Spherical Dilatation Research Articles

Right Ventricular Spherical Dilatation Combined with Pulmonary Artery Compliance Predicts Severe-Acute Right Heart Failure after LVAD Implantation

Background Right heart failure (RHF) remains a major contributor to morbidity and mortality after left ventricular assist device (LVAD) implantation. Our ability to predict which patients are at highest risk for RHF remains limited. Pulmonary artery compliance (PAC), as a measure of right ventricular (RV) pulsatile load, is associated with RHF after LVAD. We hypothesized that the addition of RV spherical dilatation, which indexes the RV response to load, could further characterize the risk of post LVAD RHF. Methods We retrospectively studied 144 patients who underwent durable LVAD between 2009 and 2018 at our center and had both preoperative echocardiographic and hemodynamic data. RV spherical dilatation (RVs) was indexed by the RV basal short axis length in the apical 4-chamber view. PAC was calculated as SV/(PASP-PADP) and was indexed to body surface area to generate PACi. We generated a new composite variable, the Sphericity Index (SpI), where SpI = RVs/PACi; higher SpI values indicate more composite RV dilatation and pulsatile load. RHF was defined per INTERMACS classifications, with Severe RHF being ≥14d postoperative inotrope dependence and Severe-Acute RHF being need for RVAD or death from RHF. Multivariate logistic regression modeling was used to assess the relationship between SpI and PACi to both Severe and Severe-Acute RHF. Results Forty patients (27.8%) developed Severe RHF and 14 patients (9.7%) developed Severe-Acute RHF. Median PACi and SpI were 0.72 ml/mmHg/m2 (IQR 0.44 ml/mmHg/m2) and 1.62 cm*mmHg/ml/m2 (IQR 1.04 cm*mmHg/ml/m2), respectively. Lower PACi (OR 0.16 [0.04-0.64], p = 0.01) and higher SpI (OR 1.79 [1.12-2.83], p = 0.01) were associated with Severe RHF, adjusted for INTERMACS profile and heart rate. However, only SpI was associated with Severe-Acute RHF (OR 2.69 [1.44-5.00], p = 0.002), whereas PACi did not reach significance (p = 0.06). Conclusion SpI, a composite index combining RV spherical dilatation and PACi, characterizes both RV load and response to load and may predict Severe-Acute RHF after LVAD better than PACi alone.

Post myocardial infarction left ventricular dysfunction – Assessment and follow up of patients undergoing surgical ventricular restoration by the endoventricular patchplasty

Authors of this important article by D'Mello et al, have nicely presented a prospective study of clinical and echocardiographic follow up of Left Ventricular (LV) geometry of 59 consecutive patients with previous transmural anterior myocardial infarction, who underwent LV restoration, analyzed between June 2007 and May 2008.1 The authors are to be complemented for this important series which showed excellent immediate and short-term results following LV restoration surgery. The results show a progressive remodeling after ventricular reconstruction mainly by excluding the scar area. Volume reduction is more important than the post surgical shape of the ventricle. The study was done before the MRI era; and hence the images of the scar are not demonstrated in the study.2,3 Analysis of the precise mechanism of remodeling is perhaps not possible without MRI. Distinction between dyskinetic and akinetic forms of the scar are not clearly brought out; it is usually transmural with dyskinesia and subendocardial with akinesia. The size of a synergy and its extension determine the extent of remodeling.4,5 It is surprising that these 59 patients were not severe cases of ischemic failing ventricle, as the mean ejection fraction was 33.5 ± 5%, preoperative end diastolic volume index 89.7 ± 6 and end systolic volume index 48.8 ± 11.3 which are below the threshold of very severe cardiac failure. White et al have given a figure of >60 ml of end systolic volume index as the major determinant of survival after recovery from myocardial infarction.6 This work is indeed of great interest and I hope the authors with their experience will present more severe cases showing a positive interest in LV reconstruction and thereby demonstrating that the S.T.I.C.H trial was a miss organized trial.7 The global approach of heart failure by Buckberg cannot be accepted; it is apparent that Buckberg is a prisoner of his “flying fancies” trying to establish something without any serious base.7 The myocardial systolic contraction is a “twist up” like a “snake” ascension. The crux of the problem of systolic heart failure is the ventricular spherical dilatation whatever be the anatomic substrate. The surgical ventricular restoration (S.V.R) or surgical anterior ventricular restoration (S.A.V.R) are acronyms in place of left ventricular reconstruction (L.V.R.) because this technique is applied most of time only for anterior LV wall, with the objective of “volume reduction” and to get an elliptical shape of LV. Finally, I would like to emphasize the following points: Ventricular wall has a systolic concentric (centripetal contraction) confirmed by MRI video examination of left ventricular wall in 4 projections.8 Heart failure is not an entity but a syndrome with various causes; in post myocardial infarction failure, the cause is an extension of the necrotic, then fibrous and finally calcified transmural or subendocardial scar, when it reaches = or <30% of LV perimeter. The dilatation is not the cause, but the consequence; dilatation is more ovoid than spherical. LVR as proposed by as in 1984, have these main goals: to suppress or exclude the scarred asynergic wall, to abolish the mechanism of progressive dilatation i.e. the eccentric systolic motion, restoring the curvature of non-infarcted myocardium and maintain the physiological diastolic volume of the rebuilt cavity by balloon sizing before “clothing” of the cavity by a patch anchored on contractile edge of normal myocardium.9 In conclusion, this article by D'Mello et al demonstrates and emphasizes the modern approach toward post myocardial infarction heart failure which is a very prevalent disease encountered in day to day clinical practice.

Analytical solution of the thermoelasticity problem in a pressurized thick-walled sphere subjected to transient thermal loading

The thermoelasticity problem in a thick-walled sphere is solved analytically using finite Hankel transform. Time-dependent boundary conditions are prescribed on the inner surface of the sphere, where for the mechanical boundary conditions the tractions are prescribed on both the inner and the outer surfaces of the hollow sphere. Obtaining the distribution of the temperature throughout the sphere, the quasi-static and the dynamical structural problem is solved and closed-form relations are derived for stress components. On solving the dynamical thermoelasticity problem, a thermal shock was observed after plotting the results. Using the obtained plots, the velocity of the spherical dilatation wave is computed and compared with the one from the classical formula and the results are compared with those in the literature, where possible.

Spherical dilatation of the apex in failing left ventricles: A target for surgical remodelling techniques

Aims: The present study investigates the geometry of failing left ventricles with a special focus on apical deformation. A new surgical remodelling technique is evaluated. Methods: In 124 patients with impaired left ventricular function undergoing CABG the geometry of the left ventricle (LV) was evaluated by MRI scanning. Besides the conventional sphericity index SI two further indices were calculated, a length index (LV lengthsyst/LV lengthdiast) and an apical conicity index (apical axis/short axis). The results were compared to 15 patients with CHD and normal LV function and 10 test persons. Perpendicular apical compression stitches were placed in 35 patients; a second MRI was performed to compare the remodelling to preoperative geometry and to patients without remodelling. Results: In failing left ventricles LV length increased (5.3±0.6cm/m2 vs. 4.7±0.8cm/m2 in control patients and 4.6±0.3cm/m2 in test persons). Longitudinal shortening was also elevated (0.94±0.04 versus 0.78±0.06 and 0.81±0.07). The classical systolic SI was 0.56±0.06 in heart failure patients, 0.50±0.05 in control patients and 0.48±0.04 in test persons. The apical conicity indices were 0.71±0.08, 0.59±0.07 and 0.58±0.06 respectively, thus the deformation was more pronounced at the apex. A significant remodelling was achieved in the apical stitch patients. The length index improved to 0.85±0.1, the apical index to 0.62±0.06. Conclusions: Besides global dilatation failing left ventricles in CHD patients demonstrated elongation and reduction in longitudinal contractility as well as pronounced apical dilatation with spherical deformation. An apical remodelling stitch was able to normalize ventricular geometry.

GKS Decomposition and Spherical Dilations

Using the generalized version of the classical F. and M. Riesz Theorem as given by Gliksberg, König, and Seever, we obtain a few decomposition theorems for tuples of commuting operators on Hilbert spaces that admit normal dilations whose joint spectra are contained in the unit sphere of Cn. Our results apply in particular to sphericaln-hypercontractions, subnormaln-tuples whose joint spectra are contained in the closed unit ball of Cn, and to spherical isometries. The questions related to the uniqueness of decompositions are addressed by appealing to a specialized version of an approximation result related to the solution of the inner function problem on the unit ball of Cn. The Henkin measures on the unit sphere play a central role in the development of the relevant theory.

Morphological evidence for a single bacterial etiology in Texas necotizing hepatcpanceatitis in Penaeus vannamei (Crustacea. Decapoda)

Morphological evidence for a single bacterial etiology in Texas necotizing hepatcpanceatitis in Penaeus vannamei (Crustacea. Decapoda)

Rickettsial and mollicute infections in hepatopancreatic cells of cultured Pacific white shrimp ( Penaeus vannamei)

Infections by multiple species of bacteria occurred in hepatopancreatic epithelial cells of cultured Pacific white shrimp ( Penaeus vannamei). Grossly, hepatopancreases of moribund shrimp were pale white. Light microscopically, hepatopancreatic tubules appeared atrophied and were associated with granulomas. Examination by scanning and transmission electron microcopy revealed heavy cytoplasmic infections by three forms of microorganisms: (1) a rickettsia-like bacterium, (2) a helical form of a mollicute-like bacterium, and (3) a filamentous mollicute-like bacterium. The rod-shaped rickettsia (900 nm long by 300 nm wide) appeared to be free in the cytoplasm and had both a plasma membrane and a cell wall. Neither form of mollicute possessed a cell wall. The helical mollicute was blunt at its wide end (about 260 nm in diameter) where it contained electronlucent bodies. Helical turns along its tapered axis resembled those of a spiroplasma (the only helical form of mycoplasma in the class Mollicutes) or a spirochete. The helical bacterium did not possess periplamic flagella characteristic of spirochetes, which lends support to its being a type of spiroplasma. The filamentous mollicute consisted of masses of short, branched filaments 60 nm wide with intermittent spherical dilations and terminal blebs on the branches. The presumed mollicutes have not been reported previously in crustaceans. Each bacterium, or concurrent infections of the bacteria, are pathogenic to cultured shrimp, could impact culture operations and thus deserve more study.

Development of spherical organelles from the endoplasmic reticulum in the nucellus of some Euphorbia species

The development of characteristic cytoplasmic inclusions from endoplasmic-reticulum (ER) cisternae in nucellar cells of some species of Euphorbia has been studied by electron microscopy. The formation of these organelles is preceded by the appearance of rough ER cisternae filled with an electron-dense material and forming complicated networks. Vesicular structures are formed which grow rapidly to give electron-dense, spherical dilations. On the outer surface of their limiting membrane numerous ribosomes and often polysomes are present. This membrane can be seen to remain continuous with the membranes of one or more cisternae of the rough ER up to when the dilations have a maximum diameter of 2.5-3 μ. At this time, continuity between the ER cisternae and the spherical dilations ceases. After this the new cell organelles remain unchanged in size, shape, and electron-density until the cell is disintegrated by the growing embryo-sac. The fate of the contents of these organelles is discussed.

A Unified Approach to Cylindrical and Spherical Elastic Waves by Method of Characteristics

A set of generalized equations is presented which governs the propagation of plane, cylindrical, and spherical dilatation waves in elastic media. The corresponding characteristic equations are then derived, including the propagation of abrupt changes (discontinuous wave fronts). Procedures of numerical integration along the characteristic directions are established and carried out for several examples on a digital computer. The solutions of four of the specific examples calculated show excellent agreement with existing solutions by other methods.

Bilateral Ureterocele

THE FOLLOWING case of bilateral ureterocele is believed to be of interest because it further confirms the very favorable— in this case dramatic—results 0 btained with conservative transurethral fulguration. In addition, it was possible to obtain very satisfactory roentgenograms of the anomalies by a modification of the routine method. The diagnostic and therapeutic measures were performed aboard a United States Navy Hospital Ship. A ureterocele is a saccular dilatation of the lower end of the ureter into the bladder. It is usually considered to be the result of increased intraureteral pressure acting against a combination of two congenital anomalies: atresia or stenosis of the ureteral orifice and a deficiency of connective-tissue attachment (Waldeyer's sheath) of the ureter to the bladder. The characteristic roentgen finding in ureterocele is a cystic ballooning or spherical dilatation of the lower end of the ureter as seen on intravenous urography or retrograde pyelography. The cystogram may show a spherical filling defect in the region of the ureteral orifice. In addition, evidence of obstructive uropathy, including dilatation of the renal pelvis and blunting and clubbing of the calices, may be noted on the affected side. While ureteroceles are relatively frequent urological anomalies Herman (5) states that they are bilateral in only 10 per cent of cases. Gutierrez (4) and Thompson and Greene (7) have shown that for the ureterocele of average size transurethral fulguration through the entire thickness of its wall is a satisfactory method for enlarging the stenosed ureteral orifice. It is also the consensus of opinion that with bilateral ureteroceles only one should be treated at a time. Case Report An 18-year-old white seaman was admitted to the urological service of the hospital ship from an aircraft carrier on March 1, 1947, complaining of “blood in the urine” of seven days duration. He gave a history of intermittent gross hematuria accompanied by burning but no pain. The blood was described as being throughout the urinary stream. No blood clots were observed. Four days before admission the bleeding stopped spontaneously. At that time a vague suprapubic discomfort was noticed. Nearly two years earlier the patient had an acute non-specific urethritis, which was treated successfully with sulfadiazine. For the past year he had had slight difficulty initiating the urinary stream. The family history revealed that his mother had “kidney disease” many years ago, from which she had apparently recovered uneventfully. On admission to the hospital ship, the patient was completely asymptomatic except for slight difficulty in starting the. urinary stream. The only positive finding on physical examination was a slightly boggy left lateral lobe of the prostate, indicating a lowgrade chronic prostatitis.

The Development of the Monotremata.—Part V. Further Observations on the Histology and the Secretory Activities of the Oviduct prior to and during Gestation.

<i>The Development of the Monotremata.</i>—Part V. <i>Further Observations on the Histology and the Secretory Activities of the Oviduct prior to and during Gestation.</i>