Spatio-temporal evolution of magnetohydrodynamic blood flow and heat dynamics through a porous medium in a wavy-walled artery.

BACKGROUND AND OBJECTIVE: In a healthy body, the elastic wall of the arteries forms wave-like structures resulting from the continuous pumping of the heart. The systolic and diastolic phases generate a contraction and expansion pattern, which is mimicked in this study by considering a wavy-walled arterial structure. A numerical investigation of the spatio-temporal flow of blood and heat transfer through a porous medium under the action of magnetic field strength is conducted. METHOD: The governing equations of the blood flow in the Darcy model are simulated by applying a vorticity-stream function formulation approach. The transformed dimensionless equations are further discretized using the finite difference method by developing the Peaceman-Rachford alternating direction implicit (P-R ADI) scheme. RESULTS: The computational results for the axial velocity, temperature distribution, flow visualization using the streamlines and vorticity contours, isotherms, wall shear stress and the average Nusselt number are presented graphically for different values of the physical parameters. CONCLUSIONS: The study shows that the axial velocity increases with an increase in the Darcy number, and a similar phenomenon is observed because of an amplitude variation in the wavy wall. Both temperature and wall shear stress decreases with an increase in the Darcy number. The average Nusselt number increases with the magnetic field strength, while it has a reducing tendency due to the permeability of the porous medium.

Isolated exon 8 deletion in type 1 spinal muscular atrophy with bilateral optic atrophy: unusual genetic mutation leading to unusual manifestation?

Proximal spinal muscular atrophy (SMA) or type 1 SMA is a fatal autosomal recessive disorder usually caused by homozygous deletion of exons 7 and 8 in the survivor motor neuron (SMN) gene. Additional deletion of the neuronal apotosis inhibitory protein (NAIP) gene exacerbates the clinical severity. Isolated exon 8 deletion has been reported in a single case series of SMA types 2 and 3 and never with SMA type 1. While extraocular muscles are typically spared, there are a few case reports documenting associated external ophthalmoplegia. Optic atrophy is a hitherto unreported association of SMA. We report a 10-month-old male infant with SMA type 1 with optic atrophy due to isolated deletion of exon 8 of the SMN gene with intact exon 7 and NAIP gene.

Optimizing tillage schedule for maintaining activity of the arbuscular mycorrhizal fungal population in a rainfed upland rice (Oryza sativa L.) agro-ecosystem.

Rainfed uplands in India are predominantly mono-cropped with rice (Oryza sativa L.) in the wet season (June/July to September/October) and grown under aerobic soil conditions. The remaining fallow period (winter followed by summer) of about 8-9 months leads to natural crash in the population of native arbuscular mycorrhizal fungi (AMF) in the soil. Attempts have been made to minimize this population crash by reducing soil disturbance-induced deleterious effects on native AMF activity of improperly scheduled off-season tillage, an agronomic recommendation for weed and disease (soil-borne) management, practiced by the upland farmers. On-farm (farmers' field) evaluation of effects of all suitable off-season tillage schedule combinations on rice during wet seasons of 2004, 2005, and 2006 revealed that a maximum of two off-season tillage schedules with a minimum gap of 13 weeks between them minimized the population crash of native AMF with a concomitant increase in phosphorus (P) uptake and grain yield of upland rice (variety "Vandana").

Vacuolar-type H+-ATPases at the plasma membrane regulate pH and cell migration in microvascular endothelial cells.

Microvascular endothelial cells involved in angiogenesis are exposed to an acidic environment that is not conducive for growth and survival. These cells must exhibit a dynamic intracellular (cytosolic) pH (pHcyt) regulatory mechanism to cope with acidosis, in addition to the ubiquitous Na+/H+ exchanger and HCO3--based H+-transporting systems. We hypothesize that the presence of plasmalemmal vacuolar-type proton ATPases (pmV-ATPases) allows microvascular endothelial cells to better cope with this acidic environment and that pmV-ATPases are required for cell migration. This study indicates that microvascular endothelial cells, which are more migratory than macrovascular endothelial cells, express pmV-ATPases. Spectral imaging microscopy indicates a more alkaline pHcyt at the leading than at the lagging edge of microvascular endothelial cells. Treatment of microvascular endothelial cells with V-ATPase inhibitors decreases the proton fluxes via pmV-ATPases and cell migration. These data suggest that pmV-ATPases are essential for pHcyt regulation and cell migration in microvascular endothelial cells.

Role of biomodulators and involvement of protein tyrosine kinase on stem cell migration in normal and leukaemic mice.

Tyrosine kinase has an important role with regard to self-renewal and as a comitogen in the movement of stem cells out of the haemopoietic stem cell pool into the progeny pool. The present investigation has an objective to evaluate the protein tyrosine kinase (PTK) activity of bone marrow derived pluripotent cells before and after application of biological response modifiers (BRMs) in normal and leukaemic mice. The PTK activity of the cytosolic fraction of bone marrow cells has been determined by the assay kit based on per-oxidase labeled substrate analog and biotin-streptavidin expression. A consequent cell population kinetic study has also been conducted. Results showed a higher activity in the cells of leukaemic mice, which under the influence of interleukin-2 (IL-2) and the non-specific BRM sheep erythrocytes (SRBC) undergo further activation. Interferon-gamma (IFN-gamma) when administered alone showed a suppressive effect and the combination of the three manifested a resultant suppression. Corresponding migration (cell population kinetics) of the bone marrow cells (BMC) also correlated well with the PTK activity of the cells concerned. The observations indicated that the pluripotent BMCs are under regulated control of the PTK activity, which can be manipulated by selective BRMs. The data also suggested the therapeutic benefit of IFN-gamma along with chemotherapeutics against leukaemia and that of IL-2 and SRBC during bone marrow failure.

Facilitation of functional compartmentalization of bone marrow cells in leukemic mice by biological response modifiers: an immunotherapeutic approach.

Biological Response Modifiers (BRMs) including interleukin-2 (IL-2), interferon-gamma (IFN-gamma) and sheep erythrocytes (SRBC) protected N,N'-ethylnitrosourea (ENU) induced leukaemic mice. Two cell types from the bone marrow were isolated in density specific gradient representing two distinct compartments, the low density cells being more CD34 positive than the high density group. Investigations with the functional efficacy of such compartments revealed significant improvement of cytotoxic efficacy and phagocytic burst at the high density compartment (HDC) level. The high density compartment was found to be more responsive towards the BRMs compared to the cells of the low density compartment (LDC). It was suggested that use of BRMs in vivo can stimulate a potent functional progenitor compartmentalization in normal as well as leukaemic mice. These observations are expected to help a logistic approach towards combined BRM therapy at the clinical level.

Lipoarabinomannan from Mycobacterium tuberculosis promotes macrophage survival by phosphorylating Bad through a phosphatidylinositol 3-kinase/Akt pathway.

Efforts in prevention and control of tuberculosis suffer from the lack of detailed knowledge of the mechanisms used by pathogenic mycobacteria for survival within host cell macrophages. The exploitation of host cell signaling pathways to the benefit of the pathogen is a phenomenon that deserves to be looked into in detail. We have tested the hypothesis that lipoarabinomannan (LAM) from the virulent species of Mycobacterium tuberculosis possesses the ability to modulate signaling pathways linked to cell survival. The Bcl-2 family member Bad is a proapoptotic protein. Phosphorylation of Bad promotes cell survival in many cell types. We demonstrate that man-LAM stimulates Bad phosphorylation in a phosphatidylinositol 3-kinase (PI-3K)-dependent pathway in THP-1 cells. Man-LAM activated PI-3K. LAM-stimulated phosphorylation of Bad was abrogated in cells transfected with a dominant-negative mutant of PI-3K (Delta p85), indicating that activation of PI-3K is sufficient to trigger phosphorylation of Bad by LAM. Since phosphorylation of Bad occurred at serine 136, the target of the serine/threonine kinase Akt, the effect of LAM on Akt kinase activity was tested. Man-LAM could activate Akt as evidenced from phosphorylation of Akt at Thr(308) and by the phosphorylation of the exogenous substrate histone 2B. Akt activation was abrogated in cells transfected with Deltap85. The phosphorylation of Bad by man-LAM was abrogated in cells transfected with a kinase-dead mutant of Akt. These results establish that LAM-mediated Bad phosphorylation occurs in a PI-3K/Akt-dependent manner. It is therefore the first demonstration of the ability of a mycobacterial virulence factor to up-regulate a signaling pathway involved in cell survival. This is likely to be one of a number of virulence-associated mechanisms by which bacilli control host cell apoptosis.

Effects of enoximone on quality of life.

To assess whether an inotropic agent may affect quality of life in severe heart failure, a double-blind, placebo-controlled crossover study was performed in 10 patients over three periods of 3 weeks, including an initial control period of 3 weeks and periods on placebo or enoximone, 150 mg t.d.s. Quality of life was assessed by a questionnaire following initial training of patients to evaluate their symptoms after certain stresses, by visual analogue scales of symptoms, and by objective assessments during graded exercise. Daily dyspnoea score decreased from 33.2 +/- 2 (placebo) to 27.7 +/- 4 (enoximone) (P less than 0.01) and daily fatigue score decreased from 14.8 +/- 2.5 (placebo) to 12.6 +/- 2 (enoximone) (P less than 0.05). There were also significant beneficial responses in the mean daily NYHA class and in the duration of a walking test. Self-assessed global quality of life score increased from 2.7 +/- 0.6 (placebo) to 3.6 +/- 0.8 (enoximone) (P less than 0.05). It was concluded that over periods of 3 weeks, enoximone significantly improved self-assessed quality of life.

[An example of the application of factorial analysis of correspondences to infant mortality and its prevention in a rural area of West Africa]. / Un exemple d'application de l'analyse factorielle des correspondances à la mortalité des enfants et à sa prévention, dans une zone rurale de l'Afrique de l'Ouest.

A retrospective study through questionnaire was made among over 800 women of a Pre-Sahel region of Mali. It confirmed the very high infant and child mortality in this population: over 250% mortality under 1 year of age and over 400% under 6 years of age. The factorial analysis of correspondences proved adequate to determine the main characteristics of the local mortality pattern. In chronological order, the most important causes are obstetrical factors (1st day of life), umbilical tetanus (1 week to 1 month of age), malaria (1 month to 1 year of age), pneumopathies (including pertussis and lung complications of measles), toxicoses and nutritional syndromes (over 1 year of age). Preventive measures at various levels are proposed on the basis of these findings. They belong to three broad groups: -Overall socioeconomic development with effective participation of the rural communities concerned. -Development of an appropriate primary health care structure, with a primary health care team in each village. -Strengthening of the programmes of control of the most important communicable diseases. Such simple and cheap actions should, given a clear political will of the national authorities and a modicum of trust in the future on the part of local leaders, be rapidly implementable even in the most underprivileged countries and bring a significant amount of progress in the rural areas.

PIP: A retrospective study to investigate infant mortality was conducted in one of the poorest rural areas in Mali. The study was conducted through questionnaires, and was made among 811 women in 11 different villages. 3204 live births were recorded; 615 newborns, however, died before 1 year of life, i.e. an infant mortality rate of almost 250/1000. Main causes of mortality were obstetrical factors, tetanus, malaria, several types of pneumopathies, toxicoses, and nutrition disorders. Symptoms were the same in all villages, convulsions, cough, fever, and diarrhea. Action to improve the socioeconomic development of the area, set up a working national health structure, and a program of control of communicable diseases should be the first concern of local leaders and of national authorities.

[Nitroglycerin infusion in patients with or without cardiac failure. Demonstration by multifactorial analysis (analysis of correspondences) of three types of hemodynamic response dependent upon the initial state (author's transl)]. / La trinitrine intraveineuse chez les malades avec et sans insuffisance cardiaque. Mise en évidence par une analyse multifactorielle (analyse des correspondances) de 3 types de réponse hémodynamique dépendant de l'état initial.

The effects of nitroglycerin on systemic vascular resistance and cardiac output are highly debated. This study demonstrates that these effects depend on the initial haemodynamic condition, and explains the conflicting results previously reported. 31 patients presenting initially with a fairly wide spectrum of various haemodynamic parameters underwent cardiac catheterisation with measures of parameters before and after nitroglycerin infusion. Multifactorial statistical analysis by correspondence analysis identifies 3 types of haemodynamic responses and demonstrates the association of each response with a particular haemodynamic profile. It is demonstrated that systemic vascular resistance is decreased only when it is initially elevated and cardiac output is increased only when initial pulmonary wedge pressure and systemic vascular resistance are elevated and cardiac output is low. The effects of nitroglycerin on cardiac output, systemic vascular resistance, heart rate and arterial pressure differ significantly according to the presence or not of cardiac insufficiency and depend mainly on the initial value of three parameters: systemic vascular resistance, pulmonary wedge pressure and cardiac output.