Gender-Related Effectiveness of Personalized Post-COVID-19 Rehabilitation

Background: Post-COVID-19 syndrome (PCS) may affect a substantial proportion of patients who have had COVID-19. The rehabilitation program might improve the physical capacity, functioning of the cardiopulmonary system, and mental conditions of these patients. This study aimed to investigate the effectiveness of personalized rehabilitation in patients with PCS according to gender. Methods: Adults who underwent a 6-week personalized PCS rehabilitation program were enrolled in a prospective post-COVID-19 Rehabilitation (PCR-SIRIO 8) study. The initial visit and the final visit included the hand-grip strength test, the bioimpedance analysis of body composition, and the following scales: modified Borg's scale, Modified Fatigue Impact Scale (MFIS), Functioning in Chronic Illness Scale (FCIS), modified Medical Research Council (mMRC) dyspnea scale, and tests: 30 s chair stand test (30 CST), Six-Minute Walk Test (6MWT), Short Physical Performance Battery test (SPPB)e. Results: A total of 90 patients (54% female) underwent the rehabilitation program. Rehabilitation was associated with an increase in skeletal muscle mass (24.11 kg vs. 24.37 kg, p = 0.001) and phase angle (4.89° vs. 5.01°, p = 0.001) and with a reduction in abdominal fat tissue volume (3.03 L vs. 2.85 L, p = 0.01), waist circumference (0.96 m vs. 0.95 m, p = 0.001), and hydration level (83.54% vs. 82.72%, p = 0.001). A decrease in fat tissue volume and an increase in skeletal muscle mass were observed only in females, while an increase in grip strength was noticed selectively in males. Patients' fatigue (modified Borg's scale, MFIS), physical capacity (30 CST, 6MWT), balance (SPPB), dyspnea (mMRC), and functioning (FICS) were significantly improved after the rehabilitation regardless of gender. Conclusions: Personalized rehabilitation improved the body composition, muscle strength, and functioning of patients diagnosed with PCS. The beneficial effect of rehabilitation on body composition, hydration, and phase angle was observed regardless of gender.

Achieving Cardiovascular Risk Management Goals and Patient Quality of Life

(1) Background: Eliminating or reducing the severity of modifiable risk factors of cardiovascular disease (CVD) and undertaking health-promoting behaviors is the basis for prevention. (2) Methods: This study included 200 subjects without a history of CVD, aged 18 to 80 years, who had been diagnosed with hypertension, hypercholesterolemia, or diabetes 6 to 24 months before study enrolment. (3) Results: The median 10-year CV risk assessed by the SCORE2 and SCORE2-OP algorithms was 3.0 (IQR 1.5-7.0). An increase in mean cardiovascular risk in the range from low and moderate to very high was associated with a decrease in quality of life both in individual subscales and the overall score. The median number of controlled risk factors was 4.0 (IQR 3.0-5.0). As the mean number of controlled risk factors increased, the quality of life improved in both of HeartQoL questionnaire subscales (emotional p = 0.0018; physical p = 0.0004) and the overall score (global p = 0.0001). The median number of reported health-promoting behaviors undertaken within 3 years before study enrolment was 3.0 (IQR 2.0-4.0). The highest quality of life in each of the studied dimensions was found in people who reported undertaking three health-promoting behaviors. (4) Conclusions: Controlling CVD risk factors and undertaking health-promoting behaviors has a positive impact on the quality of life of patients without a history of atherosclerotic CVD.

Determinants of Lipid Parameters in Patients without Diagnosed Cardiovascular Disease-Results of the Polish Arm of the EUROASPIRE V Survey

To assess the determinants of lipid parameters in primary care patients without diagnosed cardiovascular disease (CVD), a cross-sectional study was conducted during 2018-2019 with a total of 200 patients. The following lipid parameters were measured: total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), small, dense LDL (sdLDL-C), and lipoprotein (a) (Lp(a)). Predictors of elevated and adequately controlled lipid parameters were assessed with logistic regression analysis. Older age was related to higher risk of TC ≥ 6.2 mmol/L [OR 1.03 (95% CI 1.0-1.05)], sdLDL-C ≥ 1.0 mmol/L [OR 1.05 (95% CI 1.0-1.1)], and decreased risk of Lp(a) ≥ 50 mg/dL [OR 0.97 (95% CI 0.94-0.99)]. Patients with diabetes mellitus (DM) had increased probability of TG ≥ 2.25 mmol/L [OR 3.77 (95% CI 1.34-10.6)] and Lp(a) ≥ 50 mg/dL [OR 2.97 (1.34-6.10)] as well as adequate control of TG and Lp(a). Higher material status was related to lower risk of TC ≥ 6.2 mmol/L [OR 0.19 (95% CI 0.04-0.82)] and LDL-C ≥ 3.6 mmol/L [OR 0.33 (95% CI 0.12-0.92)]. High BMI was related to increased [OR 1.14 (95% CI 1.02-1.29)], and female gender [OR 0.33 (95% CI 0.12-0.96)] and hypertension [OR 0.29 (95% CI 0.1-0.87)] to decreased risk of TG ≥ 2.25 mmol/L [OR 1.14 (95% CI 1.02-1.29)]. Taking lipid-lowering drugs (LLD) was associated with LDL-C < 2.6 mmol/L [OR 2.1 (95% CI 1.05-4.19)] and Lp(a) < 30 mg/dL [OR 0.48 (95% CI 0.25-0.93)]. Physical activity was related to LDL-C < 2.6 mmol/L [OR 2.02 (95% CI 1.02-3.98)]. Higher abdominal circumference was associated with decreased risk of TG < 1.7 mmol/L [OR 0.96 (95% CI 0.93-0.99)]. Elevated lipid parameters were related to age, gender, material status, BMI, history of DM, and hypertension. Adequate control was associated with age, education, physical activity, LLD, history of DM, and abdominal circumference.

The occurrence of cardiovascular risk factors and functioning in chronic illness in the Polish population of EUROASPIRE V

BACKGROUND

The aim of this study was to assess the impact of cardiovascular risk on the functioning of patients without a history of atherosclerotic cardiovascular disease.

METHODS

Two hundred patients diagnosed with arterial hypertension, hypercholesterolemia, or diabetes were enrolled in the study. The median age was 52.0 years (interquartile range [IQR] 43.0-60.0). The following risk factors were assessed: blood pressure, body mass index, waist circumference, physical activity, smoking, LDL-cholesterol, triglycerides, and fasting plasma glucose concentration. Total cardiovascular risk was determined as the number of uncontrolled risk factors, and with the Systemic Coronary Risk Evaluation Score (SCORE). The Functioning in the Chronic Illness Scale (FCIS) was applied to assess the physical and mental functioning of patients.

RESULTS

The median number of measures of cardiovascular risk factors was 4.0 (IQR 3.0-5.0). The median of SCORE for the whole study population was 2.0 (IQR 1.0-3.0). Patients with lower total cardiovascular risk as defined by SCORE and number of uncontrolled risk factors had better functioning as reflected by higher FCIS (R = -0.315, p < 0.0001; R = -0.336, p < 0.0001, respectively). Multivariate logistic regression analysis identified abnormal blood pressure, abnormal waist circumference, tobacco smoking, and lack of regular physical activity to be negative predictors of functioning. Lack of regular physical activity was the only predictor of low FCIS total score (odds ratio 9.26, 95% confidence interval 1.19-71.77, p = 0.03).

CONCLUSIONS

The functioning of patients worsens as the total cardiovascular risk increases. Each of the risk factors affects the functioning of subjects without coronary artery disease with different strength, with physical activity being the strongest determinant of patient functioning.

Occurrence and Temporal Variability of Out-of-Hospital Cardiac Arrest during COVID-19 Pandemic in Comparison to the Pre-Pandemic Period in Poland-Observational Analysis of OSCAR-POL Registry

An investigation of the chronobiology of out-of-hospital cardiac arrest (OHCA) during the coronavirus disease 2019 (COVID-19) pandemic and the differences in comparison to the 6-year pre-pandemic period. A retrospective analysis of the dispatch cards from the Emergency Medical Service between January 2014 and December 2020 was performed within the OSCAR-POL registry. The circadian, weekly, monthly, and seasonal variabilities of OHCA were investigated. A comparison of OHCA occurrence between the year 2020 and the 6-year pre-pandemic period was made. A total of 416 OHCAs were reported in 2020 and the median of OHCAs during the pre-pandemic period was 379 (interquartile range 337−407) cases per year. Nighttime was associated with a decreased number of OHCAs (16.6%) in comparison to afternoon (31.5%, p < 0.001) and morning (30.0%, p < 0.001). A higher occurrence at night was observed in 2020 compared to 2014−2019 (16.6% vs. 11.7%, p = 0.001). Monthly and seasonal variabilities were observed in 2020. The months with the highest OHCA occurrence in 2020 were November (13.2%) and October (11.1%) and were significantly higher compared to the same months during the pre-pandemic period (9.1%, p = 0.002 and 7.9%, p = 0.009, respectively). Autumn was the season with the highest rate of OHCA, which was also higher compared to the pre-pandemic period (30.5% vs. 25.1%, p = 0.003). The COVID-19 pandemic was related to a higher occurrence of OHCA. The circadian, monthly, and seasonal variabilities of OHCA occurrence were confirmed. In 2020, the highest occurrence of OHCA was observed in October and November, which coincided with the highest occurrence of COVID-19 infections in Poland.

The impact of mild therapeutic hypothermia on platelet reactivity in comatose survivors of cardiac arrest with acute myocardial infarction treated with ticagrelor

BACKGROUND

The aim of the study was to assess the antiplatelet effect of ticagrelor in patients with myocardial infarction (MI) after out-of-hospital cardiac arrest (OHCA) treated with percutaneous coronary intervention (PCI) and mild therapeutic hypothermia (MTH) vs. MI patients without OHCA treated with PCI.

METHODS

The study was designed and performed as a phase IV, single-center, investigator-initiated, prospective, observational study assessing the early pharmacodynamic effect (within first 24 h) of a ticagrelor loading dose (180 mg) in both groups of patients (MTH group vs. MI group). For assessment of ticagrelor pharmacodynamics Multiple Electrode Aggregometry (MEA) was applied.

RESULTS

Compared with the MTH group, platelet inhibition was persistently stronger in the MI group over the entire observation period (up to 24 h), with the highest difference at 4 hours after loading with ticagrelor (25.8 ± 26.4 vs. 75.8 ± 40.9 U, p = 0.002). As a consequence, there was a higher prevalence of high platelet reactivity in the MTH group, with the most explicit difference at 6 hours after the loading dose of ticagrelor (78% vs. 7%, p < 0.001).

CONCLUSIONS

In comparison with patients treated with primary PCI for uncomplicated MI, the antiplatelet effect of ticagrelor in patients with MI complicated with OHCA, undergoing MTH and primary PCI, is attenuated and delayed.

Can we lower the rates of cystectomy complications by modifying risk factors? A review of the literature

Introduction

Radical cystectomy (RC), beyond its therapeutic effect, is associated with significant rates of complications, hospital readmissions and mortality. In recent years much research has been made in order to clarify the main reasons of these events. This article, based on a literature review, presents the impact of risk factors on RC complications and highlights possible modifications of these factors to reach better RC outcome.

Material and methods

PubMed, Science Direct, Google Scholar databases were searched using key-words to identify studies about risk factors and RC complications between 2010 and 2021. A total of 96 articles were retrieved and studied as full-text versions. The most significant data was targeted, analysed and categorized according to the article’s design.

Results

All the most valuable risk factors of RC complications were grouped in patient-related, treatment-related risk factors and subgrouped in nonmodifiable, modifiable and potentially modifiable categories. All the modifiable and potentially modifiable risk factors were found to have considerable value, as their adjustment lowers the rates of morbidity and mortality.

Conclusions

Proper identification and adjustment of the risk factors present the possibility of better RC results. Although, in advanced disease and highly morbid cases, complications are not fully omit-table. Management of bladder cancer (BC) in high-volume centres using new technologies offers lower rates of complications. To sum up, rigorous interdisciplinary presurgical patient preparation should be implemented in BC management.

Calcified Urachal Cancer Managed by Partial Cystectomy: A Case Report

This report presents the case of a rare and aggressive cancer originating from the urachus in a 73-year-old female. After 12 years of observation due to a cystic lesion in the bladder dome, the patient rapidly developed haematuria and mucinuria. The use of multiple diagnostic measures suggested urachal malignancy. Partial cystectomy and urachal excision along with pelvic lymphadenectomy were performed. Urachal adenocarcinoma with negative surgical margins and lymph nodes was reported in pathology. Follow-up after 12 months did not reveal any cancer relapse. Epidemiological, clinical and therapeutic features of this disease are also discussed.

Influence of QRS duration and axis on response to cardiac resynchronization therapy in chronic heart failure with reduced left ventricular ejection fraction: A single center study including patients with left bundle branch block

BACKGROUND

The aim of the study was to evaluate QRS duration and axis as predictors of response to cardiac resynchronization therapy (CRT) in order to reduce the proportion of non-responders.

METHODS

Retrospective single-center study including 42 CRT recipients, with left bundle branch block (LBBB), left ventricular ejection fraction (LVEF) < 40%, in New York Heart Association (NYHA) class ≥ II. Response to CRT was declared as NYHA class improvement ≥ 1 (symptomatic) and LVEF improvement by ≥ 10% (echocardiographic) > 6 months post implantation.

RESULTS

Symptomatic responders had longer pre- (172.3 ± 17.9 vs. 159.0 ± 18.3 ms; p = 0.027) and postimplantation (157.2 ± 24.1 vs. 136.7 ± 23.2 ms; p = 0.009) QRS duration. Preimplantation QRS < 150 ms predicted poor response (odds ratio [OR] for response vs. lack of response 0.04; 95% confidence interval [CI] 0.001-0.74). Predictors of symptomatic response included: postimplantation QRS > 160 ms (OR 7.2; 95% CI 1.24-41.94), longer QRS duration before (OR for a 1 ms increase 1.04, 95% CI 1.00-1.08) and post implantation (OR for a 1 ms increase 1.04; 95% CI 1.01-1.07). Area under the curve (AUC) for pre- and postimplantation QRS duration was 0.672 (95% CI 0.51-0.84) and 0.727 (95% CI 0.57-0.89), respectively, with cut-off points of 178.5 ms and 157 ms. For post implantation QRS axis, AUC was 0.689 (95% CI 0.53-0.85), with cut-off points of -60.5° or -38.5°. Preimplantation QRS axis was the only predictor of echocardiographic response (OR 0.98; 95% CI 0.96-1.00), with AUC of 0.693 (95% CI 0.54-0.85) and a threshold of -36°.

CONCLUSIONS

Marked pre- and postimplantation QRS prolongation and preimplantation negative QRS axis deviation are moderate predictors of response to CRT.

Observational analysiS of out-of-hospital Cardiac Arrest occurRence and temporal variability patterns in subpopulation of southern POLand from 2006 to 2018: OSCAR-POL registry

BACKGROUND

Temporal variability of out-of-hospital cardiac arrest (OHCA) occurrence was presented in previous studies, however, the data regarding long-term observation is scarce. The aim of this study was to investigate the temporal variability of OHCA occurrence during a long-time period and analyze the circadian pattern within particular timeframes.

METHODS

The retrospective analysis of 5058 OHCA cases was made covering the period from January 1st, 2006 to December 31st, 2018. Circadian, weekly, monthly and seasonal variabilities were investigated. The circadian variability of OHCA occurrence was assessed within particular years, seasons of the year, and days of the week.

RESULTS

The highest OHCA incidence was observed between 08:00 and 08:59 and the lowest between 01:00 and 01:59 (7.1% vs. 1.6%, p < 0.001). After division into 6-h intervals, a significantly lower number of OHCA cases occurred between 00:00 and 05:59 (12.3%) in comparison to the highest number observed in between 06:00 and 11:59 (12.3% vs. 33.5%, p < 0.001). The highest OHCA occurrence was observed on Monday (14.9%), however, no weekly variability was found (p = 0.557). The highest OHCA occurrence was observed in the winter and lowest in the summer (27.4% vs. 22.8%, p < 0.001). Significant circadian variability was observed for every day of the week, every season and year during the observation period (p < 0.001).

CONCLUSIONS

Circadian, monthly and seasonal variability of OHCA occurrence was confirmed in the long-term observation with no differences between particular days of the week. Significant circadian variability was observed within days of the week, seasons of the year, and particular years.

Age-Graded Transitions and Turning Points in Polish Offenders' Criminal Careers from the Standpoint of Life Course Theory

Both juvenile and adult criminal careers show regularities in the origins of delinquency, the dynamics of the criminal pathway, and the turning points that lead to desistance/persistence in crime. Research shows that family, education, and friendship environments contribute significantly to the individual choices that create criminal biographies. Our aim was to apply core aspects of life course theory (LCT): trajectory, the aged-graded process, transitions, institutions, and ultimately how desistance/persistence factor into explaining the criminal careers of Polish offenders. The research is based on in-depth interviews (130) carried out with both offenders (90) and experts (40). The offenders were divided into two groups: 30 were juveniles, and 60 were adults of whom half were sentenced for the first time (30) and half were recidivists (30) located in correctional institutions or released. The experts group (40) includes psychologists, educators, social rehabilitators, and prison and juvenile detention personnel working with offenders. We used triangulation of researcher, data, and methodology. Our data revealed that similar biographical experiences characterized by an early socialization, family and friends-based circles laid the groundwork for their entry and continued participation in criminal activity. Juvenile and adult first-time sentenced offenders led criminal careers significantly different from those of recidivists, who faced problems with social adaptation caused by lack of family and institutional support.

Safety and Efficacy of Different Antithrombotic Strategies after Transcatheter Aortic Valve Implantation: A Network Meta-Analysis

BACKGROUND

 The optimal pharmacological therapy after transcatheter aortic valve implantation (TAVI) remains uncertain. We compared efficacy and safety of various antiplatelet and anticoagulant approaches after TAVI by a network meta-analysis.

METHODS

 A total of 14 studies (both observational and randomized) were considered, with 24,119 patients included. Primary safety endpoint was the incidence of any bleeding complications during follow-up. Secondary safety endpoint was major bleeding. Efficacy endpoints were stroke, myocardial infarction, and cardiovascular mortality. A frequentist network meta-analysis was conducted with a random-effects model. The following strategies were compared: dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT), oral anticoagulation (OAC), and OAC + SAPT. The mean follow-up was 15 months.

RESULTS

 In comparison to DAPT, SAPT was associated with a 44% risk reduction of any bleeding (odds ratio [OR]: 0.56 [95% confidence interval, CI: 0.39-0.80]). SAPT was ranked as the safest strategy for the prevention of any bleeding (p-score: 0.704), followed by OAC alone (p-score: 0.476) and DAPT (p-score: 0.437). Consistent results were observed for major bleeding. The incidence of cardiovascular death and secondary ischemic endpoints did not differ among the tested antithrombotic approaches. In patients with indication for long-term anticoagulation, OAC alone showed similar rates of stroke (OR: 0.92 [95% CI: 0.41-2.05], p = 0.83) and reduced occurrence of any bleeding (OR: 0.49 [95% CI: 0.37-0.66], p < 0.01) versus OAC + SAPT.

CONCLUSION

 The present network meta-analysis supports after TAVI the use of SAPT in patients without indication for OAC and OAC alone in those needing long-term anticoagulation.

Five-Year Comparative Efficacy of Everolimus-Eluting vs. Resolute Zotarolimus-Eluting Stents in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

Among drug-eluting stents (DESs), the durable polymer everolimus-eluting stent (EES) and resolute zotarolimus-eluting stent (R-ZES) are widely used in clinical practice and have contributed to improve the outcomes of patients undergoing percutaneous coronary intervention (PCI). Few studies addressed their long-term comparative performance in patients with acute coronary syndrome (ACS). We aimed to investigate the 5 year comparative efficacy of EES and R-ZES in ACS. We queried ACTION-ACS, a large-scale database of ACS patients undergoing PCI. The treatment groups were analyzed using propensity score matching. The primary endpoint was a composite of mortality, myocardial infarction (MI), stroke, repeat PCI, and definite or probable stent thrombosis, which was addressed at the five-year follow-up. A total of 3497 matched patients were analyzed. Compared with R-ZES, a significant reduction in the primary endpoint at 5 years was observed in patients treated with EES (hazard ratio (HR) [95%CI] = 0.62 [0.54-0.71], p < 0.001). By landmark analysis, differences between the two devices emerged after the first year and were maintained thereafter. The individual endpoints of mortality (HR [95%CI] = 0.70 [0.58-0.84], p < 0.01), MI (HR [95%CI] = 0.55 [0.42-0.74], p < 0.001), and repeat PCI (HR [95%CI] = 0.65 [0.53-0.73], p < 0.001) were all significantly lower in the EES-treated patients. Stroke risk did not differ between EES and R-ZES. In ACS, a greater long-term clinical efficacy with EES vs. R-ZES was observed. This difference became significant after the first year of the ACS episode and persisted thereafter.

Transcatheter aortic valve replacement with Lotus and Sapien 3 prosthetic valves: a systematic review and meta-analysis

Background

Frequent occurrence of paravalvular leak (PVL) after transcatheter aortic valve replacement (TAVR) was the main concern with early-generation devices and focused technological improvements. Current systematic review and meta-analysis sought to compare outcomes of TAVR for severe native valve stenosis with next-generation devices: Lotus and Sapien 3.

Methods

Electronic databases were screened for studies comparing outcomes of TAVR with Lotus and Sapien 3. In a random-effects meta-analysis, the pooled incidence rates of procedural, clinical and functional outcomes according to VARC-2 definitions were assessed.

Results

Eleven observational studies including 2,836 patients (Lotus N=862 vs. Sapien 3 N=1,974) met inclusion criteria. No differences were observed regarding composite endpoints—device success and early safety. Similarly, 30-day mortality, major vascular complications, acute kidney injury and serious bleeding events were similar with both devices. Lotus valve demonstrated 35% reduction of the risk for mild PVL: risk ratio (RR) 0.65, 95% confidence interval (CI): 0.49–0.85, P=0.002; but there were no statistical differences with regard to moderate/severe PVL (RR 0.56, 95% CI: 0.18–1.77, P=0.320). Lotus valves produced significantly higher mean transaortic gradients: mean difference (MD) 0.88 mmHg, 95% CI, 0.24–1.53 mmHg, P=0.007; however, without translation into higher rate of prosthesis-patient mismatch (RR 1.10, 95% CI: 0.82–1.47, P=0.540). As compared to Sapien 3, Lotus device placement was associated with significantly higher rate of permanent pacemaker implantation (RR 2.30, 95% CI: 1.95–2.71, P<0.00001) and cerebrovascular events (RR 1.76, 95% CI: 1.03–2.99, P=0.040).

Conclusions

Lotus valve, as compared with Sapien 3, was associated with lower risk for PVL but higher risk for permanent pacemaker implantation and cerebrovascular events.

Impact of mild therapeutic hypothermia on bioavailability of ticagrelor in patients with acute myocardial infarction after out-of-hospital cardiac arrest

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) frequently occurs in the early phase of acute myocardial infarction (MI). Survivors require percutaneous coronary intervention (PCI) with concomitant dual antiplatelet therapy. Target temperature management, including mild therapeutic hypothermia (MTH), should be applied in comatose patients after resuscitation. However, an increased risk of stent thrombosis in patients undergoing hypothermia is observed. The aim of this study was to assess the impact of MTH on pharmacokinetics of ticagrelor in cardiac arrest survivors with MI treated with MTH and PCI.

METHODS

In a prospective, observational, single-center study pharmacokinetics of ticagrelor were evaluated in 41 MI patients, including 11 patients after OHCA undergoing MTH (MTH group) and 30 MI patients without OHCA and MTH (no-MTH group). Blood samples were drawn before administration of a 180 mg ticagrelor loading dose, and 30 min, 1, 2, 4, 6, 12, and 24 h after the loading dose.

RESULTS

In patients treated with MTH total exposure to ticagrelor during the first 12 h after the loading dose and maximal plasma concentration of ticagrelor were significantly lower than in the no-MTH group (AUC(0-12): 3403 ± 2879 vs. 8746 ± 5596 ng·h/mL, difference: 61%, p = 0.01; Cmax: 475 ± 353 vs. 1568 ± 784 ng/mL, p = 0.0002). Time to achieve maximal ticagrelor plasma concentration was also delayed in the MTH group (tmax for ticagrelor: 12 [6-24] vs. 4 [2-12] h, p = 0.01).

CONCLUSIONS

Bioavailability of ticagrelor was substantially decreased and delayed in MI patients treated with MTH after OHCA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02611934.

Mild therapeutic hypothermia after out-of-hospital cardiac arrest: What does really matter?

BACKGROUND

Mild therapeutic hypothermia (MTH) is a recommended treatment of comatose patients after out-of-hospital cardiac arrest (OHCA). The aim of the study was to examine determinants of clinical outcome in OHCA survivors treated with MTH and variables associated with MTH induction time.

METHODS

Presented herein is an analysis of combined results from a retrospective and a prospective observational study which included 90 OHCA survivors treated with MTH from January 2010 to March 2018. Multivariate regression analysis was performed to determine variables associated with poor neurologic outcome (Cerebral Performance Category 3-5), mortality, and prolonged induction time.

RESULTS

At hospital discharge, 59 (65.6%) patients were alive, of whom 36 (61%) had a good neurologic outcome. Older patients (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.03-1.12) with lower Glasgow Coma Scale (GCS) (OR 0.49, 95% CI 0.30-0.80) were at higher risk of poor neurological outcome. The predictors of in-hospital death included: older age (OR 1.08, 95% CI 1.02-1.13), lower GCS score (OR 0.47, 95% CI 0.25-0.85), presence of cardiogenic shock (OR 3.43, 95% CI 1.11-10.53), and higher doses of adrenaline (OR 1.27, 95% CI 1.04-1.56). Longer induction was associated with shorter cardio-pulmonary resuscitation (CPR) (unstandardized coefficient -3.95, 95% CI -7.09 to -0.81) and lower lactate level (unstandardized coefficient -18.55, 95% CI -36.10 to -1.01).

CONCLUSIONS

Unfavorable neurologic outcome in OHCA patients treated with MTH is associated with age and lower GCS score. Risk factors for in-hospital mortality include age, high-dose adrenaline administration, lower GCS score and presence of cardiogenic shock. CPR duration and lactate level were predictive of prolonged MTH induction time.

Comparison of temperature measurements in esophagus and urinary bladder in comatose patients after cardiac arrest undergoing mild therapeutic hypothermia

BACKGROUND

Mild therapeutic hypothermia (MTH) is a recommended method of treatment for comatose out-of-hospital cardiac arrest (OHCA) survivors. However, the proper site of temperature measurement in MTH is still not defined. The aim of this study was to compare temperature measurements in the esophagus and urinary bladder in comatose post-OHCA patients treated with MTH.

METHODS

This temperature comparison protocol was a part of a prospective, observational, multicenter cohort study. The study population included 36 unconscious patients after resuscitation for OHCA. The patient's core temperature was independently measured every hour during MTH in the urinary bladder and in the esophagus.

RESULTS

The mean temperature was lower in the esophagus (differences during induction phase: 1.04 ± 0.92°C, p < 0.0001; stabilization phase: 0.54 ± 0.39°C, p < 0.0001; rewarming phase: 0.40 ± 0.47°C, p < 0.0001). Nevertheless, a strong correlation between both sites was found (R2 = 0.83, p < 0.001). The decrease in temperature observed in the esophagus during the induction phase was faster when compared with the urinary bladder (1.09 ± 0.71°C/h vs. 0.83 ± 0.41°C/h; p = 0.002). As a consequence, time to reach temperature < 34.0°C was longer when temperature was measured in the urinary bladder (the difference between medians of the time 1.0 [0-1.5] h, p < 0.001).

CONCLUSIONS

Urinary bladder temperature measurements may lag behind temperature changes measured in the esophagus. Monitoring temperature simultaneously in the esophagus and in the urinary bladder is an accessible and reliable combination, although esophageal measurements seem to better reflect the dynamics of temperature changes, thus it seems to be more appropriate for MTH control. ClinicalTrials.gov Identifier: NCT02611934.

Epidemiology and chronobiology of out-of-hospital cardiac arrest in a subpopulation of southern Poland: A two-year observation

BACKGROUND

Although recent studies indicate temporal variations in the incidence of out-of-hospital cardiac arrest (OHCA), the Polish experience in this research is scarce to date. We evaluated the epidemiology of OHCA and circadian, weekly and seasonal variations of OHCA frequency among the adult population of the Opole district, Poland.

METHODS

The retrospective analysis of 815 OHCA cases with presumed cardiac etiology was made based on dispatch cards from the Emergency Medical Center in Opole registered during a 2 year period (2006-2007).

RESULTS

The incidence of OHCA in the studied population was 1.56/1000 inhabitants per year. Mean age of the group was 69.2 ± 14.2 years, with the majority of men (63%), younger than women (66.1 vs. 74 years, p = 0.0001). The OHCA occurrence increased with age reaching a peak between 71 and 75 years. The incidence of OHCA stayed at stable low levels between 22:00 and 4:59 and started to increase at 5:00, with trimodal peaks: 8:00-10:59, 14:00-15:59 and 18.00-21.59. The lowest number of OHCA occurred from 00:00 to 5:59, the highest from 6:00 to 11:59 (13% vs. 32.4%, p < 0.001). The day with the lowest occurrence of OHCA was Friday, the highest Saturday (10.9% vs. 16%, p = 0.01). Summer was the season of the lowest incidence of OHCA, while winter - the highest (22.6% vs. 26%, p = 0.04). These seasons were the warmest and the coldest one, respectively (average temperature 18.5°C vs. 0°C, p < 0.001).

CONCLUSIONS

Circadian and less marked, weekly variability in OHCA occurrence were confirmed. Existing seasonal differences may be affected by temperature. This is the first Polish analysis of a large subpopulation, which also includes seasonal temperature data.

Paracrine Maturation and Migration of SH-SY5Y Cells by Dental Pulp Stem Cells

Neurological disorders are characterized by neurodegeneration and/or loss of neuronal function, which cannot be adequately repaired by the host. Therefore, there is need for novel treatment options such as cell-based therapies that aim to salvage or reconstitute the lost tissue or that stimulate host repair. The present study aimed to evaluate the paracrine effects of human dental pulp stem cells (hDPSCs) on the migration and neural maturation of human SH-SY5Y neuroblastoma cells. The hDPSC secretome had a significant chemoattractive effect on SH-SY5Y cells as shown by a transwell assay. To evaluate neural maturation, SH-SY5Y cells were first induced toward neuronal cells, after which they were exposed to the hDPSC secretome. In addition, SH-SY5Y cells subjected to the hDPSC secretome showed increased neuritogenesis compared with nonexposed cells. Maturated cells were shown to increase immune reactivity for neuronal markers compared with controls. Ultrastructurally, retinoic acid (RA) signaling and subsequent exposure to the hDPSC secretome induced a gradual rise in metabolic activity and neuronal features such as multivesicular bodies and cytoskeletal elements associated with cellular communication. In addition, electrophysiological recordings of differentiating cells demonstrated a transition toward a neuronal electrophysiological profile based on the maximum tetrodotoxin (TTX)–sensitive, Na+ current. Moreover, conditioned medium (CM)–hDPSC–maturated SH-SY5Y cells developed distinct features including, Cd2+-sensitive currents, which suggests that CM-hDPSC–maturated SH-SY5Y acquired voltage-gated Ca2+ channels. The results reported in this study demonstrate the potential of hDPSCs to support differentiation and recruitment of cells with neuronal precursor characteristics in a paracrine manner. Moreover, this in vitro experimental design showed that the widely used SH-SY5Y cell line can improve and simplify the preclinical in vitro research on the molecular mechanisms of stem cell–mediated neuronal regeneration.

Survival of Patients with Cystic Fibrosis Depending on Mutation Type and Nutritional Status

The purpose of the study was to evaluate the influence of nutrition and of the severity of mutation type on survival rate in cystic fibrosis (CF) patients. Data were longitudinally collected from 60 hospitalized adult CF patients, aged 18-50. The variables consisted of body mass index (BMI) ratio, Cole's BMI cut-off points, severity of mutation type, and survival rate of CF patients. We found that the mean BMI was strongly associated with the severity of mutation type and was significantly lower in patients with severe mutations of grade I and II. The mutation type significantly affected the patients' survival rate; survival was greater in patients with mild and undefined mutation types. The BMI and Cole's cut-off points also had a significant influence on survival rate. CF patients, who suffered from malnutrition and emaciation, had a shorter survival rate than those with proper nutritional status. In conclusion, the study findings confirmed a significant effect of nutritional status and of mutation type on survival rate of CF patients.

Characterization of Human CD8(+)TCR(-) Facilitating Cells In Vitro and In Vivo in a NOD/SCID/IL2rγ(null) Mouse Model

CD8(+)/TCR(-) facilitating cells (FCs) in mouse bone marrow (BM) significantly enhance engraftment of hematopoietic stem/progenitor cells (HSPCs). Human FC phenotype and mechanism of action remain to be defined. We report, for the first time, the phenotypic characterization of human FCs and correlation of phenotype with function. Approximately half of human FCs are CD8(+)/TCR(-)/CD56 negative (CD56(neg)); the remainder are CD8(+)/TCR(-)/CD56 bright (CD56(bright)). The CD56(neg) FC subpopulation significantly promotes homing of HSPCs to BM in nonobese diabetic/severe combined immunodeficiency/IL-2 receptor γ-chain knockout mouse recipients and enhances hematopoietic colony formation in vitro. The CD56(neg) FC subpopulation promotes rapid reconstitution of donor HSPCs without graft-versus-host disease (GVHD); recipients of CD56(bright) FCs plus HSPCs exhibit low donor chimerism early after transplantation, but the level of chimerism significantly increases with time. Recipients of HSPCs plus CD56(neg) or CD56(bright) FCs showed durable donor chimerism at significantly higher levels in BM. The majority of both FC subpopulations express CXCR4. Coculture of CD56(bright) FCs with HSPCs upregulates cathelicidin and β-defensin 2, factors that prime responsiveness of HSPCs to stromal cell-derived factor 1. Both FC subpopulations significantly upregulated mRNA expression of the HSPC growth factors and Flt3 ligand. These results indicate that human FCs exert a direct effect on HSPCs to enhance engraftment. Human FCs offer a potential regulatory cell-based therapy for enhancement of engraftment and prevention of GVHD.

Novel evidence that crosstalk between the complement, coagulation and fibrinolysis proteolytic cascades is involved in mobilization of hematopoietic stem/progenitor cells (HSPCs)

The role of blood proteinases in the mobilization of hematopoietic stem/progenitor cells (HSPCs) is still not well understood. As previously reported, activation of the complement cascade (ComC) and cleavage of C5 by C5 convertase are enabling events in the release of C5a that plays a crucial role in the egress of HSPCs from bone marrow (BM) into peripheral blood (PB) and explains why C5-deficient mice are poor mobilizers. Here we provide evidence that during granulocyte colony-stimulating factor- and AMD3100-induced mobilization, not only the ComC but also two other evolutionarily ancient proteolytic enzyme cascades, the coagulation cascade (CoaC) and the fibrynolytic cascade (FibC), become activated. Activation of all three cascades was measured by generation of C5a, decrease in prothrombin time and activated partial thromboplastin time as well as an increase in the concentrations of plasmin/antiplasmin and thrombin/antithrombin. More importantly, the CoaC and FibC, by generating thrombin and plasmin, respectively, provide C5 convertase activity, explaining why mobilization of HSPCs in C3-deficient mice, which do not generate ComC-generated C5a convertase, is not impaired. Our observations shed more light on how the CoaC and FibC modulate stem cell mobilization and may lead to the development of more efficient mobilization strategies in poor mobilizers. Furthermore, as it is known that all these cascades are activated in all the situations in which HSPCs are mobilized from BM into PB (for example, infections, tissue/organ damage or strenuous exercise) and show a circadian rhythm of activation, they must be involved in both stress-induced and circadian changes in HSPC trafficking in PB.

Parental imprinting regulates insulin-like growth factor signaling: a Rosetta Stone for understanding the biology of pluripotent stem cells, aging and cancerogenesis

In recent years, solid evidence has accumulated that insulin-like growth factor-1 (IGF-1) and 2 (IGF-2) regulate many biological processes in normal and malignant cells. Recently, more light has been shed on the epigenetic mechanisms regulating expression of genes involved in IGF signaling (IFS) and it has become evident that these mechanisms are crucial for initiation of embryogenesis, maintaining the quiescence of pluripotent stem cells deposited in adult tissues (for example, very-small embryonic-like stem cells), the aging process, and the malignant transformation of cells. The expression of several genes involved in IFS is regulated at the epigenetic level by imprinting/methylation within differentially methylated regions (DMRs), which regulate their expression from paternal or maternal chromosomes. The most important role in the regulation of IFS gene expression is played by the Igf-2-H19 locus, which encodes the autocrine/paracrine mitogen IGF-2 and the H19 gene, which gives rise to a non-coding RNA precursor of several microRNAs that negatively affect cell proliferation. Among these, miR-675 has recently been demonstrated to downregulate expression of the IGF-1 receptor. The proper imprinting of DMRs at the Igf-2-H19 locus, with methylation of the paternal chromosome and a lack of methylation on the maternal chromosome, regulates expression of these genes so that Igf-2 is transcribed only from the paternal chromosome and H19 (including miR-675) only from the maternal chromosome. In this review, we will discuss the relevance of (i) proper somatic imprinting, (ii) erasure of imprinting and (iii) loss of imprinting within the DMRs at the Igf-2-H19 locus to the expression of genes involved in IFS, and the consequences of these alternative patterns of imprinting for stem cell biology.

Pivotal role of paracrine effects in stem cell therapies in regenerative medicine: can we translate stem cell-secreted paracrine factors and microvesicles into better therapeutic strategies?

Although regenerative medicine is searching for pluripotent stem cells that could be employed for therapy, various types of more differentiated adult stem and progenitor cells are in meantime being employed in clinical trials to regenerate damaged organs (for example, heart, kidney or neural tissues). It is striking that, for a variety of these cells, the currently observed final outcomes of cellular therapies are often similar. This fact and the lack of convincing documentation for donor-recipient chimerism in treated tissues in most of the studies indicates that a mechanism other than transdifferentiation of cells infused systemically into peripheral blood or injected directly into damaged organs may have an important role. In this review, we will discuss the role of (i) growth factors, cytokines, chemokines and bioactive lipids and (ii) microvesicles (MVs) released from cells employed as cellular therapeutics in regenerative medicine. In particular, stem cells are a rich source of these soluble factors and MVs released from their surface may deliver RNA and microRNA into damaged organs. Based on these phenomena, we suggest that paracrine effects make major contributions in most of the currently reported positive results in clinical trials employing adult stem cells. We will also present possibilities for how these paracrine mechanisms could be exploited in regenerative medicine to achieve better therapeutic outcomes. This approach may yield critical improvements in current cell therapies before true pluripotent stem cells isolated in sufficient quantities from adult tissues and successfully expanded ex vivo will be employed in the clinic.

The bone marrow-expressed antimicrobial cationic peptide LL-37 enhances the responsiveness of hematopoietic stem progenitor cells to an SDF-1 gradient and accelerates their engraftment after transplantation

We report that the bone marrow (BM) stroma-released LL-37, a member of the cathelicidin family of antimicrobial peptides, primes/increases the responsiveness of murine and human hematopoietic stem/progenitor cells (HSPCs) to an α-chemokine stromal-derived factor-1 (SDF-1) gradient. Accordingly, LL-37 is upregulated in irradiated BM cells and enhances the chemotactic responsiveness of hematopoietic progenitors from all lineages to a low physiological SDF-1 gradient as well as increasing their (i) adhesiveness, (ii) SDF-1-mediated actin polymerization and (iii) MAPK(p42/44) phosphorylation. Mice transplanted with BM cells ex vivo primed by LL-37 showed accelerated recovery of platelet and neutrophil counts by ∼3-5 days compared with mice transplanted with unprimed control cells. These priming effects were not mediated by LL-37 binding to its receptor and depended instead on the incorporation of the CXCR4 receptor into membrane lipid rafts. We propose that LL-37, which has primarily antimicrobial functions and is harmless to mammalian cells, could be clinically applied to accelerate engraftment as an ex vivo priming agent for transplanted human HSPCs. This novel approach would be particularly important in cord blood transplantations, where the number of HSCs available is usually limited.

Conditioning for hematopoietic transplantation activates the complement cascade and induces a proteolytic environment in bone marrow: a novel role for bioactive lipids and soluble C5b-C9 as homing factors

We have observed that conditioning for hematopoietic transplantation by lethal irradiation induces a proteolytic microenvironment in the bone marrow (BM) that activates the complement cascade (CC). As a result, BM is enriched for proteolytic enzymes and the soluble form of the terminal product of CC activation, the membrane attack complex C5b-C9 (MAC). At the same time, proteolytic enzymes induced in irradiated BM impair the chemotactic activity of α-chemokine stromal-derived factor-1 (SDF-1). As SDF-1 is considered a crucial BM chemoattractant for transplanted hematopoietic stem/progenitor cells (HSPCs), we sought to determine whether other factors that are resistant to proteolytic enzymes have a role in this process, focusing on proteolysis-resistant bioactive lipids. We found that the concentrations of sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) increase in the BM after conditioning for transplantation and that both S1P and, as we show here for the first time, C1P are potent chemoattractants for HSPCs. Next, we observed that C5-deficient mice that do not generate MAC show impaired engraftment of HSPCs. In support of a role for MAC in homing and engraftment, we found that soluble MAC enhances in a CR3 (CD11b/CD18)-dependent manner the adhesion of HSPCs to BM stromal cells and increases the secretion of SDF-1 by BM stroma. We conclude that an increase in BM levels of proteolytic enzyme-resistant S1P and C1P and activation of CC, which leads to the generation of MAC, has an important and previously underappreciated role in the homing of transplanted HSPCs.

Hematopoietic differentiation of umbilical cord blood-derived very small embryonic/epiblast-like stem cells

A population of CD133⁺lin⁻CD45⁻ very small embryonic-like stem cells (VSELs) has been purified by multiparameter sorting from umbilical cord blood (UCB). In order to speed up isolation of these cells, we employed anti-CD133-conjugated paramagnetic beads followed by staining with Aldefluor to detect aldehyde dehydrogenase (ALDH) activity; we subsequently sorted CD45⁻/GlyA⁻/CD133⁺/ALDH^high and CD45⁻/GlyA⁻/CD133⁺/ALDH^low cells, which are enriched for VSELs, and CD45⁺/GlyA⁻/CD133⁺/ALDH^high and CD45⁺/GlyA⁻/CD133⁺/ALDH^low cells, which are enriched for hematopoietic stem/progenitor cells (HSPCs). While freshly isolated CD45⁻ VSELs did not grow hematopoietic colonies, the same cells, when activated/expanded over OP9 stromal support, acquired hematopoietic potential and grew colonies composed of CD45⁺ hematopoietic cells in methylcellulose cultures. We also observed that CD45⁻/GlyA⁻/CD133⁺/ALDH^high VSELs grew colonies earlier than CD45⁻/GlyA⁻/CD133⁺/ALDH^low VSELs, which suggests that the latter cells need more time to acquire hematopoietic commitment. In support of this possibility, real-time PCR analysis confirmed that, while freshly isolated CD45⁻/GlyA⁻/CD133⁺/ALDH^high VSELs express more hematopoietic transcripts (e.g., c-myb), CD45⁻/GlyA⁻/CD133⁺/ALDH^low VSELs exhibit higher levels of pluripotent stem cell markers (e.g., Oct-4). More importantly, hematopoietic cells derived from VSELs that were co-cultured over OP9 support were able to establish human lympho-hematopoietic chimerism in lethally irradiated NOD/SCID mice 4–6 weeks after transplantation. Overall, our data suggest that UCB-VSELs correspond to the most primitive population of HSPCs in UCB.

Stem cells for neural regeneration--a potential application of very small embryonic-like stem cells

The goal of regenerative medicine is to ameliorate irreversible destruction of brain tissue by harnessing the power of stem cells in the process of neurogenesis. Several types of stem cells, including mesenchymal stem cells, hematopoietic stem cells, as well as neural cells differentiated from embryonic stem cell lines, have been proposed as potential therapeutic vehicles. In this review paper we will discuss a perspective of stem cell therapies for neurological disorders with special emphasis on potential application of cells isolated from adult tissues. In support of this our group found that murine bone marrow contains a mobile population of Oct-4+CXCR4+SSEA-1+Sca-1+lin⁻CD45⁻ very small embryonic-like stem cells (VSELs) that are mobilized into peripheral blood in a murine stroke model. The number of these cells in circulation increases also after pharmacological mobilization by administration of granulocyte colony stimulating factor (G-CSF). Recently we found that VSELs are present in various non-hematopoietic adult organs and, interestingly, our data indicate that the brain contains a high number of cells that display the VSEL phenotype. Based on our published data both in human and mice we postulate that VSELs are a mobile population of epiblast/germ line-derived stem cells and play an important role as an organ-residing reserve population of pluripotent stem cells that give rise to stem cells committed to particular organs and tissues--including neural tissue. In conclusion human VSELs could be potentially harnessed in regenerative medicine as a source of stem cells for neurogenesis.

Innate immunity as orchestrator of stem cell mobilization

Hematopoietic stem and progenitor cells (HSPCs), as well as other types of stem cells, circulate under steady-state conditions at detectable levels in peripheral blood (PB), with their numbers increasing in response to stress, inflammation and tissue/organ injury. This mobilization process may be envisioned as a danger-sensing response mechanism triggered by hypoxia or mechanical or infection-induced tissue damage that recruits into PB different types of stem cells that have a role in immune surveillance and organ/tissue regeneration. Mobilization is also significantly enhanced by the administration of pharmacological agents, which has been exploited in hematological transplantology as a means to obtain HSPCs for hematopoietic reconstitution. In this review we will present mounting evidence that innate immunity orchestrates this evolutionarily conserved mechanism of HSPC mobilization.

Transmission electron microscopy characterization of Au/Pt/Ti/Pt/GaAs ohmic contacts for high power GaAs/InGaAs semiconductor lasers

We report on transmission electron microscopy studies of Au/Pt/Ti/Pt(10-30 nm) contact structures for high power GaAs/InGaAs semiconductor lasers. The studies showed that annealing at 450 degrees C of contact structures causes the reaction of whole Pt with substrate components (Ga and As) and the formation of Pt-GaAs interlayers with smooth interfaces as required for such structures. Annealing of the structures at 470 and 490 degrees C unfavourably affects the contact structure. At this condition, the strong downward diffusion of Au and Pt from the top layers causes a formation of Au-Pt pits, which break the Ti barrier. Transmission electron microscopy observation revealed that Au/Pt/Ti/Pt(10-30 nm) system annealed at 450 degrees C is appropriate for practical applications. The EDS technique used to identify the phase composition in the Pt(30 nm)/GaAs structure (specially produced for the EDS analysis) annealed at 450 degrees C showed that two layers were formed as a result of the reaction of the whole Pt layer with GaAs, and they consist of Ga, Pt and As. The top layer has the highest concentration of Ga. However, the bottom layer, which is close to the substrate, has the highest concentration of As.

Identification of electron beam vibration sources by separation of magnetic distortion from electric distortion on scanning electron microscope imaging

Different types of distortions in scanning electron microscopy require different methods of their elimination, and therefore influence of these types on particular elements of the SEM system should be known. The proposed method allows for separation of the direct influence of the magnetic field on the electron beam in the SEM chamber from its influence in the SEM column and from the distortions generated in the SEM scanning block. For this purpose, a series of distorted images is registered for several working distances (between the final aperture of the electron column and the specimen) and for several energies of the electrons. Magnitudes of the distortions are measured on these images. For each applied electron energy, the dependence of the results versus the working distance is approximated with the second-order polynomial function. The analysis of the polynomial coefficients allows for the separation of the above-mentioned kinds of distortions. The presented method enables a selection of the most efficient solution to the distortions reduction. It utilizes the SEM itself and does not need any additional equipment.

Transmission electron microscopy study of erbium silicide formation from Ti/Er stack for Schottky contact applications

In this paper, we present results of transmission electron microscopy studies on erbium silicide structures fabricated under various thermal conditions. A titanium cap has been used as a protective layer against oxidation during rapid thermal annealing of an erbium layer in a temperature range of 300-700 degrees C. Both layers (200 nm Ti and 25 nm Er) were deposited by electron-beam sputtering. The investigations have shown that the transformation of the 25-nm-thick erbium into erbium silicide is completed after annealing at 500 degrees C. At higher temperatures, the formation of a titanium silicide layer above erbium silicide is observed. The lowest Schottky barrier has been measured in the sample annealed at 700 degrees C.

Dependence of cathodoluminescence on layer resistance applied for measurement of thin-layer sheet resistance

The dependence of spatially and spectrally resolved cathodoluminescence in a scanning electron microscope on resistances in semiconductor structures, especially on the layer resistance, is reported. This previously unstudied dependence is utilized for thin-layer sheet-resistance measurement. The method is illustrated by an assessment of lateral confinements in semiconductor-laser heterostructures.

New approach to cathodoluminescence studies in application to InGaN/GaN laser diode degradation

Cathodoluminescence (CL) studies are widely applied in semi-conductor science and technology. However, for structures with a p-n junction the CL spatial distribution can be strongly affected by internal current flows of the electron beam induced current generated within the structure. This influence is the investigated in application to CL studies of degradation in aged laser diodes with InGaN multiquantum wells.

Impaired mobilization of hematopoietic stem/progenitor cells in C5-deficient mice supports the pivotal involvement of innate immunity in this process and reveals novel promobilization effects of granulocytes

We reported that complement cascade (CC) becomes activated in bone marrow (BM) during granulocyte colony-stimulating factor (G-CSF) mobilization of hematopoietic stem/progenitor cells (HSPCs) and showed that, although third CC component (C3)-deficient mice are easy mobilizers, fifth CC component (C5)-deficient mice mobilize very poorly. To explain this, we postulated that activation/cleavage of CC releases C3a and C5a anaphylatoxins that differently regulate mobilization. Accordingly, C3a, by enhancing responsiveness of HSPCs to decreasing concentrations of stromal-derived growth factor-1 (SDF-1) in BM, prevents mobilization and promotes their BM retention. Therefore, in this study, we focused on the mobilization-enhancing role of C5a. We found that C5a receptor (C5aR) is not expressed on the surface of HSPCs, and that C5a-mediated promobilization effects are mediated by stimulation of granulocytes. Overall, our data support the following model. First C5aR(+) granulocytes are chemoattracted by plasma C5 cleavage fragments, being the first wave of cells leaving BM. This facilitates a subsequent egress of HSPCs. In the next step, after leaving BM, granulocytes undergo degranulation in response to plasma C5a and secrete some cationic peptides (cathelicidin, beta-defensin) that, as shown here for the first time, highly enhance the responsiveness of HSPCs to plasma SDF-1 gradient. In conclusion, our data reveal the underappreciated central role of innate immunity in mobilization, in which C5 cleavage fragments through granulocytes orchestrate this process.

Defective engraftment of C3aR-/- hematopoietic stem progenitor cells shows a novel role of the C3a-C3aR axis in bone marrow homing

We reported that complement (C) becomes activated and cleaved in bone marrow during preconditioning for hematopoietic transplantation and the third C component (C3) cleavage fragments, C3a and (desArg)C3a, increase responsiveness of hematopoietic stem/progenitor cells (HSPCs) to stromal-derived factor-1 (SDF-1). We also showed that this homing-promoting effect is not C3a receptor (C3aR) dependent. Herein, we report our new observation that transplantation of C3aR(-/-) HSPCs into lethally irradiated recipients results in: (1) approximately 5-7 day delay in recovery of platelets and leukocytes; (2) decrease in formation of day 12 colony-forming units-spleen; and (3) decrease in the number of donor-derived CFU-granulocyte-macrophage progenitors detectable in the bone marrow cavities at day 16 after transplantation. In agreement with the murine data, blockage of C3aR on human umbilical cord blood CD34(+) cells by C3aR antagonist SB290157 impairs their engraftment in non-obese diabetic/severe combined immunodeficient mice. However, HSPCs from C3aR(-/-) mice stimulated by C3a still better responded to SDF-1 gradient, after exposure to C3a, they secrete less matrix metalloprotease-9 and show impaired adhesion to stroma cells. We conclude that C3a, in addition to enhancing responsiveness of HSPCs to SDF-1 gradient in a C3aR independent manner, may also directly modulate HSPC homing by augmenting C3aR-mediated secretion of matrix metalloprotease-9 and cell adhesion.

Very small embryonic-like stem cells in adult tissues-potential implications for aging

Recently our group identified in murine bone marrow (BM) and human cord blood (CB), a rare population of very small embryonic-like (VSEL) stem cells. We hypothesize that these cells are deposited during embryonic development in BM as a mobile pool of circulating pluripotent stem cells (PSC) that play a pivotal role in postnatal tissue turnover both of non-hematopoietic and hematopoietic tissues. During in vitro co-cultures with murine myoblastic C2C12 cells, VSELs form spheres that contain primitive stem cells. Cells isolated from these spheres may give rise to cells from all three germ layers when plated in tissue specific media. The number of murine VSELs and their ability to form spheres decreases with the age and is reduced in short-living murine strains. Thus, developmental deposition of VSELs in adult tissues may potentially play an underappreciated role in regulating the rejuvenation of senescent organs. We envision that the regenerative potential of these cells could be harnessed to decelerate aging processes.

Identification of very small embryonic like (VSEL) stem cells in bone marrow

Bone marrow (BM) develops in mammals by the end of the second/beginning of the third trimester of gestation and becomes a major hematopoietic organ in postnatal life. The alpha-chemokine stromal derived factor-1 (SDF-1) to CXCR4 (G ai-protein-coupled seven transmembrane-spanning chemokine receptor) axis plays a major role in BM colonization by stem cells. By the end of the second trimester of gestation, BM becomes colonized by hematopoietic stem cells (HSC), which are chemoattracted from the fetal liver in a CXCR4-SDF-1-dependent manner. Whereas CXCR4 is expressed on HSC, SDF-1 is secreted by BM stroma and osteoblasts that line BM cavities. Mounting evidence indicates that BM also contains rare CXCR4(+) pluripotent stem cells (PSC). Recently, our group has identified a population of CXCR4(+) very small embryonic like stem cells in murine BM and human cord blood. We hypothesize that these cells are deposited during development in BM as a mobile pool of circulating PSC that play a pivotal role in postnatal tissue turnover, both of non-hematopoietic and hematopoietic tissues.

A hypothesis for an embryonic origin of pluripotent Oct-4(+) stem cells in adult bone marrow and other tissues

Accumulating evidence demonstrates that adult tissues contain a population of stem cells that express early developmental markers such as stage-specific embryonic antigen and transcription factors Oct-4 and Nanog. These are the markers characteristic for embryonic stem cells, epiblast stem cells and primordial germ cells. The presence of these stem cells in adult tissues including bone marrow, epidermis, bronchial epithelium, myocardium, pancreas and testes supports the concept that adult tissues contain some population of pluripotent stem cells that is deposited in embryogenesis during early gastrulation. In this review we will discuss these data and present a hypothesis that these cells could be direct descendants of the germ lineage. The germ lineage in order to pass genes on to the next generations creates soma and thus becomes a 'mother lineage' for all somatic cell lineages present in the adult body.

Cleavage fragments of the third complement component (C3) enhance stromal derived factor-1 (SDF-1)-mediated platelet production during reactive postbleeding thrombocytosis

We hypothesized that the third complement component (C3) cleavage fragments (C3a and (des-Arg)C3a) are involved in stress/inflammation-related thrombocytosis, and investigated their potential role in reactive thrombocytosis induced by bleeding. We found that platelet counts are lower in C3-deficient mice in response to excessive bleeding as compared to normal littermates and that C3a and (des-Arg)C3a enhance stromal-derived factor-1 (SDF-1)-dependent megakaryocyte (Megs) migration, adhesion and platelet shedding. At the molecular level, C3a stimulates in Megs MAPKp42/44 phosphorylation, and enhances incorporation of CXCR4 into membrane lipid rafts increasing the responsiveness of Megs to SDF-1. We found that perturbation of lipid raft formation by statins decreases SDF-1/C3a-dependent platelet production in vitro and in an in vivo model statins ameliorated post-bleeding thrombocytosis. Thus, inhibition of lipid raft formation could find potential clinical application as a means of ameliorating some forms of thrombocytosis.

In situ electron beam induced current measurements of the local thickness in semiconductor devices

A quantitative electron beam induced current method is shown, applicable in situ for electron beam current measurement on a semiconductor sample without the need for a Faraday cup. As a validation technique, the measurement of top overlayer thickness in the semiconductor structure was chosen for two reasons. First, the measured thickness is easily verified using the same electron microscope in the secondary electron mode by measuring the layer thickness at the layer edges. Second, the measurement of a layer thickness and its local variations constitute an important issue in semiconductor processing and characterization. The proposed method is used in the planar view of the sample, and also for locations far from the layer edges. Quasi-three-dimensional maps of the thickness spatial distribution are presented.

Transmission electron microscopy characterization of the erbium silicide formation process using a Pt/Er stack on a silicon-on-insulator substrate

Very thin erbium silicide layers have been used as source and drain contacts to n-type Si in low Schottky barrier MOSFETs on silicon-on-insulator substrates. Erbium silicide is formed by a solid-state reaction between the metal and silicon during annealing. The influence of annealing temperature (450 degrees C, 525 degrees C and 600 degrees C) on the formation of an erbium silicide layer in the Pt/Er/Si/SiO(2)/Si structure was analysed by means of cross-sectional transmission electron microscopy. The Si grains/interlayer formed at the interface and the presence of Si grains within the Er-related layer constitute proof that Si reacts with Er in the presence of a Pt top layer in the temperature range 450-600 degrees C. The process of silicide formation in the Pt/Er/Si structure differs from that in the Er/Si structure. At 600 degrees C, the Pt top layer vanishes and a (Pt-Er)Si(x) system is formed.

Buried amorphous-layer impact on dislocation densities in silicon

The impact of amorphous layers on dislocation densities in silicon piezo-resistors was investigated by means of transmission electron microscopy and chemical etching. Mechanical bevel polishing at a shallow angle and selective etching were applied to assess the dislocation depth distributions. It was found that, despite the presence of additional defects after recrystallization, the initial presence of a buried amorphous layer reduced, after annealing, the dislocation density in the depletion region of a p-n junction, compared with the case of a shallower, surface amorphous layer.