FLT3-targeted therapy restores GATA1 pathway function in NPM1/FLT3-ITD mutated acute myeloid leukaemia

One-third of newly diagnosed adult acute myeloid leukaemia (AML) carry FLT3 mutations, which frequently occur together with nucleophosmin (NPM1) mutations and are associated with worse prognosis. FLT3 inhibitors are widely used in clinics with limitations due to drug resistance. AML cells carrying FLT3 mutations in both mouse models and patients present low expression of GATA1, a gene involved in haematopoietic changes preceding AML. Here, we show that FLT3 inhibition induces cellular responses and restores the GATA1 pathway and functions in NPM1/FLT3-ITD mutated AML, thus providing a new mechanism of action for this drug.

GSK3β is a critical, druggable component of the network regulating the active NOTCH1 protein and cell viability in CLL

NOTCH1 alterations have been associated with chronic lymphocytic leukemia (CLL), but the molecular mechanisms underlying NOTCH1 activation in CLL cells are not completely understood. Here, we show that GSK3β downregulates the constitutive levels of the active NOTCH1 intracellular domain (N1-ICD) in CLL cells. Indeed, GSK3β silencing by small interfering RNA increases N1-ICD levels, whereas expression of an active GSK3β mutant reduces them. Additionally, the GSK3β inhibitor SB216763 enhances N1-ICD stability at a concentration at which it also increases CLL cell viability. We also show that N1-ICD is physically associated with GSK3β in CLL cells. SB216763 reduces GSK3β/N1-ICD interactions and the levels of ubiquitinated N1-ICD, indicating a reduction in N1-ICD proteasomal degradation when GSK3β is less active. We then modulated the activity of two upstream regulators of GSK3β and examined the impact on N1-ICD levels and CLL cell viability. Specifically, we inhibited AKT that is a negative regulator of GSK3β and is constitutively active in CLL cells. Furthermore, we activated the protein phosphatase 2 A (PP2A) that is a positive regulator of GSK3β, and has an impaired activity in CLL. Results show that either AKT inhibition or PP2A activation reduce N1-ICD expression and CLL cell viability in vitro, through mechanisms mediated by GSK3β activity. Notably, for PP2A activation, we used the highly specific activator DT-061, that also reduces leukemic burden in peripheral blood, spleen and bone marrow in the Eµ-TCL1 adoptive transfer model of CLL, with a concomitant decrease in N1-ICD expression. Overall, we identify in GSK3β a key component of the network regulating N1-ICD stability in CLL, and in AKT and PP2A new druggable targets for disrupting NOTCH1 signaling with therapeutic potential.

Bcor deficiency perturbs erythro-megakaryopoiesis and cooperates with Dnmt3a loss in acute erythroid leukemia onset in mice

Recurrent loss-of-function mutations of BCL6 co-repressor (BCOR) gene are found in about 4% of AML patients with normal karyotype and are associated with DNMT3a mutations and poor prognosis. Therefore, new anti-leukemia treatments and mouse models are needed for this combinatorial AML genotype. For this purpose, we first generated a Bcor^-/- knockout mouse model characterized by impaired erythroid development (macrocytosis and anemia) and enhanced thrombopoiesis, which are both features of myelodysplasia/myeloproliferative neoplasms. We then created and characterized double Bcor^-/-/Dnmt3a^-/- knockout mice. Interestingly, these animals developed a fully penetrant acute erythroid leukemia (AEL) characterized by leukocytosis secondary to the expansion of blasts expressing c-Kit+ and the erythroid marker Ter119, macrocytic anemia and progressive reduction of the thrombocytosis associated with loss of Bcor alone. Transcriptomic analysis of double knockout bone marrow progenitors revealed that aberrant erythroid skewing was induced by epigenetic changes affecting specific transcriptional factors (GATA1-2) and cell-cycle regulators (Mdm2, Tp53). These findings prompted us to investigate the efficacy of demethylating agents in AEL, with significant impact on progressive leukemic burden and mice overall survival. Information gained from our model expands the knowledge on the biology of AEL and may help designing new rational treatments for patients suffering from this high-risk leukemia.

The HDAC inhibitor valproate induces a bivalent status of the CD20 promoter in CLL patients suggesting distinct epigenetic regulation of CD20 expression in CLL in vivo

Treatment with anti-CD20 antibodies is only moderately efficient in chronic lymphocytic leukemia (CLL), a feature which has been explained by the inherently low CD20 expression in CLL. It has been shown that CD20 is epigenetically regulated and that histone deacetylase inhibitors (HDACis) can increase CD20 expression in vitro in CLL. To assess whether HDACis can upregulate CD20 also in vivo in CLL, the HDACi valproate was given to three del13q/NOTCH1wt CLL patients and CD20 levels were analysed (the PREVAIL study). Valproate treatment resulted in expected global activating histone modifications suggesting HDAC inhibitory effects. However, although valproate induced expression of CD20 mRNA and protein in the del13q/NOTCH1wt I83-E95 CLL cell line, no such effects were observed in the patients studied. In contrast to the cell line, in patients valproate treatment resulted in transient recruitment of the transcriptional repressor EZH2 to the CD20 promoter, correlating to an increase of the repressive histone mark H3K27me3. This suggests that valproate-mediated induction of CD20 may be hampered by EZH2 mediated H3K27me3 in vivo in CLL. Moreover, valproate treatment resulted in induction of EZH2 and global H3K27me3 in patient cells, suggesting transcriptionally repressive effects of valproate in CLL. Our results suggest new in vivo mechanisms of HDACis which may have implications on the design of future clinical trials in B-cell malignancies.

IBTK Differently Modulates Gene Expression and RNA Splicing in HeLa and K562 Cells

The IBTK gene encodes the major protein isoform IBTKα that was recently characterized as substrate receptor of Cul3-dependent E3 ligase, regulating ubiquitination coupled to proteasomal degradation of Pdcd4, an inhibitor of translation. Due to the presence of Ankyrin-BTB-RCC1 domains that mediate several protein-protein interactions, IBTKα could exert expanded regulatory roles, including interaction with transcription regulators. To verify the effects of IBTKα on gene expression, we analyzed HeLa and K562 cell transcriptomes by RNA-Sequencing before and after IBTK knock-down by shRNA transduction. In HeLa cells, 1285 (2.03%) of 63,128 mapped transcripts were differentially expressed in IBTK-shRNA-transduced cells, as compared to cells treated with control-shRNA, with 587 upregulated (45.7%) and 698 downregulated (54.3%) RNAs. In K562 cells, 1959 (3.1%) of 63128 mapped RNAs were differentially expressed in IBTK-shRNA-transduced cells, including 1053 upregulated (53.7%) and 906 downregulated (46.3%). Only 137 transcripts (0.22%) were commonly deregulated by IBTK silencing in both HeLa and K562 cells, indicating that most IBTKα effects on gene expression are cell type-specific. Based on gene ontology classification, the genes responsive to IBTK are involved in different biological processes, including in particular chromatin and nucleosomal organization, gene expression regulation, and cellular traffic and migration. In addition, IBTK RNA interference affected RNA maturation in both cell lines, as shown by the evidence of alternative 3′- and 5′-splicing, mutually exclusive exons, retained introns, and skipped exons. Altogether, these results indicate that IBTK differently modulates gene expression and RNA splicing in HeLa and K562 cells, demonstrating a novel biological role of this protein.

Abstract 4471: Overcoming the resistance to the anti CD20 treatments in chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia is the most common leukaemia in the Western countries. Treatment of CLL and other lymphomas is based on cytostatic drugs in combination with rituximab or other monoclonal antibodies targeting the B-cell surface marker CD20. Although the CD20-antibodies have revolutionized the therapeutic perspectives of indolent B-cell lymphomas, the treatment of CLL with CD20-antibodies is often inefficient, a feature which has been explained by the inherently low CD20 expression in CLL. It has been shown previously that CD20 is epigenetically regulated in some lymphoma cell lines and that some histone deacetylase inhibitors (HDACi) can increase CD20 expression in B-cell lymphomas both in vitro and in vivo. Therefore, we utilized the HDACi valproate to upregulate CD20 both in CLL cell lines and in patients.Two CLL patients with del13q were treated with valproate at serum levels around 800 μM for three days in three 21-day cycles. CD20 expression was analyzed by Real time-PCR and flowcytometry on the B-CLL cells isolated from peripheral blood.In addition, the valproate-induced histone modifications and changes in repressor/activator complexes of the CD20 promoter were investigated in the CLL cell lines and in patients.In the patient 1, CD20 expression was increased 2 times after 2 weeks of treatment, suggesting long-term effects by valproate. Neither the mRNA stability nor the protein stability seems to be affected by Valproate, suggesting transcriptional effects. However, no effects were observed in the patient 2. In contrast to patient results, Valproate increases CD20 transcript and protein levels by 2,5 times in the CLL-cell line I83-E95 after 48 hours. Here, the activating histone mark, acetylated H3K9, is enriched on the CD20 promoter suggesting valproate-related effects on the epigenome. Our study will continue the characterization of valproate-related effects on the epigenetic signatures of the CD20 promoter in CLL cells in vitro and in vivo, dissecting the mechanisms underling low CD20 expression in CLL.

Citation Format: Annarita Scialdone, Jesper Kofoed Damm, Urban Gullberg, Kristina Drott. Overcoming the resistance to the anti CD20 treatments in chronic lymphocytic leukaemia. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4471.

Impairment of T cell development and acute inflammatory response in HIV-1 Tat transgenic mice

Immune activation and chronic inflammation are hallmark features of HIV infection causing T-cell depletion and cellular immune dysfunction in AIDS. Here, we addressed the issue whether HIV-1 Tat could affect T cell development and acute inflammatory response by generating a transgenic mouse expressing Tat in lymphoid tissue. Tat-Tg mice showed thymus atrophy and the maturation block from DN4 to DP thymic subpopulations, resulting in CD4⁺ and CD8⁺ T cells depletion in peripheral blood. In Tat-positive thymus, we observed the increased p65/NF-κB activity and deregulated expression of cytokines/chemokines and microRNA-181a-1, which are involved in T-lymphopoiesis. Upon LPS intraperitoneal injection, Tat-Tg mice developed an abnormal acute inflammatory response, which was characterized by enhanced lethality and production of inflammatory cytokines. Based on these findings, Tat-Tg mouse could represent an animal model for testing adjunctive therapies of HIV-1-associated inflammation and immune deregulation.

CRL3IBTK Regulates the Tumor Suppressor Pdcd4 through Ubiquitylation Coupled to Proteasomal Degradation

The human inhibitor of Bruton's tyrosine kinase isoform α (IBtkα) is a BTB protein encoded by the IBTK gene, which maps to chromosomal locus 6q14.1, a mutational hot spot in lymphoproliferative disorders. Here, we demonstrate that IBtkα forms a CRL3^IBTK complex promoting its self-ubiquitylation. We identified the tumor suppressor Pdcd4 as IBtkα interactor and ubiquitylation substrate of CRL3^IBTK for proteasomal degradation. Serum-induced degradation of Pdcd4 required both IBtkα and Cul3, indicating that CRL3^IBTK regulated the Pdcd4 stability in serum signaling. By promoting Pdcd4 degradation, IBtkα counteracted the suppressive effect of Pdcd4 on translation of reporter luciferase mRNAs with stem-loop structured or unstructured 5′-UTR. IBtkα depletion by RNAi caused Pdcd4 accumulation and decreased the translation of Bcl-xL mRNA, a well known target of Pdcd4 repression. By characterizing CRL3^IBTK as a novel ubiquitin ligase, this study provides new insights into regulatory mechanisms of cellular pathways, such as the Pdcd4-dependent translation of mRNAs.

Eukaryotic Initiation Factor 4H Is under Transcriptional Control of p65/NF-κB

Protein synthesis is mainly regulated at the initiation step, allowing the fast, reversible and spatial control of gene expression. Initiation of protein synthesis requires at least 13 translation initiation factors to assemble the 80S ribosomal initiation complex. Loss of translation control may result in cell malignant transformation. Here, we asked whether translational initiation factors could be regulated by NF-κB transcription factor, a major regulator of genes involved in cell proliferation, survival, and inflammatory response. We show that the p65 subunit of NF-κB activates the transcription of eIF4H gene, which is the regulatory subunit of eIF4A, the most relevant RNA helicase in translation initiation. The p65-dependent transcriptional activation of eIF4H increased the eIF4H protein content augmenting the rate of global protein synthesis. In this context, our results provide novel insights into protein synthesis regulation in response to NF-κB activation signalling, suggesting a transcription-translation coupled mechanism of control.

Human immunodeficiency virus-1 Tat activates NF-κB via physical interaction with IκB-α and p65

Nuclear factor (NF)-κB is a master regulator of pro-inflammatory genes and is upregulated in human immunodeficiency virus 1 (HIV-1) infection. Mechanisms underlying the NF-κB deregulation by HIV-1 are relevant for immune dysfunction in AIDS. We report that in single round HIV-1 infection, or single-pulse PMA stimulation, the HIV-1 Tat transactivator activated NF-κB by hijacking the inhibitor IκB-α and by preventing the repressor binding to the NF-κB complex. Moreover, Tat associated with the p65 subunit of NF-κB and increased the p65 DNA-binding affinity and transcriptional activity. The arginine- and cysteine-rich domains of Tat were required for IκB-α and p65 association, respectively, and for sustaining the NF-κB activity. Among an array of NF-κB-responsive genes, Tat mostly activated the MIP-1α expression in a p65-dependent manner, and bound to the MIP-1α NF-κB enhancer thus promoting the recruitment of p65 with displacement of IκB-α; similar findings were obtained for the NF-κB-responsive genes CSF3, LTA, NFKBIA and TLR2. Our results support a novel mechanism of NF-κB activation via physical interaction of Tat with IκB-α and p65, and may contribute to further insights into the deregulation of the inflammatory response by HIV-1.

Electrophysiologic significance of leftward QRS axis deviation in bifascicular and trifascicular blocks

BACKGROUND

Intraventricular conduction disturbances determine complete impairment of impulse propagation along the right or left bundle branch or the two left fascicles.

HYPOTHESIS

This study was undertaken to investigate the electrophysiologic significance of QRS axis (QRSA) orientation in bifascicular and trifascicular blocks.

METHODS

A group of 76 subjects, 43 with right bundle-branch block (RBBB) and left anterior hemiblock (LAH) (Group A), and 33 with left bundle-branch block (LBBB) (Group B), was submitted to electrophysiologic evaluation.

RESULTS

In Group A, QRSA was inversely related only to intraventricular conduction, while in Group B, QRSA inversely related to infrahisal conduction times. A value of < -60 degrees was considered the cut-off point for determining subjects with a considerable leftward QRSA deviation. Of the 27 Group A patients with a QRSA < -60 degrees, 38.5% developed an infrahisal second-degree atrioventricular (AV) block during incremental atrial stimulation (IAS) in comparison with 11.1% of those with QRSA > -60 degrees. Of the 9 Group B patients with a QRSA < -60 degrees, 44.4% exhibited severe impairment of infrahisal conduction at baseline and 66.6% developed an infrahisal second-degree AV block during IAS, whereas among the remaining 24 with a QRSA > -60 degrees, in only 8.3% were both infrahisal (HV1 and HV2) intervals dangerously prolonged, and 23.8% encountered an infrahisal second-degree AV block during IAS. In Group A, atrioventricular conduction time > 200 ms exhibited a better predictive accuracy than QRSA < -60 degrees for the development of an infrahisal second-degree AV block during IAS, whereas the latter appeared the best noninvasive predictor in Group B with a slightly lesser predictive accuracy than HV > 80 ms.

CONCLUSION

The degree of leftward QRSA deviation seems to reflect the entity of intraventricular conduction delay in patients with RBBB + LAH, while it appears to be directly related to infrahisal conduction prolongation in those with LBBB.

OCT-guided photodynamic therapy for angiographic occult CNV in pathologic myopia

PURPOSE

Pathologic myopia (PM) is frequently complicated by choroidal neovascularization (CNV). Diagnosis is mainly clinical and angiographic but in recent years optical coherence tomography (OCT) has been noted to add important information. The authors report on the successfully OCT-guided photodynamic therapy (PDT) of an angiographic occult CNV complicating PM.

METHODS

Observational case report. Fluorescein angiography with a confocal SLO (HRA, Heidelberg Engineering, Germany) and OCT Stratus (Carl Zeiss Meditec, Inc.) imaging were used for diagnosis and monitoring of the CNV. Standard PDT was performed.

RESULTS

A highly myopic 17-year-old girl complained of a drop in visual acuity (VA) in left eye (LE), dating back a few weeks. Her best-corrected (BC) VA was 20/40 in the LE, with some metamorphopsia. No hemorrhage or evident signs of CNV were visible either at fundus or at dynamic fluorescein angiography. OCT scans indicated a slight elevation of the RPE-choriocapillary complex with rarefaction of neuroretinal tissue that has been interpreted as CNV. PDT was then performed. LE BCVA had improved to 20/25, metamorphopsias disappeared, and at OCT examination no retinal morphologic modification was evident. Nine months later, BCVA and ophthalmoscopy are still stable.

CONCLUSIONS

In this case, OCT was the fundamental tool for the correct diagnosis and posttherapymonitoring of CNV-complicated PM. The CNV, not clearly detectable using angiographic imaging, was treated with PDT, and results in terms of VA and anatomic resolution were good.

Atrial natriuretic factor and mitral valve prolapse syndrome

Mitral valve prolapse (MVP), is the most frequent valvulopathy, although it is difficult to evaluate its incidence since this pathology is often asymptomatic. However, in some patients a rich variety of symptoms such as chest pain, dyspnea, palpitations, syncope, dizziness, panic attacks and autonomic dysfunctions have been found. The pathogenesis of these symptoms, incompletely understood, appears to be multifactorial, related to altered autonomic function, adrenergic responsiveness and to combinations of these factors. In patients with MVP a variety of neuroendocrine anomalies has been found: high epinephrine and norepinephrine plasma levels, altered rennin-angiotensin-aldosteron (RAA) response to volume depletion and orthostatic stimulation, and high plasma levels of atrial natriuretic factor (ANF) especially in hypovolaemic individuals. The role of ANF could be important in the genesis of MVP syndrome, it could contribute to determine: the imbalance between the sympathetic and parasympathetic system, the altered RAA response to orthostatic stimulus, the volemic and venous flow reductions (with a direct action, other than diuretic and natriuretic action). Factors that can determine ANF secretion abnormality in MVP could be: 1) Mitral regurgitation; 2) increased heart rate and the high incidence, in MVP syndrome, of arrhythmias; 3) central nervous system neuroendocrine imbalance; 4) increased catecholamines secretion.

[TNF alpha and heart failure]

Tumor necrosis factor alpha (TNF alpha) is a cytokine with proinflammatory properties which produces negative inotropic effects on the heart. It is produced in a variety of conditions such as septic shock, acute myocarditis, reperfusion injury, and congestive hear failure (CHF). This production is probably due to activation of immune elements localized in the heart or periphery, or both. TNF alpha acts by binding to two specific receptors: TNF-R1 and TNF-R2. These two proteins have different effects. TNF-R1 has cytotoxic and antiviral activity, induces fibroblast proliferation, and mediates apoptosis. TNF-R2 is involved in septic shock and in lymphocyte proliferation. They both have negative inotropic effect on the heart. It has been showed that these receptors are down-regulated in congestive heart failure, while their soluble forms (sTNF-R1 and sTNF-R2) increase with the severity of symptoms. However the significance of this increase is still unclear. The role of Fas, a receptor protein that induces apoptosis, is also examined. Fas and its ligand have homologies respectively with TNF alpha and TNF-R. Also the soluble form of Fas (sFas) increases in relation to heart failure and is related to soluble forms of the similar receptor family, therefore it is possible that the same stimuli lead the three receptors to act together. SFas, as well as sTNF receptors, may play an important role in CHF.

A motorized hand piece for injectable lenses

Foldable lenses represent a major breakthrough in the effort to achieve ever smaller incisions. The plate-haptic or "taco-style" lenses are folded and implanted by a device called an injector. Although customized for each manufacturer's lens, the injectors all have a common design principle: the intraocular lens (IOL) is folded within a funnel-like structure of the tip and is advanced by a plunger that pushes and delivers the lens. To maintain optimal hand stabilization and injector management, both hands are usually required. This does not leave a hand to help with IOL positioning. To improve handling, a simple, mechanized system has been created for a new injector system that allows the delivery of the plate-haptic lens with one hand, in a pen-like fashion.

[Electrophysiological analysis of atrioventricular and intraventricular conduction in bi- and tri-fascicular blocks]

We have evaluated, at baseline and during incremental atrial pacing (AP), intracardiac conduction features of 53 patients with electrocardiographic diagnosis of bifascicular or trifascicular block, free from any pharmacological treatment potentially able to affect atrioventricular (AV) conduction system properties. The patients have been subdivided in the following groups: group A (13 patients), with LBBB and a PQ interval > or = 200 msec; group B (14 patients), with RBBB, LAH with a PQ interval > or = 200 msec; group C (8 patients), with LBBB and a PQ < 200 msec; group D (15 patients), with RBBB, LAH and a PQ < 200 msec; group E (3 patients), with RBBB, LPH and a PQ < 200 msec. In group A, 31% presented a long AH interval (> 140 msec), while 85% showed an increased infra-his conduction time (HV > 55 msec). During AP, only 38.5% maintained a 1:1 AV conduction ratio up to 140 bpm, while 30.8% developed an infra-his Mobitz 2 2nd degree AV block. 15.4% an infrahis 2:1 2nd degree AV block, 15.4% an AV nodal Mobitz 2 2nd degree AV block. In group B, 64% and 29% exhibited respectively an AV nodal and an infrahis conduction delay. During AP, 57.1% maintained a 1:1 AV conduction ratio up to 140 bpm, 14.3% developed an AV nodal Mobitz 1 2nd degree AV block, 14.3% an infrahis Mobitz 1 2nd degree AV block, 7.1% an AV nodal 2:1 2nd degree AV block, 7.1% an infrahis Mobitz 2 2nd degree AV block. In group C, no patient manifested a prolonged AH interval, while 50% exhibited a HV > 55 msec. 62.5% maintained a 1:1 AV conduction ratio up to 140 bpm, 25% developed an AV nodal Mobitz 1 2nd degree AV block and 12.5% an infrahis 2:1 2nd degree AV block. In group D, no patient showed an increased AH interval and only 13% presented a HV interval exceeding 55 msec. During AP, 86.7% maintained a 1:1 AV conduction ratio up to 140 bpm, 6.6% developed an AV nodal Mobitz 1 2nd degree AV block, 6.6% an infrahis 2:1 2nd degree AV block. In group E, no patient showed a prolonged AH interval, while 2/3 (66.6%) exhibited an infrahis conduction delay. During AP, 100% developed an infrahis 2:1 2nd degree AV block. Considering all patients with LBBB (groups A+C) and with RBBB+LAH (groups B+D), no differences were found in terms of PQ, PA and AH intervals, even though, concerning patients with a long PQ (group A vs group B), AH interval resulted significantly longer in patients with RBBB+LAH (121.85 +/- 36.4 msec vs 163.29 +/- 55.96 msec, p = 0.031). Infrahis conduction, independently from the measurement adopted (HVI interval: from the beginning of the His to the onset of the ventricular electrogram recorded at the His region; HV2 interval: from the beginning of the His to the onset of the surface QRS), resulted more compromised in patients with LBBB than in patients with RBBB+LAH (HVI: 75.24 +/- 40.23 msec vs 50.79 +/- 25.16 msec, p = 0.011; HV2: 77.24 +/- 38.12 msec vs 53.92 +/- 29.3 msec, p = 0.015). Such a difference became even more significant when comparing the percentage of patients with a prolonged HV interval (average value > 55 msec) in the above mentioned groups: 71.4% in case of LBBB, 20.7% in case of RBBB+LAH (p < 0.001). Regarding intraventricular conduction (IV), no statistically significant differences were found. In patients with RBBB+LAH, IV was not related to infrahis conduction time and PQ interval appeared more related to AH (r = 0.838, p < 0.001) than to HV (PQ-HV1: r = 0.381, p = 0.041, PQ-HV2: r = 0.474, p = 0.009). Conversely, in patients with LBBB infrahis and IV conduction appeared linearly related (HVI-V: r = 0.416, p = 0.06; HV2-V: r = 0.445, p = 0.043). As for PQ interval, it resulted more closely related to infrahis conduction (PQ-HVI: r = 0.626, p = 0.002; PQ-HV2: r = 0.674, p < 0.001), than to AH (r = 0.533, p = 0.013). In conclusion, infrahis conduction resulted more impaired in patients with LBBB. In this group, differently from patients with RBBB+LAH, infrahis conduction seems to affect the degree of IV conduction delay. (ABST

[Sotalol, propafenone, and flecainide: compared multiparametric analysis of ventricular repolarization in subjects without organic cardiopathy]

Antiarrhythmic drugs are known to affect depolarization and repolarization time in a different fashion. The aim of the present study was to compare the effects of sotalol, flecainide and propafenone on some common (mean QT and QTc, mean JT and JTc), or uncommon (QTc dispersion, T-peak to T-end interval-Tp-Te) electrocardiographic parameters in order to evaluate the effects of these antiarrhythmic drugs on repolarization time. QTc dispersion, defined as the difference between maximum and minimum QTc calculated from the standard 12 ECG leads, and the average Tp-Te interval, reflect regional variation in ventricular repolarization. We have analyzed retrospectively the standard 12-lead electrocardiograms of 28 patients (15 females and 13 males, age 36.11 +/- 16 years, range 11-67 years), recorded in the free-drug state and at the steady state after oral treatment with sotalol (160 mg/ die), flecainide (200 mg/die) and propafenone (450 mg/die). These drugs were prescribed, separately, for the treatment of patients with supraventricular tachycardia without underlying structural heart disease. Sotalol treatment prolongs ventricular repolarization times (QT, p = 0.0001; JT, p = 0.0001 and JTc, p = 0.0001) in an homogeneous fashion, as showed by the significant decrease in QTc dispersion (p = 0.026) and Tp-Te interval (p = 0.011). On the contrary, flecainide treatment is associated with an increase in QTc dispersion (p = 0.039) and Tp-Te interval (p = 0.0001), mean QT (p = 0.0001), QTc (p = 0.0001) and QRS (p = 0.0001), with no significant changes in JT and JTc (NS). Propafenone treatment does not affect repolarization time indexes, affecting only depolarization time as expressed by an increase in QRS (p = 0.046).

[Evolution of pacing modes in patients with implanted pacemakers. Personal considerations on a case load of 171 patients]

In this study retrospectively analyse pacemaker-implantation activity carried out during the last 5 years at the Laboratory of Electrophysiology, affiliated with the Cattedra di Cardiologia of the University of Naples--II Ateneo. Evolution in pacing modes is considered with regard to the patient age, the underlying pathologies and the technical progress in the field. The study has been performed in our laboratory, which is fit up for electrophysiologic studies and implantation of either temporary or permanent pacemakers. Patients included in this study have been implanted in our laboratory either for urgency or for election. They have been retrospectively divided into two groups (age < 65 yrs, 129 patients, and age < 65 yrs, 42 patients); in addition the patients have been classified according to the pathology leading to the implantation: atrio-ventricular block (second degree or third degree), low frequency fibrillation, sick sinus syndrome and carotid sinus syndrome. 171 patients have been examined, of whom 129 > 65 yrs. and 42 < 65 yrs. As for the pacing indication, 54 were atrio-ventricular block (56.1%), 50 were sick sinus syndrome (31.6%), 20 low frequency fibrillation (11.7%), and 1 was carotid sinus syndrome (0.6%). The ratio between single- and dual-chamber pacemakers has been progressively changing: in 1987 we implanted 33 single-chamber and no dual-chamber pacemaker, compared to 7 single- and 23 dual-chamber pacemaker implanted in the last year. This trend is in good agreement with literature data.

[ST elevation during ergometric test: correlation with coronary angiography]

BACKGROUND

ST elevation during ergometric stress test (EST) is relatively rare. Its prevalence depends upon the tested population but occurs more frequently in patients who have had myocardial infarction or variant angina. This phenomenon is very rare in patients with typical exertional angina and its pathogenesis is still unclear.

MATERIAL AND METHODS

We studied a group of 75 consecutive patients with exertional angina who underwent EST and coronary angiography. A symptom limited EST was performed in the upright position on a cycloergometer with load increases of 25 watts every 3 minutes and 12 leads were monitored during all test. Coronary angiography was performed according to Judkins technique. From these patients, according to Froelicher's criteria, a group of 49 patients (age 32-68, mean 51.6 years), without myocardial infarction and/or left ventricular asynergy, was selected.

RESULTS

All patients had a coronary artery disease (16 patients with 3 vessels, 11 patients with 2 vessels and 22 patients with 1 vessel disease). The EST was positive for ST depression in 31 patients (63.3%) and for ST elevation in 5 patients (10.1%), while 13 patients (26.6%) had a non diagnostic EST. The ST elevation occurs in V1-V2 and it was associated in all cases with a stenosis in the left anterior descending (LAD) artery. Therefore we divided the 19 patients with LAD stenosis into two subgroups: subgroups A (9 patients, mean age 49.6 years) with LAD stenosis > or = 90% and subgroups B with LAD stenosis between 70% and 90%. ST elevation occurs in 5 patients (55.5%) of subgroup A and in no patient of the subgroup B. Moreover, in the subgroup A ST elevation seems to be related to the anatomic localization of the stenosis: in fact it appears in 83.3% of patients with LAD stenosis located before the onset of the first diagonal branch.

CONCLUSIONS

From these data it can be desumed that ST elevation in V1-V2 that occurs in patients with exertional angina and without myocardial infarction or variant angina is strongly predictive of a very important LAD stenosis.

Excimer laser photorefractive keratectomy for myopia: results in 1165 eyes. Italian Study Group

BACKGROUND

We report the results of a prospective study conducted in Italy to evaluate the efficacy, safety, predictability, and complications of excimer laser photorefractive keratectomy for the correction of myopia. METHODS. Photorefractive keratectomy was performed on 1236 myopic sighted eyes in 16 centers, using the Summit Excimed 193 nm excimer laser. The attempted correction ranged from -0.80 to -25.00 diopters (mean, -7.83 +/- 3.88 D). The population was divided into three groups of attempted correction: between -0.80 and -6.00 D, between -6.10 and -9.90 D, and between -10.00 and -25.00 D. We report the data of 1165 eyes at 1 month, 970 eyes at 3 months, 752 at 6 months, and 330 at 12 months. At each visit, we evaluated (1) the refractive changes over time; (2) the difference between attempted and achieved correction; (3) uncorrected and best spectacle corrected visual acuity; and (4) haze.

RESULTS

Twelve months after surgery, the spherical equivalent refractive error in 146 eyes with attempted correction of -0.80 to -6.00 D was -0.52 +/- 1.04 D; 104 eyes (71.2%) were within +/- 1.00 D of attempted correction. In 145 eyes with attempted correction of -6.10 to -9.90 D, the spherical equivalent refractive error was -1.66 +/- 1.88 D; 50 eyes (34.5%) were within +/- 1.00 D of attempted correction. The spherical equivalent refractive error in 39 eyes with attempted correction of -10.00 to -25.00 D was -1.86 +/- 3.47 D; 11 eyes (28.2%) were within +/- 1.00 D of attempted correction. Eight eyes (2.4%) lost two or more Snellen lines of best spectacle corrected visual acuity. None of the treatments caused severe postoperative complications, or scarring.

CONCLUSIONS

Photorefractive keratectomy proved safe and effective, but highly predictable only in the correction of myopia up to -6.00 D.

The erodible mask in photorefractive keratectomy for myopia and astigmatism

This paper reports a new approach for performing photorefractive keratectomy (PRK) that uses an erodible mask to control shape transfer processes. The advantages of this technique, when compared to conventional PRK performed with mechanical diaphragm, are 1) the possibility of transferring almost any shape onto corneal surface; 2) a smoother corneal surface following photoablation; 3) easier eye fixation; and 4) a controlled humidified environment over ablation zone. We report our experimental study on scanning electron microscopy of polymethylmethacrylate (PMMA) plates ablated using conventional technique versus erodible mask technique; the results showed a smoother surface in the PMMA plate ablated using the erodible mask. We also report our preliminary clinical results of four eyes treated for the correction of myopia combined with astigmatism. Myopia ranged from -2.00 to -10.00 D, and astigmatism ranged from -1.50 to -2.50 D. Three months after surgery, all four eyes were within +/- 1.00 D of myopic attempted correction, but astigmatism was completely corrected only in one eye. No complications or scarring have been reported. We believe the erodible mask could be effective in the correction of myopia and myopic astigmatism, but further improvements are necessary to allow easier alignment of the mask over the eye. All commonly available excimer laser devices produce photorefractive keratectomy as a concentric ablation of the corneal stroma, deeper in the center than in the peripheral part; this is produced by means of an iris or diaphragm which, depending on the type of laser, progressively opens or closes, allowing a greater laser beam delivery in the center.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomized study of single vs double exposure in myopic PRK

Multizone PRK has been suggested to increase the predictability of higher myopic corrections. The technique consists of dividing the intended correction between two or three different concentric ablation zones, achieving less depth and a smoother ablation profile. We randomized 24 eyes with refractions between -6.00 and -9.00 D for single or double ablation-zone PRK. At 1 year no significant difference in refraction and complications were found between the two treatments. The multizone PRK technique may be safely employed to reduce the maximum central depth of the keratectomy in high myopics.

Efficacy of corticosteroids in reversing regression after myopic photorefractive keratectomy

Topical corticosteroids are given commonly after photorefractive keratectomy (PRK). We present six eyes treated for correction of myopia ranging between -6.00 and -8.00 D, to whom corticosteroid drops were given and then suspended. Each eye had an increase in myopia with a mean of 2.00 D (range 1.00 to 3.50 D). All were then treated with topical dexamethasone (0.1%) four times per day for at least 15 days, and all showed decreases in myopia with partial or complete recovery of the intended correction (mean: 1.625 D; range 1.00 to 3.50 D). All of these refractive variations were documented by corneal topography. In one eye, refractive and topographic variations were detected by 3 days after corticosteroid treatment was initiated and they increased for 15 days. We believe corticosteroids can modulate refractive changes after PRK.

Bifocal versus monofocal intraocular lenses in bilateral pseudophakia

After a mean follow up of 19 months, the visual characteristics of eyes with bifocal diffractive intraocular lenses (IOLs) ("bifocals") in one eye were compared with those of fellow eyes with monofocal IOLs ("monofocals") in 29 bilateral pseudophakic patients. All of the eyes had a distance-corrected acuity of 0.6 or more, but 24.1% of the bifocals and 48.3% of the monofocals had an acuity of 1.00. Near acuity with distance correction was J2 or more in 93.1% of the bifocals and in 17.4% of the monofocals (without correction: 79.3% and 41.4%, respectively). In 55.2% of the bifocals and 20.7% of the monofocals, the combined uncorrected acuity was 0.5 or more for distance and J2 or more for near. Fogging revealed a similar depth of focus in the monofocals and a similar distance focus in the bifocals. The bifocals had two peaks of acuity but no "plateau" between them. The eye with the monofocal IOL was preferred by 37.9% and the eye with the bifocal IOL by 10.3%. Vision in no eye was rated "poor." Visual disturbances were more frequent in the bifocals. No glasses were prescribed for 20.7% of all of these patients; 65.5% required bifocal glasses; 44.8% managed most of daytime without glasses.

Excimer laser ablation of a corneal protuberance

The ablation of a post-traumatic superficial corneal nodule with an argon fluoride excimer laser is reported. Three months postoperatively the area had a smooth surface with no distortion of adjacent cornea.

Unilateral proliferative diabetic retinopathy and uveitis in the fellow eye: report of a case

We report the case of a young man with a 20-year history of insulin-dependent diabetes mellitus, proliferative diabetic retinopathy OD, and uveitis OS. None of the common reported causes contributing to this difference between eyes was present. No features of diabetic retinopathy appeared OS after a follow-up of 36 months. This is the first case, to our knowledge, in which uveitis appeared to be associated with an asymmetric presentation in diabetes.

[EGG and arrhythmia in subjects with implanted dual-chamber VDD and DDD pacemakers]

The ECGs of four patients with implanted dual chamber VDD and DDD PMKs are shown to demonstrate the difficulty of their interpretation and show some arrhythmias related to dual chamber pacing. In the first patient the DDD PMK caused a high ventricular frequency synchronizing on the atrial fibrillation "f" waves which occurred suddenly some time after PMK implantation; this problem was solved by programming the PMK in VVI. The second and third case, with implanted DDD and VDD PMK respectively, exemplify atrial sensing dysfunction due to atrial catheter displacement. In the fourth patient, with implanted VDD PMK, VDD stimulation periods and VVI ones alternated due to non-adjusted programming. Therefore, the paper re-emphasizes the need for accurate and periodic controls of patients with implanted PMK to correct dysfunction or undesirable patterns of stimulation.

[The diagnosis of the cardiologic risk in patients destined for lung removal surgery]

The expanding role of pulmonary surgery could be expected to lead to an increase in postoperative morbidity and mortality unless surgical risk factors are identified by means of a careful preoperative assessment. A careful and intelligent preoperative evaluation can reduce the morbidity and mortality after lung resection by ensuring the appropriate selection of patients and a rational choice of operative procedure. To evaluate the cardiologic risk in patients undergoing lung resection, 18 of them underwent a diagnostic protocol based on non invasive analysis including ECG, stress test with basal and exercise blood gas analysis, M- and B-mode and Doppler echocardiography. This protocol was able to identify possible cardiologic risk in the perioperative period without applying invasive techniques and with a good cost-benefits ratio.

Argon versus krypton panretinal photocoagulation side effects on the anterior segment

The modification of corneal sensitivity, accommodation, pupillary diameter and endothelial cell density after argon versus krypton panretinal photocoagulation were studied prospectively in 88 eyes of 64 diabetic patients with proliferative diabetic retinopathy, randomized for one of the two laser treatments. In both groups a marked internal ophthalmoplegia and reduction of corneal sensitivity occurred after laser photocoagulation. At no time, 2, 90 and 180 days after PRP, were these parameters significantly different. Endothelial cell loss was non significantly greater in the krypton group. The results indicated that the side effects commonly observed on the anterior segment after PRP are comparable using argon or krypton lasers.

[Clinical usefulness of the Doppler-echocardiographic method for evaluating intracardiac shunts. Combined Doppler and hemodynamic study]

The purpose of this study was to assess the accuracy of a quantitative two-dimensional Doppler echocardiographic method for estimating systemic and pulmonary blood flows in atrial and ventricular septal defects. Twenty-eight patients (mean age 22 +/- 14), with atrial septal defect (ADS) or ventricular septal defect (VSD) underwent Doppler-echocardiography and cardiac catheterization in order to assess pulmonary blood flow (QP), systemic blood flow (QS), the left to right shunt (SH) and the ratio of pulmonary to systemic flow (QP/QS ratio). Cardiac output was also determined by the oximetry method according to Fick principle. Pulmonary output assessed by Doppler was 7.9 +/- 0.61/min, by catheterization 9.0 +/- 3.9. Linear regression analysis showed a low correlation coefficient (r = 0.10; p = NS). Systemic output evaluated by Doppler resulted 4.6 +/- 1.4 l/m, while at catheterization 5.1 +/- 1.5 l/min (r = 0.25; p = NS). Doppler evaluation of left-to right shunt was 3.3 +/- 1.5 l/min, at catheterization 3.9 +/- 3.1 (r = 0.74; p less than 0.001). Doppler QP/QS ratio resulted 1.7 +/- 0.5, at catheterization 1.8 +/- 0.5 (r = 0.96; p less than 0.0010. The results showed that, in spite of the lack of correlation between the pulmonary and systemic outputs assessed by Doppler vs catheterization, QP/QS ratio, as well as SH, are useful noninvasive indexes in order to evaluate intracardiac shunts.

Clinical evaluation of the effect of acetylcholine on the corneal endothelium

A transient corneal edema is often seen after the injection of acetylcholine solution in the anterior chamber during cataract surgery. Ninety eyes of 90 patients scheduled for extracapsular cataract extraction with posterior chamber intraocular lens implantation were randomly assigned to two groups: one which received acetylcholine solution in the anterior chamber and one, a control group, which received only external conjunctival pilocarpine drops as a miotic. At three days, endothelial folds (P = .04) and corneal edema (P = .01) were more pronounced in the acetylcholine group; at seven days, endothelial folds were more severe (P = .04) in the acetylcholine group. At 30 days, the acetylcholine group showed a 37.2% increase (P = .01) of the endothelial cell area, whereas the control group showed a 7.08% increase. The difference between the groups was statistically significant (P = .05). Anterior chamber fluorophotometry at 30 days showed an increase of the corneal transfer coefficient that was higher but not significant in the acetylcholine group. We suggest caution in the intraoperative use of acetylcholine solution, particularly in those eyes showing a preoperative compromise of the endothelium.

Prevalence of retinopathy in diabetic subjects from out-patient clinics in Lombardy (Italy), and associated risk factors. A multicentre epidemiologic study

There is little information on the prevalence of diabetic complications in Italy. For this reason, a multicentre population-based study was carried out in 1983-1985 in 12 representative out-patient clinics for the treatment of diabetes in the Lombardy region. Out of a total population of 17,704 patients 1160 diabetic subjects were randomly selected within strata based on their duration of disease (less than or equal to 5; 6-10; 11-20; greater than 20 years). Eight hundred and thirty-eight responders were examined using standardised protocols. The estimated prevalences (adjusted for duration of disease) for the total population involved in the study were 29.7% and 7.6% for background and proliferative retinopathy respectively. The overall standardised rates were higher in insulin-dependent diabetes mellitus (IDDM) (53.6%) than in non-insulin-dependent diabetes mellitus (NIDDM) (34.7%) for both background (41.1%, 28.4% respectively) and proliferative (12.5%, 6.2% respectively) retinopathy, and increased with the duration of disease. The analysis of the relationship between diabetic retinopathy and the calculated risk factors did not show any association with hypertension or metabolic control, except for post-prandial blood glucose in subjects with durations 6-10 and greater than 20 years; an association with azotaemia was found in subjects with durations less than or equal to 5 and 11-20 years. Diabetic retinopathy appeared to be independently associated with the type of treatment and not with the type of diabetes, metabolic control, or hypertension.

Bullous retinal detachment in diffuse retinal pigment epitheliopathy

Central serous choroidopathy can occur in an atypical, severe clinical expression also known as diffuse retinal pigment epitheliopathy. We report two cases in which this affection was complicated by a bullous retinal detachment of the lower quadrants. In one case the subretinal leaking point was photocoagulated. The evolution was favourable in both cases with resolution of the detachment and partial recovery of the visual acuity.

Pneumoretinopexy in the treatment of retinal detachment with macular hole

Nine eyes of nine patients affected by retinal detachment with macular hole were treated with pneumoretinopexy and postoperative positioning. All the eyes were myopic (mean 13.3 d., sd 3.3), two were amblyopic and one was aphakic. The operative technique included eye softening and intravitreal SF6 gas injection only. Barrage laser photocoagulation was carried out after retinal reattachment. In seven eyes (77.8%) the retina reattached in a mean of three days and the visual acuity improved. No recurrences were observed after a mean of 11.6 months. No severe complications occurred. Vitreous flare was present in 44% and increase of floaters in 55% of the eyes. We believe that pneumoretinopexy can be employed as the first treatment in case of myopic retinal detachment with macular hole.

Eight-year follow-up of central serous chorioretinopathy with and without laser treatment

A long-term retrospective study was conducted on two groups of patients affected with typical central serous chorioretinopathy (CSCR). One group was not treated and the other was treated by direct argon laser photocoagulation. CSCR shows a long-term good prognosis of visual acuity. The visual acuity of laser-treated eyes improves significantly (P less than or equal to 0.05), particularly in single focus cases (P less than or equal to 0.01). Unfortunately, these results cannot be statistically compared to the natural course of the non-treated patients because of the initial inhomogeneity of the two groups. Laser treatment did not produce any long-term complications. The recurrence rate in treated and untreated eyes was similar.

Virilization syndrome in a young woman due to an androgen-secreting adenoma

A virilization syndrome in a normally menstruated 20--year-old woman, due to adrenocortical tumor, is reported. Preoperative basal hormonal study showed normal plasma gonadotropins, androstenedione (A) and cortisol, slightly elevated testosterone (T), markedly increased urinary 17 ketosteroids (17KS) excretion and plasma dehydroepiandrosterone-sulfate (DHEA-S) levels. Thus DHEA-S was the major constituent of the androgen excess. Urinary 17KS and plasma DHEA-S did not change after ACTH, whereas increased after dexamethasone (DXM)-hCG administration. PRL and LH responses to TRH and LHRH tests were exaggerated. Echotomography, pneumoperitoneum radiography and selective adrenal venous angiography showed a tumor in the left adrenal gland. After the tumor removal all abnormalities were corrected. Light and electron microscopy showed well differentiation of the tumoral cells with typical ultrastructural characteristics of androgen-secreting tissue. It is concluded that the absence of amenorrhea and of LH suppression does not exclude the possibility of an androgen-secreting tumor. Moreover, the unusual finding of slightly elevated T value may be reported to enzymatic defect at the neoplastic cellular level. Furthermore the paradoxical DXM-hCG androgen response may be due to spontaneous variations in hormone secretion by the tumor or to cell receptors alteration.

[Measurement of cutaneous evaporation. 4. Cutaneous water loss in heart disease]

The purpose of this research is the measurement of the cutaneous water loss in not influenced by very specific therapies. Ep I in order to compare it with the values of normal people. We found a statistical significant increase of the CWL that is 23 cardiopathic patients by the evaporimeter.