Impact of SGLT2 inhibitor on mortality and cardiovascular outcomes in patients with type 2 diabetes mellitus with left main or multivessel coronary artery disease

Background

Sodium-glucose Cotransporter 2 inhibitors (SGLT2-i) have shown improved cardiovascular outcomes in type 2 diabetes mellitus (T2DM) that surpass their hypoglycaemic power. However, the inclusion criteria in the pivotal studies were broad in terms of cardiovascular disease, and there are no specific studies on patients with coronary artery disease (CAD).

Purpose

To compare, in patients with T2DM and extensive CAD, the hazard ratio (HR) of all-cause death in patients treated with or without SLGT2-I, adjusted by IPTW and treatment (revascularization) strategy. Secondary: To compare the adjusted HR of cardiovascular (CV) death, myocardial infarction (MI), stroke, or heart failure admission (HF) in patients treated with or without SLGT-I.

Methods

A single-centre retrospective observational study in patients with T2DM, with the first diagnosis of extensive CAD defined by >50% stenosis in LM or 3-vessels, and alive at discharge. The study was approved by the research ethics committee and recruited consecutive patients from 2015 (year of first SLGT2-I approval) to 2020. Patients with prior revascularization, severe renal failure (filtration rate <30 ml/min), less than 6 months of SLGT2-I treatment and less than 1 year of follow-up were excluded.

Results

We recruited 420 patients with a mean age of 71.2±11.1 years; 78.6% were male, 82.6% had hypertension, 72% hyperlipemia, 50.2% were smokers or former smokers, 52.9% had a history of previous myocardial infarction and 10.7% of stroke. Mean LVEF (%) was 51.5±1.5, creatinine clearance 73.94±22 ml/min and glycated haemoglobin (%) 7.3±1.2.

The presentation was acute coronary syndrome in 44.3% (27% ST elevation/73% non-ST elevation). LM was affected in 29%; 3-vessel CAD was found in 86.7%; 2-vessel in 8.3%; 1-vessel in 3.8%, and 1.2% exclusively in the LM. Treatment strategy was PCI + OMT in 48.3%, CABG + OMT 39.8% and OMT only in 21.9%.

T2DM treatment, secondary prevention treatment and metabolic control at follow up are presented in Table 1. A total of 104 patients (24.8%) started treatment with SGLT2-I during a mean of 1.6±1 years. At a mean follow-up of 3±1.6 years, mortality was 16.4%, CV mortality was 9.5%, 6.9% had a MI,3.3% had a stroke, and 11.4% had HF admission. Patients treated with SLGT2-I had a lower risk of all-cause death, cardiovascular death and the composite of CV death or HF (Table 2). After IPTW, the risk of all-cause death was persistently lower in the SLGT-I group

Conclusion

This real-life study found that in T2DM patients with LM or MVD only 1 out of 4 patients was treated with SGLT2-I as a part of their secondary prevention treatment. Those with SGLT2-I had a reduced risk of all-cause death (HR 0.34 [0.12–0.91], p=0,033) after IPTW and treatment (revascularization) strategy adjustment.

Funding Acknowledgement

Type of funding sources: None.

Follow up coronary vessel evaluation of magnesium bioresorbable stents with coronary computed tomography angiography

Background

Cardiac computed tomography angiography (CCTA) has already shown its ability to evaluate late results of polymer-based bioresorbable scaffolds (BVS) in different clinical scenarios. Recently, magnesium-based BVS (Mg-BVS) has emerged as an interesting alternative to these previous platforms due to its lower risk of thrombosis. Nonetheless, there is no systematic data about characterization of magnesium BVS with CCTA.

Purpose

To study the feasibility of Mg-BVS assessment with CCTA and to evaluate in-scaffold wall tissue characterization during the follow-up.

Methods

In this multicentre work, CCTA was performed in patients with a previously implanted Mg-BVS as a supplementary follow-up assessment. All studies were done after the theoretical resorption time of the scaffolds. A central core laboratory with an independent level 3 expert in CCTA blinded to the clinical and angiographic results analysed the studies. For this purpose, a dedicated software for coronary analysis was used to quantify coronary stenosis and evaluate coronary wall (Figure).

Results

Eight patients (55±6 years-old; 87.5% male) with a previously implanted Mg-BVS from 3 different centres in Spain and Italy were included. The presentation was equally distributed (2, 25%) among stable and unstable angina, NSTEMI and STEMI. Target vessels included 5 left anterior descending (62.5%), 2 left circumflex (25%) and 1 right coronary arteries (12.5%). CTCA was performed 13 [11.3–20] months after BVS implantation. In spite of the blinding, all scaffolds were accurately located through identification of proximal and distal radiopaque markers. Concordance of CCTA Mg-BVS sizing was good for diameter (ICC 0.66; p=0.09) and excellent for length (ICC 0.98; p<0,001) of the stents. Patency of all scaffolds was confirmed without significant diameter (0.14 [0–0.27]%) or area (0.39 [0.19–0.57]%) stenoses compared with proximal reference segments. Moreover, within the stent boundaries the maximum luminal diameter and area narrowing were 0.22 [0,12–0.3]% and 0.39 [0.23–0.5]% respectively, in keeping with mild in-scaffold late loss and/or underlying plaque growth. Regarding coronary wall tissue characterization of segments with BVS, there was a plaque burden of 0.37 [0.31–0.48]% and plaque volume of 87.6 [50.2–189.3] mm3. The most common component of the plaque was fibrous (69.5 [33.9–133.7]%), suggesting that Mg-BVS allows for stabilization of unstable culprit lesions (6/8 cases). Compared to the proximal and distal reference segments, there was no differences in plaque volume or composition, suggesting a good coronary vessel healing.

Conclusions

This short series shows for the first time the ability of CCTA to correctly locate and evaluate patency of Mg-BVS. Moreover, the lack of metal struts allows a detailed coronary plaque evaluation at treated segments. These preliminary results suggest plaque stabilization and a good coronary vessel healing with this novel scaffold.

Funding Acknowledgement

Type of funding sources: None. Mg-BVS in LCx with mixed plaque

Late results of bioabsorbable scaffolds implanted in spontaneous coronary artery dissection evaluated with computed tomography coronary angiography

Background

Percutaneous coronary intervention (PCI) in spontaneous coronary artery dissection (SCAD) should be reserved for cases presenting with ongoing extensive ischaemia. Bioresorbable scaffolds (BVS) have emerged as an alternative to avoid permanent stenting, an especially attractive concept for this clinical scenario. However, data of late angiographic outcome of this device in SCAD is lacking.

Purpose

To evaluate the long-term angiographic outcome of BVS in the setting of SCAD using computed tomography coronary angiography (CTCA)

Methods

In this multicentre prospective study, high-risk SCAD patients treated with BVS were scheduled for a follow-up CTCA at least 2 years from implantation date. Acquisition was performed according to the current recommendations. All the studies were analysed in a central core laboratory by an independent level 3 expert in CTCA blinded to the clinical and angiographic results. For this purpose, a dedicated software for coronary analysis was used to quantify coronary stenosis and evaluate coronary wall.

Results

Thirty-four BVS were implanted in 15 SCAD patients (51±12 years-old; 87% female) from 7 different centres in Spain and United Kingdom. The most common presentation was STEMI (n=9, 60%). Target vessels included 11 left anterior descending arteries (73.3%), 3 right coronary arteries (20%) and 1 left circumflex coronary artery (6.7%). One patient received target lesion revascularisation due to scaffold shrinkage in a proximal right coronary artery at 13 months. CTCA was performed 2.4±0.7 years after BVS implantation. No scaffold thrombosis or significant stenosis were detected. Patency of all scaffolds was confirmed with a median luminal area of 5.52 mm2 (IQR: 3.74–6.95) and median stenosis of 11% (IQR: 4–15%). Regarding coronary wall tissue characterization of segments with BVS, there was 32±9.3% of plaque burden and a median plaque volume of 45.3 mm3 (IQR: 26.6–61.9). The most common component of the plaque was fibrous (85±9.4%). Compared to the proximal reference segments, BVS showed more plaque burden (32.2% vs 25.3%; p=0.017) and fibrous percentage (84.7% vs 75.1%; p=0.004) whereas less fibrofatty (6 vs 4.8 mm3; p=0.007) and necrotic volume (0.4 vs 1.2 mm3; p=0.029). BVS segments showed lower absolute minimal luminal area (5.5 vs 8.9 mm2; p=0.004) and diameter (2.7 vs 3.4 mm; p=0.004) compared to the reference segment; however, non-significant differences were seen in percentage stenosis, in keeping with normal vessel tapering.

Conclusions

In this series of SCAD treated with BVS, scaffolds showed a satisfactory late angiographic outcome, with no significant restenosis and an excellent minimal luminal area and optimal coronary wall healing observed.

Funding Acknowledgement

Type of funding source: None

Clinical predictors and angiographic features of acute coronary syndromes caused by systemic embolism

Introduction

Systemic embolism to coronary arteries is one of the mechanisms of acute myocardial infarction (AMI) of non-atherosclerotic cause. However, its clinical profile has not been properly established yet.

Purpose

To identify clinical predictors and angiographic characteristics of acute coronary syndromes caused by systemic embolism to a principal coronary artery (ACS-E), as well as to describe in-hospital mortality of these patients.

Methods

40 patients with ACS-E, admitted between 2003 and 2018 in a tertiary hospital. Epidemiological, clinical and angiographic characteristics of these cases were compared with those from 4989 patients, attended for acute coronary syndrome of atherosclerotic cause (ACS-A) in the same hospital during the same period.

Results

Patients with ACS-E were younger (28% vs 10% were <45 years old, p<0.001) and had a higher proportion of women (43% vs 22%, p 0.003), atrial fibrillation (40% vs 5%, p<0.001) and neoplasia (18% vs 7%, p 0.009). They had also undergone previous valvular surgery more frequently than patients with ACS-A (13% vs 0.5%, p<0.001) and a higher proportion of them were under treatment with warfarin (15% vs 3%, p<0.001). Variables identified as independent predictors of ACS-E in the multivariate analysis are shown in the table. Regarding clinical presentation, ST elevation AMI was more frequent in ACS-E cases (83% vs 67%, p 0.04). Patients with ACS-E did not present any significative stenosis in other vessels apart from the culprit one (number of other vessels with at least 1 severe stenosis was 0 in the ACS-E group vs 1.33 + 1 in the ACS-A arm, p<0.001). PCI was attempted in 75% of the patients with ACS-E, resulting successful in 80% of the cases. On the other hand, 100% of SCA-A underwent PCI, with a success proportion of 99% (p<0.001). In-hospital mortality in ACS-E group was 15% and 4% in the control group (p<0.001).

Conclusions

ACS-E and ACS-A have different clinical and angiographic features. Atrial fibrillation, chronic warfarin treatment, previous valvular surgery, presence of any neoplasia and female sex are independent predictors for ACS-E.

Funding Acknowledgement

Type of funding source: None

P4352Usefulness of speckle tracking echocardiography in the detection of ventricular mechanics changes after percutaneous intervention of coronary chronic total occlusions

Background

Previous studies show contradictory results of the effect of chronic total occlusions (CTO) revascularization on LVEF. Deformation parameters based on speckle tracking (2D-ST) echo allows the evaluation of the systolic regional function.

Purpose

To examine the usefulness of 2D-ST to detect changes in regional ventricular mechanics in a consecutive cohort of patients with successful CTO percutaneous revascularization.

Methods

Prospective study that included 13 consecutive patients (72±8 y, 85% men). Revascularization was justified based on the evidence of viability of the underlying territory. 2D-ST was performed before, one and three months after of the procedure. Based on 16 segments model (n: 208), these were classified in two groups (dependent/non-dependent) according to their relationship with the treated CTO. Strain rate (Sr) and Strain (S) of the three myocardial layers were measured.

Results

208 segments analyzed. 62 (30%) perfusion dependent, (mean 5 segments/patient), non-dependent: 146 (70%). During follow-up (median: 3.3 m), there were no significant differences with respect to LVEF (56±6 vs. 59±6, p: 0.2). Although non-dependent segments showed no significant changes of deformation parameters after the procedure, dependent segments showed an increase (Δ) of both the S and Sr, being statistically significant the Δ of the three layers S at 3 months vs. non-dependent.

Table 1 PRE POST p Δ Non-Dependent segments (N: 146)   S-epicardial −16.6±4.9 −16.0±4.0 0.06 0.6±4.0   S-mesocardiac −17.4±4.8 −16.8±4.2 0.08 0.6±3.9   S-endocardial −18.1±5.1 −17.7±4.9 0.337 0.4±4.5   Sr −1.15±0.4 −1.09±0.4 0.080 0.07±0.47 Dependent segments (N: 62)   S-epicardial −13.7±5.8 −16.3±4.5 <0.001 −2.6±5.2*   S-mesocardiac −14.7±6.1 −17.0±4.5 <0.05 −2.3±5.2*   S-endocardial −15.8±6.7 −17.9±4.9 <0.05 −2.1±5.6*   Sr −0.98±0.4 −1.03±0.4 0.353 −0.05±0.42 *p<0.05 ΔNon-dependents vs. ΔDependents.

S (%) improvement post RCA CTO treatment

Conclusions

This study shows that CTO treatment improves regional myocardial function in LV segments dependent on CTO at three months of follow-up, without changes in LVEF. 2D-ST allows to examine the effect of flow restoration, providing new information on the potential short-term benefits of this strategy

P5613Proportional relationship between early mobilization of bone marrow progenitor cells and the extent of vascular injury during coronary stenting: insights on the role of systemic mechanisms of vascular

Background

The role of circulating progenitor cells (CPCs) on vascular repair after everolimus-eluting stent (EES) implantation is largely unknown.

Objectives

The aim of the study was to investigate the quantitative and temporal variations of CPCs levels after EES implantation, and its relationship with the degree of peri-procedural vascular damage, stent healing and neointimal hyperplasia, as measured by optical coherence tomography (OCT).

Methods

In a consecutive series of patients with stable coronary artery disease undergoing stent implantation CPC subpopulations (CD34+/CD45low, CD133+/CD45low, CD34/KDR/CD45low, CD133/KDR/CD45low) were evaluated using a flow cytometry technique at baseline, 1 and 4 weeks. OCT evaluation was performed immediately after stent implantation to quantify stenting-related injury, and at 9-month follow-up to assess mid-term vascular response.

Results

Twenty patients (mean age 66±9 years; 80%male) with 24 stenoses treated with EES were included in the study. Vascular injury score was associated with the increase of CD133+/KDR/CD45 low at 1-week (β0.28 [95% CI0.15; 0.41], p<0.001) and with the maximum neointimal thickness at 9-month follow-up (β0.008 [95% CI-0.0004; 0.002]:p=0.04). Mean neointimal area at 9-month was associated with the increase in the number of CD34+/CD45low at 1 week (β0.029 [95% CI0.025;-0.033]; p<0.0001). Inverse relationships between the number of uncoated and apposed struts at 9-month and the 1-week delta values of CD34/KDR/CD45low and CD133/KDR/CD45low (β-4.49 [95% CI-8.17;-0.82]; p=0.017 and β −12.53 [95% CI: −22.17; −2.90]; p=0.011, respectively) were also found.

Conclusion

Long-term vascular healing after EES implantation is modulated by early changes in levels of CPC subpopulations. This systemic response is proportional to the extent of vessel wall injury. Early mobilization of CPCs influences mid-term strut coverage and the development of neointimal hyperplasia.

Acknowledgement/Funding

Dr Jimenez-Quevedo is a recipient of the ISCIII (Instituto de Salud Carlos III) grant “Fondo de Investigaciόn Sanitaria” (PI11/00299) to perform this

Loss of Bardet-Biedl syndrome proteins causes synaptic aberrations in principal neurons

Bardet-Biedl syndrome (BBS), a ciliopathy, is a rare genetic condition characterised by retinal degeneration, obesity, kidney failure, and cognitive impairment. In spite of progress made in our general understanding of BBS aetiology, the molecular and cellular mechanisms underlying cognitive impairment in BBS remain elusive. Here, we report that the loss of BBS proteins causes synaptic dysfunction in principal neurons, providing a possible explanation for the cognitive impairment phenotype observed in BBS patients. Using synaptosomal proteomics and immunocytochemistry, we demonstrate the presence of Bbs proteins in the postsynaptic density (PSD) of hippocampal neurons. Loss of Bbs results in a significant reduction of dendritic spines in principal neurons of Bbs mouse models. Furthermore, we show that spine deficiency correlates with events that destabilise spine architecture, such as impaired spine membrane receptor signalling, known to be involved in the maintenance of dendritic spines. Our findings suggest a role for BBS proteins in dendritic spine homeostasis that may be linked to the cognitive phenotype observed in BBS.

Diabetic retinopathy

This paper describes the importance of diabetic retinopathy in the loss of visual function. We exposed the most important risk factors, such as diabetes duration, poor metabolic control, pregnancy, puberty, hypertension, poor control of blood lipids, renal disease, and sleep apnea syndrome. We describe the pathogenesis of the disease, small retinal vessel microangiopathies which produce extravasation, edema and ischemia phenomena. We put special emphasis on the vascular endothelial growth factor (VEGF) and its pathogenic importance. They are also described the main clinical symptoms as microaneurysms, intraretinal hemorrhages, hard and soft exudates, intraretinal microvascular abnormalities (IRMA), venous disorders, formation of new vessels and diabetic macular edema (the latter being the most common cause of vision loss). Finally we describe the latest diagnostic techniques and eye treatment, with special emphasis on obesity surgery importance as more important preventive factor to eliminate the predisposing and precipitating disease symptoms.

Brain metastases from lung cancer responding to erlotinib: the importance of EGFR mutation

Median survival of patients with brain metastases from nonsmall cell lung cancer (NSCLC) is poor and more effective treatments are urgently needed. We have evaluated the efficacy of erlotinib in this setting and its association with activating mutations in the epidermal growth factor receptor (EGFR) gene. We retrospectively identified patients with NSCLC and brain metastases treated with erlotinib. EGFR mutations in exons 19 and 21 were analysed by direct sequencing. Efficacy and tolerability were compared according to EGFR mutational status. 69 NSCLC patients with brain metastases were identified, 17 of whom harboured EGFR mutations. Objective response rate in patients with EGFR mutations was 82.4%; no responses were observed in unselected patients (p<0.001). Median (95% CI) time to progression within the brain for patients harbouring EGFR mutations was 11.7 (7.9-15.5) months, compared to 5.8 (5.2-6.4) months for control patients whose EGFR mutational status had not been assessed (p<0.05). Overall survival was 12.9 (6.2-19.7) months and 3.1 (2.5-3.9) months (p<0.001), respectively. The toxicity of erlotinib was as expected and no differences between cohorts were observed. Erlotinib is active in brain metastases from NSCLC; this clinical benefit is related to the presence of activating mutations in exons 19 or 21 of the EGFR gene.

Multifocal epithelioid glioblastoma mimicking cerebral metastasis: case report

OBJECTIVE

Epithelioid glioblastoma is a rare morphologic subtype of glioblastoma that closely mimics metastatic carcinoma or metastatic melanoma histologically. All previous case reports of this unusual glioblastoma variant have been solitary lesions. We report here the first case to our knowledge of multifocal epithelioid glioblastoma mimicking cerebral metastasis.

CLINICAL PRESENTATION

A 67-year-old man with a prior history of mycosis fungoides, a common form of cutaneous T-cell lymphoma, presented with memory loss and impaired peripheral vision. Two discrete brain lesions highly suspicious for metastases were identified by magnetic resonance imaging (MRI).

INTERVENTION

The patient underwent two separate craniotomies; both lesions were successfully resected in toto with an excellent post-surgical outcome.

CONCLUSION

Epithelioid glioblastoma is one of the rarest morphologic subtypes of glioblastoma. Here we describe the first case to our knowledge of multifocal epithelioid glioblastoma that convincingly mimicked a secondary metastatic process. Multifocal epithelioid glioblastoma should be included in the differential diagnosis of patients who present with multiple discrete brain lesions. An attempt at gross total resection is recommended when anatomically feasible for definitive histopathological diagnosis and to improve progression free survival of patients who present with similarly ambiguous and potentially misleading multiple lesions.

Erlotinib in patients with advanced squamous cell carcinoma of the lung

7174

Background: Erlotinib is a potent HER1/EGFR TKI that is approved for the treatment as a single agent in 2nd and 3rd line NSCLC. Several phase II studies have shown that adenocarcinoma histology together with female gender, Asian origin, and never having smoked are associated with responsiveness of NSCLC to erlotinib. The purpose of the analyisis we present here was to describe the outcome in a group of patients with squamous carcinoma of the lung treated with erlotinib. Methods: Eligilibility criteria included stage IIIB-IV chemotherapy-naive patients with confirmed NSCLC, PS 0–2, age ≥ 18 years, adequate organ functions, measurable disease and written informed consent. Patients with diagnosis of squamous cell lung cancer that received erlotinib 150 mgr/day p.o until disease progression or withdrawal were the subject of this analysis. Results: From June 2004 to March 2005, 121 patients with histological diagnosis of squamous cell lung cacer from more than 100 different Spanish hospitals were included in the TARGET study. Median age was 66 yrs. All patients in our analysis were Caucasian. 111 patients were male (92%) and 113 (93%) were current smokers or have smoke sometime in their life. 88% of them have stage IV carcinoma and 74% have received previous treatment for metastatic disease. PS 0/1/≥2 18 (15%)/68 (56%)/32 (29%). In the evaluable population for response (69 pts) 5 PR and 0 CR were observed for an overall RR of 7.25%. Clinical benefit defined as CR+PR+SD was 54%. In the ITT populations median TTP was 3.6 months [95% CI 2.7–5.3]. Median OS was 5,7 m [95% CI 4.0–6.7]. Erlotinib was well tolerated.No unexpected toxicities were observed. Conclusions: This subgroup analysis confirms that erlotinib is active and well tolerated in patients with advanced or metastatic squamous cell carcinoma of the lung. Responses were seen in both genders and in patients with or without smoking history. At this moment histology should not be used as the only selection criteria for treatment of patients with NSCLC after failure to chemotherapy.

[Table: see text]

Clinical graft evolution of lymphocytes, polymorphonuclear cells, and antigen expression in tubular renal cells in the urine sediment of 20 renal allograft recipients

Urinary samples from 20 kidney transplant recipients were studied to determine the cellular composition of the sediments using an immunocytological (IC) technique. The expression of HLA class I (A, B, C) and class II (DR, DQ, DP), CD2, CD3, CD4, CD8, and interleukin (IL)-2 receptor (IL-2R) on lymphocytes was assessed using a panel of monoclonal antibodies. The results were correlated with graft function and with the number of episodes of acute renal graft rejection (AR) during a period of 6 months posttransplantation. The cellular infiltration of lymphocytes (LC) and polymorphonuclear cells (PMNC) also was studied using a standard cytology (SC) technique. During this period, 17 of 30 episodes of graft dysfunction due to AR occurred in 12 patients: 8 to acute tubular necrosis (ATN) (n = 8); 4 to cyclosporine (CsA) toxicity (n = 4) and 1 to amphotericin toxicity (n = 1). The diagnosis of AR was made clinically by 3 independent observers, using biopsy in some cases. The immunocytology showed a significantly increased expression of HLA-DR, DO, and DP namely, greater than 20% positivity in 10% of samples on the tubular epithelial cells (TEC) of patients presenting with versus without AR (P < or =.001). In addition, a high correlation was observed between the expression of IL-2R and the presence of AR (p < or =.002). The standard cytology results showed a significantly increased percentage of LC and decreased percentage of PMNCs in samples obtained 2 days prior to the clinical manifestations of patients who developed AR (P =.001). A greater level of expression of antigen determinants was observed prior to AR. These results suggest that immunocytology of urinary sediments, which is a noninvasive technique, has enormous clinical potential for the differential diagnosis of AR, ATN, and CsA toxicity. In our study, the use of HLA class IL-specific monoclonal antibodies (Abs) gave a 100% specificity, 95% sensitivity, and 95% predictability. Although our results also indicate a potential value in the increased IL-2R expression, these findings must be confirmed by further studies. Furthermore, the combination of both immunologic and SC techniques in urinary sediments allows early detection of AR and is cost effective and simple features that could be used routinely for follow-up of renal transplant recipients.

An immunocytochemical mapping of methionine-enkephalin-arg6-gly7-leu8 in the human brainstem

Using an indirect immunoperoxidase technique, we studied the distribution of immunoreactive fibers and cell bodies containing methionine-enkephalin-Arg(6)-Gly(7)-Leu(8) in the adult human brainstem. Immunoreactive cell bodies were found in the reticular formation of the medulla oblongata (in which we observed the highest density of immunoreactive cell bodies) and the pons, the solitary nucleus, the hypoglossal nucleus, the medial and spinal vestibular nuclei, the lateral cuneate nucleus, the nucleus prepositus, the central gray of the pons and mesencephalon, the central and pericentral nuclei of the inferior colliculus, the superior colliculus, ventral to the superior olive and in the midline region of the pons and mesencephalon. The highest density of immunoreactive fibers containing methionine-enkephalin-Arg(6)-Gly(7)-Leu(8) was found in the spinal trigeminal nucleus, the central gray and the reticular formation of the medulla oblongata, pons and mesencephalon, the solitary nucleus, the spinal vestibular nucleus, the dorsal accessory olivary nucleus, the raphe obscurus, the substantia nigra and in the interpeduncular nucleus. The widespread distribution of immunoreactive structures containing methionine-enkephalin-Arg(6)-Gly(7)-Leu(8) in the human brainstem indicates that this neuropeptide might be involved in several physiological mechanisms, acting as a neurotransmitter and/or neuromodulator.

Identification and analysis of Escherichia coli proteins that interact with the histidine kinase NtrB in a yeast two-hybrid system

In this work we used the yeast two-hybrid (Y2H) system to deepen our understanding of protein-protein interactions that are involved in the nitrogen regulatory network in Escherichia coli. Three different genes, encoding GlnB, GlnK and AspA, respectively, were found among 64 positive clones identified from E. coli Sau3AI Y2H libraries using the nitrogen regulator NtrB as bait. Structural and functional analysis of the prey clones provided information on library features and the degree of saturation achieved in the screens. Further analysis revealed that the C-terminal kinase domain of NtrB is required for the interaction with GlnK, while AspA(91-312) interacts specifically with the conserved histidine phosphotransfer domain of NtrB, thus providing additional evidence for the involvement of the conserved transmitter module of the histidine kinase NtrB in input sensory functions.

Cloning and characterization of the cDNA coding for the catalytic alpha subunit of CK2 from tobacco

We have previously reported the participation of the protein kinase CK2 in the mechanism by which salicylic acid activates transcription of genes, such as those coding for glutathion S-transferases, in tobacco. With the purpose of further studying the participation of CK2 in this signal transduction pathway, we isolated and sequenced the cDNA from the NtCK2A gene, coding for the catalytic alpha subunit of CK2 from tobacco. The NtCK2A cDNA was isolated by screening of a tobacco cDNA library with a heterologous probe from Arabidopsis thaliana, followed by 3' RACE to obtain the 3' region. Sequence analysis of the NtCK2A cDNA showed a high level of identity between this CK2alpha protein sequence and the corresponding sequences of other plant species such as Arabidopsis and maize (92-95% identity), or those of animal species such as human and Xenopus laevis (75% identity). The expression of the NtCK2A gene in different tissues from tobacco plants was analyzed by Northern blot. High levels of expression of this gene were observed in proliferating tissues such as shoot and root apical meristems. A recombinant CK2alpha protein was obtained after expression of the NtCK2A cDNA in Escherichia coli. The ability of this recombinant CK2alpha subunit to phosphorylate casein was inhibited by heparin and stimulated by the CK2beta subunit from Xenopus laevis.

Treatment of Trypanosoma cruzi-infected children with nifurtimox: a 3 year follow-up by PCR

Patients suffering from Chagas' disease, as determined by positive serological results, were tested for further evidence of Trypanosoma cruzi infection by xenodiagnosis and PCR. The patients included 67 children aged from 0 to 10 years and 75 adults. All children were positive by PCR on their pre-therapy sample, while only 69% of the seropositive adults and none of the 78 seronegative control adults were PCR positive. Xenodiagnosis was positive in 79% of the children, but only in 21% of the adults. A group of 66 children was treated with nifurtimox, and followed up every 3 months during the first year and every 6 months during the second and third year post-therapy, by PCR, xenodiagnosis and serology. We concluded that PCR was the most effective test to monitor children for 3 years post-chemotherapy, when all the cases converted from positive to negative. Conventional serology, however, remained positive after that period in most cases. In contrast, conversion to negative xenodiagnosis occurred very early after treatment.

Two-hybrid analysis of domain interactions involving NtrB and NtrC two-component regulators

Signal transduction by two-component regulatory systems involves phosphorylation of the receiver domain of a response regulator by the transmitter domain of the cognate histidine kinase. In the NtrBC system, phosphorylation of NtrC by NtrB results in transcriptional activation of nitrogen-regulated genes. We have used the yeast two-hybrid system to probe interactions between domains of the NtrB and NtrC proteins from Klebsiella pneumoniae. We constructed fusions from each of a series of proteins or protein domains to the activation and the DNA-binding domains of GAL4 and analysed expression of GAL1:lacZ and GAL1:HIS3 reporters in yeast. The DNA-binding domain of NtrC and the so-called sensor domain of NtrB appeared to provide the major determinants for dimerization of the fusion proteins. A strong and specific interaction was also shown between NtrB and NtrC, localized to the HN region of the NtrB transmitter module and to the NtrC receiver domain, whereas other domains of these proteins do not appear to contribute to the recognition specificity. The results presented here indicate that communication between two-component partners also involves protein-protein interactions that can be detected in vivo, suggesting that the yeast two-hybrid system is a powerful genetic tool for identifying functional partners of prokaryotic signal transduction pathways.

Ultrastructural evidence of the protective effect of Na+/H+ exchange inhibition on the in vitro damage induced by ischaemia reperfusion in the interventricular septum of the rabbit heart

We investigated the effects of the Na+/H+ antiporter inhibitor, dimethylamiloride, on myocardial injury after 1 h global ischaemia and 30 min. reperfusion in the isolated arterially perfused interventricular septum of the rabbit heart. After ischaemia and reperfusion challenge, dimethylamiloride significantly increased the recovery of developed tension in a dose-dependent manner, and significantly decreased the maximal increase in resting tension. Ultrastructural analysis of myocytes submitted to the experimental in vitro model supported functional maintenance of physiologically-like conditions. Where myocardial portions were submitted to ischaemic conditions and reperfusion, myocyte cell damage reached usual characteristics of infarct-like induced lesions. Intracellular oedema, severe disruption of myofibrils with loss of muscle striation and both swelling and fragmentation of mitochondria were the main characteristics observed. Dimethylamiloride treatment clearly modifies ultrastructural findings towards the normalization of cell shape and structure, only a slight-middle intracellular oedema and contraction bands were found. On the basis of the present results, we suggest that the protective effects exhibited by dimethylamiloride on the ischaemic myocardium are compatible with its Na+/H+ antiporter inhibition properties, they diminish Na+ accumulation and then either Ca2+ overload or non-exocytotic noradrenaline release during the ischaemia and reperfusion challenge.

[Diagnostic use of ELISA, IgG, IgM, IgA and ELISA IgG avidity in recent and chronic toxoplasmosis]

Toxoplasmosis, a world-wide zoonotic infection, is generally asymptomatic and benign in immunocompetent individuals, but it can be serious in immunodeficiencies particularly in patients with acquired immunodeficiency syndrome and in children infected in utero. So, it is important to dispose methods which permit discriminate between recent and chronic infections. In order to contribute to improve the diagnosis of toxoplasmosis ELISA IgG, IgM, IgA and ELISA IgG avidity were performed in 15 and 24 sera from patients suspected of having acute and chronic infection respectively, according dye test (DT) titres. ELISA IgG was positive in both groups, ELISA IgM was positive in 78.6 and 58.3% respectively, while ELISA IgA was positive in 85.7 and 33.3% of recent and chronic group respectively. In those sera with low IgG avidity (18.8%) we found specific IgM in 71.5 and 4.2% and IgA in 78.6 and 0.0% of recent and chronic groups respectively. Parallelling, 208 sera samples were classified according to the results of DT, indirect hemagglutination and complement fixation tests in the following groups: acute (97), intermediate (36), chronic (35) and negative (40). The results were: acute (96.9-64.9-55.6 and 65.9%); intermediate (97.2-63.8-44.4 and 47.2%); chronic (45.7-42.8-5.7 and 34.3%) for IgG, IgM, IgA and low IgG avidity respectively. The use of both acute markers, IgA and low IgG avidity in the diagnosis of toxoplasmosis is discussed.

[Standardization of ELISA IgM and IgA for immunodiagnosis of human trichinosis]

An ELISA test for trichinosis using as antigen a larvae soluble fraction from Trichinella spiralis was carried out for the detection of IgM and IgA specific antibodies in 45 serum samples from patients confirmed or suspected to have trichinosis by strong clinical and epidemiological evidences. All the patients had positive serology detected by precipitin test, bentonite floculation test, indirect hemagglutination test and ELISA IgG test. The cut-off value was determined using two criteria. Criterion A was determined in each plate, using three positive controls and two negative ones; the average of the negative controls and the weakest positive control, multiplied by a 1.2 factor was, considered the cut-off value. Criterion B was determined using the average plus three standard deviations from 64 apparently healthy persons serum samples. In both cases, three serum dilutions (1:10, 1:100 and 1:500) were used. The sensitivity of ELISA IgM was 100.0, 93.3 and 82.2% using serum dilutions of 1:10, 1:100 and 1:500 respectively (criterion A) and 100.0, 97.8 and 95.6% for the same dilutions (criterion B), whereas the values for ELISA IgA were: 100.0, 91.1 and 86.7% (criterion A) and 100.0, 100.0 and 91.1% (criterion B). In order to find out the specificity of ELISA IgM and ELISA IgA, additional 118 serum samples from individuals with other parasitoses, such as cysticercosis (18) hydatidosis (39), fascioliasis (12), toxocariasis (30), Chagas' disease (12) and individuals with non-specific eosinophilia (7), were also tested. ELISA IgM presented a specificity of 92.3, 93.4 and 97.3% (criterion A) and 96.2, 97.8 and 97.8% (criterion B) whereas the results for ELISA IgA were 97.8, 98.9 and 99.4% (criterion A) and 98.4% for the 1:10 and 1:100 dilutions and 100.0% for the 1:500 dilution (criterion B). The positive predictive values of ELISA IgM were 76.3, 77.8 and 88.1% (criterion A) and 86.5, 91.7 and 91.5% (criterion B) whereas the negative ones were 100.0, 98.3 and 95.7% (criterion A) and 100.0, 99.4 and 98.9% (criterion B). The positive predictive values of ELISA IgA were 91.8, 95.3 and 97.5% (criterion A) and 93.8, 93.8 and 100.0% (criterion B) whereas the negatives ones were: 100.0, 97.8 and 96.8% (criterion A) and 100.0, 100.0 and 97.8% (criterion B). The use of ELISA IgM and ELISA IgA in the immunodiagnosis of trichinosis is discussed.

[Human hydatidosis in Chile. Seroprevalence and estimate of the number of infected people]

Chile is located in the southwestern border of South America. The country is 4,329 km long and 96-342 wide. From north to south it is divided into five marked different biogeographical zones: deserts, steppes, bushes, forests (cattle raising) and austral (sheep raising). Population (June 1999) 15,017,760 (14.6% rural). Human hydatidosis is endemic in Chile. According to Ministry of Health information about 320 cases are registered each year. In order to find out the likely prevalence of human hydatidosis in Chile, a series of serosurveys was carried out in 1988-1997 throughout the total country. By using the indirect hemagglutination reaction and ELISA for hydatidosis (tests with good sensibility and specificity) 60,790 unselected apparently healthy persons: 41,399 from urban areas (16,428 blood donors, 13,894 delivering mothers and 11,077 middle grade schoolchildren) and 19,361 from rural areas--from randomly selected family groupings--were studied. A total individuals 82 (136/100,000) resulted positive: 36 (87/100,000) urban and 46 (241/100,000) rural, being the prevalence higher in rural areas, particularly in the southern austral zone (mean 1068/100,00). These figures agree with those observed in clinical epidemiological studies. In conformity with the present results, in the whole country 17,002 individuals should have hydatidosis: 10,318 urban and 6,784 rural. All these possible infected people, not necessarily should present pathology in the future, as it has been observed in autopsies from unselected individuals, performed at the Medico-Legal Service in Santiago, in whom 71.3% of diagnosed hydatosis with hydatid cysts in many different locations, was an autopsy finding.

[Seroepidemiological survey of human toxoplasmosis in Osorno, Region X, Chile, 1998]

A serological survey was carried out in Osorno X Region, Chile (40 degrees 21'-40 degrees 46' South lat, and 73 degrees 26' -72 degrees-46' West long.). An indirect hemagglutination test (IHAT) for toxoplasmosis was performed to 305 persons--160 blood donors and 145 with sexually transmitted disease (STD). The age of the surveyed persons (167 males and 138 females) varied between 10 and 72 years. IHAT titers > 16 were considered as positive. The general prevalence was 20.3%--21.2% in blood donors and 19.3% in persons with some STD--with no differences between males and females. However, significant differences between males and females with STD were found (35.6% and 8.1% respectively). No differences between urban and rural inhabitants were found with a slight higher prevalence in the urban ones. No antibodies against Toxoplasma gondii were detected in six AIDS patients. The importance of performing toxoplasmosis immunodiagnosis and individual prophylaxis to avoid the infection in high risk group are recommended.

[Yield of xenodiagnosis and PCR in the evaluation of specific chemotherapy of Chagas' disease in children]

Amplification by the polymerase chain reaction (PCR) of Trypanosoma cruzi kinetoplastic DNA was used to enhance sensitivity in the detection of the parasite in blood, with the ultimate goal of improving the parasitological diagnosis of Chagas' disease in 0-10 year-old infected children. Twenty eight children were evaluated by using xenodiagnosis (XD) and PCR. Whereas XD detected 75.0% of the cases PCR was positive in 96.8%. The usefulness of the PCR was further investigated in the 28 children who have received specific treatment with nifurtimox. Negativation of XD after three and six months post treatment was observed in all the cases, but only 21.4% and 35.8% negativation of the PCR after three and six months post treatment respectively. These observations suggest that PCR is the most sensitive and quick technique available for direct detection of T. cruzi in chagasic children and that it can be a very useful tool for the follow-up of infected subjects after specific chemotherapeutical treatment.

Cat carotid body chemosensory responses to non-hypoxic stimuli are inhibited by sodium nitroprusside in situ and in vitro

We studied the effects of sodium nitroprusside, a nitric oxide donor, on the chemosensory responses to cyanide and nicotine in the cat carotid body. In situ, sodium nitroprusside infusion reduced the cyanide-evoked responses in a dose-dependent manner. In vitro, Tyrode containing nitroprusside reversibly reduced the cyanide- (by 59%) and nicotine-induced (by 45%) chemosensory responses. The present results suggest that chemosensory responses induced by cyanide and nicotine are reduced by increased nitric oxide content, similarly to the hypoxic chemosensory responses.

[Immunodiagnosis in 647 suspected clinical cases of toxoplasmosis]

Though Toxoplasma gondii can cause severe pathology in human, in most of the cases it produces only asymptomatic infection. So, it is important to dispose some methods capables to discriminate between acute and chronic infections. An indirect hemagglutination test (IHAT), dye test (DT) and complement fixation test (CFT) were performed in 647 sera from patients suspected of having toxoplasmosis infection. IHAT and DT titer > or = 4 and CFT > or = 5 were considered positive. Titers were classified as follows: low (4-16), median (64-512) and high (> or = 1000) for IHAT and DT. The pathologies for demanding these serological tests were: adenopathies (58), nephropathies (72), neuropathies (30), obstetrical problems (65), opthalmopathies (147), AIDS (237) and miscellaneous (37). Global positivity of 49.5% and 4.5% for IHAT/DT and CFT respectively were found. The positivity for the different groups were: adenopathies (48.3% and 13.8%), nephropathies (43.1% and 1.4%), neuropathies (26.7% and 3.3%), obstetrical problems (40.0% and 0.0%), ophthalmopathies (59.9% and 8.2%), AIDS (52.1% and 2.5%) and miscellaneous (40.5% and 2.7%) for IHAT/DT and CFT respectively. Low and median titers for IHAT/DT were found in 81.3% of cases. A high agreement in frequency of concordant and discordant titers of IHAT/DT and CFT, indicating a recent or acute infection was observed. This fact was more relevant in adenopathies, ophthalmopathies (uveitis) and AIDS groups.

Seroepidemiology of human toxoplasmosis in Chile

A series of already published and unpublished seroepidemiological surveys for toxoplasmosis, carried out in Chile in 1982-1994, is reviewed, expanded and analyzed. The surveys included 76,317 apparently healthy individuals of different ages (0.57% of the country's total population), from 309 urban and rural-periurban localities. Urban groups were integrated by blood donors, delivering mothers and middle grade schoolchildren, while rural-periurban individuals corresponded to unselected family groups. Blood samples were collected in filter paper. The presence of antibodies to Toxoplasma gondii was determined by the indirect hemagglutination test (IHAT), titers > or = 16 were considered positive. The test resulted positive in 28,124 (36.9%) of the surveyed people. Two hundred and six (0.3%) individuals presented IHAT titers > or = 1000, probably corresponding to acute or reactivated infections. A progressive increase of positive IHAT from northern to southern regions of the country was noted, phenomenon probably related to geographical conditions and to a higher production and consumption of different types of meat in the latter regions. It is postulated that ingestion of T gondii cysts by humans is epidemiologically as important as ingestion of oocysts. The result presented stress the epidemiological importance of toxoplasmosis in humans, and warn about eventual implications in immunocompromised patients and in transplacental transmission, organ transplants and transfusions.