Indian Journal of Experimental Biology

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VOLUME 45

NUMBER 1

JANUARY 2007

CODEN : IJEB (A6) 45(1) 1-128(2007)

ISSN : 0019-5189

 

Special Issue on Biomedicine

 

CONTENTS

 

Biorheologic Mechanisms

 

RBC aggregation: Laboratory data and models

9

    H J Meiselman, B Neu, M W Rampling & O K Baskurt

 

 

 

Rheological and flow properties of blood investigated by ultrasound

18

M Boynard, L Haider, H Lardoux & P Snabre

 

 

 

Hemodynamic effects of red blood cell aggregation

25

Oguz K Baskurt & Herbert J Meiselman

 

 

 

Hemorheological changes in microcirculation: Their mechanism and
measurement technique

32

George Mchedlishvili

 

 

 

Blood flow regulation in the cerebral microvasculature with an arcadal network: a numerical simulation

41

Hideyuki Niimi, Yutaka Komai & Saburo Yamaguchi

 

 

 

Biotechnologic Mechanisms

 

Localization of protein-protein interactions in live cells using confocal and spectral imaging FRET microscopy

48

Y Chen & Ammasi Periasamy

 

 

 

Monte Carlo method for bioluminescence tomography

58

D Kumar, W X Cong & G Wang

 

 

 

Multiprobe laser reflectometry in imaging and characterization of biological tissues

64

M Singh, S Chacko, D Kumar & S Nandakumar

 

 

 

Infrared spectroscopic analysis of tumor pathology

71

Ranjana Mehrotra, Alka Gupta, Ajeet Kaushik, Neeraj Prakash & Hem Kandpal

 

 

 

Biomarkers of induced electromagnetic field and cancer

77

J Behari & R Paulraj

 

 

 

Development of a tele-stethoscope and its application in pediatric cardiology

86

F L Hedayioglu, S S Mattos, L Moser & M E de Lima

 

 

Patho-physiologic Mechanisms

 

Inflammation and neovascularization in diabetic atherosclerosis

93

K R Purushothaman, P Meerarani & P R Moreno

 

 

 

Atherothrombosis: Role of tissue factor; link between diabetes, obesity and inflammation

103

P Meerarani, P R Moreno, G Cimmino & J J Badimon

 

 

 

Microrheologic dysfunction in blood during malaria

111

Sanjay Jayavanth & Bock Choon Park

 

 

 

Erythrocyte deformability and its variation in diabetes mellitus

121

Sehyun Shin, Yunhee Ku, Narayanan Babu & Megha Singh

 

 

 

Announcements

8

XXVth National Symposium of Reproductive Biology and Comparative Endocrinology

 

National Conference on Microbial Diversity: Avenues and Applications

 

 

 

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Announcements

 

 

XXVth National Symposium of Reproductive Biology and Comparative Endocrinology

1517 January 2007, Thiruvananthapuram

 

To be held under the auspices of the Society for Reproductive Biology and Comparative Endocrinology, Department of Zoology, University of Kerala, and the Translational Cancer Research trust, the Silver Jubilee Symposium will be held at the Department of Zoology, University of Kerala, Thiruvananthapuram. The focal theme of the symposium is 典ranslational Endocrinology and Reproductive Biology. The scientific sessions will be grouped under the following heads: (i) Molecular endocrinology, (ii) Vertebrate endocrinology, (iii) Invertebrate endocrinology, (iv) Reproductive physiology, (v) Fertility and sterility, (vi) Neuroendocrinology, (vii) Clinical endocrinology, (viii) Endocrine disruptors, and (ix) Developmental biology. For details please contact, Professor Oommen V Oommen, Department of Zoology, University of Kerala, Thiruvananthapuram 695 581. Phone: 0471-2418906. E-mail: oommenvo@gmail.com. Website: www.srbce.org

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National Conference on Microbial Diversity: Avenues and Applications

(17-18 March, 2007, Dehradun)

 

The National Conference on Microbial Diversity: Avenues and Applications, sponsored by Uttaranchal State Council for Science and Technology (UCOST), DST, Govt. of Uttaranchal, is being organized at Division of Life Sciences, Sardar Bhagwan Singh Post Graduate Institute of Biomedical Sciences and Research, Gaurav Bharti Shiksha Sansthan, Balawala, Dehradun, Uttaranchal on 17-18 March, 2007. The topics covered will be in the areas: Advances in Microbial Diversity and Taxonomy; Biochemistry, Molecular biology and Immunology; Bioinformatics and Computational Biology; Microbes in different Ecosystems; Genomics and Proteomics; Microbial diversity and Bioprospecting for Industrial and Environmental Biotechnology; Medical and Veterinary Microbiology; Microbial resource in the upliftment of Agriculture, Health and Medicine; and Forestry, Industry and Environment. For registration and other details please contact: Dr. Shivesh Sharma, Organizing Secretary (E-mail: sharmashivesh@email.com); OR Piyush Pandey, Joint Organizing Secretary, (piyushgkp@rediffmail.com), Department of Microbiology, Division of Life Sciences, Sardar Bhagwan Singh Post Graduate Institute of Biomedical Sciences and Research, Balawala, Dehradun 248161(U.A.). Phone: 09897138234, 9358108007. For other information please visit www.sbspgi.com.

 

 

 

Author Index

Babu Narayanan

121

Badimon J J

103

Baskurt Oguz K

9, 25

Behari J

77

Boynard M

18

Chacko S

64

Chen Y

48

Cimmino G

103

Cong W X

58

de Lima M E

86

Gupta Alka

71

Haider L

18

Hedayioglu F L

86

Jayavanth Sanjay

111

Kandpal Hem

71

Kaushik Ajeet

71

Komai Yutaka

41

Ku Yunhee

121

Kumar D

58, 64

Lardoux H

18

Mattos S S

86

Mchedlishvili George

32

Meerarani P

93, 103

Mehrotra Ranjana

71

Meiselman Herbert J

9, 25

Moreno P R

93,103

Moser L

86

Nandakumar S

64

Neu B

9

Niimi Hideyuki

41

Park Bock Choon

111

Paulraj R

77

Periasamy Ammasi

48

Prakash Neeraj

71

Purushothaman K R

93

Rampling M W

9

Shin Sehyun

121

Singh Megha

64, 121

Snabre P

18

Wang G

58

Yamaguch Saburo

41

 

 

Keyword Index

Absorption

58

Aggregation

9

Angiogenesis

93

Arcadal network

41

Artificial neural networks

111

Atherosclerosis

93

Atherothrombosis

103

Biological tissues imaging

64

Bioluminescence tomography                

58

Biomarkers

77

Blood

18

C/EBPa

48

Cancer

77

Cell proliferation

77

Cerebral microcirculation

41

Confocal

48

CT/micro-CT

58

Diabetes mellitus

121

Ductal carcinoma proliferation              

71

Ektacytometry

121

Electromagnetic field

77

Electronic stethoscope

86

Erythrocyte deformability

121

Flow properties

18

Flow regulation

41

Flow-induced response

41

Fluidity

121

Fluorescent proteins

48

Fourier transform

71

FRET

48

Hemodynamic mechanism,

25

Hemorheological disorders

32

Hemorrhage

93

Inflammation

103

Infrared spectroscopy

71

Investigation techniques

32

Microcirculatory changes

32

Micro-pore filtration

121

Microrheological dysfunctions

111

Microscopy

48

Monte Carlo simulation

58

Multiprobe reflectometer

64

Neovessels

93

Numerical simulation

41

Optical parameters

64

Protein localization

48

Protein-protein interactions

48

RBC

9

Red blood cell aggregation

25

Red cell aggregation and deformability  

111

Reflectance

64

Rheological properties

18

Shape descriptors

121

Spectral imaging

48

Telemedicine

86

Tissue factor

103

Ultrasound

18

Vivax malaria

111

 

 

 

 

 

Preface

 

Interdisciplinary research plays an important role in understanding the complexities of the biological system and the knowledge gained through this helps in strengthening the diagnostic and curative medicine. International collaboration is another basic requirement for this purpose as the variation in infrastructure and research methodologies are now essential to achieve the objectives of such advanced research. Over the years 腺iomedicine has emerged as one of the leading interdisciplinary fields drawing inputs from various disciplines and in turn providing inputs to the fields of biotechnology and medicine.

This special issue of the Indian Journal of Experimental Biology on 釘iomedicine has kept up the healthy tradition of international collaboration through contributions from leading scientists working in various fields. The articles in this issue are divided into three sections: Biorheologic, Biotechnologic and Patho-physiologic mechanisms. Biorheologic mechanisms cover macro- to micro-hemorheological aspects of blood flow, Biotechnologic mechanisms focus on technological developments that provide the details of tissue compositional variation through imaging and signal analysis and biomarkers, while Patho-physiologic mechanisms provide the salient features of the alterations at cellular level in tissues and erythrocytes due to conditions like diabetes, atherosclerosis and malaria. The authors of these articles have provided wide coverage of recent work in these topics, which I am sure, will lead to future research in these areas. I gratefully acknowledge their contributions and support in bringing out this memorable issue on 釘iomedicine.

I wish to express my thanks to Dr Sehyun Shin (School of Mechanical Engineering, Kyungpook National University, Daegu 702-701, Korea) for his valuable suggestions. My special thanks to the editorial team of the Indian Journal of Experimental Biology for the excellent work in bringing out the special issue.

 

Megha Singh

(Guest Editor)

Center for Biomedical Engineering

S.G.N. Educational Foundation

# 12, III Street, Park Avenue

Velachery, Chennai 600 042, India

E-mail: msingh_iitm@yahoo.com

 

 

 

 

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 9-17

 

 

rbc aggregation: laboratory data and models

H J Meiselman, B Neu, M W Rampling & O K Baskurt

 

Received 5 June 2006

The reversible aggregation of red blood cells (RBC) into linear and three-dimensional structures continues to be of basic science and clinical interest: RBC aggregation affects low shear blood viscosity and microvascular flow dynamics, and can be markedly enhanced in several clinical states. Until fairly recently, most research efforts were focused on relations between suspending medium composition (i.e., protein levels, polymer type and concentration) and aggregate formation. However, there is now an increasing amount of experimental evidence indicating that RBC cellular properties can markedly affect aggregation, with the term 迭BC aggregability coined to describe the cell痴 intrinsic tendency to aggregate. Variations of aggregability can be large, with some changes of aggregation substantially greater than those resulting from pathologic states. The present review provides a brief overview of this topic, and includes such areas as donor-to-donor variations, polymer-plasma correlations, effects of RBC age, effects of enzymatic treatment, and current developments related to the mechanisms involved in RBC aggregation.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 18-24

 

 

Rheological and Flow Properties of Blood Investigated by Ultrasound

M Boynard, L Haider, H Lardoux, P Snabre

 

Received 5 June 2006

Ultrasonic waves of 1-15 MHz frequencies easily propagate through soft biological tissues, thus providing qualitative and quantitative information on mechanical and flow properties of blood and red blood cell (RBC) suspensions. Two types of techniques allow to investigate blood behaviors: echographic devices via amplitude detection and Doppler effect based devices via frequency detection of the ultrasonic signal. When ever B mode serves to construct images of tissue slabs from the ultrasonic backscattering coefficient and can give qualitative information on the mechanical properties of blood, A-mode allows to quantify the ultrasonic backscattering coefficient. Ultrasonic Doppler modes also provide both qualitative and quantitative information on blood flow velocity: continuous and pulsed Doppler modes provide curves of blood flow versus time when color Doppler and power Doppler imaging visualize blood flowing in human vessels. Association of echographic and Doppler modes to investigate simultaneously structure and velocity of blood is commercially available. Some examples of results given by such ultrasonic techniques that contribute to characterize, both in vitro and in vivo, structure and flow properties of blood or red blood cell (RBC) suspensions are presented.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 25-31

 

 

Hemodynamic effects of red blood cell aggregation

Oguz K Baskurt & Herbert J Meiselman

 

Received 22 June 2006

The influence of red blood cell (RBC) aggregation on blood flow in vivo has been under debate since early 1900痴, yet a full understanding has still has not been reached. Enhanced RBC aggregation is well known to increase blood viscosity measured in rotational viscometers. However, it has been demonstrated that RBC aggregation may decrease flow resistance in cylindrical tubes, due to the formation of a cell-poor zone near the tube wall which results from the enhanced central accumulation of RBC. There is also extensive discussion regarding the effects of RBC aggregation on in vivo blood flow resistance. Several groups have reported increased microcirculatory flow resistance with enhanced RBC aggregation in experiments that utilized intravital microscopy. Alternatively, whole organ studies revealed that flow resistance may be significantly decreased if RBC aggregation is enhanced. Recently, new techniques have been developed to achieve well-controlled, graded alterations in RBC aggregation without influencing suspending phase properties. Studies using this technique revealed that the effects of RBC aggregation are determined by the degree of aggregation changes, and that this relationship can be explained by different hemodynamic mechanisms.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 32-40

 

 

Hemorheological changes in microcirculation: Their mechanism and
measurement technique

George Mchedlishvili

 

Blood fluidity in the capillaries is affected significantly in diseases such as cardiac and brain infarcts, diabetic gangrene and many others. In view of the importance of physiology and pathology of capillary circulation, the hemorheological characteristics of the capillary blood flow are discussed in this article. Also, a new diagnosing technique for blood fluidity disorders is proposed. A computerized system for image analysis and determining blood rheological disorders for clinical and experimental use has also been discussed.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 41-47

 

 

Blood flow regulation in the cerebral microvasculature with an arcadal network:
A numerical simulation

Hideyuki Niimi, Yutaka Komai, and Saburo Yamaguchi

 

Received 26 June 2006

Blood flow regulation in the cerebral microvasculature with an arcadal network was investigated using a numerical simulation. A mathematical model for blood flow in the arcadal network, based on in vivo data of cat cerebral microvasculature and flow velocity was developed. The network model consists of 45 vessel segments and 25 branching points. To simulate microvascular response to blood flow, non-reactive (solid), cerebral arteriole-like, or skeletal muscle arteriole-like responses to wall shear stress were taken into account. Numerical calculation was carried out in the flow condition where the inlet (arterial) pressure was changed from 60 to 120 mmHg. Flow-rate in each efferent vessel and the mean flow-rate over all efferent vessels were evaluated for assessment of blood supply to the local area of cerebral tissue. The simulation demonstrated the wall shear stress-induced vasodilation in the arcadal network worked to maintain the blood flow at a constant level with pressure variable in a wide range. It is suggested that an individual microvessel (segment) should join in the regulatory process of flow, interacting with other microvessels (cooperative regulation).

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 48-57

 

 

Localization of protein-protein interactions in live cells using confocal and spectral imaging FRET microscopy

Ye Chen & Ammasi Periasamy

 

Received 10 May 2006

Microscopy has become an essential tool for cellular protein investigations. The development of new fluorescent markers such as green fluorescent proteins generated substantial opportunities to monitor protein-protein interactions qualitatively and quantitatively using advanced fluorescence microscope techniques including wide-field, confocal, multiphoton, spectral imaging, lifetime, and correlation spectroscopy. The specific aims of the investigation of protein dynamics in live specimens dictate the selection of the microscope methodology. In this article confocal and spectral imaging methods to monitor the dimerization of alpha enhancer binding protein (C/EBPa) in the pituitary GHFT1-5 living cell nucleus have been described. Also outline are issues involved in protein imaging using light microscopy techniques and the advantages of lifetime imaging of protein-protein interactions.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 58-63

 

 

Monte Carlo method for bioluminescence tomography

D Kumar, W X Cong & G Wang

 

Received 3 July 2006

Bioluminescence imaging plays an important role in the areas of cancer biology, cell biology, gene therapy, and so on. The 2D planar bioluminescent imaging has been transformed into a 3D framework by bioluminescence tomography (BLT) that enables bioluminescent source reconstruction in a mouse using a modality fusion approach. To solve this BLT problem, a geometrical model of the mouse is usually built from a CT/micro-CT/micro-MRI scan, which facilitates the assignment of optical parameters to various anatomical regions in the model. This optical model is then used to facilitate BLT. The forward model is based on Monte Carlo simulation to calculate the diffuse light flux on the surface of the mouse. The forward model data are used to define the imaging system and perform the BLT reconstruction. In this paper, we report the reconstruction of sources inside a heterogeneous highly scattering physical phantom to demonstrate the feasibility of this Monte Carlo based BLT method.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 64-70

 

 

Multiprobe laser reflectometry in imaging and characterization of biological tissues

M Singh, S Chacko, D Kumar & S Nandakumar

 

Received 4 July 2006

Laser backscattered radiation from human forearm and foot were measured by multi-probe reflectometer, which consisted of one input probe and three output probes placed at distances of 2, 4 and 6 mm from the input probe. The normalized backscattered intensity (NBI) signals from the tissue surface, measured by the output probes, after digitization, were used to reconstruct the reflectance images of tissues in various layers below the skin surface. From NBI profiles measured at various locations of the tissues on the forearm the corresponding optical parameters, the scattering (μs) and absorption (μa) coefficients and the anisotropy parameter g, by matching these with profiles as simulated by Monte Carlo procedure were determined. From these data the optical parametric images of forearm were reconstructed which show the variation of these parameters at various locations. Similarly, the NBI data were collected from the foot sole region of healthy and diabetes subjects and their images reconstructed. These images showed the variation in the NBI in the diabetic foot sole compared to that of healthy subject, indicating the tissue structural changes. These procedures could be useful for diagnostic and therapeutic applications of lasers.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 71-76

 

 

Infrared spectroscopic analysis of tumor pathology

Ranjana Mehrotra, Alka Gupta, Ajeet Kaushik, Neeraj Prakash

and

Hem Kandpal

 

Received 3 July 2006

Infrared spectra of normal and malignant breast tissues were measured in the 600 cm-1 to 4000 cm-1 region. The measured spectroscopic features which are the spectroscopic fingerprints of the tissues contain the vital information about the malignant and normal tissues. Fourier Transform Infrared (FTIR) data on 25 cases of infiterating ductal carcinoma of breast with different grades of malignancy from patients of different age groups were analyzed. The samples were taken from the tumor sections of the tissue removed during surgery. Infrared spectra demonstrate significant spectral differences between the normal and the cancerous breast tissues. In particular changes in frequency and intensity in the spectra of protein, nucleic acid and glycogen vibrational modes as well as the band intensity ratios for lipid/proteins, protein/nucleic acids, protein/glycogen were observed. This allows to make a qualitative and semi quantitative evaluation of the changes in proliferation activity from normal to diseased tissue. It was evident that the sample to sample or patient to patient variations were small and the spectral differences between normal and diseased tissues were reproducible. The findings establish a framework for additional studies, which may enable us to establish a relation of the diseased state with its infrared spectra.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 77-85

 

 

Biomarkers of induced electromagnetic field and cancer

J Behari & R Paulraj

 

Received 5 July 2006

The present article delineates the epidemiological and experimental studies of electromagnetic field which affects various tissues of human body. These affects lead to cell proliferation, which may lead to cancer formation. Certain bio-markers have been identified which are one way or the other responsible for tumor promotion or co-promotion. These are (i) melatonin, a hormone secreted by pineal gland, (ii) Ca2+, which is essential in the regulation of the resting membrane potential and in the sequence of events in synaptic excitation and neurotransmitter, release are affected by electromagnetic field, (iii) ornithine decarboxylase (ODC), a rate-limiting enzyme in the biosynthesis of polyamines, considered as a useful biological marker; over expression of ODC can cause cell transformation and enhancement of tumor promotion. (iv) protein kinase is an enzyme, which transfers phosphate groups from ATP to hydroxyl groups in the amino acid chains of acceptor proteins, and (v) Na++ ATPase, which transports sodium and potassium ions across the membrane has a critical role in living cells. The various possible mechanisms depending upon non equilibrium thermodynamics, co-operativism, stochastic and resonance are discussed as possible models of signal transduction in cytosol, thereby controlling the transcription phenomena. Finally a mechanism comprising the extremely low frequency and radio frequency (RF)/ microwave (MW) modulated field is compared.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 86-92

 

 

Development of a tele-stethoscope and its application in pediatric cardiology

F L Hedayioglu, S S Mattos, L Moser & M E de Lima

 

Received 11 July 2006

Over the years, many attempts have been made to develop special stethoscopes for the teaching of auscultation. The objective of this article is to report on the experience with the development and implementation of an electronic stethoscope and a virtual library of cardiac sounds. There were four stages to this project: (1) the building of the prototype to acquire, filter and amplify the cardiac sounds, (2) the development of a software program to record, reproduce and visualize them, (3) the testing of the prototype in a clinical scenario, and (4) the development of an internet site, to store and display the sounds collected. The first two stages are now complete. The prototype underwent an initial evaluation in a clinical scenario within the Unit and during virtual out-patient clinical sessions. One hundred auscultations were recorded during these tests. They were reviewed and discussed on-line by a panel of experience cardiologists during the sessions. Although the sounds were considered 都atisfactory for diagnostic purposes by the cardiology team, they identified some qualitative differences in the electronic recorded auscultations, such as a higher pitch of the recorded sounds. Prospective clinical studies are now being conducted to further evaluate the interference of the electronic device in the physiciansエ capability to diagnose different cardiac conditions. An internet site (www.caduceusvirtual.com.br/ auscultaped) was developed to host these cardiac auscultations. It is set as a library of cardiac sounds, catalogued by pathologies and already contains examples from auscultations of the majority of common congenital heart lesions, such as septal defects and valvar lesions.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 93-102

 

 

Inflammation and neovascularization in diabetic atherosclerosis

 

K R Purushothaman, P Meerarani & P R Moreno

 

Received 26 July 2006

Diabetes mellitus, the major cardiovascular risk factor, accentuates the inflammation and neovascularization processes leading to enhanced progression of atherosclerotic complications. Inflammation in diabetes mellitus is the key initiator of atherosclerotic process, which results in acute coronary events. Atherosclerosis evolves from the endothelial cell dysfunction and succeeding entry of hemodynamically derived leukocytes by migration, activation and production of lipid gruel leading to atheromatous plaque progression and subsequent regression. Diabetic plaque progression is associated with increased neovascularization, which is a nature痴 compliment in the sustenance of plaque growth by its nutrient supply. Neovessels may act as conduit for lipid debridment and alternative channel for inflammatory process. In addition, neovascularization induces intra-plaque hemorrhage due to the fragility of the neovessels and associated inflammation, resulting in plaque instability. The intra-plaque hemorrhage is a detrimental base, which begets the progress of atheroma by inducing oxidative stress and endothelial dysfunction. Intra-plaque hemorrhage is increased in diabetes with an associated increase in hemoglobin-haptoglobin complex (Hb-Hp2-2), which further induces oxidative stress and endothelial cell dysfunction. We conclude that inflammation and neovascularization of the plaque may act as major mechanism augmenting plaque instability in diabetes mellitus.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 103-110

 

 

Atherothrombosis: Role of tissue factor
Link between diabetes, obesity and inflammation

P Meerarani , P R Moreno, G Cimmino & J J Badimon

 

Received 7 July 2006

Atherothrombotic vascular disease is a complex disorder in which inflammation and coagulation play a pivotal role. Rupture of high-risk, vulnerable plaques with the subsequent tissue factor (TF) exposure is responsible for coronary thrombosis, the main cause of unstable angina, acute myocardial infarction, and sudden cardiac death. Tissue factor (TF), the key initiator of coagulation is an important modulator of inflammation. TF is widely expressed in atherosclerotic plaques and found in macrophages, smooth muscle cells, extracellular matrix and acellular lipid-rich core. TF expression can be induced by various stimulants such as C-reactive protein, oxLDL, hyperglycemia and adipocytokines. The blood-born TF encrypted on the circulating microparticles derived from vascular cells is a marker of vascular injury and a source of procoagulant activity. Another form of TF, called alternatively spliced has been recently identified in human and murine. It is soluble, circulates in plasma and initiates coagulation and thrombus propagation. Evidence indicates that elevated levels of blood-borne or circulating TF has been associated with metabolic syndrome, type 2 diabetes and cardiovascular risk factors and is a candidate biomarker for future cardiovascular events. Therapeutic strategies have been developed to specifically interfere with TF activity in the treatment of cardiovascular disease.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 111-120

 

 

Microrheologic dysfunctions in blood during malaria

Sanjay Jayavanth & Bock Choon Park

 

Received 1 August 2006

Among the Plasmodium variants that cause human malaria, vivax malaria is considered to be non-malignant. Recent research has indicated that severe vivax infection can turnout to be as pathological as falciparum. This review evidences microrheologic pathology in vivax malaria, similar to that as seen in malignant falciparum. The parasite invasion, internalization and growth in the RBC lead to membrane rigidification and progressive loss of deformability, rosetting and cytoadherence, enhanced aggregation, clumpy, non-deforming, sticky aggregates and chronic sedimentation profiles. A model that reflects the net effect of these changes is of clinical value to establish disease severity in specific malaria. In this respect an artificial neural network (ANN) model, implemented in malaria severity analysis, is discussed. Results of this model suggest that a good degree of severity classification (60 to 100%) can be achieved even with small sample size (malaria samples n=12, normal =10). With larger sample size, ANN may be very apt as microrheological model for severity analysis.

 

 

Indian Journal of Experimental Biology

Vol. 45, January 2007, pp. 121-128

 

 

Erythrocyte deformability and its variation in diabetes mellitus

Sehyun Shin, Yunhee Ku, Narayanan Babu & Megha Singh

 

Received 1 August 2006

Erythrocyte deformability improves blood flow in the microvessels and in large arteries at high shear rate. The major determinants of RBC deformability include cell geometry, cell shape and internal viscosity (i.e., mean cell hemoglobin concentration and components of the erythrocyte membrane). The deformability is measured by several techniques but filtration of erythrocytes through micro-pore membranes and ektacytometry are two sensitive techniques to detect changes in erythrocytes under varied experimental and diseased conditions. Diabetes mellitus (DM) is a metabolic disorder, characterized by varying or persistent hyperglycemia, which induces several changes in the erythrocyte membrane and its cytoplasm, leading to alteration in the deformability. A decreasing trend of deformability in these patients is observed. The shape descriptor form factor, as determined by processing of erythrocyte images, increases with the increase of blood glucose levels and shows a pattern similar to filtration time of erythrocyte suspensions through cellulose membranes. Fluidity of the membrane as measured in erythrocytes of these patients is decreased. With prolonged diabetic conditions the deformability of erythrocytes is further decreased, which may complicate the flow of these cells in microvessels.