Role of Cardiac Magnetic Resonance in the Diagnosis of Infiltrative, Hypertrophic, and Arrhythmogenic Cardiomyopathies

Cardiac magnetic resonance has become a reliable imaging modality providing structural and functional data, and fundamental information about tissue composition. Cardiac magnetic resonance imaging with late gadolinium enhancement, T1-mapping, T2-mapping, T2*-imaging, and extracellular volume, has proved to be a valuable tool in investigating the etiology of heart failure. Such analysis is helpful for the diagnostic evaluation of both ischemic and non-ischemic cardiomyopathies. As primary heart muscle diseases, the ability to characterize the myocardial substrate is essential. Determining the heart failure etiology is fundamental and has implications regarding the prognosis prediction and best treatment. Investigation in cardiac magnetic resonance in heart failure patients has grown in the past decade, and the true value of this imaging modality to detect early disease likely remains underestimated. This review describes the importance of cardiac magnetic resonance for the diagnosis and prognosis of non-ischemic cardiomyopathies, particularly hypertrophic, infiltrative, and arrhythmogenic cardiomyopathies.

Preventable newborn deaths: analysis of the newborn infection component in Brazil from 2007 to 2017

The Universal Agenda 2030 was developed by representatives of all countries as an action plan covering the three dimensions of sustainable development: economic, social and environmental. 17 objectives were agreed upon, highlighting objective 03, which aims to ensure a healthy life and promote well-being for all at all ages, having as one of the established goals to end preventable deaths of newborns by 2030. Infections neonatal care reflects deficits in health care, covering the entire perinatal period, and it is necessary to understand its causes in order to promote quality preventive and health promotion actions. The question is: what are the causes that make up the indicator of early neonatal mortality, due to preventable causes in Brazil between 2007 to 2017? Retrospective study carried out between September and October 2019 using secondary data collection from Department of Informatics of the Unified Health System - SUS (DATASUS). The outcome variable was early neonatal mortality from preventable causes and the independent variable was the infections component of the newborn). Twelve preventable causes of death have been identified in this category: congenital rubella syndrome; congenital syphilis; neonatal tetanus; diphtheria; haemophilus and non-haemophilus meningitis; human immunodeficiency virus diseases; neonatal infections; pneumonia; acute infections of lower airways; bacterial diseases and intestinal infectious diseases. The main cause of preventable death was infections from the neonatal period, which include congenital viral diseases (cytomegalovirus and herpes simplex); newborn bacterial septicemia; congenital parasitic diseases; omphalitis of newborn with or without mild hemorrhage; intra-amniotic infection of the fetus, neonatal infection of the urinary tract and/or skin. There is a need for more effective public health actions to modify the neonatal mortality situation, as well as health surveillance actions.

Key messages

Warn about causes of perinatal mortality that can be avoided. Strengthen the fulfillment of objective 3 of the 2030 Agenda to ensure and promote health in the perinatal period.

[Central neuropathic pain and its relation to the quality of life of a person with a traumatic spinal cord injury]

INTRODUCTION AND AIMS

To conduct an exploratory cross-sectional study carried out in the city of Fortaleza (Ceara, Brazil) with the aim of evaluating the relation between central neuropathic pain and the quality of life in individuals with central neuropathic pain due to traumatic injury.

PATIENTS AND METHODS

The study examined the cases of 17 adult paraplegic patients with complete traumatic injuries, mainly due to perforations caused by gunshot wounds. The sample was divided into two groups: 1) those with pain, and 2) those with intense pain (more than 20 points according to McGill and eight on the numerical visual scale). The instruments used were the following: the MOS 36-item Short-Form Health Survey (SF-36) and the McGill pain questionnaire, oriented towards the descriptors and the numerical visual scale.

RESULTS

The quality of life of patients with central neuropathic pain due to a spinal cord injury is greatly compromised and when the pain is intense the quality of life is even more effected, especially in the following areas: "functional capacity" (p = 0.005), "general state of health" (p = 0.003), "mental health" (p = 0.035), "social aspects" (p = 0.006) and "pain" (p = 0.003).

CONCLUSIONS

The quality of life in patients with neuropathic pain due to a traumatic spinal cord injury is severely compromised and the more intense this pain is, the greater its effect on the quality of life will be. It can also be stated that the instruments used were valid for this type of patients (in spite of certain shortcomings) given the complexity and subjectivity of the matter.

Proteinase activity regulation by glycosaminoglycans

There are few reports concerning the biological role and the mechanisms of interaction between proteinases and carbohydrates other than those involved in clotting. It has been shown that the interplay of enzymes and glycosaminoglycans is able to modulate the activity of different proteases and also to affect their structures. From the large number of proteases belonging to the well-known protease families and also the variety of carbohydrates described as widely distributed, only few events have been analyzed more deeply. The term "family" is used to describe a group of proteases in which every member shows an evolutionary relationship to at least one other protease. This relationship may be evident throughout the entire sequence, or at least in that part of the sequence responsible for catalytic activity. The majority of proteases belong to the serine, cysteine, aspartic or metalloprotease families. By considering the existing limited proteolysis process, in addition to the initial idea that the proteinases participate only in digestive processes, it is possible to conclude that the function of the enzymes is strictly limited to the cleavage of intended substrates since the destruction of functional proteins would result in normal tissue damage. In addition, the location as well as the eventual regulation of protease activity promoted by glycosaminoglycans can play an essential role in the development of several physiopathological conditions.

Cathepsin B activity regulation. Heparin-like glycosaminogylcans protect human cathepsin B from alkaline pH-induced inactivation

It has been shown that lysosomal cysteine proteinases, specially cathepsin B, has been implicated in a variety of diseases involving tissue remodeling states, such as inflammation, parasite infection, and tumor metastasis, by degradation of extracellular matrix components. Recently, we have shown that heparin and heparan sulfate bind to papain specifically; this interaction induces an increase of its alpha-helix content and stabilizes the enzyme structure even at alkaline pH (Almeida, P. C., Nantes, I. L., Rizzi, C. C. A., Júdice, W. A. S., Chagas, J. R., Juliano, L., Nader, H. B., and Tersariol, I. L. S. (1999) J. Biol. Chem. 274, 30433-30438). In the present work, a combination of circular dichroism analysis, affinity chromatography, cathepsin B mutants, and fluorogenic substrate assays were used to characterize the interaction of human cathepsin B with glycosaminoglycans. The nature of the cathepsin B-glycosaminoglycans interaction was sensitive to the charge and type of polysaccharide. Like papain, heparin and heparan sulfate bind cathepsin B specifically, and this interaction reduces the loss of cathepsin B alpha-helix content at alkaline pH. Our data show that the coupling of cathepsin B with heparin or heparan sulfate can potentiate the endopeptidase activity of the cathepsin B, increasing 5-fold the half-life (t(12)) of the enzyme at alkaline pH. Most of these effects are related to the interaction of heparin and heparan sulfate with His(111) residue of the cathepsin B occluding loop. These results strongly suggest that heparan sulfate may be an important binding site for cathepsin B at cell surface, reporting a novel physiological role for heparan sulfate proteoglycans.

[Cancellation of scheduled surgery at a university hospital: an exploratory study]

In spite of the extensive available literature on surgery patients' preparation and on the performance of surgeries, the focus given to the cancellation of the surgical act has been quite restricted. This study aims at identifying the number of scheduled and cancelled surgeries as well as the services that are mostly affected by such cancellations and was carried out in the surgery service of a big public university hospital located in the metropolitan area of Fortaleza, Ceará. The data were collected through surgery registration books, daily maps of surgery schedules and from the files of patients scheduled for surgery from September to December, 1996. The gathered data were analyzed quantitatively and introduced in charts. The results demonstrate that from the 1,145 surgeries programmed in the selected period, 379 (33%) had been cancelled. The mostly prejudiced services were General Surgery, Ophthalmology, Head and Neck Surgery, Trauma and Orthopedics, Otorhinolaryngology, Nephrology and Renal Transplant, and Proctology. Further investigation in this area in order to know the determinant causes of surgery cancellation as well as the participation of nursing in the study of this problem are necessary.

Hydrolysis by plasma kallikrein of fluorogenic peptides derived from prorenin processing site

Human plasma kallikrein (HPK) activates plasma prorenin to renin, and the physiological significance of this activation is still unknown. In this paper we investigated the efficiency and the cleavage pattern of the hydrolysis by HPK of the internally quenched fluorescent peptides (qf-peptides) derived from the amino acid sequence of human prorenin cleavage site. The peptide Abz-F-S-Q-P-M-K-R-L-T-L-G-N-T-T-Q-EDDnp (Abz=ortho-aminobenzoic acid, and EDDnp=N-[2,4-dinitrophenyl]-ethylene diamine), that corresponds to the amino acid sequence P(7) to P(7)' of human prorenin cleavage site, is hydrolyzed at the correct processing site (R-L bond) with k(cat)/K(m)=85 mM(-1) s(-1). Alanine was scanned in all positions from P(5) to P(5)' in order to investigate the substrate specificity requirements of HPK. The qf-peptides derived from the equivalent segment of rat prorenin, that has Lys-Lys as basic amino acid pair, and the peptide Abz-NVTSPVQ-EDDnp that contains the proposed cleavage site of rat prorenin have very low susceptibility to hydrolysis by rat plasma kallikrein. These data are according to the previously reported absence of rat plasma prorenin activation by rat plasma kallikrein (RPK), and with the view that prorenin activation in rat requires alternative enzymes and/or mechanism. All the obtained peptides described in this paper were also assayed with bovine trypsin that was taken as a reference protease because it is commonly used to activate prorenin.

Hydrolysis by cathepsin B of fluorescent peptides derived from human prorenin

Cathepsin B is a lysosomal thiolprotease that, because of its colocalization with renin and its ability to activate prorenin, has been proposed as a prorenin processing enzyme. To characterize the biochemical aspect of this potential cathepsin B activity in more detail, we synthesized and assayed with human cathepsin B the internally quenched fluorescent peptide Abz-FSQPMKRLTLGNTTQ-EDDnp (Abz, ortho-aminobenzoic acid fluorescent group and EDDnp, N-¿2, 4-dinitrophenyl-ethylenediamine quencher group) that contains 7 amino acids for each side of the R-L bond that is the processing site of human prorenin. Human cathepsin B hydrolyzed this peptide at the correct site (R-L bond), with k(cat)/K(m)=75 mmol/L(-1) s(-1). Analogues of this peptide obtained by Ala scanning at positions P(5) to P(5)' were also synthesized and assayed as substrates for human cathepsin B. The obtained specificity constant (k(cat)/K(m)) values have a significant parallel with the previous data of prorenin activation by AtT-20 cells and in vitro by cathepsin B. In addition, we demonstrated the presence of cathepsin B-like activity in rat mesangial cells and the ability of its whole soluble fraction lysates, as well as that of purified cloned rat cathepsin B, to hydrolyze Abz-IKKSSF-EDDnp at the K-S bond, which contains 6 amino acids of rat prorenin processing site. The specificity data of cathepsin B toward peptides derived from prorenin processing site support the view that human or rodent cathepsin B could be involved in the intracellular processing of prorenin that is locally synthesized or taken up from the extracellular compartment.

Characterization of thiol-, aspartyl-, and thiol-metallo-peptidase activities in Madin-Darby canine kidney cells

We combined fluorogenic substrates or internally quenched fluorescent peptides with specific inhibitors in the pH profile of proteolytic activity experiments in order to detect proteolytic activities in lysates of MDCK cells. Hydrolytic activities related to cathepsin B, L, and D were observed. Serine-proteinase was not detected; however, we clearly demonstrated the presence of a thiol-metallo-endo-oligopeptidase, also called thimet-oligopeptidase (TOP). This peptidase from MDCK cells has substrate and inhibitor specificities as well as an activation profile with mercaptoethanol that are indistinguishable from the recombinant rat testis TOP (EC 3. 4.24.15). In addition, polyclonal purified antibodies to this enzyme depleted the TOP activity of MDCK cells in whole homogenate. Although we present only preliminary data, TOP is secreted by MDCK cells. The presence of TOP in a phenotype polarized MDCK cells can have special significance in the cytoplasmic selection, transport, or clearance of short peptides due to restriction of the enzyme to sequences from 6 to 17 amino acids. Therefore, the MDCK cell could be a very useful cellular model with which to study some of the suggested TOP biological functions as processing of biological active peptides and antigen presentation.

Cysteine proteinase activity regulation. A possible role of heparin and heparin-like glycosaminoglycans

Papain is considered to be the archetype of cysteine proteinases. The interaction of heparin and other glycosaminoglycans with papain may be representative of many mammalian cysteine proteinase-glycosaminoglycan interactions that can regulate the function of this class of proteinases in vivo. The conformational changes in papain structure due to glycosaminoglycan interaction were studied by circular dichroism spectroscopy, and the changes in enzyme behavior were studied by kinetic analysis, monitored with fluorogenic substrate. The presence of heparin significantly increases the alpha-helix content of papain. Heparin binding to papain was demonstrated by affinity chromatography and shown to be mediated by electrostatic interactions. The incubation of papain with heparin promoted a powerful increase in the affinity of the enzyme for the substrate. In order to probe the glycosaminoglycan structure requirements for the papain interaction, the effects of two other glycosaminoglycans were tested. Like heparin, heparan sulfate, to a lesser degree, was able to decrease the papain substrate affinity, and it simultaneously induced alpha-helix structure in papain. On the other hand, dermatan sulfate was not able to decrease the substrate affinity and did not induce alpha-helix structure in papain. Heparin stabilizes the papain structure and thereby its activity at alkaline pH.

Synthesis of N alpha-protected aminoacyl 7-amino-4-methyl-coumarin amide by phosphorous oxychloride and preparation of specific fluorogenic substrates for papain

We report an improved procedure for the synthesis of fully protected aminoacyl 7-amino-4-methylcoumarin amide (MCA) employing the phosphorous oxychloride anhydride method. Seven Boc-X-MCA [where X = Arg(NG Tos), Cys(S-Bzl), Thr(O-Bzl), Ser(O-Bzl), Phe, Leu and Gly] and Z-Tyr(O-Me) were synthesized using this procedure, with yields ranging from 50% to 75%. These aminoacyl-MCA derivatives were employed for the synthesis of epsilon-NH2-caproyl-Leu-X-MCA, a fluorescent peptide series, which were assayed as papain substrates. All of them were completely hydrolyzed by papain, indicating that all of the Boc-X-MCA derivatives obtained were practically free of racemization. Since epsilon-NH2-Caproyl-Leu-(S-Bzl)Cys-MCA is very susceptible to hydrolysis by papain, quite resistant to hydrolysis by chymotrypsin and not hydrolyzed by trypsin, it is recommended for assays of thiol-proteinases in which specificity is required.

Determinants of the unusual cleavage specificity of lysyl-bradykinin-releasing kallikreins

Kinetic data for the hydrolysis by human tissue kallikrein of fluorogenic peptides with o-aminobenzoyl-Phe-Arg (Abz-FR) as the acyl group and different leaving groups demonstrate that interactions with the S'1, S'2 and S'3 subsites are important for cleavage efficiency. In addition, studies on the hydrolysis of fluorogenic peptides with the human kininogen sequence spanning the scissile Met-Lys bond [Abz-M-I-S-L-M-K-R-P-N-(2,4-dinitrophenyl)ethylenediamine] and analogues with different residues at positions P'1, P'2 and P'3 showed that (a) the presence of a proline residue at P'3 and the interactions with the tissue kallikrein-binding sites S2 to S'2 are determinants of Met-Lys bond cleavage and (b) residues P3, P4 and/or P5 arc important for cleavage efficiency. The substitution of phenylalanine for methionine or arginine in substrates with scissile Met-Lys or Arg-Xaa bonds demonstrated that lysyl-bradykinin-releasing tissue kallikreins also have a primary specificity for phenylalanine. The replacement of arginine by phenylalanine in (D)P-F-R-p-nitroanilide (pNA) produced an efficient and specific chromogenic substrate, (D)P-F-F-pNA, for the lysyl-bradykinin-releasing tissue kallikreins as it is resistant to plasma kallikrein and other arginine hydrolases.