical experience with this approach. A 35 yr-old man was admitted to our burns unit after an industrial accident. He had sustained a 60% total body surface area full-thickness burn combined with severe inhalation injury. Fiberoptic bronchoscopy confirmed the diagnosis, demonstrating severe blisters and ulcers of the bronchial mucosa. Refractory hypoxaemia (PaO (2)/FiO (2)56 mm Hg, where PaO (2)is oxygen tension in arterial blood and FiO (2)is the fraction of inspired oxygen) was treated with optimal mechanical ventilatory support; additionally, an initial dose of natural bovine surfactant (Alveofact) of 50 mg/kg body weight was administered by intrabronchial instillation on day 3 postburn. A significant improvement in oxygenation was observed 12 h after administration (from 56 mm Hg initially to 194 mm Hg), followed by an improvement in dynamic compliance (from 26 ml/cm H (2)O initially to 41 ml/cm H (2)O) and inspiratory resistance (from 14 cm H (2)O/lps initially to 11 cm H (2)O/lps). The same dose of surfactant was repeated 48 h later to prevent potential deterioration, resulting in maintenance of gas exchange and lung mechanics at the above levels. No complication associated with the surfactant administration was observed. However, the patient died on day 9 post-burn owing to extrapulmonary causes. Our results demonstrate a significant improvement in gas exchange and lung mechanics in a burn patient with severe inhalation injury after repeated administration of exogenous surfactant. Further study is needed in order to elucidate the clinical impact of surfactant administration and the complications associated with its use in cases of inhalation injury.