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Controlled cross-linking of porcine cholecyst extracellular matrix for preparing tissue engineering scaffold. Biomed Mater Res. part B
No full textTreatment with cross‐linking agents for stabilizing biomolecules is an integral step during the preparation of many extracellular matrix‐based tissue engineering scaffolds from mammalian organs. However, excess cross‐linking may cause nonavailability of biomolecules and consequent deterioration of bioinductive properties of the scaffold. The present study considered controlling the extent of cross‐linking in a porcine cholecyst extracellular matrix scaffold prepared by a nonenzymatic and nondetergent method, by ex situ incubation of the source organ in varying concentrations of neutral buffered formaldehyde (10, 4, 1 or 0%; v/v) for in situ cross‐linking of biomolecules. Reduction of the formaldehyde concentration resulted in an increase in the extent of biodegradation and a decrease in the compactness of the mesh‐like surface microarchitecture of the scaffold. Retention of collagen was maximum when treated with 10% neutral buffered formaldehyde without any variation in the content of elastin and sulphated glycosaminoglycans. Although there was a reduction in the quantity of growth factors following the cross‐linking, fibroblasts remained viable on the scaffolds. The retention of major biomolecule was maximum and autodigestion was minimum in the scaffold prepared by the ex situ treatment of cholecyst in 10% neutral buffered formalin and found suitable for preparing the tissue engineering scaffold
Correlation between pulsatility index (pi) in transcranial doppler (tcd) and cognitive profile of patients with alzheimer’s dementia and vascular dementia
No full textThe World Health Organization (WHO) predicts that by 2025, about 3/4th of the
estimated 1.2 billion people aged >60 years will reside in developing countries1
. 4.6
million new cases of dementia are added every year, and the highest rate of growth is
expected in South Asian countries including India. Education attainment is known to
protect against dementia. Diet and lifestyle can also influence risk of dementia, and
studies suggest that disorders affecting the vascular system, such as hypertension,
diabetes mellitus and obesity, increase the risk for dementia, including Alzheimer's
disease (AD).
There is increasing evidence linking cerebral hypoperfusion and neurodegeneration,
specifically in Alzheimer’s disease (AD) and vascular dementia (VaD)2
. In the
Rotterdam study3
, cerebral hypoperfusion was demonstrated to be a risk or an
aggravating factor in dementia. Hypoperfusion because of microangiopathy,
macroangiopathy or cardiac dysfunction can promote or accelerate
neurodegeneration, blood-brain barrier disruption and neuroinflammation.4
Diagnostic
tools that can provide real-time functional assessment of the cerebrovascular tree can
have a significant impact on our understanding of the vascular contribution to
neurodegeneration at different stages of cognitive decline.
Ultrasound can evaluate the cerebrovascular tree for pathological structure and
functional changes contributing to cerebral hypoperfusion. Studies have shown an
association between leukoaraiosis and transcranial doppler (TCD) pulsatility index
(PI) in several kinds of patients.5
Despite increasing evidence supporting the utility of
these methods in detection of microvascular pathology, cerebral hypoperfusion, neurovascular unit dysfunction and disease progression, non-availability for routine
use and incomplete standardisation limit their use in daily routine.
Studies have evaluated the utility of Middle cerebral artery-Pulsatility index (MCA
PI) to differentiate between AD and VaD and have found conflicting results.6
PI has
been correlated with severity of cognitive decline in few studies. Studies have also
evaluated correlation of PI with decline in cognition. However, correlation of PI with
detailed cognitive profile has not been evaluated.
In this background, we planned our study to assess whether MCA PI can be used to
differentiate between patients with AD and VaD. Also, we propose that increase in PI
correlates with severity of cognitive deficit in patients with dementia
Myocardial t1 mapping: relation of t1 values to myocardial perfusion, early gadolinium enhancement and late gadolinium enhancement in hypertrophic cardiomyopathy
No full textHypertrophic cardiomyopathy (HCM) is a disorder of myocardium with a genetic basis,
characterized by an increase in myocardial thickness, non-dilated left ventricle and increased
in ejection fraction(1). Incidence is believed to be 1 in 500 people(2) with heterogeneous
phenotypic expression. Natural history is variable presenting as sudden cardiac death, heart
failure or arrhythmias. HCM is usually a diagnosis of exclusion, while other ethology of LV
hypertrophy needs to be ruled out. Most common differential diagnosis are hypertension,
valvular heart diseases and infiltrative cardiomyopathies(2). HCM is defined as a wall
thickness of > 15 mm either any echocardiography, Computed tomography or cardiac magnetic
resonance imaging (CMR), without any identifiable cause(3). Cardiac involvement is usually
asymmetric, most commonly involving the basal septum, followed by apical and mid cavity
involvement. Echocardiogram is usually the first modality for diagnosis and assessment of
HCM. CMR is the established modality for diagnosis, risk stratification, and management of
the patients diagnosed with HCM. Myocardial fibrosis has proven to be associated with severe
hypertrophy, and an increase in fibrosis reflects onto failing LV function and risk of sudden
cardiac death secondary to arrythmias in patients of HCM(4). Myocardial fibrosis determined
by Late gadolinium enhancement (LGE) has been established as the maker for future risk of
sudden cardiac death(5). Increase in myocardial crypts in phenotype positive HCM is
associated with particular gene mutations(6). These crypts can be assessed using Early
gadolinium enhancement (EGE) sequence which can predict areas of subtle changes even
before fibrosis sets in.
Assessment of LGE requires CMR contrast for fibrosis quantification. T1 mapping is a novel
technique which can assess the local/diffuse fibrosis without the requirement of an MR contrast
agent. Native T1 maps have proven to be a cost-effective method or fibrosis assessment without 10
exposure to gadolinium-based contrast agent(7). Microvascular perfusion defects in HCM
patients is an important marker of prognosis and future arrhythmic episodes causing sudden
cardiac death(8).
This study was aimed at determining the relationship between Early gadolinium enhancement
(EGE)/Late gadolinium enhancement (LGE) and native T1 values in patients of hypertrophic
cardiomyopathy
Ultrasound guided parasternal modified intercostal nerve block: role as a preemptive analgesic adjunt in fast tracking for mitigating postoperative sternotomy pain
No full textFear of uncontrolled pain is among the primary concerns of many patients who are about
to undergo surgery. Pain affects patients physiological and psychological recovery (1).
Adequate postoperative analgesia prevents unnecessary patient discomfort, may decrease
morbidity, may decrease postoperative hospital lengths of stay, and thus may decrease
costs. So aggressive implementation of well-planned pain management strategy is crucial
for decreasing post-sternotomy pain and resultant morbidity and mortality in
cardiothoracic surgeries (2)(3). Inadequate analgesia and/or an uninhibited stress
response during the postoperative period may increase morbidity by causing adverse
hemodynamic, metabolic, immunologic, and hemostatic alterations.
Analgesic medication modalities, providing optimal relief from pain-anxiety, can
facilitate early tracheal extubation, with minimal compromise on airway-reflexes during
post-tracheal extubation period after cardiac surgery. This would result in optimal patient
comfort-satisfaction without any post-operative pain (4).Also in the recent years, a
multimodal approach utilizing combined regional and systemic analgesics with different
mechanisms of action has been found to be promising and beneficial in terms of treating
acute pain and preventing chronic pain after cardiac surgery.
Pre-emptive analgesia execution assumes a critical role in blunting traumatic or surgical
damage induced stimulus modification in both peripheral and central nervous system, and
therefore this modality must be considered during the decision making of preoperative
analgesic techniques (5)(6)
Role of quantitative susceptibility weighted imaging in evaluating disease activity of lesions in multiple sclerosis
No full textMultiple sclerosis (MS) is an inflammatory demyelinating and neurodegenerative disease of
the central nervous system. Majority of the patients start with a relapsing –remitting course,
which has clearly defined episode of neurologic disability and recovery. Pathologic hallmark
of MS was presence of focal plaques in white and gray matter associated with heavy
infiltration of macrophages with myelin debris, lymphocytes, and large reactive
multinucleated astrocytes called Creutzfeldt-Peters cells1
. The etiologic mechanism
underlying this demyelinating disease is generally believed to be autoimmune inflammation
however the intial triggerer and the further development of CNS plaques are not well
established1
. Conventional magnetic resonance imaging (MRI) has been used routinely to
diagnose and monitor the disease spatially and temporally. The use of conventional MRI to
measure the disease activity and assess effects of therapy is now standard in clinical practice
and drug trials. T2-weighted imaging (T2WI) is highly sensitive in the detection of
hyperintensities in white matter but, hyperintensities on T2WI can correspond to a wide
spectrum of pathology, ranging from edema and mild demyelination to lesions in which the
neurons and supporting glial cells are replaced by glial scars or liquid necrosis. In MS ,
gadolinium enhancement on T1-weighted imaging (T1WI) can suggest an acute
inflammation, which is a marker of disease activity2,3. It is becoming a consensus among
many studies that iron is enriched within oligodendrocytes and myelin in both normal and
diseased tissue. One explanation for such findings proposes that iron is associated with the
biosynthetic enzymes of myelinogenesis4
. In MS , stages of relapse and remission alternate
during disease progression, identification and characterization of active lesions are critical for
correct diagnosis and therapy. In clinical practice, current active lesion assessment is based
on gadolinium (Gd) enhancement on T1-weighted MR imaging2,3. However, because Gd
enhancement reflects leakage of the blood-brain barrier, it is considered as an indirect
measure of inflammation that is preceded and outlasted by infiltration of immune cells. The 8
activation of resident innate immune cells may not be captured on T1WI Gd5
. In addition,
concerns over repeated Gd exposure have recently been raised, as new data showing long term Gd retention in the brain of patients with normal renal function who have undergone
multiple Gd injections is emerging. In patients with MS in whom Gd retention seems also to
be associated with secondary progression of the disease.
6,7 Therefore it has become a
necessity to identify a ‗Gd-enhancing‘ or ‗active MS‘ lesions without the use of a contrast
agent to reduce scan time, cost, Gd accumulation and adverse effects. A non-contrast based
imaging modality to detect active lesions also helps in routine follow up / monitoring of MS
patients on therapy. It is known that microglia and macrophages in an alternative activation,
M2 type macrophages (ferritin poor macrophages) remove myelin debris from MS lesions
which usually accumulate in the periphery of the active lesion,
8 whereas the classic pro inflammatory M1 type macrophages (ferritin rich macrophages)- which tend to accumulate
iron- was more commonly present in the chronic lesions9
. Both M1 and M2 type macrophage
accumulation varies in different types of lesions which may result in change in susceptibility
values and iron content in them.
Susceptibility weighted imaging (SWI) has been shown to be very sensitive to iron in the
form of hemosiderin, ferritin, and deoxyhemoglobin, offering the ability to measure iron on
the order of several µg/g of tissue in vivo10,11. SWI is a 3D, high-resolution, fully flow compensated gradient-echo sequence that uses magnitude and phase data both separately and
together to enhance information about local tissue susceptibility. In the past, phase images
were seldom used because artifacts from the background field destroyed the integrity of small
changes seen in pristine tissue. As we know now, phase images contain a wealth of
information that may not be observed from the magnitude images. Recently, SWI-filtered
phase images were used to map out putative iron content in the brain11,12. Phase images are a
direct measure of the sources of local susceptibility changes. MR imaging have demonstrated 9
that, the magnetic susceptibility of an MS lesion changes rapidly as the lesion evolves
longitudinally which can be measured by various iron quantification methods. Our study was
designed to assess whether Quantitative SWI (Routine SWI) is a viable technique to identify
active enhancing MS lesions without Gd injection. In this study, we explore the routine SWI
imaging with quantification of phase values and iron content. To best of our knowledge, this
is the first study , in which the routinely available SWI sequence was used for quantification
of iron content in MS lesions. The goal of this study is to investigate whether the measured
phase values and iron content in the lesions will differentiate active lesions from inactive
lesions
Black phosphorous, a prospective graphene substitute for biomedical applications
No full text2D materials have gained spectacular status across various scientific and technological disciplines owing to their exceptional unique properties. The very recent member of 2D family, Black Phosphorus monolayers, known as Phosphorene have attracted recent scientific attention since its first exfoliation and appreciable rediscovery in 2014. Compared to other 2D materials and graphene analogs, it has outstanding properties like tunable band gap, good carrier mobility, excellent ON-OFF current ratio, potent in vivo biocompatibility and non-toxic biodegradability. Although the outlook of this material seems to be a promising candidate for future biomedical technology, its practical applications are still highly challenging. Unveiling those challenges by proper characterization and functionalization makes this material a mile stone for future theranostic and biomedicine scenario. This review has given precise attention to familiarize with the unique fundamental properties of black phosphorus, which makes it an excellent platform for future biomedical applications. Also underlines various synthesis procedures applicable for BP nanosheets and quantum dot synthesis. Its various biomedical applications including biosensors, cancer therapy, imaging and photothermal/photo acoustic/photodynamic therapy, drug delivery, neuronal regeneration, 3D printing scaffold etc., are subsequently reviewed. Furthermore this review briefly focused on the toxicity of this emerging material
Evaluation of Immune response in Acute Promyelocytic Leukemia treated with Arsenic Trioxide
No full textEffects of Yoga on Motor Cortex plasticity, Motor Learning and Motor Deficits of Parkinson’s disease
No full textPEG grafted chitosan scaffold for dual growth factor delivery for enhanced wound healing
No full textApplication of growth factors at wound site has improved the efficiency and quality of healing. Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) induce proliferation of various cells in wound healing. Delivery of growth factor from controlled release systems protect it from degradation and also result in sustained delivery of it at the site of injury. The goal of the study was to develop a Polyethylene glycol (PEG) cross-linked cotton-like chitosan scaffold (CS-PEG-H) by freeze-drying method and chemically conjugate heparin to the scaffold to which the growth factors can be electrostatically bound and evaluate its wound healing properties in vitro and in vivo. The growth factor containing scaffolds induced increased proliferation of HaCaT cells, increased neovascularization and collagen formation seen by H and E and Masson’s trichrome staining. Immunohistochemistry was performed using the Ki67 marker which increased proliferation of cells in growth factor containing scaffold treated group. Frequent dressing changes are a major deterrent to proper wound healing. Our system was found to release both VEGF and bFGF in a continuous manner and attained stability after 7 days. Thus our system can maintain therapeutic levels of growth factor at the wound bed thereby avoiding the need for daily applications and frequent dressing changes. Thus, it can be a promising candidate for wound healing
Morphological abnormalities in hypertrophic cardiomyopathy - a cardiac mri based study
No full textHypertrophic cardiomyopathy (HCM) has a varied clinical course due to its
genotypic and phenotypic heterogeneity. Several autopsy studies have shown
abnormalities of the mitral valve in some HCM patients. Cardiovascular magnetic
resonance (CMR) has become the imaging modality of choice due to its high spatial
resolution, well suited to define the diverse phenotypic expression of this complex
disease.
HCM has been documented to have various mitral valve abnormalities like an
increased length of the leaflets and area, leaflet thickening, impaired mitral leaflet
coaptation, and left ventricular outflow tract obstruction (LVOT) due to the systolic
anterior motion of the mitral leaflets. Cardiovascular magnetic resonance (CMR)
provides an excellent opportunity to assess the papillary muscle (PM) abnormalities like
an increased number and mass, bifidity, hypertrophy, antero-apical displacement and
LGE of the papillary muscle.
Various guidelines recommend surgical myectomy as the preferred modality for
patients with left ventricular outflow tract (LVOT) gradient ≥50 mm Hg who fail to
respond to medications or who experience side effects. Alcohol septal ablation (ASA) in
patients with mitral valve abnormalities results in persistent SAM, gradients, and mitral
regurgitation (MR)