A spatial cell atlas of neuroblastoma reveals developmental, epigenetic and spatial axis of tumor heterogeneity

Neuroblastoma is a pediatric cancer arising from the developing sympathoadrenal lineage with complex inter- and intra-tumoral heterogeneity. To chart this complexity, we generated a comprehensive cell atlas of 55 neuroblastoma patient tumors, collected from two pediatric cancer institutions, spanning a range of clinical, genetic, and histologic features. Our atlas combines single-cell/nucleus RNA-seq (sc/scRNA-seq), bulk RNA-seq, whole exome sequencing, DNA methylation profiling, spatial transcriptomics, and two spatial proteomic methods. Sc/snRNA-seq revealed three malignant cell states with features of sympathoadrenal lineage development. All of the neuroblastomas had malignant cells that resembled sympathoblasts and the more differentiated adrenergic cells. A subset of tumors had malignant cells in a mesenchymal cell state with molecular features of Schwann cell precursors. DNA methylation profiles defined four groupings of patients, which differ in the degree of malignant cell heterogeneity and clinical outcomes. Using spatial proteomics, we found that neuroblastomas are spatially compartmentalized, with malignant tumor cells sequestered away from immune cells. Finally, we identify spatially restricted signaling patterns in immune cells from spatial transcriptomics. To facilitate the visualization and analysis of our atlas as a resource for further research in neuroblastoma, single cell, and spatial-omics, all data are shared through the Human Tumor Atlas Network Data Commons at www.humantumoratlas.org.

Methylation profiling reveals novel molecular classes of rhabdomyosarcoma

Rhabdomyosarcomas (RMS) represent a family of aggressive soft tissue sarcomas that present in both children and adults. Pathologic risk stratification for RMS has been based on histologic subtype, with poor outcomes observed in alveolar rhabdomyosarcoma (ARMS) and the adult-type pleomorphic rhabdomyosarcoma (PRMS) compared to embryonal rhabdomyosarcoma (ERMS). Genomic sequencing studies have expanded the spectrum of RMS, with several new molecularly defined entities, including fusion-driven spindle cell/sclerosing rhabdomyosarcoma (SC/SRMS) and MYOD1-mutant SC/SRMS. Comprehensive genomic analysis has previously defined the mutational and copy number spectrum for the more common ERMS and ARMS and revealed corresponding methylation signatures. Comparatively, less is known about epigenetic correlates for the rare SC/SRMS or PRMS histologic subtypes. Herein, we present exome and RNA sequencing, copy number analysis, and methylation profiling of the largest cohort of molecularly characterized RMS samples to date. In addition to ARMS and ERMS, we identify two novel methylation subtypes, one having SC/SRMS histology and defined by MYOD1 p. L122R mutations and the other matching adult-type PRMS. Selected tumors from adolescent patients grouped with the PRMS methylation class, expanding the age range of these rare tumors. Limited follow-up data suggest that pediatric tumors with MYOD1-mutations are associated with an aggressive clinical course.

DNA Methylation Profiling Reveals Prognostically Significant Groups in Pediatric Adrenocortical Tumors: A Report From the International Pediatric Adrenocortical Tumor Registry

PURPOSE

Pediatric adrenocortical carcinomas (ACCs) are aggressive; the overall survival of patients with ACCs is 40%-50%. Appropriate staging and histologic classification are crucial because children with incomplete resections, metastases, or relapsed disease have a dismal prognosis. The clinical course of pediatric adrenocortical tumors (ACTs) is difficult to predict using the current classification schemas, which rely on subjective microscopic and gross macroscopic variables. Recent advances in adult ACT studies have revealed distinct DNA methylation patterns with prognostic significance that have not been systematically interrogated in the pediatric population.

PATIENTS AND METHODS

We performed DNA methylation analyses on 48 newly diagnosed ACTs from the International Pediatric Adrenocortical Tumor Registry and 12 pediatric adrenal controls to evaluate for distinct methylation groups. Pediatric methylation data were also compared systematically with the adult ACC cohort from The Cancer Genome Atlas (TCGA).

RESULTS

Two pediatric ACT methylation groups were identified and showed differences in selected clinicopathologic and outcome characteristics. The A1 group was enriched for CTNNB1 variants and unfavorable outcome. The A2 group was enriched for TP53 germline variants, younger age at onset, and favorable outcome. Pediatric ACT methylation groups were maintained when International Pediatric Adrenocortical Tumor Registry cohort data were combined with TCGA cohort data. The CpG-island hypermethylator phenotype characterizing the TCGA cohort was not identified in the pediatric patients. When methylome findings were combined with independent histopathologic review using the Wieneke criteria, a high-risk population was identified with uniform fatal outcome.

CONCLUSION

Our results indicate DNA methylation analysis can enhance current diagnostic algorithms. A combination of methylation and histologic classification produced the strongest prediction model and may prove useful in future risk-adapted therapeutic trials.

OR02-1 DNA Methylation Profiling in Pediatric Adrenocortical Tumors Reveals Distinct Methylation Signatures with Prognostic Significance: A Report from the International Pediatric Adrenocortical Tumor Registry

Pediatric adrenocortical tumors (ACTs) are heterogeneous and have a poor prognosis. Overall survival is around 60%. In pediatric ACT that is managed only with surgery, features associated with adverse outcome include age greater than 3 years, non-functioning tumors, and metastatic (Stage IV) or residual tumor after surgery (Stage III). These factors individually do not account for most treatment failures, however. As current histopathologic classification systems are hindered by poor reproducibility and lack of predictive value, new prognostic markers are critically needed. In adults, methylation profiling can distinguish benign from malignant ACT, but similar data on pediatric ACT have not been reported. We performed DNA methylation profiling (MethylationEPIC BeadChip Array) on 52 pediatric ACTs and 13 normal pediatric adrenocortical tissue samples. The median age of 38 girls and 14 boys was 2.8 years (range, 0.3-17). ACTs were histologically classified as carcinoma (n=29), adenoma (n=10), and indeterminate (n=13). Overall survival was used as a primary endpoint. Unsupervised analysis of the 20,000 most variably methylated probes segregated cases into two distinct subgroups (designated A1 and A2). Differentially methylated genes (q-value<0.05) between A1 and A2 groups included those associated with IGF-, mTOR, WNT, and HGF/cMET signaling pathways. Other genes commonly mutated in pediatric malignancies (DICER1, EZH2,EGFR, PTEN, RB1, TERT, SF1, and MEN1) were also differentially methylated. Normal adrenal cortex samples segregated with the A2 group. The A1 subgroup had unique copy number changes, and recurrent global hypomethylation of chromosomes 4, 13, and 18. Moreover, the A1 group was significantly associated with higher frequency of CTNNB1 mutations (OR = 4.2, p = 0.03), lower frequency of TP53 mutations (p = 0.04), and use of chemotherapy (OR = 9.7, p = 0.0007). Methylation subgroups were not significantly associated with sex, histopathologic classification, disease stage, or ATRX status. In a univariable analysis, vascular invasion (HR=6.2, p=0.02), tumor weight (HR=10.9, p=0.001), tumor size (HR=11.3, p=0.002), tumor volume (cm³, HR=8.53, p=0.008), diffuse necrosis (HR=9.21, p=0.03), proliferative index by Ki-67 immunohistochemical staining (HR=7.1, p=0.02), disease stage III/IV (HR = 9.8, p = 0.03), age > 4 years (HR = 16.8, p = 0.008) and A1 methylation group (HR 7.7, p=0.0011) were each significantly correlated with overall survival. A1 subgroup remained significantly associated with overall survival in a series of models that adjusted for features including: clinical diagnosis, histopathologic characteristics, Ki67 index, and advanced stage. Methylation profiling provides prognostic significance that is independent of most current predictive variables, and in the future, may serve as a powerful biomarker in the prognostication of pediatric ACT.

In Vivo Imaging of Human MDR1 Transcription in the Brain and Spine of MDR1-Luciferase Reporter Mice

P-glycoprotein (Pgp) [the product of the MDR1 (ABCB1) gene] at the blood-brain barrier (BBB) limits central nervous system (CNS) entry of many prescribed drugs, contributing to the poor success rate of CNS drug candidates. Modulating Pgp expression could improve drug delivery into the brain; however, assays to predict regulation of human BBB Pgp are lacking. We developed a transgenic mouse model to monitor human MDR1 transcription in the brain and spinal cord in vivo. A reporter construct consisting of ∼10 kb of the human MDR1 promoter controlling the firefly luciferase gene was used to generate a transgenic mouse line (MDR1-luc). Fluorescence in situ hybridization localized the MDR1-luciferase transgene on chromosome 3. Reporter gene expression was monitored with an in vivo imaging system following D-luciferin injection. Basal expression was detectable in the brain, and treatment with activators of the constitutive androstane, pregnane X, and glucocorticoid receptors induced brain and spinal MDR1-luc transcription. Since D-luciferin is a substrate of ABCG2, the feasibility of improving D-luciferin brain accumulation (and luciferase signal) was tested by coadministering the dual ABCB1/ABCG2 inhibitor elacridar. The brain and spine MDR1-luc signal intensity was increased by elacridar treatment, suggesting enhanced D-luciferin brain bioavailability. There was regional heterogeneity in MDR1 transcription (cortex > cerebellum) that coincided with higher mouse Pgp protein expression. We confirmed luciferase expression in brain vessel endothelial cells by ex vivo analysis of tissue luciferase protein expression. We conclude that the MDR1-luc mouse provides a unique in vivo system to visualize MDR1 CNS expression and regulation.

Drug transporters on arachnoid barrier cells contribute to the blood-cerebrospinal fluid barrier

The subarachnoid space, where cerebrospinal fluid (CSF) flows over the brain and spinal cord, is lined on one side by arachnoid barrier (AB) cells that form part of the blood-CSF barrier. However, despite the fact that drugs are administered into the CSF and CSF drug concentrations are used as a surrogate for brain drug concentration following systemic drug administration, the tight-junctioned AB cells have never been examined for whether they express drug transporters that would influence CSF and central nervous system drug disposition. Hence, we characterized drug transporter expression and function in AB cells. Immunohistochemical analysis showed P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) in mouse AB cells but not other meningeal tissue. The Gene Expression Nervous System Atlas (GENSAT) database and the Allen Mouse Brain Atlas confirmed these observations. Microarray analysis of mouse and human arachnoidal tissue revealed expression of many drug transporters and some drug-metabolizing enzymes. Immortalized mouse AB cells express functional P-gp on the apical (dura-facing) membrane and BCRP on both apical and basal (CSF-facing) membranes. Thus, like blood-brain barrier cells and choroid plexus cells, AB cells highly express drug transport proteins and likely contribute to the blood-CSF drug permeation barrier.

Plerixafor (AMD3100) in myeloma and lymphoma patients undergoing autologous stem cell transplantation

7100

Background: Poor peripheral blood stem cell (PBSC) mobilization has been reported as an obstacle to autologous stem cell transplant (ASCT). Plerixafor (AMD3100) has been recently approved as a mobilization agent for PBSC in the setting of ASCT. Methods: We retrospectively analyzed the data on patients who received plerixafor in our institution over two-year period. Four lymphoma patients received the drug in their first cycle of mobilization and 17 patients (hard to mobilize, HTM) as a rescue after failing to achieve cell target using G-CSF alone. These patients include 8 multiple myeloma (MM) and 9 lymphoma patients. A control group of 26 randomly picked MM and lymphoma patients who were good mobilizers and received ASCT during the same period were used for comparison. Results: Sixteen of the 17 HTM patients proceeded to ASCT with median CD34+ cell dose of 3.68 X 106/kg (range, 1.88–5.01 X 106), and two of them had tandem transplants. All MM patients achieved minimum cell dose for two ASCTs. One MM patient died of progressive disease prior to ASCT. In comparison to the control group, plerixafor patients tended to have lower median CD34+ cell dose/kg collected and higher number of apheresis days, however the content of CFU-GM/kg on 1st day of apheresis was either equal or higher in the plerixafor group versus the control. The length of hospital stay, number of serious bacterial infection, time to granulocyte engraftment (AGC > 500) and long-term hematopoietic recovery at ≥ 12 mo post ASCT were not different among the two groups. Time to platelet recovery > 20,000/mm3 was similar for the MM patients, while more delayed for the plerixafor mobilized lymphoma patients (24 versus 12 days in the control group). One lymphoma patient in the control died of transplant-related complications before engraftment and none in the plerixafor group. Disease relapse at 12 months post ASCT was 0 and 10 % for plerixafor and control MM patients, respectively, and 46 and 20 % for lymphoma patients. However, the overall survival for both groups was not significantly different. Conclusions: all poor mobilizers were able to obtain adequate transplant CD34+ cell dose by using plerixafor and G-CSF. In general, patients mobilized with plerixafor had similar post transplant course and long-term outcome.

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The major human pregnane X receptor (PXR) splice variant, PXR.2, exhibits significantly diminished ligand-activated transcriptional regulation

The pregnane X receptor (PXR; PXR.1) can be activated by structurally diverse lipophilic ligands. PXR.2, an alternatively spliced form of PXR, lacks 111 nucleotides encoding 37 amino acids in the ligand binding domain. PXR.2 bound a classic CYP3A4 PXR response element (PXRE) in electrophoretic mobility shift assays, but transfected PXR.2 failed to transactivate a CYP3A4-promoter-luciferase reporter plasmid in HepG2 cells treated with various PXR ligands. Cotransfection experiments showed that PXR.2 behaved as a dominant negative, interfering with PXR.1/rifampin activation of CYP3A4-PXRE-LUC. In HepG2 and LS180 cells stably transduced with PXR.1, PXR target genes (CYP3A4, MDR1, CYP2B6, and UGT1A1) were higher than mock-transduced cells in the absence of ligand and were further induced in the presence of rifampin. In contrast, PXR.2 stably introduced into the same host cells failed to induce target genes over levels in mock-transfected cells after drug treatment. Our homology modeling suggests that ligands bind PXR.1 more favorably, probably because of the presence of a key disordered loop region, which is missing in PXR.2. Yeast two-hybrid assays revealed that, even in the presence of ligand, the corepressors remain tightly bound to PXR.2, and coactivators are unable to bind at helix 12. In summary, PXR.2 can bind to PXREs but fails to transactivate target genes because ligands do not bind the ligand binding domain of PXR.2 productively, corepressors remain tightly bound, and coactivators are not recruited to PXR.2.

Gender aspects on survival among patients admitted to hospital with suspected or diagnosed heart failure

OBJECTIVES AND DESIGN

There are conflicting data on gender differences in survival among heart failure (HF) patients. We prospectively assessed gender differences in survival among 930 consecutive patients (464 [49.9%] women, mean age 76.1+/-10.1 years), admitted to hospital with suspected or diagnosed HF.

RESULTS

Overall, women had lower unadjusted mortality hazard ratio (HR) than men: HR 0.827; 95% confidence interval (CI) 0.690-0.992; p=0.040. Adjusted HR was 0.786; 95% CI 0.601-1.028; p=0.079. Unadjusted mortality was significantly higher among patients with a discharge HF diagnosis, compared to those without: HR 1.330; 95% CI 1.107-1.597; p=0.002; adjusted p=0.289. Women and men with a discharge HF diagnosis had similar survival: unadjusted HR 1.052; 95% CI 0.829-1.336; p=0.674; adjusted HR 0.875; 95% CI 0.625-1.225; p=0.437. Women had lower mortality risk among patients without a discharge HF diagnosis: HR 0.630, 95% CI 0.476-0.833, p=0.001; adjusted HR 0.611, p=0.036.

CONCLUSION

Prognosis was poor among patients hospitalised with suspected or diagnosed HF. Among all patients, women had better survival, whereas both sexes had similar survival when the HF diagnosis was certified.

Effects on quality of life, symptoms and daily activity 6 months after termination of an exercise training programme in heart failure patients

BACKGROUND

Exercise training in heart failure patients improves exercise capacity, physical function, and quality-of-life. Prior studies indicate a rapid loss of these effects following termination of the training. We wanted to assess any sustained post-training effects on patients global assessment of change in quality-of-life (PGACQoL) and physical function.

METHODS

Fifty-four stable heart failure patients were randomised to exercise or control. The 4-month exercise programme consisted of bicycle training at 80% of maximal intensity three times/week, and 49 patients completed the active study period. At 10 months (6 months post training) 37 patients were assessed regarding PGACQoL, habitual physical activity, and dyspnea-fatigue-index.

RESULTS

Both post-training patients (n=17) and controls (n=20) deteriorated PGACQoL during the 6-month extended follow-up, although insignificantly. However, post-training patients improved PGACQoL slightly but significantly from baseline to 10 months (P=0.006), differing significantly (P=0.023) from controls who were unchanged. Regarding dyspnea-fatigue-index, post-training patients were largely unchanged and controls deteriorated insignificantly, during the extended follow-up as well as from baseline to 10 months. Both groups decreased physical activity insignificantly during the extended follow-up, and from baseline to 10 months post-training patients tended to decrease whereas controls significantly (P=0.007) decreased physical activity.

CONCLUSION

There was no important sustained benefit 6 months after termination of an exercise training programme in heart failure patients. A small, probably clinically insignificant sustained improvement in PGACQoL was seen in post-training patients. Controls significantly decreased the habitual physical activity over 10 months and post-training patients showed a similar trend. Exercise training obviously has to be continuing to result in sustained benefit.

Angiotensin converting enzyme (ACE) inhibitors and heart failure. The consequences of underprescribing

Heart failure (HF) is a common and expensive cardiovascular disease, in economic terms as well as in lives lost. Angiotensin converting enzyme (ACE) inhibitors have been shown to significantly reduce mortality and hospitalisation in HF. However, recent surveys show that the prescription rate of ACE inhibitors for HF is far below what is considered to be optimal. Furthermore, prescribed dosages are usually lower than those recommended based on evidence from clinical trials. This article estimates the consequences, both economic and human, of underprescribing ACE inhibitors in patients with HF. The indication for prescribing an ACE inhibitor varies, and clinical trials have included different categories of patients; it is inappropriate to assess costs in all eligible patients without taking these factors into account. Therefore, we analysed the data with respect to 4 different groups: (i) asymptomatic left ventricular systolic dysfunction (LVSD)--an early stage leading to chronic HF; (ii) chronic HF; and post-myocardial infarction (MI) LVSD differentiated into (iii) post-MI asymptomatic LVSD and (iv) post-MI chronic HF. We also estimated the cost effectiveness of adding an ACE inhibitor to the treatment of patients with HF for whom an ACE inhibitor is not currently prescribed. If only patient populations in which large trials have shown a significant effect of ACE inhibition on mortality are included in the analysis (i.e. excluding asymptomatic patients with LVSD), increasing the number of Swedish patients receiving an ACE inhibitor could save in excess of 3700 lives each year, in addition to reducing the annual number of hospitalisations by 8400. The additional cost would be 101.5 million Swedish kronor (SEK), a cost per life saved of SEK27 200. Chronic HF is the most cost-effective patient population to treat, generating cost savings under certain assumptions. A further 6700 hospitalisations can be avoided should the use of ACE inhibitors be extended to asymptomatic patients with LVSD. Increasing dosages to those used in the large clinical trials may generate additional savings in lives and hospitalisations. In conclusion, the use of ACE inhibitors in HF and LVSD has clearly been proven to be cost effective, and compares favourably with the cost effectiveness of treating hypertension or hypercholesterolaemia. At present, however, ACE inhibitors are not optimally utilised. Given the increasingly constrained resources for healthcare, every effort should be made to increase the use of cost-effective treatments, such as ACE inhibitors in chronic HF and post-MI LVSD.

Left atrioventricular plane displacement is related to both systolic and diastolic left ventricular performance in patients with chronic heart failure

AIMS

Left atrioventricular plane displacement is proposed to reflect left ventricular systolic function and is strongly related to prognosis in patients with heart failure. Left atrioventricular plane displacement is a different measure of left ventricular function compared to ejection fraction, and the factors influencing left atrioventricular plane displacement are insufficiently characterized. We wanted to assess any relationship between left atrioventricular plane displacement and left ventricular diastolic performance.

METHODS AND RESULTS

Left ventricular diastolic filling, left atrioventricular plane displacement, and fractional shortening were assessed by echocardiography/Doppler in 54 patients with chronic heart failure (age 64 +/- 7 years). Left atrioventricular plane displacement correlated significantly with Doppler variables of left ventricular filling, in particular the inverse logarithm of early transmitral flow deceleration time; log-1 Edt (r = -0.61, P < 0.0001, n = 54). Left atrioventricular plane displacement also correlated with fractional shortening (r = 0.49, P < 0.001, n = 50). However, fractional shortening did not correlate with any Doppler variable. Log-1 Edt, fractional shortening, age, heart rate, left ventricular and atrial size, and degree of mitral regurgitation were included in a multiple regression analysis. Only log-1 Edt (P = 0.001) and fractional shortening (P = 0.03) correlated independently with left atrioventricular plane displacement. Among patients with similar fractional shortening, those with more compromised diastolic performance had lower left atrioventricular plane displacement.

CONCLUSION

Left atrioventricular plane displacement was related to both systolic and diastolic left ventricular performance, which may explain some of the discrepancies between left atrioventricular plane displacement and ejection fraction.

Maternal cradling and infant nipple preferences in rhesus monkeys (Macaca mulatta)

This study investigated lateral biases in nipple preferences, maternal cradling, carrying, and retrieval in 41 rhesus macaque (Macaca mulatta) mother-infant dyads living in two captive social groups. Observations were made during the first 6 weeks of infant life using a combination of scan sampling and ad-libitum sampling techniques. Infants exhibited a significant left-nipple preference in the first weeks of life but the bias decreased with infant age. Mothers showed a left-arm bias in carrying their infants but no significant lateral bias in cradling or retrieval. Our results suggest that the left-side cradling bias reported in studies of humans and some other primates reflects a bias in the infant's nipple preference rather than in maternal behavior. The infants' preference for the left nipple is consistent with both Salk's (1960) heartbeat hypothesis and with more recent hypotheses linking this lateral bias with brain asymmetry and hemispheric specialization for mother-infant communication.

Exercise training in heart failure improves quality of life and exercise capacity

AIMS

Benefit from exercise training in heart failure has mainly been shown in men with ischaemic disease. We aimed to examine the effects of exercise training in heart failure patients < or = 75 years old of both sexes and with various aetiology.

METHODS AND RESULTS

Fifty-four patients with stable mild-to-moderate heart failure were randomized to exercise or control, and 49 completed the study (49% > or = 65 years; 29% women; 24% non-ischaemic aetiology; training, n = 22; controls, n = 27). The exercise programme consisted of bicycle training at 80% of maximal intensity over a period of 4 months. Improvements vs controls were found regarding maximal exercise capacity (6 +/- 12 vs -4 +/- 12% [mean +/- SD], P < 0.01) and global quality-of-life (2 [1] vs 0 [1] units [median ¿inter-quartile range¿], P < 0.01), but not regarding maximal oxygen consumption or the dyspnoea-fatigue index. All of these four variables significantly improved in men with ischaemic aetiology compared with controls (n = 11). However, none of these variables improved in women with ischaemic aetiology (n = 5), or in patients with non-ischaemic aetiology (n = 6). The training response was independent of age, left ventricular systolic function, and maximal oxygen consumption. No training-related adverse effects were reported.

CONCLUSION

Supervised exercise training was safe and beneficial in heart failure patients < or = 75 years, especially in men with ischaemic aetiology. The effects of exercise training in women and patients with non-ischaemic aetiology should be further examined.

Quality of life in patients with ischaemic heart disease: a prospective controlled study

OBJECTIVES

To assess quality of life in patients after acute myocardial infarction (AMI), coronary artery by-pass grafting surgery (CABG) and percutaneous transluminal coronary angioplasty (PTCA) as compared with healthy controls.

DESIGN

Self-administered questionnaires were completed 1 month and 1 year after the event.

SETTING

Department of Cardiology, University Hospital, Malmö, Sweden; 1989-1992.

SUBJECTS

296 AMI, 99 CABG, 18 PTCA patients and 88 randomly selected healthy controls were included; 349 patients completed the entire programme.

MAIN OUTCOME MEASURES

Quality of life in the dimensions of perceived general health, thoracic pain, breathlessness, feeling of arrhythmia, anxiety, depression, self-esteem, experience of social life and sex life.

RESULTS

Patients differed from controls in both psychological and somatic aspects of QL after 1 month. Furthermore, 1 month after the event AMI patients experienced more anxiety (P = 0.001) than CABG patients, whilst CABG patients experienced a poorer sex life (P < 0.001) than AMI patients. One year after the event patients differed from controls primarily in somatic symptoms: no significant differences were found across patient groups. Patients who sought emergency out-patient care during the follow-up year for clinically diagnosed angina pectoris or cardiac incompensation had reported higher levels of thoracic pain (P < 0.001) and breathlessness (P < 0.001) at 1 month follow-up than patients who did not seek such care.

CONCLUSIONS

Quality of life is considerably affected in patients following a cardiac event, especially during the initial recovery phase. Although substantial improvement in quality of life occurs over time, the persistence of residual distress at 1-year follow-up is a challenge for clinicians concerned with the full rehabilitation of the cardiac patient.

Left ventricular atrioventricular plane displacement: an echocardiographic technique for rapid assessment of prognosis in heart failure

OBJECTIVE

To assess the prognostic value of atrioventricular plane displacement in heart failure patients.

DESIGN

Patients were followed prospectively for one year after atrioventricular plane displacement determination.

SETTING

Malmö University Hospital, with a primary catchment area of 250,000 inhabitants.

PATIENTS

181 patients with a clinical diagnosis of heart failure; age 75.7 (SD 5.2) years, duration of heart failure 2.7 (5.7) years; 100 men, 81 women.

MAIN OUTCOME MEASURES

Mortality in relation to atrioventricular plane displacement.

RESULTS

Total mortality was 22.7% (41/181), and was highly significantly (P = 0.001) related to atrioventricular plane displacement. Mortality within prospectively defined categories of displacement was: > or = 10.0 mm, 0% (0/19); 8.2 to 9.9 mm, 10.3% (3/29); 6.4 to 8.1 mm, 19.4% (12/62); and < 6.4 mm, 36.6% (26/71). The groups were similar in age, sex, angiotensin converting enzyme inhibitor and beta blocker treatment, and cause and duration of heart failure.

CONCLUSIONS

Mortality in heart failure is strongly related to atrioventricular plane displacement.

Distribution and morphology of dopaminergic amacrine cells in the retina of the turtle (Pseudemys scripta elegans)

A light microscopical study of the cell types that stain by immunohistochemistry for the synthesizing enzyme for dopamine, tyrosine hydroxylase, has been performed on the retina of the turtle Pseudemys scripta elegans. The immunostain can be localized to a single morphological type of amacrine cell. The cells are like A28 cells of a Golgi classification. They have medium sized dendritic fields that range in diameter from 200 to 700 micron with eccentricity from the visual streak. The amacrines have a tri-stratified dendritic tree with tiers of fine, curved dendrites ramifying in strata S1, lower S2 and the S4/5 border of the inner plexiform layer. We, like others, can find no good evidence that these cells are interplexiform cells. The dopaminergic amacrine cells have a low frequency (approximately 1300-1500 total cells in 130 mm2 retina), with their highest density occurring in the visual streak (60 cells per mm2). The density profiles fall in elliptical isodensity rings from the visual streak towards the peripheral retina. At all points on the retina the dendritic fields maintain a constant coverage factor independent of eccentricity. A comparison of the dopaminergic amacrine cells in the turtle and other vertebrate retinae is made.

Localization of fodrin during fertilization and early development of sea urchins and mice

Fodrin, a spectrin-like protein, is localized in gametes, zygotes, and embryos from sea urchins and mice. Mammalian fodrin comprises two polypeptides with molecular weights of approximately 240 kDa (alpha) and 235 kDa (beta). An antibody specific for mammalian alpha-fodrin cross-reacted with a 240-kDa polypeptide from sea urchin egg extracts. This indicates that sea urchins contain a protein of similar electrophoretic mobility and immunological properties to mammalian alpha-fodrin. When this antibody was used to stain the sea urchin gametes with indirect immunofluorescence, fodrin-specific fluorescence was localized to the acrosome of the sperm and was distributed over the entire egg near the surface in a punctate pattern similar to the distribution of polymeric actin. During sperm incorporation, the fodrin-specific fluorescence is found at the site of sperm incorporation, in the fertilization cone. After fertilization, the intensity of fodrin fluorescence increases. During mitosis and cytokinesis in sea urchins, the entire surface of the egg remains stained; the cleavage furrow also was stained but no more intensely than was the rest of the egg surface. Antibody labeling with colloidal gold followed by electron microscopy showed that fodrin was loated in the cytoplasm immediately beneath the plasma membrane. In unfertilized mouse oocytes, both actin and fodrin were stained most intensely beneath the membrane adjacent to the meiotic spindle. After insemination, the cell surfaces of the pronucleate egg and the second polar body were stained; however, the actin matrix surrounding the apposed pronuclei did not bind the fodrin antibody. During cytokinesis in the mouse, the cleavage furrow stained more intensely than did the rest of the egg cortex, and in embryos the cell borders were delineated. These results indicate that organisms as unrelated to mammals as sea urchins have fodrin-like proteins; the rearrangements of such proteins suggest that they participate in the actin-mediated events at the cell surface during fertilization and early development in both mice and sea urchins.

Latrunculin inhibits the microfilament-mediated processes during fertilization, cleavage and early development in sea urchins and mice

Latrunculin A, a marine toxin from a Red Sea sponge, is a potent inhibitor of the microfilament-mediated processes of fertilization and early development in sea urchins and in mice. Sperm from sea urchins, but not those from Limulus or mice, were affected by latrunculin, and fertilization in both sea urchins and in mice was arrested but at different stages. Sea urchin sperm treated with 2.6 microM latrunculin are unable to assemble acrosomal processes and their ability to fertilize eggs is impaired. The unwinding of the Limulus sperm acrosomal process occurs in the presence of latrunculin. Treated mouse sperm are able to fertilize mouse oocytes in vitro, suggesting that microfilaments may not be required in this mammalian sperm. In sea urchin eggs, sperm incorporation, microvillar elongation and cytokinesis are inhibited. Microtubule-mediated motility occurs normally. 20 nM latrunculin prevents the morphogenetic movements during gastrulation. It reduces the viscosity of actin gels from sea urchin egg homogenates. In unfertilized mouse oocytes, it prevents the colcemid-induced dispersion of the meiotic chromosomes; accumulations of cortical actin are noted adjacent to the scattered chromosomes. Sperm incorporation during mouse fertilization in vitro is unaffected suggesting that sperm entry may occur independent of microfilament activity in mammals. However, the apposition of the pronuclei at the center of the egg cytoplasm does not occur, providing evidence that cytoplasmic microfilaments may be required for the motions leading to pronuclear union during mouse fertilization. It inhibits the second polar body formation and cytokinesis. These results indicate that latrunculin is a potent inhibitor of microfilament-mediated processes in sperm, eggs and embryos, and that it may prove to be a powerful new drug for exploring the cellular behavior of microfilaments in the maintenance of cell shape and during motility.

The effects of artificial postoperative hematoma on patency of microvascular anastomoses in rat femoral blood vessels

The effect of hematoma formation on thrombus formation at microvascular anastomotic sites in the femoral arteries and veins of rats was investigated. No difference in anastomotic patency or thrombus formation was observed in the presence of perivascular hematoma, although compression secondary to hematoma formation was not an experimental variable. This study suggests the possibility that the velocity of blood flow (which increases with vasoconstriction) counteracts the thrombogenicity of changes in the flow volume (which decreases with vasoconstriction) by preventing the accumulation of thrombogenic materials. The authors suggest that the role of vasoconstriction in relation to thrombus formation and anastomotic patency should be explored further using topical vasoconstrictors and appropriate platelet fractions.