Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Ancestry and demography and descendants of Iron Age nomads of the Eurasian Steppe

During the 1st millennium before the Common Era (BCE), nomadic tribes associated with the Iron Age Scythian culture spread over the Eurasian Steppe, covering a territory of more than 3,500 km in breadth. To understand the demographic processes behind the spread of the Scythian culture, we analysed genomic data from eight individuals and a mitochondrial dataset of 96 individuals originating in eastern and western parts of the Eurasian Steppe. Genomic inference reveals that Scythians in the east and the west of the steppe zone can best be described as a mixture of Yamnaya-related ancestry and an East Asian component. Demographic modelling suggests independent origins for eastern and western groups with ongoing gene-flow between them, plausibly explaining the striking uniformity of their material culture. We also find evidence that significant gene-flow from east to west Eurasia must have occurred early during the Iron Age.

Multiple biomarkers and atrial fibrillation in the general population

Background

Different biological pathways have been related to atrial fibrillation (AF). Novel biomarkers capturing inflammation, oxidative stress, and neurohumoral activation have not been investigated comprehensively in AF.

Methods and Results

In the population-based Gutenberg Health Study (n = 5000), mean age 56±11 years, 51% males, we measured ten biomarkers representing inflammation (C-reactive protein, fibrinogen), cardiac and vascular function (midregional pro adrenomedullin [MR-proADM], midregional pro atrial natriuretic peptide [MR-proANP], N-terminal pro-B-type natriuretic peptide [Nt-proBNP], sensitive troponin I ultra [TnI ultra], copeptin, and C-terminal pro endothelin-1), and oxidative stress (glutathioneperoxidase-1, myeloperoxidase) in relation to manifest AF (n = 161 cases). Individuals with AF were older, mean age 64.9±8.3, and more often males, 71.4%. In Bonferroni-adjusted multivariable regression analyses strongest associations per standard deviation increase in biomarker concentrations were observed for the natriuretic peptides Nt-proBNP (odds ratio [OR] 2.89, 99.5% confidence interval [CI] 2.14–3.90; P<0.0001), MR-proANP (OR 2.45, 99.5% CI 1.91–3.14; P<0.0001), the vascular function marker MR-proADM (OR 1.54, 99.5% CI 1.20–1.99; P<0.0001), TnI ultra (OR 1.50, 99.5% CI 1.19–1.90; P<0.0001) and. fibrinogen (OR 1.44, 99.5% CI 1.19–1.75; P<0.0001). Based on a model comprising known clinical risk factors for AF, all biomarkers combined resulted in a net reclassification improvement of 0.665 (99.3% CI 0.441–0.888) and an integrated discrimination improvement of >13%.

Conclusions

In conclusion, in our large, population-based study, we identified novel biomarkers reflecting vascular function, MR-proADM, inflammation, and myocardial damage, TnI ultra, as related to AF; the strong association of natriuretic peptides was confirmed. Prospective studies need to examine whether risk prediction of AF can be enhanced beyond clinical risk factors using these biomarkers.

Depression in atrial fibrillation in the general population

Background

Initial evidence suggests that depressive symptoms are more frequent in patients with atrial fibrillation. Data from the general population are limited.

Methods and Results

In 10,000 individuals (mean age 56±11 years, 49.4% women) of the population-based Gutenberg Health Study we assessed depression by the Patient Health Questionnaire (PHQ-9) and a history of depression in relation to manifest atrial fibrillation (n = 309 cases). The median (25th/75th percentile) PHQ-9 score of depressive symptoms was 4 (2/6) in atrial fibrillation individuals versus 3 (2/6) individuals without atrial fibrillation, . Multivariable regression analyses of the severity of depressive symptoms in relation to atrial fibrillation in cardiovascular risk factor adjusted models revealed a relation of PHQ-9 values and atrial fibrillation (odds ratio (OR) 1.04, 95% confidence interval (CI) 1.01–1.08; P = 0.023). The association was stronger for the somatic symptom dimension of depression (OR 1.08, 95% CI 1.02–1.15; P = 0.0085) than for cognitive symptoms (OR 1.05, 95% CI 0.98–1.11; P = 0.15). Results did not change markedly after additional adjustment for heart failure, partnership status or the inflammatory biomarker C-reactive protein. Both, self-reported physical health status, very good/good versus fair/bad, (OR 0.54, 95% CI 0.41–0.70; P<0.001) and mental health status (OR 0.61 (0.46–0.82); P = 0.0012) were associated with atrial fibrillation in multivariable-adjusted models.

Conclusions

In a population-based sample we observed a higher burden of depressive symptoms driven by somatic symptom dimensions in individuals with atrial fibrillation. Depression was associated with a worse perception of physical or mental health status. Whether screening and treatment of depressive symptoms modulates disease progression and outcome needs to be shown.

Patient gender does not affect outcome after transcatheter aortic valve implantation (TAVI)

BACKGROUND AND AIM OF THE STUDY

Female gender has recently been suggested to predict a beneficial outcome and lower mortality following transcatheter aortic valve implantation (TAVI). The study aim was to address gender differences in outcome following TAVI and potentially to replicate these findings.

METHODS

The present single-center prospective registry of 326 patients with severe aortic stenosis treated by TAVI between 2008 and 2011 consisted of 181 women and 145 men.

RESULTS

The procedural risk was not significantly different between men and women at baseline. For all-cause mortality no difference was observed at 30 days and at 12 months after TAVI.

CONCLUSION

While several baseline characteristics between men and women treated by TAVI were shown to be different among the study population, no difference was observed in survival between both genders.

Association of MR-proadrenomedullin with cardiovascular risk factors and subclinical cardiovascular disease

AIMS AND BACKGROUND

Midregional proadrenomedullin (MR-proADM) is a protein, which exerts various effects on the cardiovascular system. Recent studies underscored its prognostic implications in patients with acute dyspnea and cardiovascular diseases. Therefore, we aimed to determine the distribution of MR-proADM in the general population and to reveal potential associations of MR-proADM with cardiovascular risk factors and measures of subclinical cardiovascular disease.

METHODS AND RESULTS

MR-proADM plasma concentrations were determined in individuals of the population-based cohort of the Gutenberg Health Study (N = 5000) using a commercially available fluoroimmunoassay. Individuals were enrolled between April 2007 and October 2008. Subclinical cardiovascular disease was assessed using echocardiographic and functional measures of myocardial and vascular function. The mean age of the study population was 55.5 ± 10.9 years. In the overall population we determined a median MR-proADM plasma concentration of 0.44 nmol/L in men and women. MR-proADM concentrations were elevated in individuals with hypertension, diabetes, dyslipidemia, known cardiovascular disease, heart failure, peripheral artery disease, atrial fibrillation, and history of myocardial infarction and stroke. In men, we observed a positive association of MR-proADM with reduced ejection fraction, intraventricular septal diameter, wall thickness, and echocardiographic measures of diastolic dysfunction.

CONCLUSIONS

In this study, we present age-dependent reference values for MR-proADM in a representative population sample. Elevated MR-proADM plasma concentrations were strongly associated with classical cardiovascular risk factors and manifest cardiovascular diseases. Furthermore, we revealed a gender-specific association with echocardiographic measures of hypertension. MR-proADM seems to be a promising prognostic biomarker for subclinical and manifest cardiovascular disease.

Predictors and outcomes after transcatheter aortic valve implantation using different approaches according to the valve academic research consortium definitions

OBJECTIVES

We report the results of a large single-center study evaluating predictors and outcomes after transcatheter aortic valve implantation (TAVI) with different devices and access routes according to the Valve Academic Research Consortium (VARC).

BACKGROUND

The widespread adoption of TAVI warrants a systematic analysis of outcomes. Only few comprehensive data exist comparing different approaches as selected by a heart team.

METHODS

TAVI was performed in 326 consecutive patients (mean age 80.6 ± 7.1 years, 55.5% female) at high risk for surgery with balloon-expandable and self-expanding devices through transfemoral or transapical access. Data were analyzed according to VARC endpoints; predictors of mortality were identified.

RESULTS

All-cause mortality was 10.1% (30 days) and 29.9% (1 year) overall and comparable with regard to valve or access choice (P = 0.295) despite different risk profiles at baseline. Device success and 30-day safety endpoints were achieved in 87.1 and 21.2%. Myocardial infarction [hazard ratio (HR) 6.52], stage-2 and -3 acute kidney injury (HR 2.52 and 6.80) and major access site complications (HR 1.96) were independent predictors of 1-year all-cause mortality. Device success had a protective effect (HR 0.58). Baseline predictors included body mass index <20 kg/m(2) (HR 3.20), NYHA class IV (HR 1.87), left ventricular ejection-fraction <30% (HR 2.30), higher STS-PROM scores (HR 1.05 per percent), and age (group 75-85 years, HR 0.47).

CONCLUSIONS

Comparable results were achieved with different devices and access routes in a heart team approach. Baseline and perioperative predictors of all-cause mortality were identified, contributing to the refinement of patient and device selection criteria for TAVI.

Multiple endothelial biomarkers and noninvasive vascular function in the general population: the Gutenberg Health Study

Vascular reactivity is reflected by blood biomarkers and noninvasive vascular function measurement. The relation of biomarkers to flow-mediated dilation and peripheral arterial tonometry in the general population is little understood. In 5000 individuals (mean age, 56±11 years; age range, 35-74 years; 49% women) of the population-based Gutenberg Health Study we simultaneously assessed 6 biomarkers of cardiovascular function (midregional proadrenomedullin [MR-proADM], midregional pro atrial natriuretic peptide [MR-proANP], N-terminal pro B-type natriuretic peptide, copeptin, C-terminal proendothelin 1, and neopterin) in relation to flow-mediated dilation and peripheral arterial tonometry. Strongest partial correlations (adjusted for age and sex) were observed for baseline pulse amplitude with MR-proADM (r=0.13) and MR-proANP (r=-0.13); hyperemic response variables showed the highest correlation for MR-proADM and peripheral arterial tonometry ratio (r=-0.14). In multivariable linear regression models, strongest associations with baseline vascular function were observed for MR-proANP with baseline pulse amplitude (β per SD increase [99.17%], -0.080 [-0.115 to -0.044]; P<0.0001 after Bonferroni correction for multiple testing) and MR-proADM (-0.044 [-0.070 to -0.017]; P<0.0001), as well as MR-proANP (-0.033 [-0.057 to -0.009]; P=0.0017) and N-terminal pro B-type natriuretic peptide (-0.027 [-0.051 to -0.003]; P=0.015) with brachial artery diameter. For hyperemic response variables, highest associations were seen for peripheral arterial tonometry ratio with MR-proADM (-0.022 [-0.043 to -0.004]; P=0.043), MR-proANP (0.016 [-0.0034 to 0.035]; P=0.18), and C-terminal proendothelin 1 (-0.025 [-0.043 to -0.008]; P=0.00094]. In our large, population-based study, we identified MR-proADM and MR-proANP as circulating biomarkers of vascular function most strongly related to noninvasive measures of conduit artery and peripheral arterial performance. Whether determination of blood biomarkers helps to better understand vascular pathology and may provide prognostic information needs to be investigated in future studies.

Atrial fibrillation: its prevalence and risk factor profile in the German general population

BACKGROUND

Atrial fibrillation (AF) is an increasingly common problem in primary care, but little is known about its prevalence and the distribution of AF risk factors in the general population.

METHODS

We determined the prevalence of AF and the distribution of known AF risk factors among persons participating in the population-based Gutenberg Health Study. To this end, we used interview data about the medical diagnosis of AF and electrocardiograms (ECGs) that were performed for the study in 5000 persons aged 35 to 74. The response rate was 60.4%.

RESULTS

There were 5000 persons in the study sample (age 52.2 ± 11 years; 50.6% were women). The prevalence of AF, weighted for the age and sex distribution of the general population, was 2.5%. AF was found to be more common in older persons, with a more pronounced increase in men: whereas its prevalence was 0.7% in 35- to 44-year-old men, the corresponding figure for the age group 65- to 74 was as high as 10.6%. Twenty five participants (15.5% of AF cases) received their initial diagnosis of AF on the basis of the study ECG. Compared to persons without AF, persons with AF were older and more commonly male, and they had a higher burden of cardiovascular risk factors. 14.3% of persons with AF had none of the well-established risk factors for AF (systolic blood pressure, antihypertensive medication, increased body-mass-index, heart failure). 42.7% of persons with AF were not taking either anticoagulants or platelet inhibitors.

CONCLUSION

These data indicate that the prevalence of AF in the middle-aged general population is 2.5% overall, and higher in the elderly. AF is thus a significant public health problem, and greater awareness of it is needed.

Sex differences in early carotid atherosclerosis (from the community-based Gutenberg-Heart Study)

The objectives of this study were to describe gender differences in intima-media thickness (IMT) in a community-based population study and to define normal IMT values for healthy men and women. In total, 4,814 participants (aged 35 to 74 years; 2,433 men, 2,381 women) from the Gutenberg-Heart Study (GHS) were included. IMT was measured at both common carotid arteries using an edge detection system. Median IMT was 0.62 mm (25th percentile 0.55, 75th percentile 0.70) in women and 0.65 mm (25th percentile 0.57, 75th percentile 0.75) in men and was significantly associated with age (p <0.0001). On multivariate analysis, advanced age, smoking, and arterial hypertension were positively associated with higher IMT in men and women. A subgroup of 1,025 subjects without cardiovascular risk factors or previous cardiovascular disease was analyzed to define normal IMT values. Nomograms were calculated according to age and gender. For each age group, IMT >95th percentile was defined as abnormal. In this subgroup, gender differences in IMT became nonsignificant at older ages. At the age of 35 years, IMT was 0.71 mm in men and 0.61 mm in women at the 95th percentile. In comparison, at the age of 74 years, IMT at the 95th percentile was 0.90 mm in men and 0.89 mm in women. In conclusion, men had higher carotid IMT than women, but predictors of early carotid atherosclerosis were similar across genders. In young subjects without cardiovascular risk factors, normal values for IMT were lower in women compared with men. In contrast, in older subjects, gender differences in IMT became nonsignificant.

A genome-wide association study identifies LIPA as a susceptibility gene for coronary artery disease

BACKGROUND

eQTL analyses are important to improve the understanding of genetic association results. We performed a genome-wide association and global gene expression study to identify functionally relevant variants affecting the risk of coronary artery disease (CAD).

METHODS AND RESULTS

In a genome-wide association analysis of 2078 CAD cases and 2953 control subjects, we identified 950 single-nucleotide polymorphisms (SNPs) that were associated with CAD at P<10(-3). Subsequent in silico and wet-laboratory replication stages and a final meta-analysis of 21 428 CAD cases and 38 361 control subjects revealed a novel association signal at chromosome 10q23.31 within the LIPA (lysosomal acid lipase A) gene (P=3.7×10(-8); odds ratio, 1.1; 95% confidence interval, 1.07 to 1.14). The association of this locus with global gene expression was assessed by genome-wide expression analyses in the monocyte transcriptome of 1494 individuals. The results showed a strong association of this locus with expression of the LIPA transcript (P=1.3×10(-96)). An assessment of LIPA SNPs and transcript with cardiovascular phenotypes revealed an association of LIPA transcript levels with impaired endothelial function (P=4.4×10(-3)).

CONCLUSIONS

The use of data on genetic variants and the addition of data on global monocytic gene expression led to the identification of the novel functional CAD susceptibility locus LIPA, located on chromosome 10q23.31. The respective eSNPs associated with CAD strongly affect LIPA gene expression level, which was related to endothelial dysfunction, a precursor of CAD.

Noninvasive vascular function measurement in the community: cross-sectional relations and comparison of methods

BACKGROUND

Several methods of noninvasive vascular function testing have been suggested for cardiovascular risk screening in the community. A direct comparison of the different methods and their relation to classical cardiovascular risk factors in a large cohort is missing.

METHODS AND RESULTS

In 5000 individuals (mean age, 55.5 ± 10.9 years; age range, 35 to 74 years; women, 49.2%) of the population-based Gutenberg Heart Study, we performed simultaneous measurement of flow-mediated dilation (FMD) and peripheral arterial volume pulse determined by infrared photo (reflection index) and pneumatic plethysmography (PAT) and explored their associations. All function measures were recorded at baseline and after reactive hyperemia induced by 5-minute brachial artery occlusion. Correlations between different measures of vascular function were statistically significant but moderate. The strongest association for hyperemic response variables was observed for PAT ratio and FMD (Spearman r = 0.17; age- and sex-adjusted partial correlation, 0.068). Classical risk factors explained between 15.8% (baseline reflection index) and 58.4% (brachial artery diameter) of the baseline values but only accounted for 3.2% (reflection index), 15.4% (FMD), and 13.9% (PAT ratio) of the variability of reflective hyperemic response. Regression models varied in their relations to classical risk factors for the individual vascular function measures. Consistently associated with different vascular function methods were age, sex, body mass index, and indicators of hypertension. Peripheral tonometry also showed a relation to fasting glucose concentrations.

CONCLUSIONS

Noninvasive measures of conduit artery and peripheral arterial function are modestly correlated, differ in their relation to classical cardiovascular risk factors, and may thus reflect different pathologies.

Distribution and categorization of left ventricular measurements in the general population: results from the population-based Gutenberg Heart Study

BACKGROUND

Echocardiography, the dominant imaging modality for quantification of left ventricular metrics, has undergone continuing development in the past few decades. However, given the lack of population-based data, current guidelines are still based on restricted and small data sets analyzed with methods including expert opinion. This work presents empirically derived reference values from a large-scale, epidemiologic study conducted with state-of-the-art imaging technology and methods.

METHODS AND RESULTS

The distribution of echocardiographic measurements of the left ventricle was analyzed in a population-based sample of 5000 mid-Europeans from the Gutenberg Heart Study in Germany. The randomly selected, noninstitutionalized sample provides data on apparently healthy individuals, as well as on those with prevalent disease. Standardized echocardiograms were recorded in a comprehensive data set at a single site with centralized training and certification of sonographers. Sex-specific reference limits and categories indicating the grade of deviation from the reference were calculated, and nomograms were created by quantile regression. Detailed information is given on the association between left ventricular geometry and age.

CONCLUSIONS

The rapidly evolving echocardiographic technology with persistent improvements in image quality and new measurement conventions require the evaluation of new reference limits for left ventricular metrics. The present investigation formulates reference limits and nomograms from state-of-the-art technology and methods based on a large population-based data set. The distribution of echocardiographic measures of left ventricular geometry presents, in part, nonlinear associations with age, which should be the subject of future investigations.

New loci associated with kidney function and chronic kidney disease

Chronic kidney disease (CKD) is a significant public health problem, and recent genetic studies have identified common CKD susceptibility variants. The CKDGen consortium performed a meta-analysis of genome-wide association data in 67,093 individuals of European ancestry from 20 predominantly population-based studies in order to identify new susceptibility loci for reduced renal function as estimated by serum creatinine (eGFRcrea), serum cystatin c (eGFRcys) and CKD (eGFRcrea < 60 ml/min/1.73 m(2); n = 5,807 individuals with CKD (cases)). Follow-up of the 23 new genome-wide-significant loci (P < 5 x 10(-8)) in 22,982 replication samples identified 13 new loci affecting renal function and CKD (in or near LASS2, GCKR, ALMS1, TFDP2, DAB2, SLC34A1, VEGFA, PRKAG2, PIP5K1B, ATXN2, DACH1, UBE2Q2 and SLC7A9) and 7 loci suspected to affect creatinine production and secretion (CPS1, SLC22A2, TMEM60, WDR37, SLC6A13, WDR72 and BCAS3). These results further our understanding of the biologic mechanisms of kidney function by identifying loci that potentially influence nephrogenesis, podocyte function, angiogenesis, solute transport and metabolic functions of the kidney.

A tandem-based compact dual-energy gamma generator

A dual-energy tandem-type gamma generator has been developed at E. O. Lawrence Berkeley National Laboratory and Sandia National Laboratories. The tandem accelerator geometry allows higher energy nuclear reactions to be reached, thereby allowing more flexible generation of MeV-energy gammas for active interrogation applications. Both positively charged ions and atoms of hydrogen are created from negative ions via a gas stripper. In this paper, we show first results of the working tandem-based gamma generator and that a gas stripper can be utilized in a compact source design. Preliminary results of monoenergetic gamma production are shown.

Distinct profiles of REST interactions with its target genes at different stages of neuronal development

Differentiation of pluripotent embryonic stem (ES) cells through multipotent neural stem (NS) cells into differentiated neurons is accompanied by wholesale changes in transcriptional programs. One factor that is present at all three stages and a key to neuronal differentiation is the RE1-silencing transcription factor (REST/NRSF). Here, we have used a novel chromatin immunoprecipitation-based cloning strategy (SACHI) to identify 89 REST target genes in ES cells, embryonic hippocampal NS cells and mature hippocampus. The gene products are involved in all aspects of neuronal function, especially neuronal differentiation, axonal growth, vesicular transport and release, and ionic conductance. Most target genes are silent or expressed at low levels in ES and NS cells, but are expressed at much higher levels in hippocampus. These data indicate that the REST regulon is specific to each developmental stage and support the notion that REST plays distinct roles in regulating gene expression in pluripotent ES cells, multipotent NS cells, and mature neurons.

Constitutive activation of STAT transcription factors in acute myelogenous leukemia

Hematopoietic growth factors (HGF) are essential for proliferation and differentiation of hematopoietic precursors and activate a distinct set of JAK-STAT (Janus kinases-signal transducers and activators of transcription) proteins. Previous results from our group have shown a strong expression of JAK-STAT proteins in primary acute myelogenous leukemia (AML) blasts and AML cell lines. Here, we asked whether a constitutive activation of the JAK-STAT pathway might be involved in the pathogenesis of AML. We could demonstrate a constitutive activation of STAT1, 3 and 5 by immunoprecipitation of the tyrosine phosphorylated proteins in different human AML cell lines. Three patterns of STAT activation were found: (I) activation of only STAT1, (II) activation of STAT1 in combination with STAT3, and (III) activation of STAT1, 3 and 5. Furthermore, STAT1 and 3 formed stable heterodimers only in cell lines with constitutive STAT3 activation. In all cell lines analyzed, tyrosine phosphorylation of the four known Janus kinases could not be detected, although JAK1 was stably associated with STAT3. To further analyze whether a constitutive activation of tyrosine kinases might contribute to the autonomous growth of AML blasts, inhibitor studies were performed. The tyrphostin AG490, an inhibitor of the JAK-STAT pathway, but not A1, an inactive tyrphostin induced a time- and dose-dependent growth arrest without overt morphological signs of differentiation in AML cell lines. Our results show that STAT transcription factors are constitutively activated in human AML cell lines and might contribute to the autonomous proliferation of AML blasts. Inhibition of this pathway might be of interest for the establishment of more specific antileukemic strategies.

Microalbuminuria during cisplatin therapy: relation with pharmacokinetics and implications for nephroprotection

BACKGROUND

To assess the relation of cisplatin-induced nephrotoxicity to its pharmacology.

PATIENTS AND METHODS

In 22 chemonaive patients (median age, 32 years) receiving 100-150 mg/m2 cisplatin for a total of 54 courses of therapy pharmacokinetics of ultra-filtrable platin were analyzed. Nephrotoxicity was sensitively assessed by nephelometric analyses of urinary marker-proteins.

RESULTS

The parameters calculated for ultrafiltrable platin were (two-compartment-model): terminal half-life, 36 hours (coefficient of variation [CV], 22%); AUC, 12852 ng h/ml (33%); volume of distribution, 3531 (44%); total clearance, 285 ml/min (30%); renal clearance, 149 ml/min (23%); maximum concentration, 1720 ng/ml (66%); renal elimination, 57% of applied dose (26%). A pathological urinary excretion of albumin > 20 mg/l and alpha-1-microglobulin > 10 mg/l was detected in 39 out of 54 and 42 out of 54 cycles, respectively. The degree of albuminuria was related with urinary monoaquoplatin concentrations (p = 0.003).

CONCLUSION

Nephrotoxicity of cisplatin appears to depend on the urinary monoaquoplatin concentrations which may be modulated by application of saline.

Expression of granulocyte colony-stimulating factor- and granulocyte-macrophage colony-stimulating factor-associated signal transduction proteins of the JAK/STAT pathway in normal granulopoiesis and in blast cells of acute myelogenous leukemia

Acute myelogenous leukemia (AML) is characterized by the malignant transformation of hematopoietic stem cells leading to dysregulated growth and differentiation of myeloid cells. Normally, proliferation and differentiation of myeloid cells are regulated by cytokines such as granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF). Abnormal signaling of the signal transduction pathway from the cytokine receptors via Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) might be involved in the pathogenesis of AML. We examined whether an abnormal expression of one of the four JAKs, STAT1, STAT3, STAT5, or the tyrosine phosphatase SHP-1, a negative regulator of this pathway, is associated with malignant transformation in AML. Analysis of the expression of proteins of the JAK/STAT pathway in normal myeloid cells at three stages of maturation revealed a strong expression of all proteins in CD34+ cells, whereas the level of the proteins was significantly lower in granulocytic precursors and mature neutrophils. Furthermore, during maturation the relation of the isoforms of STAT1 and STAT3 changed from predominantly alpha to predominantly beta. Leukemic blast cells from 25 patients and 12 cell lines showed a high level of STAT proteins and SHP-1, whereas a deficiency of at least one of the four JAKs was found in 10 of 25 patients. In primary AML blast cells a deficiency of three JAKs was more common in patients with an abnormal karyotype. In addition, a lack of JAK2 and Tyk2 protein was strongly associated with the FAB M2 phenotype. The proliferation rate in response to GM-CSF available in a small number of patients appears to be related to the JAK2 expression. Our data suggest that the degree of expression of G-CSF/GM-CSF receptor-associated proteins of the JAK/STAT pathway in normal myeloid cells is related with their clonogenic potential. STAT3 appears to be involved in early differentiation. Similar to CD34+ cells, it is likely that the high levels of STATs and SHP-1 found in leukemic cells reflects their proliferative activity, whereas a lack of members of the JAK family might lead to an inability to proliferate in response to G-CSF/GM-CSF described in a considerable percentage of AML blasts.

Pharmacokinetics of Ara-CMP-Stearate (YNK01): phase I study of the oral Ara-C derivative

Ara-CMP-Stearate (1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate, YNK 01, Fosteabine) is the orally applicable prodrug of cytosine-arabinoside (Ara-C). During a phase I study in patients with advanced low-grade non-Hodgkin lymphomas or acute myeloid leukemia, the pharmacokinetic parameters of Ara-CMP-Stearate (kindly provided by ASTA Medica, Frankfurt, Germany) were determined by HPLC analysis. Seventy-two hours after a first starting dose which served for the determination of baseline pharmacokinetic parameters, Ara-CMP-Stearate was administered over 14 days by daily oral application. Ara-CMP-Stearate was started at a dose of 100 mg/day and was escalated in subsequent patients to 200 mg/day and 300 mg/day. Plasma and urine concentrations of Ara-CMP-Stearate, Ara-C and Ara-U were measured during the initial treatment phase and within 72 h after the end of the 14-day treatment cycle. So far six patients have been treated with 100 mg/day, three with 200 mg/day and another six with 300 mg/day. One patient was treated consecutively with 100 mg, 300 mg and 600 mg. Fitting the results of the plasma concentration measurements of Ara-CMP-Stearate to a one-compartment model, the following pharmacokinetic parameters were obtained (average and variation coefficient VC). Ara-CMP-Stearate dose-independent parameters: lag time = 1.04 h (0.57); tmax = 5.72 h (0.30); t1/2 = 9.4 h (0.36). Dose-dependent parameters: at 100 mg: AUC = 1099 ng/h/ml (0.31); concentration(max) = 53.8 ng/ml (0.28); at 200 mg: AUC = 2753 ng/h/ml (0.32); concentration(max) = 154.8 ng/ml (0.46); at 300 mg: AUC = 2940 ng/h/ml (0.66); concentration(max) = 160.0 ng/ml (0.59). The long lag time and late tmax can be explained by resorption in the distal part of the small intestine. No Ara-CMP-Stearate was detected in urine samples (limit of detection = 500 pg/ml). Pharmacokinetic parameters of Ara-C following Ara-CMP-Stearate application showed the following characteristics: t1/2 = 24.3 h (0.39); AUC (100 mg) = 262 ng/h/ml (0.93); AUC (200 mg) = 502 ng/h/ml (0.87); AUC (300 mg) = 898 ng/h/ml (1.07). Since Ara-CMP-Stearate causes intravascular hemolysis after intravenous administration, it was not possible to determine its bioavailability by comparing the AUC after oral and i.v. application. Instead, the renal elimination of Ara-U, as the main metabolite of Ara-C was measured during the first 72-h period and after the last application.(ABSTRACT TRUNCATED AT 400 WORDS)

Strategies of therapist interventions : a preliminary empirical study

Forty-one categories of patient communications just before therapist interventions were identified from a review of psychotherapy transcripts. For each communication type, a set of possible therapist interventions was constructed. Descriptions of these interactions were sent in the form of a questionnaire to 350 experienced clinicians, who were asked to indicate their degree of agreement with each possible response. Ratings from the 141 responding clinicians showed little relation to age, gender, experience level, or orientation but showed marked differences for different response alternatives. A separate group of seven experienced clinicians used these data to develop a new categorization of 15 types of therapist interventions and 5 types of patient communications. A tentative information-processing model of patient-therapist communications is proposed.