Polygenic risk modeling for prediction of epithelial ovarian cancer risk

Polygenic risk scores (PRS) for epithelial ovarian cancer (EOC) have the potential to improve risk stratification. Joint estimation of Single Nucleotide Polymorphism (SNP) effects in models could improve predictive performance over standard approaches of PRS construction. Here, we implemented computationally efficient, penalized, logistic regression models (lasso, elastic net, stepwise) to individual level genotype data and a Bayesian framework with continuous shrinkage, "select and shrink for summary statistics" (S4), to summary level data for epithelial non-mucinous ovarian cancer risk prediction. We developed the models in a dataset consisting of 23,564 non-mucinous EOC cases and 40,138 controls participating in the Ovarian Cancer Association Consortium (OCAC) and validated the best models in three populations of different ancestries: prospective data from 198,101 women of European ancestries; 7,669 women of East Asian ancestries; 1,072 women of African ancestries, and in 18,915 BRCA1 and 12,337 BRCA2 pathogenic variant carriers of European ancestries. In the external validation data, the model with the strongest association for non-mucinous EOC risk derived from the OCAC model development data was the S4 model (27,240 SNPs) with odds ratios (OR) of 1.38 (95% CI: 1.28-1.48, AUC: 0.588) per unit standard deviation, in women of European ancestries; 1.14 (95% CI: 1.08-1.19, AUC: 0.538) in women of East Asian ancestries; 1.38 (95% CI: 1.21-1.58, AUC: 0.593) in women of African ancestries; hazard ratios of 1.36 (95% CI: 1.29-1.43, AUC: 0.592) in BRCA1 pathogenic variant carriers and 1.49 (95% CI: 1.35-1.64, AUC: 0.624) in BRCA2 pathogenic variant carriers. Incorporation of the S4 PRS in risk prediction models for ovarian cancer may have clinical utility in ovarian cancer prevention programs.

Hypermethylation of mismatch repair gene hMSH2 associates with platinum-resistant disease in epithelial ovarian cancer

Purpose

One major reason of the high mortality of epithelial ovarian cancer (EOC) is due to platinum-based chemotherapy resistance. Aberrant DNA methylation may be a potential mechanism underlying the development of platinum resistance in EOC. The purpose of this study is to discover potential aberrant DNA methylation that contributes to drug resistance.

Methods

By initially screening of 16 platinum-sensitive/resistant samples from EOC patients with reduced representation bisulfite sequencing (RRBS), the upstream region of the hMSH2 gene was discovered hypermethylated in the platinum-resistant group. The effect of hMSH2 methylation on the cellular response to cisplatin was explored by demethylation and knockdown assays in ovarian cancer cell line A2780. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry was employed to examine the methylation levels of hMSH2 upstream region in additional 40 EOC patient samples. RT-qPCR and IHC assay was used to detect the hMSH2 mRNA and protein expression in extended 150 patients.

Results

RRBS assay discovered an upstream region from − 1193 to − 1125 of hMSH2 was significant hypermethylated in resistant EOC patients (P = 1.06 × 10⁻¹⁴). In vitro analysis demonstrated that global demethylation increased cisplatin sensitivity along with a higher expression of the hMSH2 mRNA and protein. Knockdown hMSH2 reduced the cell sensitivity to cisplatin. MALDI-TOF mass spectrometry assay validated the strong association of hypermethylation of hMSH2 upstream region with platinum resistance. Spearman’s correlation analysis revealed a significantly negative connection between methylation level of hMSH2 upstream region and its expression. The Kaplan-Meier analyses showed the high methylation of hMSH2 promoter region, and its low expressions are associated with worse survival. In multivariable models, hMSH2 low expression was an independent factor predicting poor outcome (P = 0.03, HR = 1.91, 95%CI = 1.85–2.31).

Conclusion

The hypermethylation of hMSH2 upstream region is associated with platinum resistant in EOC, and low expression of hMSH2 may be an index for the poor prognosis.

Genome-wide association studies identify susceptibility loci for epithelial ovarian cancer in east Asian women

OBJECTIVE

Genome-wide association studies (GWASs) for epithelial ovarian cancer (EOC) have focused largely on populations of European ancestry. We aimed to identify common germline variants associated with EOC risk in Asian women.

METHODS

Genotyping was performed as part of the OncoArray project. Samples with >60% Asian ancestry were included in the analysis. Genotyping was performed on 533,631 SNPs in 3238 Asian subjects diagnosed with invasive or borderline EOC and 4083 unaffected controls. After imputation, genotypes were available for 11,595,112 SNPs to identify associations.

RESULTS

At chromosome 6p25.2, SNP rs7748275 was associated with risk of serous EOC (odds ratio [OR] = 1.34, P = 8.7 × 10-9) and high-grade serous EOC (HGSOC) (OR = 1.34, P = 4.3 × 10-9). SNP rs6902488 at 6p25.2 (r2 = 0.97 with rs7748275) lies in an active enhancer and is predicted to impact binding of STAT3, P300 and ELF1. We identified additional risk loci with low Bayesian false discovery probability (BFDP) scores, indicating they are likely to be true risk associations (BFDP <10%). At chromosome 20q11.22, rs74272064 was associated with HGSOC risk (OR = 1.27, P = 9.0 × 10-8). Overall EOC risk was associated with rs10260419 at chromosome 7p21.3 (OR = 1.33, P = 1.2 × 10-7) and rs74917072 at chromosome 2q37.3 (OR = 1.25, P = 4.7 × 10-7). At 2q37.3, expression quantitative trait locus analysis in 404 HGSOC tissues identified ESPNL as a putative candidate susceptibility gene (P = 1.2 × 10-7).

CONCLUSION

While some risk loci were shared between East Asian and European populations, others were population-specific, indicating that the landscape of EOC risk in Asian women has both shared and unique features compared to women of European ancestry.

Genetic Data from Nearly 63,000 Women of European Descent Predicts DNA Methylation Biomarkers and Epithelial Ovarian Cancer Risk

DNA methylation is instrumental for gene regulation. Global changes in the epigenetic landscape have been recognized as a hallmark of cancer. However, the role of DNA methylation in epithelial ovarian cancer (EOC) remains unclear. In this study, high-density genetic and DNA methylation data in white blood cells from the Framingham Heart Study (N = 1,595) were used to build genetic models to predict DNA methylation levels. These prediction models were then applied to the summary statistics of a genome-wide association study (GWAS) of ovarian cancer including 22,406 EOC cases and 40,941 controls to investigate genetically predicted DNA methylation levels in association with EOC risk. Among 62,938 CpG sites investigated, genetically predicted methylation levels at 89 CpG were significantly associated with EOC risk at a Bonferroni-corrected threshold of P < 7.94 × 10-7. Of them, 87 were located at GWAS-identified EOC susceptibility regions and two resided in a genomic region not previously reported to be associated with EOC risk. Integrative analyses of genetic, methylation, and gene expression data identified consistent directions of associations across 12 CpG, five genes, and EOC risk, suggesting that methylation at these 12 CpG may influence EOC risk by regulating expression of these five genes, namely MAPT, HOXB3, ABHD8, ARHGAP27, and SKAP1. We identified novel DNA methylation markers associated with EOC risk and propose that methylation at multiple CpG may affect EOC risk via regulation of gene expression. SIGNIFICANCE: Identification of novel DNA methylation markers associated with EOC risk suggests that methylation at multiple CpG may affect EOC risk through regulation of gene expression.

Quality of life, binge eating and sexual function in participants treated for obesity with sustained release naltrexone/bupropion

Objective

This multicenter, randomized, controlled, open‐label trial examined weight‐related quality of life, control over eating behaviour and sexual function after 26 weeks of treatment with either 32 mg naltrexone sustained release (SR)/360 mg bupropion SR plus a comprehensive lifestyle intervention program (NB + CLI, N = 153) or usual care (UC, N = 89), which included minimal lifestyle intervention.

Methods

Impact of Weight on Quality of Life‐Lite, Binge Eating Scale and Arizona Sexual Experiences Scale were assessed at baseline (BL) and weeks 16 and 26.

Results

NB + CLI and UC participants lost 9.46 and 0.94% respectively of initial body weight at week 26 (P < 0.0001). NB + CLI participants had greater improvements in Impact of Weight on Quality of Life‐Lite total score than UC participants (P < 0.0001). In participants with moderate/severe Binge Eating Scale scores at BL, 91% of NB + CLI and 18% of UC participants experienced categorical improvements. In participants with Arizona Sexual Experiences Scale‐defined sexual dysfunction at BL, 58% of NB + CLI and 19% of UC participants no longer met dysfunction criteria at week 26. The most frequent adverse events leading to discontinuation before week 26 in NB + CLI included nausea (10.5%); anxiety (3.3%); and headache, hypertension, insomnia and palpitations (1.3% each).

Conclusion

Compared with UC, participants treated with NB + CLI experienced greater improvements in weight‐related quality of life, control over eating behaviour, and sexual function.

Significance of PC cell-derived growth factor and cyclin D1 expression in cutaneous squamous cell carcinoma

BACKGROUND

PC cell-derived growth factor (PCDGF) is an autocrine growth factor originally purified from the highly tumorigenic teratoma PC cell line. It participates in tumorigenesis and tumour progression through upregulation of cyclin D1. To date, there has been no report on the role of PCDGF in skin cancer, to our knowledge.

AIM

To investigate the expression of PCDGF and cyclin D1 in basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and seborrhoeic keratosis (SK), and their relationship with the clinicopathological parameters of SCC.

METHODS

Immunohistochemical expression of PCDGF and cyclin D1 was examined in 42 SCC, 30 BCC and 20 SK tissues.

RESULTS

PCDGF and cyclin D1 were overexpressed in SCC or BCC tissues compared with normal skin or SK, and their expressions were significantly higher in SCC than in BCC. Moreover, positive expression of PCDGF and cyclin D1 was significantly correlated with depth of invasion and metastasis of SCC. There was significant correlation between PCDGF and cyclin D1 expression in SCC.

CONCLUSIONS

Expression of PCDGF and cyclin D1 plays an important role in the tumorigenesis of BCC and SCC. Abnormal expression of PCDGF and Cyclin D1 may be related to invasion and metastasis of SCC.

Association between polymorphisms of ERCC1 and survival in epithelial ovarian cancer patients with chemotherapy

Aim: We evaluated whether the ERCC1 polymorphisms had an effect on survival in epithelial ovarian cancer (EOC) patients with platinum-based chemotherapy. Materials & methods: Clinical data of 209 EOC patients between 2002 and 2008 were reviewed. The genotypes of 19007T/C and 8092C/A polymorphisms were assessed in all patients using PCR–RFLP. Results: The 19007T/C polymorphism was significantly associated with response to treatment. Compared with the patients carrying C/C genotype, the patients with the T/T genotype have a significantly decreased response to platinum-based chemotherapy (odds ratio: 32.26; 95% CI: 3.66–250.00). Cox’s multivariate analysis suggested that EOC patients with the T/T genotype had an increased risk of disease progression (hazard ratio: 3.34; 95% CI: 1.77–6.29) and death (hazard ratio: 2.87; 95% CI: 1.38–5.96) compared with those carrying the C/C genotype. Conclusion: The 19007T/C polymorphism may be a useful prognostic marker in patients with EOC treated with platinum-based chemotherapy in Chinese women.

Original submitted 26 October 2011; Revision submitted 5 December 2011

Association of three single nucleotide polymorphisms of the E-cadherin gene with endometriosis in a Chinese population

Endometriosis, one of the most frequent diseases in gynecology, is a benign but invasive and metastatic disease. The altered expression of E-cadherin may play an important role in developing endometriosis. In this paper, we discuss the association of three single nucleotide polymorphisms (SNPs) on the E-cadherin gene and risk of endometriosis. We examined the genotype frequency of three polymorphisms in 152 endometriosis patients and 189 control women. There was a significant difference in the frequency of the E-cadherin 3'-UTR C --> T genotypes between endometriosis and controls (P = 0.01). The frequency of the C allele in patients (71.1%) was significantly higher than in the controls (63.8%; P = 0.04). When compared with the T/T + T/C genotypes, the C/C genotype had a significantly increased susceptibility to endometriosis, with an adjusted odds ratio of 1.79 (95% confidence interval = 1.17-2.76). No significant difference was found between endometriosis and control women on two polymorphisms (-160 C --> A, -347 G --> GA) at the gene promoter region of E-cadherin. The -160 C --> A and -347 G --> GA polymorphisms displayed linkage disequilibrium (D' = 0.999). The -160 A/-347 GA haplotype was only detected in endometriosis patients (2%). These data show a relation between the E-cadherin 3'-UTR C --> T polymorphism, the -160 A/-347 GA haplotype of two promoter polymorphisms and risk of endometriosis, suggesting a potential role in endometriosis development, at least in North Chinese women.

p16(CDKN2) gene polymorphism: association with histologic subtypes of epithelial ovarian cancer in China

p16 is an important tumor suppressor gene, which is inactivated in many kinds of tumors. The common variants of p16 may be associated with the risk of certain tumors development. We analyzed the frequency of two adjacent polymorphisms in p16 exon 3 (540C-->G and 580C-->T) and their haplotype in blood samples from epithelial ovarian cancer (EOC) patients and healthy controls using polymerase chain reaction-restriction fragment length polymorphism. The results showed that the genotype frequency of p16 580C-->T polymorphism was significantly different among histologic subtypes of EOC (P= 0.02). T allele carriers significantly reduced the risk of serous EOC; the adjusted odds ratio was 0.40 (95% CI = 0.19-0.84). There are neither association between p16 540C-->G polymorphism and EOC development, progression, nor association between the haplotypes of two single nucleotide polymorphisms and the tumor development. Our results suggested that the p16 580C-->T polymorphism might affect the individual susceptibility to specific subtypes of EOC. Different types of ovarian cancer might adopt distinct carcinogenetic pathways. However, this result may be further validated in a larger sample of patients.

Polymorphisms in the promoter regions of the matrix metalloproteinases-7, -9 and the risk of endometriosis and adenomyosis in China

Matrix metalloproteinases (MMPs) may contribute to the development of endometriosis. The aim of this study was to assess the effects of the polymorphisms in the promoters of MMP-7 (181A/G) and MMP-9 (1562C/T) on the risk of occurrence of endometriosis and adenomyosis. We genotyped 219 patients (143 women with endometriosis, 76 women with adenomyosis) and 160 control women in North China. There was a significant difference in frequency of the MMP-7 genotype between endometriosis and controls (P = 0.01) and also between adenomyosis and controls (P = 0.01). The frequency of the G allele in two groups of patients (7.3 and 7.9%) was significantly higher than in the controls (2.8%) (P = 0.01 and 0.01, respectively). Compared to the A/A genotype, the genotype with the -181G allele showed a significantly increased susceptibility to both diseases, with adjusted odds ratio of 2.62 [95% confidence interval (CI) = 1.17-5.87] for endometriosis and 3.14 (95% CI = 1.26-7.81) for adenomyosis. However, the overall genotype and allelotype distribution of the MMP-9 in the two case groups were not different from that of controls. We conclude that MMP-7-181A/G polymorphism has a potential to be a susceptibility factor for endometriosis and adenomyosis while MMP-9-1562C/T polymorphism may not provide a useful marker to predict susceptibility to endometriosis and adenomyosis, at least in women from North China.

The function of the SNP in the MMP1 and MMP3 promoter in susceptibility to endometriosis in China

Matrix metalloproteinases (MMPs) may contribute to the development of endometriosis. Genetic variations in several MMP promoters may influence the transcription and expression of MMPs. The purpose of the present study was to assess how gene polymorphisms in the MMP1 and MMP3 promoters affect the risk of development of endometriosis. We genotyped 100 women with endometriosis and 150 control subjects in North China. There was a significant difference in frequency of the MMP1 genotype between cases and controls (P=0.03). The 2G homozygote in endometriosis and controls was significantly different (P=0.02). The frequency of the 2G allele among affected women (79%) was significantly higher than among the healthy controls (66.9%; P=0.003). However, the overall genotype and allelotype distribution of the MMP3 single nucleotide polymorphism (SNP) in patients was not different from that of controls (P> or =0.05). MMP1 and MMP3 polymorphisms were in linkage disequilibrium in cases and controls (D'=0.47; P=0.00). The haplotype frequency distribution derived from these two polymorphisms was significantly different between cases and controls (P=0.00). The haplotype analysis suggested an implication of both MMP1 and MMP3 polymorphisms in the susceptibility to endometriosis. We conclude that the MMP1 promoter SNP and MMP 2G/6A haplotype may modify susceptibility to endometriosis, but that the MMP3 promoter SNP is unlikely to be associated with endometriosis in the population of North China.

Deceleration time in ischemic cardiomyopathy: relation to echocardiographic and scintigraphic indices of myocardial viability and functional recovery after revascularization

BACKGROUND

In patients with heart failure secondary to left ventricular (LV) systolic dysfunction, a short deceleration time (DT) successfully predicts clinical outcome. The impact of myocardial viability and revascularization on the mitral inflow velocities, however, is unknown.

METHODS AND RESULTS

Forty patients with ischemic cardiomyopathy underwent (201)Tl scintigraphy (SPECT) and 2D, Doppler, and dobutamine echocardiography (DE, to 40 microg. kg(-1). min(-1)) 2 days before CABG. Echocardiography was repeated 3 months after revascularization to determine recovery of function. Significant correlations were present between DT and LV contractile reserve by DE (r=0.72), scar perfusion defect by SPECT (r=-0.69), and the change in ejection fraction (DeltaEF) after surgery (r=0.77) (all P:<0.01). DT >150 ms effectively identified (sensitivity 79%, specificity 81%) patients with DeltaEF >/=5%. The population was divided into 2 groups according to DT: group 1 (DT >150 ms, n=21) and group 2 (DT </=150 ms, n=19). At baseline, NYHA class, LV EF, age, and use of cardiovascular drugs were similar between the 2 groups. The number of viable segments by both DE and SPECT, however, was higher in group 1 (both P:<0.01), and only patients in group 1 had an increase in EF (29+/-4.8% to 40+/-8%, P:<0.01) after surgery. Death and heart transplantation occurred in 7 patients from group 2 and 1 patient from group 1 (P:=0.017).

CONCLUSIONS

In patients with ischemic cardiomyopathy, the reduced amount of viable myocardium results in a restrictive mitral inflow pattern, which in turn predicts poor survival.

Altered adrenergic receptor density in myocardial hibernation in humans: A possible mechanism of depressed myocardial function

BACKGROUND

Alterations in adrenergic receptor densities can potentially contribute to myocardial dysfunction. Their relevance to myocardial hibernation in humans is unknown.

METHODS AND RESULTS

Accordingly, 22 transmural myocardial biopsies were obtained in 11 patients with ischemic ventricular dysfunction during bypass surgery, guided by transesophageal echocardiography. Patients underwent dobutamine echocardiography (DE) and rest scintigraphic studies before revascularization and DE at 3 to 4 months. alpha- and ss-receptor density (ARD and BRD) and extent of fibrosis were quantified from the myocardial biopsies. Of the 22 segments, 16 had abnormal rest function and 6 were normal. Severely hypokinetic or akinetic segments showed a 2.4-fold increase in ARD with a concomitant 50% decrease in BRD compared with normal segments. An increase in ARD, a decrease in BRD to a lesser extent, and thus an increase in ARD/BRD ratio were seen in dysfunctional segments with contractile reserve compared with normal segments and were most pronounced in those without contractile reserve (P:<0.001). Similar findings were observed if recovery of function or scintigraphic uptake was analyzed as a marker for viability. No significant relation between either ARD or BRD and percent myocardial fibrosis was noted (r=0.37 and -0.39, respectively).

CONCLUSIONS

Thus, graded and reciprocal changes in alpha- and ss-adrenergic receptor densities occur in viable, hibernating myocardium and may account in part for the observed depression in resting myocardial function and preserved contractile reserve in this entity.

Relation of tissue Doppler derived myocardial velocities to myocardial structure and beta-adrenergic receptor density in humans

OBJECTIVES

We sought to evaluate the relation of segmental tissue Doppler (TD) velocities to both the regional amount of interstitial fibrosis and the myocyte beta-adrenergic receptor density in humans.

BACKGROUND

The systolic myocardial velocity (Sm) and early diastolic myocardial velocity (Em) acquired by TD are promising new indexes of left ventricular function. However, their structural and functional correlates in humans are still unknown.

METHODS

Ten patients with coronary artery disease underwent echocardiographic examination including TD imaging, along with transmural endomyocardial biopsy at the time of coronary bypass surgery (two biopsies per patient for a total of 20 specimens). The specimens were analyzed for percent interstitial fibrosis and beta-adrenergic receptor density.

RESULTS

Normal segments (n = 8) had a higher beta-adrenoceptor density (2,280 +/- 738 vs. 1,373 +/- 460, p = 0.03) and a lower amount of interstitial fibrosis (13 +/- 3.3% vs. 28 +/- 11.5%, p = 0.002) than dysfunctional segments (n = 12). Myocardial systolic velocity and Em were also significantly higher (9.5 +/- 2.7 vs. 5.9 +/- 1.8 cm/s, p = 0.025 and 11.3 +/- 2.8 vs. 6.4 +/- 2.1 cm/s, p = 0.002, respectively) in normal segments. A significant relationship was present between Em and the beta-adrenergic receptor density (r = 0.78, p < 0.001) and percent interstitial fibrosis (r = -0.7, p = 0.0026), which together accounted for 81% of the variance observed in Em. Likewise, a significant relationship was present between Sm and the beta-adrenergic receptor density (r = 0.68, p < 0.001) and the percent interstitial fibrosis (r = -0.66, p = 0.004) and together accounted for 62% of the variance observed in Sm.

CONCLUSIONS

Systolic myocardial velocity and Em are strongly dependent on both the number of myocytes and the myocardial beta-adrenergic receptor density.

Assessment of myocardial viability with stress echocardiography

Over the past two decades, there has been an increased realization that systolic myocardial dysfunction, outside of the setting of acute ischemia, does not necessarily imply irreversible myocardial injury. Echocardiographic techniques, particularly dobutamine stress echocardiography, have emerged as important diagnostic modalities that can identify residual viable myocardium in patients following acute myocardial infarction and in those with suspected myocardial hibernation. Dobutamine echocardiography can also help risk stratify patients with coronary artery disease and depressed ventricular function and identify patients who would benefit best from revascularization procedures.

Incremental value of rubidium-82 positron emission tomography for prognostic assessment of known or suspected coronary artery disease

Myocardial perfusion imaging using positron emission tomography (PET) may be more accurate for the diagnosis of coronary artery disease (CAD) than conventional imaging. The purpose of this study was to evaluate the prognostic implications of perfusion abnormalities in 685 patients (age 62 +/- 11 years, 199 women) studied by PET, and to assess the incremental value of these data in relation to prognostic implications of clinical and angiographic findings. Rubidium (Rb)-82 PET was performed before and after dipyridamole stress. Transient defects were detected in 227 patients (33%), and were moderate or greater in severity (> 15% of the left ventricle) in 84 (12%). Resting defects were present in 435 (64%) and were moderate or greater in severity in 216 (32%). The total extent of abnormally perfused myocardium was small (< 15% of the left ventricle) in 198 (29%), moderate in 216 (32%), and extensive in 105 (15%). Clinic review or standardized phone interview in 657 patients (96%) identified 151 cardiac events, including 81 cardiac deaths, 16 patients with myocardial infarction, 7 with unstable angina, and 47 with late revascularization (> 3 months after PET). Normal scans had a 90% event-free survival, compared with 87% in patients with small, 75% with moderate, and 76% with extensive defects (log rank chi-square 30, p <0.0001). Functional class, extent of CAD, and the presence and extent of perfusion defects (both at rest and during stress) were independent predictors of cardiac death and total cardiac events. In sequential Cox proportional-hazards models, the results of PET were incremental to those of clinical and angiographic evaluation. Thus, the presence and extent of damaged and jeopardized myocardium are independent and incremental predictors of outcome in patients undergoing Rb-82 PET.

Increased left ventricular cavity size, not wall thickness, potentiates myocardial ischemia

Left ventricular (LV) hypertrophy increases the vulnerability of the myocardium to ischemia. The purpose of this study was to determine whether LV diameter or wall thickness was the principal determinant of the effect of LV mass on the development of ischemia, measured by exercise thallium perfusion imaging, in a population with coronary artery disease (CAD). We studied 109 patients with CAD but no prior myocardial infarction who underwent exercise thallium imaging within 1 year of coronary angiography. Thallium perfusion defects were present in 76% of patients. LV mass index was associated with thallium perfusion abnormalities (odds ratio 2.09 for 50 gm increments), an association that persisted after adjusting for extent of CAD. LV end-diastolic diameter had a strong correlation with a thallium defect (odds ratio 3.7 for 10 mm increments), but LV wall thickness had no correlation (odds ratio 1.0 for 5 mm increments). In a stepwise regression model that included extent of CAD and other potential clinical variables, LV end-diastolic diameter was the strongest predictor of thallium defects (adjusted odds ratio 4.5). This study confirms the association of LV hypertrophy with ischemia in patients with CAD, specifically in patients with eccentric hypertrophy.

The role of cytokines in disease progression in heart failure

Recent studies have identified the importance of biologically active molecules such as neurohormones as mediators of disease progression in heart failure. More recently it has become apparent that in addition to neurohormones, another portfolio of biologically active molecules, termed cytokines, are also expressed in the setting of heart failure. This article reviews recent clinical and experimental material that suggests that the cytokines, much like the neurohormones, may represent another class of biologically active molecules that are responsible for the development and progression of heart failure.

Basic mechanisms in heart failure: the cytokine hypothesis

Although the development and progression of heart failure have traditionally been viewed as hemodynamic disorders, there is now an increasing awareness that the syndrome of heart failure cannot be simply and/or precisely defined solely in hemodynamic terms. The inability of the so-called hemodynamic hypothesis to explain the progression of heart failure has given rise to the notion that heart failure may progress as a result of the overexpression of an ensemble of biologically active molecules referred to generically as neurohormones. More recently, it has become apparent that in addition to neurohormones, another portfolio of biologically active molecules, termed cytokines, are also expressed in the setting of heart failure. This article reviews recent clinical and experimental material that suggests that the cytokines, much like the neurohormones, may represent another class of biologically active molecules that are responsible for the development and progression of heart failure.

Anthracycline-induced cardiotoxicity

PURPOSE

To review the current understanding of the clinical significance, detection, pathogenesis, and prevention of anthracycline-induced cardiotoxicity.

DATA SOURCES

A MEDLINE search of the English-language medical literature and a manual search of the bibliographies of relevant articles, including abstracts from national cardiology meetings.

STUDY SELECTION

Pertinent clinical and experimental studies addressing the clinical relevance, pathogenesis, detection, and prevention of anthracycline cardiotoxicity were selected from peer-reviewed journals without judgments about study design. A total of 137 original studies and 9 other articles were chosen.

DATA EXTRACTION

Data quality and validity were assessed by each author independently. Statistical analysis of combined data was inappropriate given the differences in patient selection, testing, and follow-up in the available studies.

DATA SYNTHESIS

Anthracycline-induced cardiotoxicity limits effective cancer chemotherapy by causing early cardiomyopathy, and it can produce late-onset ventricular dysfunction years after treatment has ceased. Detection of subclinical anthracycline-induced cardiomyopathy through resting left ventricular ejection fraction or echocardiographic fractional shortening is suboptimal. Conventional doses of anthracycline often lead to permanent myocardial damage and reduced functional reserve. Underlying pathogenetic mechanisms may include free-radical-mediated myocyte damage, adrenergic dysfunction, intracellular calcium overload, and the release of cardiotoxic cytokines. Dexrazoxane is the only cardioprotectant clinically approved for use against anthracyclines, and it was only recently introduced for selected patients with breast cancer who are receiving anthracycline therapy.

CONCLUSIONS

A rapidly growing number of persons, including an alarming fraction of the 150 000 or more adults in the United States who have survived childhood cancer, will have substantial morbidity and mortality because of anthracycline-related cardiac disease. The development of effective protection against anthracycline-induced cardiotoxicity will probably have a significant effect on the overall survival of these patients.

Use of positron emission tomography for prediction of perioperative and late cardiac events before vascular surgery

The efficacy of myocardial perfusion imaging for cardiac-risk stratification of patients undergoing vascular surgery has been disputed recently. In comparison with conventional techniques, positron emission tomography (PET) has the benefit of permitting a true resting scan, allows accurate measurement of the extent of ischemia, and is highly specific for the diagnosis of coronary disease. We therefore investigated the use of PET for risk stratification at the time of vascular surgery and subsequent follow-up in 78 patients (aged 67 +/- 11 years, 52 men), selected for testing before the performance of extensive surgery or because of one or more clinical risk factors. Perfusion images were obtained by using a standard rubidium 82 protocol before and after dipyridamole-handgrip stress. With use of a quantitative color scale in a 24-segment model of the left ventricle, scans were reported as showing normal perfusion, resting defects, or stress-induced defects (deterioration > 15% with stress). After exclusion of 6 patients referred for myocardial revascularization, 72 patients were followed up in the perioperative period and for 18 +/- 12 months for late cardiac death, myocardial infarction, or unstable angina. Perioperative events occurred in 14 patients (5 with myocardial infarction and 9 with unstable angina), 10 of whom had ischemia at PET (sensitivity, 71%; predictive value of a positive test, 45%). Isolated resting perfusion defects were not associated with events. The presence of extensive ischemia (more than five segments) had a positive predictive value of 64%, and its absence gave a negative predictive value of 89%.(ABSTRACT TRUNCATED AT 250 WORDS)

The diagnosis of prosthetic valve endocarditis by echocardiography

Echocardiography, using the standard transthoracic and transesophageal (TEE) approaches, has been shown to be a useful tool in the diagnosis and management of patients with prosthetic valve endocarditis (PVE). The role of echocardiography involves (1) finding evidence for vegetations, (2) characterizing valvular dysfunction, (3) identifying periprosthetic spread of infection, and (4) determining preoperative prognostic data that impact on the need and timing of surgical intervention. Incorporation of echocardiography into the diagnostic criteria for endocarditis prevents delay in management and costly errors, particularly in patients with culture-negative infections and complications of the infection including jet lesions and deep tissue infections of the heart. TEE is particularly helpful in PVE, because shielding by the prosthesis may prevent adequate transthoracic imaging, which give false-negative results. With the aid of intraoperative TEE, the surgical mission should be to extirpate all the infection and reconstruct the heart with as little prosthetic material as possible. Transthoracic echocardiography is also useful in the follow-up management of patients with PVE.

Introduction of unnatural amino acids into chalcone isomerase

The active site cysteine residue of chalcone isomerase was rapidly and selectively modified under denaturing conditions with a variety of electrophilic reagents. These denatured and modified enzyme were renatured to produce enzyme derivatives containing a series of unnatural amino acids in the active site. Addition of methyl, ethyl, butyl, heptyl, and benzyl groups to the cysteine sulfur does not abolish catalytic activity, although the activity decreases as the steric bulk of the amino acid side-chain increases. Modification of the cysteine to introduce a charged homoglutamate or a neutral homoglutamine analogue results in retention of 22% of the catalytic activity. Addition of a methylthio group (SMe) to the cysteine residue of native chalcone isomerase preserves 85% of the catalytic activity measured with 2',4',4-trihydroxychalcone, 2',4',6',4-tetrahydroxychalcone, or 2'-hydroxy-4-methoxychalcone as substrates. The competitive inhibition constant for 4',4-dihydroxychalcone, the substrate inhibition constant for 2',4',4-trihydroxychalcone, and other steady-state kinetic parameters for the methanethiolated enzyme are very similar to those of the native enzyme. The strong binding of 4',4-dihydroxychalcone to the methanethiolated enzyme shows that there is no steric repulsion between this modified amino acid residue and the substrate analogue. This structure-activity study clearly demonstrates that the active site cysteine residue does not function as an acid-base or nucleophilic group in producing the catalysis or substrate inhibition observed with chalcone isomerase. The method presented in this paper allows for the rapid introduction of a series of unnatural amino acids into the active site as a means of probing the structure-function relationship.

Prescription of benzodiazepines in a London teaching hospital

A study of the extent of hospital inpatient prescribing of benzodiazepines and their continuation at discharge was carried out on all patients admitted to St Bartholomew's Hospital, London, during a 7-day period. A large majority (73.6%) were not prescribed benzodiazepines at any time. No discharge prescriptions for these drugs were initiated in hospital. The data do not suggest that hospital prescribing of benzodiazepines is contributing to community prescribing.