Three‐dimensional transesophageal echocardiography incremental value in a rare case of a bileaflet tricuspid valve

Detailed assessment of the tricuspid valve using two‐dimensional echocardiography is always challenging, as only two of three leaflets can be seen at a time. Three‐dimensional echocardiography can provide the enface view of the tricuspid valve that allows simultaneous visualization of all of the three leaflets. In a 42‐year‐old male patient scheduled for pulmonary endarterectomy, 3DTEE showed that the tricuspid valve is bileaflet, with one septal and another lateral leaflet. There were two commissures, one of them is anteriorly positioned and the other one is posterior. Our findings were confirmed intra‐operatively by direct surgical visualization of the tricuspid valve.     

Canine electrophysiology of encainide, a new antiarrhythmic drug

Encainide, a new benzanillide derivative with high potency and a good therapeutic/toxic ratio, was evaluated with the use of standard His bundle recording techniques to determine its effects on the cardiac conduction system in closed chest animals. Twenty mongrel dogs weighing 18 to 29 kg were anesthetized with 4 percent chloralose and classified into groups: group 1, a control group and groups 2,3, and 4, which were given 0.3, 0.9 and 2.7 mg/kg body weight, respectively, of encalnide In an intravenous infusion over a 15 minute period. Plasma concentration, blood pressure, surface electrocardiogram and atrlal and His bundle electrograms were recorded before, during and after drug infusion for a total of 120 minutes. Heart rate, A-H and H-V intervals, the QRS complex and Q-Tc interval were measured every 5 minutes during sinus rhythm and with constant atrial pacing. In addition, sinus nodal recovery time and atrial, atrioventrlcular (A-V) nodal and left ventricular refractory periods were measured before and immediately after infusion and every 30 minutes for 2 hours. Peak plasma concentration averaged 450 ng/ml in group 2,1,300 ng/ml in group 3 and 4,000 ng/ml in group 4. Blood pressure was not altered at any dose level throughout the study. The QRS complex and H-V interval were significantly prolonged (P < 0.005) at doses of 0.9 mg/kg and greater. These effects correlated well with plasma concentration. There was no significant change in heart rate, corrected sinus nodal recovery time, A-H interval, Q-Tc Interval atrial, A-V nodal or left ventricular refractory period. It is concluded that, unlike other antiarrhythmic agents, encainide prolongs His-Purkinje system conduction without significantly affecting conduction or refractoriness of other parts of the cardiac conduction system in animals.     

The Return of Actionable Variants Empirical (RAVE) Study,a Mayo Clinic Genomic Medicine Implementation Study: Design and Initial Results

Objectives

To identify clinically actionable genetic variants from targeted sequencing of 68 disease-related genes, estimate their penetrance, and assess the impact of disclosing results to participants and providers.

Anatomical definition of aortic root abscesses by transesophageal echocardiography: Planning a surgical strategy using homograft valves

Infective endocarditis of the native or a prosthetic aortic valve may be complicated by abscess cavity development in the aortic root, and successful treatment depends upon early diagnosis, clear anatomical definition preoperatively, and maintaining sterility of the second implant. Homograft valves offer many advantages in this setting. Timing of surgery and the choice of the particular technique depends on accurate characterization of the anatomical details of the abscess. Five cases of paravalvular aortic root abscess in the setting of prosthetic valve endocarditis are described. In each case the diagnosis was made with transesophageal echocardiography, and the information was used in planning the operative procedure of homograft valve replacement. This strategy is proposed as optimal management of this potentially lethal condition.     

Antagonism of leukotriene receptors and administration of a 5-lipoxygenase inhibitor do not affect hypoxic vasoconstriction

The role of leukotrienes in hypoxic vasoconstriction remains controversial. Our previous study using the lipoxygenase inhibitor BW 755C in dogs failed to show a substantive role for leukotrienes in hypoxic vasoconstriction. To clarify further the role of leukotrienes, we designed 3 protocols. In the first protocol, we examined the effects of LTD₄ boluses on the pulmonary circulation in 6 anesthetized dogs. LTD₄, 1 μg/kg, (a large dose relative to other species) produced no detectable constriction of the pulmonary artery, while systemic vascular resistance increased 41±17% (SD), left atrial pressure rose 3.5±1.5 mmHg, and cardiac output fell 18±8%. Two leukotriene receptor antagonists, LY171883 and L-648051, decreased these effects by more than 50%. In the second protocol, we tested these antagonists in 7 anesthetized, paralyzed, closed-chest dogs with acute left lower lobe atelectasis. Two manifestations of hypoxic vasoconstriction were examined: shunt fraction (as an inverse indicator of regional constriction in response to local hypoxia) and the pulmonary pressor response to global alveolar hypoxia (as an index of general hypoxic vasoconstriction). During normoxia before administration of the inhibitor, shunt fraction, measured using an SF₆ infusion, was 25±7%. The pulmonary pressor response to hypoxia, defined as the increase in pulmonary end-diastolic gradient (PDG) produced by 10% O₂ inhalation, averaged +10.5±3.6 mmHg. The increase in pulmonary vascular resistance (PVR) with hypoxia was +2.4±1.7 mmHg/L/min. Then, during normoxia, 1 of the 2 antagonists was administered. Shunt fraction was unchanged (26±4%; p=0.5). The pressor response to hypoxia was slightly less but remained substantial (the increase in PDG with hypoxia was +7.9±2.8 mmHg; p<0.05; the increase in PVR was +1.8±1.2 mmHg/L/min, p<0.10). In the third protocol we gave RG 5901, a relatively specific 5-lipoxygenase inhibitor, to 5 dogs with lobar atelectasis. The indices of hypoxic vasoconstriction were not affected by RG 5901. Shunt fraction was 29.5±8.1% before and 27.0±7.4% after RG 5901 (p>0.05). The pressor response to hypoxia was + 8.9±2.1 mmHg before and +8.7±3.7 mmHg after RG 5901 (p>0.05). We conclude that in dogs, hypoxic vasoconstriction does not appear to be mediated by leukotrienes.     

Mucilage-capped silver nanoparticles for glucose electrochemical sensing and fuel cell applications

A simple, cost-effective and green mucilage-capped silver nanoparticles (Mucilage-AgNPs) modified glassy carbon electrode (GC) composite was constructed for efficient and facile electrochemical oxidation of glucose for the first time. Mucilage-AgNPs were synthesized through the direct chemical reduction of Ag⁺ by mucilage extracted from Opuntia ficus-indica. Mucilage-AgNPs were identified and characterized using ultraviolet-visible spectroscopy, transmission electron microscopy and square wave voltammetry. Modification of the GC with AgNPs was carried out via a transfer-sticking technique with an immobilization time of 1 h. The Mucilage-AgNPs/GC composite was studied as a possible anode for glucose oxidation in a biofuel cell. The composite resulted in glucose oxidation with a current density and power density of 85.7 μA cm⁻² and 25.7 μW cm⁻², respectively. Glucose sensing using the Mucilage-AgNPs/GC composite was achieved successfully via two pathways: glucose oxidation and AgNP inhibition. The glucose oxidation-based sensor showed a lower detection limit of 0.01 mM and a linear range of 0.01 to 2.2 mM. The AgNPs inhibition-based sensor provides an indirect determination pathway of glucose with a detection limit of 0.1 mM and a linear range of 0.1 to 1.9 mM. AgNP inhibition is a novel pathway that could be used for determining a large number of organic and inorganic molecules. Overall, the Mucilage-AgNPs/GC is considered a pioneering composite for glucose sensing and fuel cell applications.

A simple, cost-effective and green mucilage-capped silver nanoparticles (Mucilage-AgNPs) modified glassy carbon electrode (GC) composite was constructed for efficient and facile electrochemical oxidation of glucose for the first time.     

Mixed gynecomastia

Gynecomastia is an enlargement of male breast resulting from a proliferation of its glandular component, and it is usually due to an altered estrogen-androgen balance. It should be differentiated from pseudogynecomastia, which is characterized by fat deposition without glandular proliferation and from breast carcinoma. Gynecomastia could be physiological in neonates and pubertal or pathological due to drug intake, chronic liver, or renal disease, hyperthyroidism, testicular or adrenal neoplasms, and hypogonadism whether primary, or secondary. Properly organized work-up is needed to reach the cause of gynecomastia. Here, we reported a case of a young Omani man with gynecomastia with the aim of creating awareness of the occurrence of Klinefelter’s syndrome (KS) in patients with gynecomastia, to observe any differences in clinical presentation of KS from those reported in the literature, and highlight the needed diagnostic work-up and treatment.Gynecomastia is an enlargement of male breast resulting from a proliferation of its glandular component. It is usually benign, bilateral, and characterized by the presence of a rubbery or firm mass around the nipples. It usually results from either increased estrogen level, increased breast sensitivity to estrogen,1 or low testosterone level. The highest incidence of gynecomastia is reported during neonatal period, puberty, and aging due to physiological disturbances. Pseudogynecomastia, which is often seen in obese men, refers to fat deposition without glandular proliferation and should be differentiated from gynecomastia. Therefore, male breast enlargement can be fatty (pseudogynecomastia or lipomastia), pure gynecomastia, or mixed. Our objective in presenting this particular case is to create awareness of the occurrence of Klinefelter’s syndrome (KS) in patients with gynecomastia, to observe any differences in clinical presentation of KS from those reported in the literature, and highlight the needed diagnostic work-up and treatment.