Modeling and Mathematical Investigation of Blood-Based Flow of Compressible Rate Type Fluid with Compressibility Effects in a Microchannel

In this investigation, the compressibility effects are visualized on the flow of non-Newtonian fluid, which obeys the stress-strain relationship of an upper convected Maxwell model in a microchannel. The fundamental laws of momentum and mass conservation are used to formulate the problem. The governing nonlinear partial differential equations are reduced to a set of ordinary differential equations and solved with the help of the regular perturbation method assuming the amplitude ratio (wave amplitude/half width of channel) as a flow parameter. The axial component of velocity and flow rate is computed through numerical integration. Graphical results for the mean velocity perturbation function, net flow and axial velocity have been presented and discussed. It is concluded that the net flow rate and Dwall increase in case of the linear Maxwell model, while they decrease in case of the convected Maxwell model. The compressibility parameter shows the opposite results for linear and upper convected Maxwell fluid.

Clinical and echocardiographic features of valvular aneurysms

Funding Acknowledgements

Type of funding sources: None.

Introduction

 Valvular aneurysm (VA) is a rare disease whose etiology most frequently includes infective endocarditis but also connective tissue or degenerative myxomatous diseases or traumatism related to a remote surgical procedure. Purpose: Our study aims to describe clinical and echocardiographic features of VA. Methods:  12 years retrospective observational study. Inclusion criteria: patients (pts) found to have a VA by echocardiography (E). A VA was defined as a saccular bulging or a cyst-like outpouching of a valve leaflet that expands and collapses during systole or diastole. The ability of different E techniques in imaging and sizing the valve aneurysm and clinical data were collected. Results: In a 12 years observational period, 12 pts (7 male, 5 female) with a mean age of 41 years ± 16.6 were found to have VA as diagnosed by two experienced readers. In 10 pts there was a diagnosis of IE according to the ESC, AHA criteria. In two pts IE work up was negative. In the patient with definite IE, blood cultures were reported as positive in 7/10 pts (staphylococci 4 pts, Pseudomonas 2 pts, clostridium difficile 1) and 9 pts out of 10 pts underwent surgery and 1 died; all of them had valve replacement except one had mitral valve (MV) repair. Severe regurgitation was found in 9 cases. Associated IE features were: perforation (11 pts), abscess (3pts), vegetation (7pts), fistula (1pt), and embolism (6 pts). Echo features are reported in table 1. Transthoracic E was able to image the VA in only 3/12 pts. Discussion: The spectrum of the VA in our cohort is very unusual. We reported a VA in a bioprosthesis MV not IE related and never described, one case of valvular aneurysm in a bicuspid aortic valve, and 2 cases in the posterior mitral leaflet (PML). The etiology of VA was related to IE as the leading cause (ten in our cohort). In the two pts where no IE was diagnosed, the possible pathogenesis in one patient may have been related to a remote surgical procedure (left atrial dissection) and in the second patient to degenerative phenomena of the MV bioprosthesis. Being the imaging uncommon, it is important to not misinterpret the VA features with large vegetations, cystic lesions, and abscess. Conclusion:  In our series, both the typical spectrum of the disease and less common presentations have been found. We reported one of the largest series of VA with never described unusual presentation. 2-dimensional (D) transesophageal E (TEE) was the key E modalities in the diagnosis integrated by 3D TEE allowing an anatomical imaging useful in surgical decision planning. Almost all cases were associated with perforation and severe regurgitation and a high incidence of embolism. All the cases with IE required surgery except one that died while medical therapy and follow up in the other etiologies . The unusual echocardiographic features have to be as early as possible detected in order to let the patient have the best therapeutical interventions. Abstract Table 1: Echocardiographic features  Abstract Figure. Valvular aneurysm imaging

Dietary fat intake, circulating and membrane fatty acid composition of healthy Norwegian men and women

BACKGROUND

The present study aimed to assess the dietary fat intake and blood fatty acid status of healthy Norwegian men and women living in Bergen whose habitual diet is known to be high in long-chain omega-3 fat.

METHODS

Healthy men (n = 41) and women (n = 40) aged 20-50 years who were regular blood donors completed 7-day food diaries and their nutrient intake was analysed by Norwegian food database software, kbs, version 4.9 (kostberegningssystem; University of Oslo, Oslo, Norway). Blood samples were obtained before blood donation and assessed for the fatty acid composition of plasma triglycerides and cholesterol esters, phosphatidylcholine, and red cell phosphatidylcholine and phosphatidylethanolamine.

RESULTS

There was no difference in dietary fat intake between men and women. Total and saturated fat intakes exceeded the upper limits of the recommendations of the National Nutrition Council of Norway. Although polyunsaturated fat intake was close to the lower limit of the recommended level, the intake varied greatly among individuals, partly as a result of the use of supplementary fish oil. Moreover, the proportional fatty acid composition of plasma and red cell lipids was similar between men and women. Enrichment of docosahexaenoic acid in red cell phosphatidylethanolamine was found in fish oil users.

CONCLUSIONS

The results of the present study provide a snapshot of the current nutritional status of healthy Norwegian adults. Moreover, the detailed blood fatty acid composition of men and women whose habitual diet constitutes high long-chain polyunsaturated omega-3 fat as well as saturated fat could be used as reference value for population studies.

Application of CO-Foam as a Means of Reducing Carbon Dioxide Mobility

Abstract

Reducing the mobility of carbon dioxide through co-injection of CO2 and a suitable surfactant solution to form a CO2-foam system is a promising method for improving the oil recovery in carbon dioxide flooding projects. This paper presents the results of a set of experiments on screening and selecting a suitable surfactant for CO2 -foam purposes in a carbonate porous medium, as well as the effect of various parameters on the mobility of the CO2-foam system.

Four surfactants were examined and the one that performed best throughout the screening experiments was used in the subsequent flow experiments. The surfactants tested were Surfonic N- 95, Surfonic L24–9, Bio-Terge AS-40, and Chaser CD-1045. The screening criterion selected was the fall in foam height with time at 60 ° C for 0.1 wt% solution of the above mentioned surfactants. Chaser CD-1045 performed best in all screening tests and was used during the flow experiments.

Flow experiments were conducted through a porous medium made of crushed carbonate at pressures of 8,270 kPa and 10,336 kPa, and temperatures of 22 ° C and 50 ° C. Mobility of CO2 -brine (simulating the WAG process) and CO2-surfactant systems were compared through a series of experiments. The effect of operating pressure and temperature, brine concentration, and the ratio of the amount of CO2 to total foam (i.e., foam quality) on the mobility of a CO2-foam system were investigated and results are presented. The results indicate that additional oil is recoverable for CO2-foam vs. the co-injection of CO2 and brine simulating the WAG process.

Introduction

From the pore-scale point of view, dense carbon dioxide is an ideal displacement fluid for many crude oils because it can achieve miscibility with oil through a multi-contact miscibility process under the pressure and temperature conditions of a wide range of reservoirs. However, even when pressure conditions for miscibility are met, this high microscopic sweep efficiency is not often approached in reservoir operations due to the non-uniformity of the flow patterns. Large-scale reservoir heterogeneities, such as fractures or high-permeability streaks, cause early breakthrough of injected carbon dioxide, which will reduce oil recovery efficiency.

One effective way of increasing the ultimate oil recovery under CO2 flooding conditions is by reducing the mobility of the injected carbon dioxide. The most common method for achieving this goal is through the injection of slugs of CO2 and water alternatively (i.e., the WAG process). During the WAG process, water reduces the mobility of carbon dioxide; but it also traps oil, increases water flow, and decreases extraction of hydrocarbons from oil by carbon dioxide(1).

Another method for reducing the mobility of carbon dioxide is the CO2-foam technique. In this method, a surfactant solution is injected along with carbon dioxide into the reservoir. This combination forms foam in the reservoir, and the presence of foam reduces the mobility of carbon dioxide considerably. However, for any CO2 -foam project, there are challenges that must be met.

Regulators of apoptosis in human breast cancer

OBJECTIVES

Apoptosis or programmed cell death represents a mechanism by which tumor cells with DNA damage can be deleted. Bcl-2 and p53 gene products have been both linked to apoptosis. Bcl-2 plays a role as an inhibitor of apoptosis that may extend the viability of cells containing genetic alterations and facilitate tumor progression. Mutant p53 has a similar effect. The purpose of this study was to investigate expression of bcl-2 in 70 malignant and 30 benign breast lesions using different methods (enzyme immunoassay, immunodot blot, Western blot) and to compare it with the established clinicopathological prognostic factors (age, tumor size, type, grade, lymph node status) and some molecular genetic markers in breast cancer.

RESULTS

bcl-2 and mutant p53 were highly expressed in breast cancer than benign breast lesions and aneuploidy was more frequently detected in malignant breast samples. No correlation could be observed between bcl-2 expression and node status, tumor size, differentiation, type, age at excision or mutant p53 expression. However, a strong positive associations were seen between bcl-2 and estrogen receptors (ER), DNA aneuploidy. Eighty-five percent of bcl-2 positive tumors were ER positive and 65% were aneuploid, while in bcl-2 negative tumors only 28% were ER positive and 37% were aneuploid.

CONCLUSIONS

The association seen between bcl-2 and ER raises the possibility that bcl-2 is an ER-regulated gene which suggests a potential important role for bcl-2 as a modulator of response to hormonal therapy in breast cancer. Monitoring hormonal therapy can easily be done by bcl-2 quantitative EIA method.

Increased atrial natriuretic factor receptor density in cultured vascular smooth muscle cells of the spontaneously hypertensive rat

To explore the role of the atrial natriuretic factor (ANF) system in the pathophysiology of hypertension we examined the binding kinetics of synthetic ANF to cultured vascular smooth muscle cells (VSMCs) derived from the spontaneously hypertensive rat (SHR) and two normotensive controls-the Wistar Kyoto (WKY) and American Wistar (W). The number of maximal binding sites (Bmax) per cell (mean +/- SEM; X10(3] were: SHR = 278.0 +/- 33.0, WKY = 28.3 +/- 7.1 and W = 26.6 +/- 4.2. The differences between the SHR and normotensive strains were significant at p less than 0.001. The equilibrium dissociation constant (Kd; X 10(-9)M) was higher in SHR VSMCs (0.94 +/- 0.14) than in WKY (0.22 +/- 0.09; p less than 0.01) and W (0.39 +/- 0.14; p less than 0.02) cells. The plasma levels of the immunoreactive ANF were higher in SHR than the normotensive controls. We suggest that the relatively greater ANF receptor density in cultured VSMCs of the SHR represents a response to the in vitro environment which is relatively more deficient in ANF for VSMCs of the SHR as compared with the normotensive rats. Thus, the capacity of the SHR VSMC to regulate ANF receptor density appears to be independent of the blood pressure level.

Na+-K+ regulation in cultured vascular smooth muscle cell of the spontaneously hypertensive rat

Na+-K+ passive transport and activity of the Na+ pump were examined in serially passed cultured vascular smooth muscle cells originating from spontaneously hypertensive (SH), Wistar-Kyoto (WKY), and Wistar (W) rats. Measurements included 22Na+ and 86Rb+ (K+ analogue) uptake and washout rate constants as well as intracellular Na+ and K+ levels. The aforementioned variables were studied in cells subjected to either 2 mM Ca2+ or Ca2+-deficient media. In 2 mM Ca2+ medium, SH rat cells demonstrated the highest exchange (uptake and washout) rate constants for Na+ and Rb+ (K+) among cells of the three rat strains. At this extracellular Ca2+ concentration, the Na+ pump activity of SH rat cells was higher than that of WKY rat cells and was not different from that of W rat cells. Incubation in Ca2+-deficient medium resulted in increased magnitudes of Rb+ washout and Na+ uptake rate constants in all cell preparations associated with elevated intracellular Na+ concentrations and augmented activity of the Na+ pump. Under this condition, cells derived from SH rats showed the highest Na+ uptake and Rb+ washout rate constants associated with the highest Na+ pump activity. The increase in intracellular Na+ level in Ca2+-deficient medium was the highest in SH rat cells. These findings show that innate membrane defects and the response of the Na+ pump to these abnormalities can be demonstrated in in vitro-grown vascular smooth muscle cells of the SH rat.

Ouabain binding to cultured vascular smooth muscle cells of the spontaneously hypertensive rat

The binding of ouabain and K+ to the Na+ pump were analyzed in serially passed cultured vascular smooth muscle cells (VSMCs) originating from spontaneously hypertensive (SH), Wistar-Kyoto (WKY), and American Wistar (W) rats. Our techniques have utilized analyses of displacement of [3H]ouabain by both unlabeled ouabain and K+ from specific binding sites on the VSMCs. We have found that each of the VSMC preparations from the three rat strains appeared to demonstrate one population of specific ouabain receptors (Na+ pumps); the number of Na+ pump units (mean +/- SE, expressed as 10(5) units/cell; number of observations indicated in parentheses) of both the SH and WKY rats was significantly lower than the number of Na+ pump units of W rat VSMCs [SH: 3.00 +/- 0.02 (231), WKY: 2.87 +/- 0.05 (245), and W: 3.62 +/- 0.04 (225)]; the equilibrium dissociation constant values (microM) for ouabain in VSMCs of SH and WKY rats were similar but were significantly higher than that of VSMCs derived from W rats [SH: 4.69 +/- 0.09 (231), WKY: 4.57 +/- 0.12 (245), and W: 3.69 +/- 0.17 (225)]; and among the VSMCs originating from the three rat strains, the apparent equilibrium dissociation constant value for K+ (mM) was the lowest in those of the SH rat [1.04 +/- 0.003 (143), compared with VSMCs of the WKY rat [1.54 +/- 0.006 (135)] and W rat [1.19 +/- 0.003 (136)]. Our previous studies have demonstrated increased passive Na+ and K+ transport rate constants of SH rat VSMCs compared with either W or WKY rat cells. These findings suggest the possibility of higher permeabilities of the SH cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of metabolically active B12 and inactive B12 analog titers in human blood using several microbial reagents and a radiodilution assay

Metabolically active B12 analogs and inactive B12 analogs were measured in plasma, red blood cells (RBC), and pooled pernicious anemia serum. B12 values by Lactobacillus leichmannii, Escherichia coli, Euglena gracilis, and radioisotope dilution method (RIDA) as assays for total B12 (active analogs + inactive analogs) were compared to Ochromonas malhamensis values as index of only metabolically active B12. B12 values above those with O malhamensis distinguished inactive analogs from active B12. Inactive analogs contribute 85, 97, 135, and 163% above active B12 activity in normal plasma when E gracilis, L leichmannii, RIDA, and E coli, respectively, were used for B12 analysis. RIDA B12 determinations for active B12 in plasma showed that 44% of the B12 measured was still due to inactive analogs when compared to O malhamensis B12 activity. Inactive B12 analogs contributed 21, 151, and 224% above O malhamensis active B12 in RBC when E gracilis, L leichmannii, and E coli, respectively, were used.

Cultured rat vascular smooth muscle cells: extracellular calcium and Na+-K+ regulation

This study explores the relationship between extracellular calcium (Cao) and Na+-K+ regulation as it particularly pertains to the activity of the Na+ pump in cultured vascular smooth muscle cells (VSMCs) originating from Sprague-Dawley rats. As compared with cells incubated in media containing 0.5, 2.0, or 4.0 mM calcium, when the Na pump is active, VSMCs incubated in a Ca-deficient medium show a marked increase in intracellular sodium and no significant change in intracellular potassium. Associated with the rise in intracellular sodium there is an augmented activity of the Na pump. When the Na pump is inhibited, VSMCs incubated in either high-Ca medium (Cao = 4.0 mM) or Ca-deficient medium manifest a greater decline in intracellular potassium than cells incubated in media containing 0.5 or 2.0 mM calcium. Furthermore, when the Na pump is inhibited, VSMCs incubated in a Ca-deficient medium exhibit higher intracellular sodium levels in comparison with their counterparts incubated in media containing calcium. Flux experiments indicate that the aforementioned changes reflect increased membrane permeabilities to Na+ and K+. It is concluded that by regulating the permeability of the VSMC membrane, Cao plays an important role in the intracellular Na+-K+ homeostasis and that its effect on the Na pump is mediated via perturbations in the intracellular Na+ and K+ concentrations.

[3H]ouabain binding to cultured rat vascular smooth muscle cells

The number of Na+ pump units (Bmax) and the equilibrium dissociation constant (Kd) for ouabain as well as parameters of K+ binding to the Na+ pump were examined in in vitro-grown vascular smooth muscle cells ( VSMC ) derived from Sprague-Dawley rats. The technique to measure these variables utilizes analyses of [3H]ouabain displacement from its VSMC receptors by nonlabeled ouabain and K+. The mean values for Bmax and Kd in the cultured VSMCs were 1.95 X 10(5) receptor sites per single VSMC and 2.68 X 10(-6) M, respectively. The equilibrium dissociation constant for K+ (Ki) was 0.92 mM. K+ binding to the cultured VSMCs demonstrated positive cooperativity with a Hill coefficient (n) of 1.78.

Vanadate effect on the Na,K-ATPase and the Na-K pump in in vitro-grown rat vascular smooth muscle cells

The impact of vanadate on the Na,K-ATPase system in the vascular smooth muscle cell is poorly understood. The present study describes the kinetics of the effect of vanadate on Na,K-ATPase and the Na-K pump in in vitro grown rat VSMC's. Vanadate interaction with the Na,K-ATPase system in vascular smooth muscle cells was examined by observing its influence on ouabain-sensitive adenosine triphosphate hydrolysis in disrupted cells rendered permeable by osmotic shock, and the uptake of rubidium by intact cells. The I50 for vanadate inhibition of ouabain-sensitive hydrolysis of adenosine triphosphate occurred at vanadate concentrations of 10(-6) to 10(-7) M. This inhibition was potassium dependent. The maximal inhibitory effect of vanadate occurred at potassium concentrations of 10-20 mEq/liter. Sodium exerted a moderate antagonistic influence on vanadate inhibition of ouabain-sensitive adenosine triphosphate hydrolysis. Rubidium uptake by vascular smooth muscle cells was not altered within 120 minutes when 10(-5) M vanadate was added to the medium containing intact vascular smooth muscle cells. Yet, vanadium concentrations in the vascular smooth muscle cells within this incubation period reached levels 1.48-fold higher than the extracellular vanadate concentrations of 10(-5) M. These observations indicate that vanadate is a potent inhibitor of the VSMC Na,K-ATPase in disrupted vascular smooth muscle cells. However, in intact vascular smooth muscle cells vanadium gaining access into the vascular smooth muscle cell's interior does not inhibit the Na-K pump, probably because of its binding to intracellular proteins and/or conversion from the vanadate to the vanadyl ion.

Serum 5-nucleotidase in some rachitic and jaundiced Egyptian children

5-Nucleotidase (5-Nase) was determined in the serum of 67 Egyptian Children: 15 cases as a control group, 10 cases with infantile rickets, 8 cases with the so-called physiological jaundice of the newborn, 4 cases with rhesus incompatibility, and 30 cases with infective hepatits. In rachitic cases and in cases with icterus neonatorum, 5-Nase was not increased, while in cases with infective hepatitis it showed a statistically significant elevation when compared with the control group.