Defining the biological functions and clinical significance of AKR1C3 in gastric carcinogenesis through multiomics functional analysis and immune infiltration analysis

Background: Human aldo-keto reductase family 1 member C3 (AKR1C3) is an important molecule that participates in multiple physiological metabolic processes. However, its expression, biological functions and clinical significance in gastric carcinogenesis are unclear. Methods: We collected data from several public data portals and clinical samples and systematically analyzed the clinical significance of tissue and plasma AKR1C3 expression. Then, we filtered prognostic risk factors and established novel prognosis-related nomogram models for predicting overall survival time and postoperative recurrence risk. The application value of the nomogram models was further assessed using clinical samples. Moreover, we explored the potential biological functions of AKR1C3 in gastric carcinogenesis and metastasis through multiomics functional analysis and immune infiltration analysis. Results: AKR1C3 levels were reduced in cancer tissue but increased significantly in the plasma of GC patients; AKR1C3 expression in either sample type was closely associated with multiple clinicopathological characteristics. By combining clinicopathological factors and AKR1C3 levels, two novel nomogram models were developed to predict overall survival time and postoperative recurrence risk. Multiomics functional analysis revealed that when its expression is dysregulated, AKR1C3 can widely participate in gene expression regulation through multiple regulatory modes at the gene, RNA and protein levels and exert various crucial biological effects in carcinogenesis and metastasis. Moreover, AKR1C3 expression was correlated with the infiltration of several immune cell types, and AKR1C3 was predicted to interact with several clinical drugs. Conclusion: Dysregulated AKR1C3 expression is related to gastric carcinogenesis and immunotherapy response and is a promising biomarker and effective biotherapy target in GC.

Comparison of Survival Among Adults With Rectal Cancer Who Have Undergone Laparoscopic vs Open Surgery: A Meta-analysis

IMPORTANCE

Two large randomized clinical trials (RCTs) found that laparoscopic surgery failed to yield noninferior pathologic outcomes compared with open surgery for patients with rectal cancer. The results raised concerns regarding the effectiveness of the laparoscopic approach for patients with rectal cancer.

OBJECTIVE

To compare the long-term oncologic outcomes of laparoscopic and open surgery for patients with rectal cancer.

DATA SOURCES

PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials were searched from database inception to August 13, 2021. Studies published in English were retrieved.

STUDY SELECTION

The meta-analysis included RCTs that compared laparoscopic surgery with open surgery for patients with rectal cancer and reported the outcome of disease-free survival (DFS) or overall survival (OS). The following exclusion criteria were used: (1) non-RCTs, (2) studies without long-term survival outcomes of interest, and (3) studies that did not report Kaplan-Meier survival curves.

DATA EXTRACTION AND SYNTHESIS

This meta-analysis was performed in line with the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline for individual participant data development groups. Individual participant data on DFS and OS were extracted from the published Kaplan-Meier survival curves. One-stage and 2-stage meta-analyses were performed.

MAIN OUTCOMES AND MEASURES

Meta-analyses were conducted for DFS and OS. Hazard ratios (HRs) were used as effective measures.

RESULTS

Of 8471 records screened, 10 articles with 12 RCTs and 3709 participants were selected. The reconstructed survival curves for the combined population showed that the 5-year estimated DFS rates were 72.2% (95% CI, 69.4%-74.8%) for the laparoscopic group and 70.1% (95% CI, 67.0%-73.0%) for the open surgery group, and the 5-year estimated OS rates were 76.2% (95% CI, 73.8%-78.5%) for the laparoscopic group and 72.7% (95% CI, 69.8%-75.3%) for open surgery group. In 1-stage meta-analyses, DFS had a nonsignificant HR of 0.92 (95% CI, 0.80-1.06; P = .26), which suggested that DFS in the laparoscopic and open surgery groups was comparable; however, OS was significantly better in the laparoscopic group (HR, 0.85; 95% CI, 0.74-0.97; P = .02). The results were confirmed by 2-stage meta-analyses and were validated by sensitivity analysis with large RCTs.

CONCLUSIONS AND RELEVANCE

A similar DFS but significantly better OS were found for patients who have undergone laparoscopic surgery compared with open surgery for rectal cancer. These findings address concerns regarding the effectiveness of laparoscopic surgery and support the routine use of laparoscopic surgery for patients with rectal cancer.

Case Report: Abdominal Cocoon With Jejuno-Ileo-Colonic Fistula

Introduction

Abdominal cocoon is a unique peritoneal disease that is frequently misdiagnosed. The occurrence of the abdominal cocoon with a jejuno-ileo-colonic fistula has not been previously reported.

Case Presentation

We admitted a 41-year-old female patient with an abdominal cocoon and a jejuno-ileo-colonic fistula. She was admitted to our hospital for the following reasons: “the menstrual cycle is prolonged for half a year, and fatigue, palpitations, and shortness of breath for 2 months”. On the morning of the 4th day of admission, the patient experienced sudden, severe, and intolerable abdominal pain after defecating. An emergency abdominal CT examination revealed intestinal obstruction. Surgery was performed, and the small intestine and colon were observed to be conglutinated and twisted into a mass surrounded by a fibrous membrane, and an enteroenteric fistula was observed between the jejunum, ileum, and sigmoid colon. We successfully relieved the intestinal obstruction and performed adhesiolysis. The patient was discharged from our hospital on the 6th postoperative day, then she recovered and was discharged from Feicheng People's Hospital after another 11 days of conservative treatment, and she recovered well-during the 2-month follow-up period.

Conclusion

Abdominal cocoon coexisting with a jejuno-ileo-colonic fistula is very rare. During the process of abdominal cocoon treatment, the patient's medical history should be understood in detail before the operation, and the abdominal organs should be carefully evaluated during the operation to avoid missed diagnoses.

Impact of second forward-view examination on adenoma detection rate during unsedated colonoscopy: a randomized controlled trial

Objectives

Colorectal cancer on the right side of the colon has been suggested to be harder to detect by colonoscopy. The aim of this study was to evaluate whether a second forward-view examination of the right side of the colon could increase the adenoma detection rate (ADR) and/or polyp detection rate (PDR).

Methods

This was a single-centre randomized controlled trial. Patients undergoing colonoscopy were recruited and randomly assigned to the second forward-view examination (SFE) group, in which the right side of the colon was examined twice or the traditional colonoscopy (TC) group in which the colonoscopy was performed in a standard manner. The primary outcome was the ADR of right colon. The overall PDR and ADR, PDR of the right colon, per-adenoma miss rate of the right colon, and advanced lesion detection rate were also recorded and compared.

Results

A total of 392 patients were included in the study (SFE group 197 vs. TC group 195). The ADR and PDR of the right colon in the SFE group were significantly higher than those in the TC group (ADR 10.7% vs. 5.1%; P = 0.042); PDR 17.8% vs. 9.7%, P = 0.021). No significant difference was found in overall PDR/ADR, or advanced lesion detection rate between the two groups.

Conclusions

This prospective controlled study revealed that a second forward-view examination could modestly increase the ADR and PDR of the right colon during unsedated colonoscopies. This simple, safe and time-effective technique might be recommended for routine unsedated colonoscopy.

Trial registration: Clinical Trials.gov, NCT03619122. Registered on 7/8/2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01783-9.

Serum Inflammatory Cytokines Comparison in Gastric Cancer Therapy

To compare serum inflammatory cytokines between laparoscopic-assisted and open radical gastrectomy in the perioperative period, 80 cases of advanced gastric cancer were chosen for the study. They were divided into laparoscopy group (40 cases) and abdominal open surgery group (40 cases), performed laparoscopic-assisted radical gastrostomy and conventional open radical gastrectomy, respectively. Serum Heme oxygenase-1 (HO-1), TNF-α, IL-6 and CRP were measured by ELISA on preoperative day 1, post-operative day 1 and post-operative day3. Serum HO-1, TNF-α, IL-6 and CRP had no significant difference between the laparoscopy group and the open group on pre-operative day 1. Serum HO-1, IL-6 and CRP of the laparoscopy group were significantly lower than that of the open group on post-operative day 1 and day 3 except for Serum TNF-α which had no significant difference. Laparoscopic-assisted radical gastrectomy was minimally invasive compared with conventional open radical gastrectomy in advanced gastric cancer patients.

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.

[Correlation and clinical significance of expressions of HIF-1α and Sema4D in colorectal carcinoma tissues]

OBJECTIVE

To compare the expressions of hypoxia-inducible factor 1 alpha(HIF-1α) and Semaphorin 4D(Sema4D) in colorectal carcinoma and normal colorectal tissues, and to investigate their correlation and clinical significance.

METHODS

The expressions of HIF-1α and Sema4D were examined in 86 cases of colorectal carcinoma and 52 normal colorectal tissues by SP immunohistochemical staining. Correlation between these two expressions and association of the expressions with clinicopathological characters and prognosis were analyzed.

RESULTS

The positive rates of HIF-1α and Sema4D protein in colorectal carcinoma tissues were significantly higher than those in normal colorectal tissues(58.1% vs. 7.7%, χ(2)=34.624, P<0.01; 60.5% vs. 11.5%, χ(2)=31.839, P<0.01). HIF-1α and Sema4D protein expressions were closely associated with colorectal carcinoma histological types(P=0.003, P=0.010), TNM staging (P=0.003, P=0.017) and lymphatic metastasis (P=0.003, P=0.020), and a significant correlation was observed between the expressions of HIF-1α and Sema4D protein (r=0.567, P<0.01). The 5-year overall survival rate was 37%. Univariate analysis showed that 5-year survival rates of patients with positive and negative HIF-1α protein expression were 24% and 56%(P=0.003), and those with positive and negative Sema4D protein expression were 23% and 59%(P=0.001). Multivariate Cox analysis showed that expression of Sema4D was an independent prognostic factor of colorectal cancer patients(P=0.026), while expression of HIF-1α was not(P=0.501).

CONCLUSION

Combined detection of HIF-1α and Sema4D has the potential to predict the development trend of colorectal carcinoma and prognosis of patients.

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.

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.

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.