Recovery of vanadium and nickel from heavy oil fly ash (HOFA): a critical review

Heavy oil fly ash "HOFA" is the fly ash generated in power stations using heavy oil as fuel. HOFA is considered a hazardous waste because it contains considerable amounts of heavy metals. However, it contains significant amounts of vanadium "V" and nickel "Ni", which are precious metals for manufacturing processes. This paper presents a critical review of various approaches described in the literature for the recovery of V and Ni from HOFA, including processes of leaching, chemical precipitation, solvent extraction, and ion exchange. The optimum operational parameters and their effects on recovery efficiency are discussed. The digestion mixtures of strong mineral acids used for dissolving all metals present in HOFA are also highlighted. The leaching processes of V and Ni use mainly acidic and alkaline solutions. Bioleaching is a promising environmentally friendly approach for the recovery of V and Ni through using appropriate bacteria and fungi. After leaching, V and Ni compounds are recovered and purified using various techniques, including chemical precipitation, solvent extraction, and ion exchange. In most cases, V and Ni are recovered as thermally decomposable compounds that undergo calcination to produce V₂O₅ and NiO. Eventually, V and Ni are recovered as pure oxides in most approaches, but pure metals are obtained in exceptional procedures.

Positron emission tomography/computed tomography perfusion imaging with myocardial blood flow has diagnostic and prognostic value for cardiac allograft vasculopathy

Background

Cardiac allograft vasculopathy (CAV) is a leading cause of morbidity and mortality in patients with orthotopic heart transplantation (OHT). Invasive coronary angiography is the traditional method of screening for and diagnosing CAV. Alternative non-invasive modalities have been sought to screen for CAV. A small, single-center study utilizing Positron Emission Tomography/Computed Tomography Perfusion Imaging (PET/CT) with stress myocardial blood flow (MBF) demonstrated good diagnostic and prognostic value for CAV.

Purpose

The purpose of this study was to validate the proposed algorithm for diagnosing and prognosticating CAV by PET/CT with stress MBF in a large and contemporary series.

Methods

Patients with a history of OHT with no prior revascularization in the transplanted heart who underwent PET/CT with MBF were included in the prognostic portion of the study. For the diagnostic value of PET/CT with MBF, only patients who had a PET/CT within 12 months of coronary angiography were included. The diagnostic accuracy of PET/CT was compared to the most recent coronary angiogram. A composite outcome of death, heart failure hospitalization, acute coronary syndrome, revascularization, and re-transplantation was used to validate the prognostic ability of PET/CT with MBF.

Results

450 PET/CT scans with MBF were performed and included in the prognostic portion of the study. 78 patients had PET/CT within 12 months of coronary angiography and were included in the diagnostic portion. Normal perfusion with normal myocardial blood flow had a 100% negative predictive value for moderate-severe CAV by angiography. PET/CT CAV 2/3 had a positive predictive value of 69% for moderate-severe CAV. Over 24 months, there were 20 events in the 39 patients with a PET CAV grade of 2/3 versus 21 events in the 411 patients with a PET CAV grade of 0/1 with a hazard ratio 13.3 (p<0.001).

Conclusions

The current proposed algorithm for diagnosing CAV by PET/CT with stress MBF has excellent negative predictive value along with good positive predictive value for detecting moderate-severe CAV by coronary angiography. A PET/CT with stress MBF with CAV classification of 2/3 is associated with a poor prognosis.

Funding Acknowledgement

Type of funding sources: None.

Comparison of CT acquired valvular calcification scores in hemodialysis vs peritoneal dialysis patients undergoing open heart surgery

Background

Several factors have been identified as independent risk factors for cardiac valvular calcification (CVC), including but not limited to age, inflammatory conditions, loss of calcification inhibitors, and dysregulated bone mineral metabolism. However, data is scarce regarding which dialysis modality portends more severe CVC.

Purpose

Our aim was to compare the degree of valvular calcification in hemodialysis (HD) and peritoneal dialysis (PD) patients prior to open heart surgery (OHS) using a computed CT calcium score.

Methods

Dialysis patients who underwent OHS at our institution from 2009–2019 who had a pre-surgical cardiac CT were grouped according to duration of dialysis modality prior to their surgical date. There were two study cohorts to evaluate outcomes of interest: mitral and aortic calcification. We included the first surgical record per patient for patients undergoing isolated CABG, or CABG+valve surgery (repair or replacement), or valve-only surgery (repair or replacement). To evaluate mitral calcification, we excluded any patients undergoing any mitral valve surgery (repair or replacement). We also excluded patients with a history of mitral valve repair/replacement. To evaluate aortic calcification, we excluded any patients undergoing any aortic valve surgery (repair or replacement). We also excluded patients with a history of aortic valve repair/replacement. Mitral annular and aortic valvular calcification were assessed using the Agatston score. Logistic regression was performed to test for the association of PD and HD cumulative dialysis duration with presence of valvular calcification.

Results

A total of 296 patients met inclusion criteria for at least one of the strata in our study. Of those, 214 met inclusion for the mitral strata, and 166 met criteria for the aortic strata (Table 1). In the logistic regression model for the mitral strata, age and female sex were associated with higher odds of presence of mitral calcification (Figure 1). Cumulative years on PD and cumulative years on HD were not significantly associated with presence of mitral calcification. In the logistic regression model for the aortic strata, age was associated with higher odds of presence of aortic calcification, while female sex was associated with lower odds (Figure 1). Cumulative years on PD and cumulative years on HD were not significantly associated with presence of aortic calcification.

Conclusion

Presence of mitral and aortic calcification for patients undergoing OHS was not significantly associated with cumulative length of PD or HD after adjusting for age and gender, suggesting that there may be more factors at play in the progression of valvular calcification in end stage renal disease patients than what was previously thought.

Funding Acknowledgement

Type of funding sources: None.

Impact of doppler velocity index after transcatheter aortic valve replacement using Sapien-3 valve – a single centre experience

Background

Little is known about the hemodynamic performance of Edwards Sapien-3 (S3) valve after Transcatheter Aortic Valve Replacement (TAVR). Doppler velocity index (DVI) is a better indicator of prosthetic valve function as it is independent of valve size and flow, unlike mean gradient and peak velocity which are flow-dependent.

Methods

In this study, we compare outcomes based on differences in DVI among a consecutive series of patients who underwent S3 TAVR between April 2015 and December 2018. Our institutional review board approved the study and informed consents were obtained from the subjects.

Results

Among 921 patients who had follow-up echocardiograms within 30 days after TAVR, 60.8% had DVI ≤0.5, while 39.2% had DVI >0.5. The median 30-day DVI was 0.47 with a standard deviation of 0.11 and mean 0.49 and interquartile range 0.41–0.55. The baseline clinical and procedural characteristics were similar between both groups with the exception of less post-dilation (36.8% vs. 47.4%; p=0.001) and greater implantation depth (2.59±1.99 vs. 2.31±1.9mm; p=0.031) with DVI ≤0.5. The rates of aortic valve calcification, pre dilation, pre-TAVR aortic regurgitation (AR) were similar. At baseline, there were no differences between both groups in mean or peak gradients or aortic velocity time integral (VTI). At 1 year, mean gradients were higher with DVI ≤0.5 (12.7±5.6 vs. 11.1±4.6 mmHg; p=0.001). DVI ≤0.5 was associated with higher peak gradients (24.2±10.2 vs. 21.4±8.7 mmHg; p=0.002), and aortic VTI (51.4±13.5 vs. 46.8±12.2 cm; p<0.001) at 1 year, especially with the 26mm and 29mm prostheses. Compared with DVI>0.5 group, patients in DVI<0.5 group had lower baseline left ventricular ejection fraction (LVEF) (54.5±12.2% vs. 58.9±11.2%; p<0.001), higher left ventricular end-diastolic volume index (LVEDVi) (54.3±20.9 vs. 49.4±17.4 ml/m2; p=0.001), higher LV end-systolic volume index (LVESVi) (25.2±16.5 vs. 21.3±12.7 ml/m2; p=0.001), and similar LV mass index (110.7±31.9 vs. 106.9±32.7 g/m2; p=0.134). 1-year mortality rates among patients who had DVI ≤0.5 compared to DVI >0.5 were lower (6.6% vs. 10.6%; log-rank p=0.033), however no difference was noted at both 2 years (17.3% vs. 20.1%; log-rank p=0.151), and 3 years after TAVR (30.7% vs. 31.2%; log-rank p=0.333).

Conclusions

DVI<0.5 was associated with higher peak gradients and lower baseline LVEF. DVI <0.5 group patients had lower 1-year mortality but similar mortality at 2 and 3-years of follow up.

Funding Acknowledgement

Type of funding sources: None. Figure 1. All-cause SurvivalFigure 2. Hemodynamic Data

Prognostic value of the hemodynamic gain index in different groups of patients undergoing cardiopulmonary exercise stress testing

Background

A novel hemodynamic parameter obtained from the cardiopulmonary exercise testing (CPET), the hemodynamic gain index (HGI), was developed and shown to be a strong independent predictor of all-cause mortality in a large male cohort. The HGI also strongly correlates with exercise parameters such as peak oxygen consumption and metabolic equivalents (METs). However, prognostic implications of the HGI have not been externally validated with subgroup analyses based on sex, heart failure (HF), coronary artery disease (CAD) and the use of beta-blockers.

Purpose

We aimed to validate the prognostic value of the HGI in men, women, and patients with and without HF, CAD, and beta-blocker use.

Methods

We identified 126,356 consecutive patients undergoing treadmill exercise testing for symptom evaluation between 1/1/1991–02/27/2015. HGI was calculated using the formula, [(SBPpeak x HRpeak) − (SBPrest x HRrest)] / (SBPrest x HRrest). Univariable and multivariable cox regression models were used to determine the associations between the HGI stratified by quartiles and all-cause mortality at 10 years with adjustment for cardiovascular risk factors (age, sex, diabetes, hypertension, dyslipidemia, chronic kidney disease, smoking status and body mass index) and exercise testing parameters (chronotropic reserve index, METs, abnormal heart rate recovery, and total exercise time).

Results

In our study cohort, mean age was 53.5±12.6 years. There were 74,724 (59.1%) male, 5,940 (4.7%) HF, 21,123 (16.7%) CAD, and 30,568 (24.2%) beta-blocker-using patients. During the mean follow up of 8.7 years, 9,929 (7.9%) died. Mean HGI was 2.0±1.2 bpm/mmHg. Lower HGI was associated with all-cause mortality in the entire cohort (Figure 1A, log rank p<0.001). After adjustment for the covariates, the lowest quartile of the HGI was independently associated with all-cause mortality in subgroups of men, women, and patients with and without HF, CAD, and beta-blocker use (Figure 1B, all p≤0.001) compared with the highest quartile of the HGI.

Conclusions

HGI is an independent predictor of long-term mortality after adjusted for traditional cardiovascular risk factors, and exercise performance across patient subgroups.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Kaplan-Meier curve and Cox regression

Impact of pacing-related differences on clinical and echocardiographic outcomes after TAVR with SAPIEN-3 valve

Background

Data regarding the impact of pacing on outcomes after transcatheter aortic valve replacement (TAVR) is evolving especially with regards to pre-existing PPM. We examined the impact of new and prior PPM on clinical and hemodynamic outcomes after SAPIEN-3 (S3) TAVR.

Methods

Consecutive patients who underwent transfemoral-TAVR using S3 valve between April 2015 and December 2018 at our Clinic were included.

Results

Among 1028 patients, 10.2% required new PPM within 30 days, while 14% had pre-existing PPM. The presence of either prior or new PPM had no impact on 3-year mortality (log-rank p=0.6), or 1-year major adverse cardiac and cerebrovascular event (MACCE) (log-rank p=0.65). New PPM was associated with lower left ventricular ejection fraction (LVEF) at both 30 days (54.4±11.3% vs. 58.4±10.1%; p=0.001), and 1 year (54.2±12% vs. 59.1±9.9%; p=0.009) compared to no PPM. Similarly, prior PPM was associated with worse LVEF at 30 days (53.6±12.3%; p<0.001) and 1 year (55.5±12.1%; p=0.006) compared to no PPM. Interestingly, new PPM was associated with lower 1-year mean gradient (11.4±3.8 vs. 12.6±5.6 mmHg; p=0.04), and peak gradient (21.3±6.5 vs. 24.1±10.4 mmHg; p=0.01) despite no baseline differences. Prior PPM was also associated with lower 1-year mean gradient (10.3±4.4 mmHg; p=0.001), and peak gradient (19.4±8 mmHg; p<0.001), and higher doppler velocity index (0.51±0.12 vs. 0.47±0.13; p=0.039). Moreover, 1-year LV end-systolic volume (LVESVi) was higher with new (23.2±16.1 vs. 20±10.8 ml/m2; p=0.038), and prior PPM (24.5±19.7; p=0.038) compared to no PPM. Prior PPM was associated with higher moderate-to-severe tricuspid regurgitation (35.3% vs. 17.7%; p<0.001). There were no differences with regards to the rest of the studied echocardiographic outcomes at 1 year.

Conclusion

In this S3 cohort, new and prior PPM did not affect 3-year mortality or 1-year MACCE, however they were associated with worse LVEF, higher LVESVi and lower mean and peak gradients on follow-up compared to no PPM.

Funding Acknowledgement

Type of funding sources: None. Figure 1. All-cause Survival

Outcomes of transfemoral-transcatheter aortic valve replacement with Sapien-3 valve in liver cirrhosis patients

Background

Little is known about the outcomes of liver cirrhosis patients with severe aortic stenosis (AS) who undergo transcatheter aortic valve replacement (TAVR).

Methods

We undertook a retrospective analysis of consecutive patients with severe symptomatic AS who underwent transfemoral-TAVR with Sapien-3 valve at our Clinic between April 2015 and December 2018, yielding 32 patients with liver cirrhosis on imaging including ultrasound and/or computed tomography. Their baseline characteristics, procedural and long-term outcomes after TAVR with the non-cirrhotic group were compared, along with their management strategies as per the hepatology team.

Results

Among 1028 patients, 32 were assigned to the cirrhosis, and 996 were assigned to the non-cirrhosis (control) group. Compared with the control group cirrhotic patients were slightly younger in age (74.5 vs 81.2 years), had a slightly higher BMI (31.3 vs 29.3), and had a higher incidence of prior history of myocardial infarction (38% vs 33%). Baseline variables including the history of smoking, hypertension, diabetes, and atrial fibrillation were comparable in both groups. Among cirrhotic patients (n=32), the most common etiologies were non-alcoholic steatohepatitis (NASH) (37.5%), Alcoholism (18.75%), and Hepatitis C (12.5%). The mean MELD-NA score was 11.8 and 67% of patients were Child PUGH Class A and 33% were Child PUGH Class B and all patients had a Child PUGH score of ≥5. 53% of patients (n=17) in the cirrhosis group were evaluated by Hepatology and 12.5% (n=4) were evaluated for a liver transplant but only 1 patient had a liver transplant post-TAVR. Compared with the control group cirrhotic patients had similar 1-year mortality (12% vs 12%, p=1), had a lower rate of 30-day new pacemaker post tavr (6% vs 9% p=0.85), had a higher rate of 1-year readmission for heart failure (12% vs 5% p=0.12) and similar 1-year major adverse cardiac and cerebrovascular event (MACCE) rate (15% vs 14% p=0.98)

Conclusion

Patients with severe AS undergoing TAVR with concomitant liver cirrhosis demonstrate comparable outcomes compared with their non- cirrhotic counterparts. NASH followed by alcoholic cirrhosis was found to be most common etiology.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Gender differences in exercise stress testing protocol selection, exercise capacity, and prognostic value of METs

Background

Exercise capacity, as measured by metabolic equivalents of task [METs], varies with gender and is an independent predictor of mortality. We sought to investigate gender differences in the protocol selected, the estimated exercise capacity, and the prognostic value of METs.

Purpose

Investigate the gender differences in the protocol chosen (adjusting for age and comorbidities), the METs achieved (also adjusting for the protocol selected), and the predictive value of exercise capacity adjusted to METs achieved.

Methods

In a 25-year stress testing registry spanning from 1991 to 2015, we identified 120,705 patients who underwent exercise stress testing. Protocols were split into Bruce vs. non-Bruce. METs were estimated based on established gender-specific formulas (the St James Take Heart Project formula for women, and the Veterans Affairs cohort formula for men).The primary outcome was all-cause mortality.

Results

The mean age was 53.3±12.5 years, and 59% were male. Table 1 presents the baseline characteristics and exercise parameters. A total of 8426 death occurred over 8.7 years of mean follow-up duration. Females were more commonly referred for non-Bruce protocols [adjusted OR 2.6; 95% CI (2.5–2.7)] even after adjusting for age and comorbidities. Within the same protocol chosen, females achieved lower estimated METs [Beta −1.4; 95% CI (−1.43 to −1.37)]. Exercise capacity was inversely related to mortality in both genders and across protocols (figure 1), however, after adjusting for age, comorbidities, protocol chosen, and the number of METs achieved, the HR for death was significantly lower for women [adjusted HR=0.44; 95% CI (0.41–0.46)].

Conclusion

After adjusting for age and comorbidities, women tend to be more commonly referred for non-Bruce protocols, achieve less estimated METs (after adjusting for the protocol chosen), and have half the mortality for the same METs achieved.

Death vs. Exercise capacity by gender

Funding Acknowledgement

Type of funding source: None

4097Validation of seven different exercise treadmill stress testing protocols in a large 25-year stress testing registry

Background

While the Bruce protocol has been extensively validated, other modified exercise protocols with less workload burden are commonly used, though their prognostic value is not well established.

Purpose

We sought to assess whether exercise capacity (or workload achieved in metabolic equivalents of task [METs]) remains predictive of mortality across various exercise stress testing protocols.

Methods

In a 25-year stress testing registry spanning from 1991 to 2015, we identified 120,705 patients who underwent 7 different standardized symptom-limited exercise stress testing protocols: Bruce, Modified Bruce, Cornell 0%, Cornell 5%, Cornell 10%, Naughton, and modified Naughton. The choice of the protocol was dependent on the supervising exercise physiologist according to purpose of the test and the individual patient. The primary outcome was all-cause mortality.

Results

Mean age was 53.3±12.5 years and 59% were male. There were 74953 Bruce, 8368 modified Bruce, 2648 Cornell 0%, 9972 Cornell 5%, 20425 Cornell 10% 1226 Naughton, and 3113 modified Naughton individual protocols. A total of 8426 death occurred over 8.7 years of mean follow-up duration. Figure 1 shows that there was an inverse relationship between peak METs achieved and mortality across all 7 protocols. On multivariable analysis, increasing METs remained protective against death [adjusted HR of 0.46; 95% CI (0.44 - 0.48); p<0.001] even after adjusting for the protocol chosen, age, gender, hypertension, diabetes, coronary disease, end-stage renal disease, smoking, and statin use.

METS vs. mortality by protocol

Conclusion

Across 7 different exercise protocols with various workloads, the predicted exercise capacity remained predictive of mortality irrespective of the protocol chosen, patients' demographics and comorbidities. Different testing choices likely represent different estimated functional capacity.

P1512The selected stress testing protocol is independently associated with mortality irrespective of exercise capacity and comorbidities

Background

A variety of exercise stress testing protocols with various workloads are available. The test protocol is typically selected according to patient's expected exercise performance.

Purpose

We sought to assess whether the choice of the protocol is by itself independently associated with mortality even after adjusting for clinical variables and estimated workload achieved in metabolic equivalents of task (METS).

Methods

In a 25-year stress testing registry spanning from 1991 to 2015, we identified 120,705 patients who underwent 7 different standardized exercise protocols: Bruce, Modified Bruce, Cornell 0%, 5%, and 10%, Naughton, and modified Naughton. The choice of the protocol was dependent on the supervising exercise physiologist, mainly according to patient's expected exercise performance. The primary outcome was all-cause mortality.

Results

Mean age was 53.3±12.5 years and 59% were male. There were 74953 Bruce, 8368 modified Bruce, 2648 Cornell 0%, 9972 Cornell 5%, 20425 Cornell 10% 1226 Naughton, and 3113 modified Naughton protocols. A total of 8426 death occurred over 8.7 years of mean follow-up duration. Table 1 presents the baseline characteristics by protocol. After adjusting for the number of METs, age, gender, hypertension, diabetes, coronary disease, end-stage renal disease, smoking, and statin use, the protocol selected remained predictive of mortality. Figure 1 shows the adjusted HR for death by protocol selected when compared to Bruce.

Baseline characteristics by protocol Variable Bruce (n=74953) Modified Bruce (n=8368) Cornell 0% (n=2648) Cornell 5% (n=9972) Cornell 10% (n=20425) Naughton (n=1226) Modified Naughton (n=3113) Age, mean ± SD 49.4±11.3 61.3±10.3 66.4±11.7 62.5±11.8 57.2±11.5 67.5±9.8 55.5±11.9 Male, % 64.6 51.8 37.8 42.3 51.7 49 66.7 Coronary disease, % 8.7 32.5 31.7 26.7 21.1 49.7 45.6 Diabetes mellitus, % 7.6 16.5 25.3 20 14.2 27.2 26.2 Hypertension, % 41.7 64 85.4 77.9 67.1 82.5 97.5 Smoker, % 40.9 55 50.7 50.9 50.8 56.9 60.6 ESRD, % 0.7 1 3.7 2.4 1.6 2.7 8.1 Mets, mean ± SD 10.3±2.4 7.2±1.7 5.2±1.6 6.7±1.5 8.3±1.9 4.8±1.5 4.6±1.5 Statin use, % 22.4 15.2 41.8 38.3 35.1 19 40.1 ESRD = end-stage renal disease; METS = metabolic equivalents of task.

Adjusted HR by protocol selected

Conclusion

The choice of the stress testing protocol, which is in large part dependent on patient's expected exercise performance is in itself independently associated with mortality even after adjustment for METs achieved and patients' demographics and comorbidities. The choice of the modified-Naughton is associated with the greatest risk of mortality, likely chosen based on limited functional capacity

Influence of grain size on radionuclide activity concentrations and radiological hazard of building material samples

The knowledge of radioactivity content in various radionuclides in building materials plays an important role in health physics; therefore, we measured the amount of naturally occurring radionuclides in building material (sand, granite, marble, and limestone) samples of different grain sizes by using NaI (Tl) and MCA1024 gamma-ray spectrometers. Data analyses were performed to determine ²²⁶Ra, ²³²Th, and ⁴°K activity concentrations. The results revealed an inverse relationship between activity concentration and grain size of the samples. The radium equivalent activity (Ra_eq), representative level index I, and annual absorbed dose rate were calculated.

Natural radioactivity and external gamma radiation exposure at the coastal Red Sea in Egypt

Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. In this work, superficial samples of beach sand were collected from the Red Sea coastline (Ras Gharib, Hurghada, Safaga, Qusier and Marsa Alam areas) and at 20 km on Qena-Safaga road. The distribution of natural radionuclides in sand beach samples was studied by gamma spectrometry. The activity concentrations of primordial and artificial radionuclides in samples that are collected from the coastal environment of the Red Sea were 19.2 +/- 3 Bq kg(-1) for (210)Pb, 21.1 +/- 1 Bq kg(-1) for (226)Ra, 22.7 +/- 2 Bq kg(-1) for (238)U, 1.0 +/- 0.1 Bq kg(-1) for (235)U, 11.6 +/- 1 Bq kg(-1) for (228)Ra, 13.0 +/- 1 Bq kg(-1) for (228)Th, 12.4 +/- 1 Bq kg(-1) for (232)Th, 930 +/- 32 Bq kg(-1) for (40)K and 1.2 +/- 0.3 Bq kg(-1) for (137)Cs. The mean external gamma-dose rate was 62.5 +/- 3.2 nSv h(-1), 54.4 +/- 2.8 nGy h(-1) Ra equivalent activity (Ra(eq)) was 107 +/- 5.8 Bq kg(-1), 0.86 +/- 0.04 Bq kg(-1) for representative level index (I(gamma)) and effective dose rate was 0.067 +/- 0.003 mSv y(-1) in beach sand red sea, in air due to naturally occurring radionuclides.

Evaluation of radioactive exposure from 137Cs in contaminated areas of Northern Ukraine

The paper gives averages of 137Cs deposition densities in soils from three areas in Northern Ukraine measured 12 to 15 y following the Chernobyl accident: in an area near Narodici (75 km west of the Chernobyl nuclear power plant in the so-called zone II) heavily contaminated by the Chernobyl fall-out and in areas around Korosten and Zhitomir showing contamination levels to be much lower. The three areas exhibited very different 137Cs deposition densities of 2.2 MBq m(-2), 400 kBq m(-2), and 5 kBq m(-2), respectively. During a 1-y observation, measurements of the 137Cs transfer in the food chain to humans and 137Cs whole body contents dependent on the 137Cs daily intake were carried out under realistic conditions of the rural inhabitants who lived in settlements within zone II. Detailed investigations of components of the daily diet showed that the high 137Cs contamination levels found in soils of zone II do not affect in any way low 137Cs concentrations of all important agricultural products harvested and consumed by villagers. With regard to consumption habits of the population of zone II, mushrooms and wild berries were found to contribute more than 95% of the 137Cs daily intake to the 137Cs whole body content of about 12 kBq (with maximum values up to 760 kBq) measured in a group of inhabitants of zone II during a period from July 1998 to July 1999. The median of the annual dose of these inhabitants from external and internal exposures was 1.2 mSv y(-1) with a geometric standard deviation of 2.6. Excluding extreme habits, the geometric mean of the total exposure was 1.0 mSv y(-1) with a geometric standard deviation of 1.3.

[Practical assessment using transmitral Doppler echocardiography for the evaluation of left ventricular filling pressure in patients with systolic ventricular dysfunction]

Transmitral flow velocity profiles by Doppler echocardiography are strongly related to left ventricular diastolic properties. The aim of this study was to address the assessment of left ventricular filling pressures by transmitral flow velocity curves in patients with impaired systolic function. 90 patients (23 female, 67 men, age 60.0 +/- 9,9 a) with an ejection fraction < or = 45% either due to coronary artery disease (n = 67) or dilated cardiomyopathy (n = 23) were investigated by Doppler echocardiography prior to left heart catheterization. Early diastolic deceleration time (DT) and ratio of early to late diastolic peak velocities (VE/VA) were measured. Both, DT and VE/VA showed a significant correlation to left ventricular enddiastolic pressures (r = -0.79 respectively r = 0.73, p < 0.001 for all). According to DT three different transmitral flow patterns were identified. All patients with restrictive filling patterns (DT < 160) had elevated left ventricular filling pressures, whereas impaired relaxation (DT > 210) was a strong predictor of normal filling pressures. In patients with pseudonormal transmitral flow patterns (DT 160 to 210) filling pressures could not be predicted. Furthermore DT was strongly related to clinical signs of left heart failure. Doppler echocardiography gives useful additional information on left ventricular filling pressures in patients with systolic dysfunction.

[The Doppler echocardiographic assessment of left ventricular diastolic function in coronary heart disease]

BACKGROUND AND OBJECTIVE

Changes in left ventricular (LV) diastolic function lead to characteristic changes in the transmitral flow profile as determined by Doppler echocardiography (DEC). Although DEC cannot provide direct quantitative measurement of LV filling pressures and is influenced by several factors, transmitral flow correlates well with LV haemodynamics. In this prospective study the results of transthoracic DEC were compared with haemodynamic parameters in patients with coronary heart disease (CHD) and their clinical value assessed.

PATIENTS AND METHODS

254 consecutive patients with CHD (67 women, 187 men, aged 62.5 +/- 8.5 years) underwent transthoracic DEC. The ratio of early to late diastolic velocity (VE/VA) and early diastolic deceleration time (DT) of the transmitral flow were measured as an indication of diastolic LV function.

RESULTS

Patients with reduced LV compliance and increased filling pressure (LV end-diastolic pressure [LVEDP] > 15 mm hg) had a restrictive transmitral flow profile with a significantly higher than normal VE/VA and a shorter DT (1.35 +/- 0.84 vs. 0.86 +/- 0.26, P < 0.001; and 158 +/- 45 vs. 213 +/- 35, P < 0.001, respectively). VE/VA and DT also significantly correlated with LVEDP (r = 0.65, P < 0.001 and r = -0.60, P < 0.001 respectively). Sensitivity and specificity of an LVEDP of > 15 mm Hg were 67% and 84%, respectively, for a VE/VA of more than 1, and 65% and 91% for a DT of less than 170. The combination of the two parameters increased specificity to 97%.

CONCLUSION

Determining the transmitral flow profile makes it possible noninvasively to obtain an indication of LV end-diastolic function. Patients with severe diastolic dysfunction and increased filling pressures are recognized with a high degree of specificity.

[Preoperative diagnosis of a patent foramen ovale: rational use of transthoracic and transesophageal contrast echocardiography]

BACKGROUND

The detection or ruling out of a patent foramen ovale (PFO) can be determined noninvasively by contrast echocardiography (CE). The transesophageal technique is superior to the transthoracic technique regarding sensitivity, whereas the specificity of both methods is equally high. This prospective study shows the rational use of transesophageal CE for the detection of a PFO, in patients without cardiovascular disorders.

METHODS

165 patients (92 female, 73 male, age 48 +/- 18 years) with planned neuro-surgery in a sitting position, underwent CE to rule out a PFO. If the CE was positive, an alternative position was selected in order to avoid a paradoxical air embolism.

RESULTS

Initially, a transthoracic CE was performed in all patients resulting in 21 patients (13%) being positive and 39 patients (24%) being negative by sufficient image quality. A transesophageal CE was performed in 96 of the remaining 105 patients (63%). Here, further 25 patients showed a positive CE in the sense of a PFO. The combined use of transthoracic and transesophageal CE revealed a PFO in 46 of 165 patients (28%).

CONCLUSION

The use of both, transthoracic and transesophageal CE is an efficient approach to the preoperative detection of a PFO in the sense of quality and economics. Depending upon the image quality, the use of a transesophageal examination could be avoided in one third of the cases.

Yersinia enterocolitica impairs activation of transcription factor NF-kappaB: involvement in the induction of programmed cell death and in the suppression of the macrophage tumor necrosis factor alpha production

In this study, we investigated the activity of transcription factor NF-kappaB in macrophages infected with Yersinia enterocolitica. Although triggering initially a weak NF-kappaB signal, Y. enterocolitica inhibited NF-kappaB activation in murine J774A.1 and peritoneal macrophages within 60 to 90 min. Simultaneously, Y. enterocolitica prevented prolonged degradation of the inhibitory proteins IkappaB-alpha and IkappaB-beta observed by treatment with lipopolysaccharide (LPS) or nonvirulent, plasmid-cured yersiniae. Analysis of different Y. enterocolitica mutants revealed a striking correlation between the abilities of these strains to inhibit NF-kappaB and to suppress the tumor necrosis factor alpha (TNF-alpha) production as well as to trigger macrophage apoptosis. When NF-kappaB activation was prevented by the proteasome inhibitor MG-132, nonvirulent yersiniae as well as LPS became able to trigger J774A.1 cell apoptosis and inhibition of the TNF-alpha secretion. Y. enterocolitica also impaired the activity of NF-kappaB in epithelial HeLa cells. Although neither Y. enterocolitica nor TNF-alpha could induce HeLa cell apoptosis alone, TNF-alpha provoked apoptosis when activation of NF-kappaB was inhibited by Yersinia infection or by the proteasome inhibitor MG-132. Together, these data demonstrate that Y. enterocolitica suppresses cellular activation of NF-kappaB, which inhibits TNF-alpha release and triggers apoptosis in macrophages. Our results also suggest that Yersinia infection confers susceptibility to programmed cell death to other cell types, provided that the appropriate death signal is delivered.

Simultaneous bilateral contrast transcranial doppler monitoring in patients with intracardiac and intrapulmonary shunts

The prevalence of a right-to-left intracardiac shunt, demonstrated by echocardiography and transcranial Doppler sonography has been shown to be higher in stroke patients than in normal controls. The aim of this study was to assess the sensitivity and specificity of contrast transcranial Doppler sonography in comparison to transesophageal echocardiography in the detection and differentiation of intracardiac and intrapulmonary shunts and to correlate the transcranial Doppler findings with clinical outcome and morphological findings. Forty five consecutive stroke patients with suspected paradoxical embolism were entered into the study. In all 25 patients with middle cerebral artery stroke of the left (56%) or right (44%) territory and echocardiographic demonstrated patent foramen ovale (80%) or intrapulmonary shunt (20%), simultaneous bilateral transcranial Doppler sonography of the middle cerebral arteries was performed after contrast medium injection during rest and valsalva straining under standardized and optimized conditions. Overall sensitivity for the detection of a right-to-left shunt by contrast transcranial Doppler sonography was 97% and overall specificity was 70%. Bilateral appearance of microbubbles, microbubble count and time delay of microbubble appearance significantly increased after valsalva straining. In patients with intracardiac shunts, a significantly higher microbubble count (32 vs. 13 in patients with an intrapulmonary shunt) and a shorter time interval of microbubble appearance (11 vs. 14 s in patients with intrapulmonary shunts) was observed. There was no correlation between the side and numerical distribution of microbubble count and the location and severity of the current clinical symptoms, as well as between microbubble count and presence and hemispherical distribution of brain infarcts. Transcranial Doppler sonography is a highly sensitive method for the detection of right-to-left shunts, whether of cardiac or pulmonary location. However. no correlation was found between the side and number of microbubbles counted and the clinical symptomatology.

[Quantitative determination of left ventricular myocardial perfusion with electron beam computerized tomography]

Myocardial perfusion is one of the most important functional parameters of the heart. Presently various indirect methods are used to determine coronary blood flow or myocardial perfusion as inertgas-, thermodilution-, Doppler catheter- and radiopharmacological techniques. Electron-beam-computed-tomographical technology is able to perform CT data acquisition with a very short exposure time of 50 ms. Using this method it is not only possible to determine left ventricular volumes but also to measure myocardial perfusion in ml/100 g/min. The measurement of the left myocardial perfusion is performed using the short axis view. This position is obtained by moving the table 25 degrees to the patient's right and 15 degrees caudally. To determine the position of the left ventricle, a localization scan is obtained in multi-slice-mode using all for target-rings, thus obtaining 8 tomographic levels over 68 mm (each tomographic level having a slice thickness of 7 mm, with an interslice gap of 4 mm between each two adjacent tomographic levels). In this short axis position, using the multi slice flow mode with 3 target-rings and after administration of 50 ml of contrast medium intravenously with a flow of 3 ml/s, 6 tomographic levels are imaged. Each tomographic level is obtained 13 times at 80% of the R-R-interval at each 2 or 3 heart beat (ECG-gated). The left ventricular myocardial contrast enhancement is measured by drawing manually the outline of the left ventricular myocardium using time-density-software of the Imatron workstation. For calculation of the myocardial perfusion the so-called "slope method" is used and the results are expressed as the maximum slope of enhancement of the myocardium divided by the difference of the precontrast and peak CT-value in the left ventricle. The global myocardial perfusion is calculated as a mean of all evaluated tomographic levels. In this study left ventricular volumes as enddiastolic volume endsystolic volume and stroke volume were measured and ejection fraction and cardiac output calculated. The measurements were performed in the log axis view. This view is obtained by moving the table 15 degrees to the patients left in a horizontal position. In this long axis position 6 tomographic levels are imaged using the multi-slice-cine-mode with 3 target-rings after administration of 50 ml of contrast medium intravenously with a flow of 3 ml/s. Each tomographic level is obtained 13 times starting at 0% of the R-R-interval (ECG-triggering). The exposure time is 50 ms with an interscan time delay of 8 ms. In 9 studied patients of whom one had 3 significant coronary artery stenotic lesions (> 50%), 2 patients had each 2 non significant stenotic lesions (< 50%) and 6 revealed nearly normal coronary angiograms. The mean global myocardial perfusion was 70 ml/100 g/min (min.32 and max. 116 ml/100 g/min). This mean value of 70 ml/100 g/min is reflecting 5% of the cardiac output supposing that the mean heart weight of these patients was 300 g. In this study the mean of the left ventricular muscle mass determined by the use of EBCT was 130 g. A comparative evaluation of coronary angiographic findings in these patients with the measured myocardial perfusion values revealed, that is not sufficient to look only at the absolute values of the measured myocardial perfusion. Furthermore it seems to be necessary to interpret these perfusion values with respect to the calculated cardiac output. Additional studies of well defined patients groups are necessary to determine normal values of myocardial perfusion at rest in patients with and without coronary artery disease. This seems to be important as comparative analysis of myocardial scintigraphic and EBCT-studies is difficult because of methodical inherent differences. The results of this study suggest that despite the presence of some beam hardening artifacts it is possible to measure myocardial perfusion using EBCT in patients with suspected coronary artery disease in the

[Doppler echocardiography in chronic right ventricular pressure load]

Doppler-echocardiography (DEC) was performed before cardiac catheterization in 61 consecutive patients (25 women, 36 men; aged 59 +/- 10.6 years) with pulmonary hypertension. Chronic obstructive lung disease was its cause in 32, mitral valve disease in 16 and dilated cardiomyopathy in 13 patients. The subcostal approach was possible in all patients and a semiquantitative assessment into three degrees of severity determined from right ventricular wall thickness and size, as well as the diameter of the inferior vena cava. The severity grade was closely correlated with the level of pulmonary hypertension. In the absence of all signs of increased right ventricular load (grade 0) the mean pulmonary arterial pressure was 18.7 +/- 6.2 mm Hg, in grade I it was 15 and 22 mm Hg (only two patients), in grade II 29.9 +/- 11.9 and in grade III 41.1 +/- 8.6 mm Hg. 13 of the 21 patients in grade 0 or I had no manifest signs of pulmonary hypertension, but this was the case in only 6 of 22 in grade II and none in grade III. In 42 patients (69%) the systolic pulmonary artery pressure could be measured by DEC and it correlated well with the values obtained by cardiac catheterization (P < 0.001, r = 0.92). These findings show that DEC can provide semiquantitative and, in most cases, even exact evidence of chronic right ventricular overload.