Determination of Positivity of Computed Tomographic Angiography in Poorly Visualized Left Anterior Descending Artery on Conventional Angiography.

OBJECTIVE: To determine the positivity of CT angiography in visualization of poorly visualized left anterior descending artery (LAD) on conventional angiography for decision of its surgical revascularization. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Department of Cardiac Surgery, Faisalabad Institute of Cardiology, Faisalabad, from July 2014 to March 2015. METHODOLOGY: This study involved 55 patients who had non-graftable LAD on conventional coronary angiography (CCA). All patients underwent computed tomography angiography (CTA). Patients having graftable LAD on CTA then underwent coronary artery bypass grafting (CABG). Peroperatively, the characteristics of LAD such as diameter, calcification and graftability were also recorded. RESULTS: The mean age of the patients was 52.76 ±8.52 years. There were 45 (81.8%) male and 10 (18.2%) female patients. Out of 55 patients, CTA revealed graftable LAD in 33 (60%) cases while LAD was non-graftable in 22 (40%) cases. Out of 33 patients having graftable LAD, 26 (78.79%) patients underwent CABG; whereas, remaining 7 (21.21%) patients had different reasons like other associated diseases and refusal from surgery. Among those who underwent surgery, LAD was graftable in all the patients (100%) peroperatively. Peroperatively 11 (42.3%) patients had mild calcification followed by severe calcification in 9 (34.6%) and moderate calcification in 6 (23.1%) cases. Fifteen (57.7%) patients had LAD caliber >1.5 mm while 11 (42.3%) patients had LAD caliber between 1.25 - 1.5 mm peroperatively. CONCLUSION: Positivity of the CT angiography for poorly visualized LAD on conventional angiography was 60% in the present study.

Mechanisms of intracellular calcium homeostasis in developing and mature bovine corpora lutea.

Although calcium (Ca(2+)) is accepted as an intracellular mediator of prostaglandin F2 alpha (PGF2alpha) actions on luteal cells, studies defining mechanisms of Ca(2+) homeostasis in bovine corpora lutea (CL) are lacking. The increase in intracellular Ca(2+) concentration ([Ca(2+)]i) induced by PGF2alpha in steroidogenic cells from mature CL is greater than in those isolated from developing CL. Our hypothesis is that differences in signal transduction associated with developing and mature CL contribute to the increased efficacy of PGF2alpha to induce a Ca(2+) signal capable of inducing regression in mature CL. To test this hypothesis, major genes participating in Ca(2+) homeostasis in the bovine CL were identified, and expression of mRNA, protein, or activity, in the case of phospholipase Cbeta (PLCbeta), in developing and mature bovine CL was compared. In addition, we examined the contribution of external and internal Ca(2+) to the PGF2alpha stimulated rise in [Ca(2+)]i in LLCs isolated from developing and mature bovine CL. Three differences were identified in mechanisms of calcium homeostasis between developing and mature CL, which could account for the lesser increase in [Ca(2+)]i in response to PGF2alpha in developing than in mature CL. First, there were lower concentrations of inositol 1,4,5-trisphosphate (IP3) after similar PGF2alpha challenge, indicating reduced phospholipase C beta (PLCbeta) activity, in developing than mature CL. Second, there was an increased expression of sorcin (SRI) in developing than in mature CL. This cytoplasmic Ca(2+) binding protein modulates the endoplasmic reticulum (ER) Ca(2+) release channel, ryanodine receptor (RyR), to be in the closed configuration. Third, there was greater expression of ATP2A2 or SERCA, which causes calcium reuptake into the ER, in developing than in mature CL. Developmental differences in expression detected in whole CL were confirmed by Western blots using protein samples from steroidogenic cells isolated from developing and mature CL. Localization of these genes in steroidogenic luteal cells was confirmed by immunohistochemistry. Therefore, it is concluded that the cellular mechanisms that allow PGF2alpha to induce a calcium signal of greater magnitude in mature than in developing CL involve 1) greater PLCbeta activity with enhanced generation of IP3, 2) an enhanced Ca(2+) release from the ER via unrestrained RYR2 due to a decrease in SRI expression, and 3) a reduction in calcium reuptake to the ER due to lower expression of ATP2A2. Accordingly, the increase in [Ca(2+)]i induced by PGF2alpha in mature large steroidogenic cells had less dependency from extracellular calcium than in those isolated from immature CL.

Grewialin and optivanin new constituents from the stem bark of Grewia optiva Drummond ex Burret (Tiliaceae).

Studies on the chemical constituents from the stem bark of Grewia optiva have led to the isolation of two new compounds, grewialin (1) and optivanin (2), along with three known constituents which were hitherto unreported from this species. The structures of the new constituents have been elucidated by spectral studies including 1D and 2D NMR experiments (HSQC, HMBC, COSY, NOESY and J-resolved) as well as HR EI-MS spectroscopic data analysis, as 2S*-(3-hydroxy-4-methoxyphenyl)-3R*-methyl-2H-[1,4]-dioxin [2,3]-chromen-7(3H)-one (1); a coumarinolignan and 3-hydroxy-1-(3-hydroxy-4-methoxyphenyl) propan-1-one (2). The known compounds were identified as ß-sitosterol, stigmasterol and lupeol by comparing their spectral data with those reported in the literature.

Studying wedge factors and beam profiles for physical and enhanced dynamic wedges.

This study was designed to investigate variation in Varian's Physical and Enhanced Dynamic Wedge Factors (WF) as a function of depth and field size. The profiles for physical wedges (PWs) and enhanced dynamic wedges (EDWs) were also measured using LDA-99 array and compared for confirmation of EDW angles at different depths and field sizes. WF measurements were performed in water phantom using cylindrical 0.66 cc ionization chamber. WF was measured by taking the ratio of wedge and open field ionization data. A normalized wedge factor (NWF) was introduced to circumvent large differences between wedge factors for different wedge angles. A strong linear dependence of PW Factor (PWF) with depth was observed. Maximum variation of 8.9% and 4.1% was observed for 60 degrees PW with depth at 6 and 15 MV beams respectively. The variation in EDW Factor (EDWF) with depth was almost negligible and less than two per cent. The highest variation in PWF as a function of field size was 4.1% and 3.4% for thicker wedge (60 degrees ) at 6 and 15 MV beams respectively and decreases with decreasing wedge angle. EDWF shows strong field size dependence and significant variation was observed for all wedges at both photon energies. Differences in profiles between PW and EDW were observed on toe and heel sides. These differences were dominant for larger fields, shallow depths, thicker wedges and low energy beam. The study indicated that ignoring depth and field size dependence of WF may result in under/over dose to the patient especially doing manual point dose calculation.