Caracterização Histológica das Lesões da Valva Mitral de Pacientes com Cardiopatia Reumática

Background:The underlying mechanisms by which rheumatic heart disease (RHD) lead to severe valve dysfunction are not completely understood.Objective:The present study evaluated the histopathological changes in mitral valves (MV) seeking an association between the pattern of predominant valvular dysfunction and histopathological findings.Methods:In 40 patients who underwent MV replacement due to RHD, and in 20 controls that underwent heart transplant, histological aspects of the excised MV were analyzed. Clinical and echocardiographic data were also collected. Histological analyses were performed using hematoxylin-eosin staining. Inflammation, fibrosis, neoangiogenesis, calcification and adipose metaplasia were determined. A p value<0.05 was considered to be statistically significant.Results:The mean age of RHD patients was 53±13 years, 36 (90%) were female, whereas the mean age of controls was 50±12 years, similar to the cases, with the majority of males (70%). The rheumatic valve endocardium presented greater thickness than the controls (1.3±0.5 mm versus 0.90±0.4 mm, p=0.003, respectively), and a more intense inflammatory infiltrate in the endocardium (78% versus 36%; p=0.004), with predominance of mononuclear cells. Moderate to marked fibrosis occurred more frequently in rheumatic valves than in control valves (100% vs. 29%; p<0.001). Calcification occurred in 35% of rheumatic valves, especially among stenotic valves, which was associated with the mitral valve area (p=0.003).Conclusions:Despite intense degree of fibrosis, the inflammatory process remains active in the rheumatic mitral valve, even at late disease with valve dysfunction. Calcification predominated in stenotic valves and in patients with right ventricular dysfunction.     

Multiple Extrauterine Pregnancy with Early and Near Full-Term Mummified Fetuses in a New Zealand White Rabbit (Oryctolagus cuniculus)

Extrauterine pregnancy (EP) is infrequent in mammalian species and occurs when fertilized ova implant and develop outside the uterus. A common outcome is abdominal pregnancy resulting in mummified fetuses (lithopedia). Here we describe an unusual case of abdominal pregnancy with early and near full-term lithopedia. Macroscopic findings supported the diagnosis of lithopedia with distinct age differences and facilitated further characterization of primary ectopia and risk factors leading to this occurrence.Abbreviation: EP, extrauterine pregnancyExtrauterine pregnancy (EP) occurs infrequently in most mammalian species.¹² The term derives from the Latin prefix meaning ‘outside’ or ‘beyond’ and refers to the implantation of a fertilized ovum outside the uterine cavity. Extrauterine pregnancy was first recognized more than 900 y ago² among other discoveries with a hereditary nature.¹³ Early reports compared EP in women, cats, dogs, and rabbits⁷ and described the presence of mummified fetuses in laboratory rabbits.^16,35EP is a serious obstetric complication that occurs asymptomatically in most cases.¹⁷ There are 4 classifications of EP: tubal, ovarian, abdominal–peritoneal, and cervical. The fallopian tube is the most common location and leads to tubal pregnancy. When gestation occurs in the abdominal–peritoneal cavity, abdominal pregnancy results and is subdivided as primary, when fertilization occurs outside the uterus after an oocyte is accidentally released from the fimbria, and secondary, when an oocyte is released due to direct tubal trauma.⁴⁵ A rare form of EP associated with high maternal morbidity and fetal mortality is called heterotopic (or combined) pregnancy, which occurs when 2 fertilized eggs coexist, one outside the uterus and the other inside.^18,33,44Undetected EP is frequently associated with fatal outcomes to the dam and offspring, including the formation of mummified fetuses, which may eventually become calcified and are called lithopedia (from the Greek: lithos, stone; paidion, child).^11,51,53 The condition is infrequent, and the factors that influence the unexpected outcomes of this pathology are not well understood.^26,34,35 Epizootiologic investigations are few,¹² although a recent report outlined the prevalence of EP in large NZW rabbit breeding colonies.⁵¹Examples of EP have been documented in dogs,¹⁷ cats,^14,39,42,49 rabbits,^20,29,45,51 hamsters,^9,46 rats,²⁶ mice,^8,12 guinea pigs,^3,30 lambs,⁴⁰ nonhuman primates,^10,34,38,50 and other species including humans.^11,12 However, despite the number of documented species, the majority of reports failed to note detailed clinical symptoms that interfered with reproduction even in instances that led to the formation of lithopedions.⁴²Experimentally, mouse embryos have successfully been transferred to a variety of sites including the peritoneal cavity, kidney, spleen, muscles, testis, and the anterior chamber of the eye.^1,6,21,31 The aim of the current report is to describe a rare case of abdominal pregnancy in which lithopedia developed clinically silently and coexisted with multiple pregnancies in a healthy doe rabbit.     

Ibutilide-induced long QT syndrome and torsade de pointes

Ibutilide is a class III antiarrhythmic agent used for the termination of atrial fibrillation and atrial flutter. It mainly affects membrane potassium currents and prolongs the cardiac action potential. This effect is reflected as QT interval prolongation on the surface electrocardiogram. Like other drugs that affect potassium currents, ibutilide is prone to induce a malignant ventricular tachycardia, torsade de pointes. We report four cases of torsade de pointes after administration of ibutilide for pharmacologic cardioversion of atrial fibrillation and atrial flutter; three of these cases required direct current cardioversion for termination of torsade de pointes. All four patients were female. We discuss the risk factors for development of ibutilide-induced torsade de pointes.     

A Chromosome 17 Locus Engenders Frequency-Specific Non-Progressive Hearing Loss that Contributes to Age-Related Hearing Loss in Mice

The 129S6/SvEvTac (129S6) inbred mouse is known for its resistance to noise-induced hearing loss (NIHL). However, less is understood of its unique age-related hearing loss (AHL) phenotype and its potential relationship with the resistance to NIHL. Here, we studied the physiological characteristics of hearing loss in 129S6 and asked if noise resistance (NR) and AHL are genetically linked to the same chromosomal region. We used auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) to examine hearing sensitivity between 1 and 13 months of age of recombinant-inbred (congenic) mice with an NR phenotype. We identified a region of proximal chromosome (Chr) 17 (D17Mit143-D17Mit100) that contributes to a sensory, non-progressive hearing loss (NPHL) affecting exclusively the high-frequencies (>24 kHz) and maps to the nr1 locus on Chr 17. ABR experiments showed that 129S6 and CBA/CaJ F1 (CBACa) hybrid mice exhibit normal hearing, indicating that the hearing loss in 129S6 mice is inherited recessively. An allelic complementation test between the 129S6 and 101/H (101H) strains did not rescue hearing loss, suggesting genetic allelism between the nphl and phl1 loci of these strains, respectively. The hybrids had a milder hearing loss than either parental strain, which indicate a possible interaction with other genes in the mouse background or a digenic interaction between different genes that reside in the same genomic region. Our study defines a locus for nphl on Chr 17 affecting frequencies greater than 24 kHz.     

Acurácia da Redução do Segmento-ST Pós-Trombólise como Preditor de Reperfusão Adequada em Estratégia Fármaco-Invasiva

Background Primary percutaneous coronary intervention is considered the “gold standard” for coronary reperfusion. However, when not available, the drug-invasive strategy is an alternative method and the electrocardiogram (ECG) has been used to identify reperfusion success.Objectives Our study aimed to assess ST-Segment changes in post-thrombolysis and their power to predict recanalization and using the angiographic scores TIMI-flow and Myocardial Blush Grade (MBG) as an ideal reperfusion criterion.Methods 2,215 patients with ST-Segment Elevation Myocardial Infarction (STEMI) undergoing fibrinolysis [(Tenecteplase)-TNK] and referred to coronary angiography within 24 h post-fibrinolysis or immediately referred to rescue therapy were studied. The ECG was performed pre- and 60 min-post-TNK. The patients were categorized into 2 groups: those with ideal reperfusion (TIMI-3 and MBG-3) and those with inadequate reperfusion (TIMI and MBG <3). The ECG reperfusion criterion was defined by the reduction of the ST-Segment >50%. A p-value <0.05 was considered for the analyses, with bicaudal tests.Results The ECG reperfusion criterion showed a positive predictive value of 56%; negative predictive value of 66%; sensitivity of 79%; and specificity of 40%. There was a weak positive correlation between ST-Segment reduction and ideal reperfusion angiographic data (r = 0.21; p <0.001) and low diagnostic accuracy, with an AUC of 0.60 (95%CI: 0.57-0.62).Conclusion The ST-Segment reduction was not able to accurately identify patients with adequate angiographic reperfusion. Therefore, even patients with apparently successful reperfusion should be referred to angiography soon, to ensure adequate macro and microvascular coronary flow.