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Non viral gene delivery in cancer cells using polysaccharides modified with polyethyleneimine and vinyl monomers
No full textImaging of indirect carotid cavernous fistula comparing advanced mri sequences with digital subtraction angiography
No full textCarotid-cavernous fistulas (CCFs) are abnormal arteriovenous communications either
directly between the internal carotid artery (ICA) and the cavernous sinus or between the dural
branches of the internal and external carotid arteries. Several classification schemes have
categorized CCFs according to aetiology (traumatic or spontaneous), hemodynamic features (high
versus low flow), or the angiographic arterial architecture (direct or indirect). Direct CCFs usually
arise after trauma or a ruptured aneurysm. These fistulae are less likely to resolve spontaneously
and may require intervention if symptomatic. The remaining types are indirect and are best
described as dural arteriovenous malformations. Their rate of flow and exact aetiology are variable.
They have been associated with pregnancy, cavernous sinus thrombosis, sinusitis, and minor
trauma. Most of the patients are managed conservatively and may require intervention if there is
any deterioration during follow up. (1)
Intra-arterial digital subtraction angiography (DSA) is the standard of reference for the
diagnosis of CSDAVFs. Its high spatial and temporal resolution facilitates the accurate analysis of
feeders, venous drainage, and fistula sites. However, DSA is invasive and not without possible
complications; morbidity of 0.03% and mortality of 0.06% have been reported for patients
undergoing diagnostic cerebral angiography(2,3). Therefore, a noninvasive, reliable method is
needed for the appropriate selection of patients with CSDAVF with high risk (aggressive
symptoms), exclusion of patients with CSDAVF considered benign and for follow-up. Carotid cavernous fistula descriptions are with type, location, laterality, size of fistula, feeding arteries,
draining veins and cortical venous reflux. 7
Recently few studies are published on cranial dural arteriovenous fistulas (cDAVF)
comparing the efficacy of advanced vascular MR imaging with DSA. Comparison of 3D-TOF (3T)
with DSA in the evaluation of intracranial DAVF showed good intermodality agreement in the
gross characterization of DAVF(4). Few studies showed SWI can reliably detect the fistulous
point, presence of cortical venous reflux in cases of DAVF and also helps in differentiating nidus
from haemorrhage and calcification in cases of brain AVM(5,6).
Susceptibility-weighted angiography (SWAN) is a new 3D T2*- based gradient-echo
sequence generating several echoes that are read out at different TE times, allowing high resolution visualization of both cerebral veins and arteries. SWAN sequence has a potential role
for the diagnosis of intracranial DAVF in visualising intracranial arteriovenous shunt(7).
Silence Magnetic resonance angiography is a relatively new technique available in 3.0
Tesla Magnetic Resonance scanners. The advantages of this arterial spin labelling (ASL) based
ultra-short echo-time technique is that it is less affected by susceptibility effects and has excellent
background suppression. Few preliminary studies have found that the vascular anatomy is better
depicted on Silence magnetic resonance(8).
To our knowledge, there are no systematic studies on the reliability of unenhanced 3T 3D
TOF MRA, Silent MRA and SWAN for assessing feeders, fistula sites, and venous drainage of
CSDAVFs. Thus, this intended to study the utility of these noninvasive magnetic resonance
angiography techniques to determine the angiomorphology of CCF, in treatment planning and
follow up. If found reliable it may supplant DSA in follow up imaging
Zinc oxide nanoparticle induced neurotoxic potential upon interaction with primary astrocytes
No full textAs obvious from the basic prerequisite of any particle in nanoscale, Zinc oxide nanoparticles (ZnO NPs) possess numerous tunable properties distinct from their bulk formulations. Emerging innovations in various sectors of nanotechnology are exploiting ZnO NPs largely. This inturn picks up the occasions of human exposure irrespective of the application fields. Although the platform of nanotoxicology has been garnished with nano-bio interaction studies using different cell lines, a few are existing so far comprising primary cells which symbolize realistic in vivo environment. The present study addresses the neurotoxic potential of ZnO NPs using primary astrocytes isolated from post-natal 0–2 day old rat pups. Cells were cultured and maintained in DMEM F12 followed by purification. ZnO NPs generated by wet chemical method was then characterized both physico chemically and biologically. All of the techniques confirmed homogenous distribution of NPs and ensured enough colloidal stability. Bio-nano interaction studies commence on cell viability assays (MTT and NRU) and both of which confirmed dose and time dependent cytotoxicity. Alterations within cellular morphology, cytoskeletal arrangement, lysosomal stability, mitochondrial membrane potential (MMP) and caspase activation were evaluated by standardized techniques. All of the assays substantiated significant toxic consequences in astrocytes with characteristic hall marks. Apoptotic cell death was noted without any deformations of nuclear material. A comparative toxicity study using ZnO NPs, ZnCl2 and ZnO bulk form was performed which confirmed nanospecific toxicity of ZnO NPs. Overall study evidently provide cautious information that ZnO NPs is capable of eliciting serious neuronal tissue damages which can turn out to be fatal during prolonged exposure
Comparison of Effects of Propofol and Dexmedetomidine on Motor Evoked Potentials in Neurosurgery: A Prospective Randomised Single Blinded Interventional Study
No full textIntraoperative neurophysiological monitoring (IONM) is often used in various
intracranial and spine procedures to prevent damage to eloquent areas, cranial nerves or
motor or sensory tracts. Motor evoked potential (MEP) monitoring is invariably an
essential tool in the armamentarium of the operating surgeons to avoid injury to the motor
tract in various intracranial and spine surgeries. (1)
Transcranial motor evoked potential (TcMEP) monitoring is stimulation of the motor
cortex through the skull and eliciting compound muscle action potentials (CMAP) from
the peripheral muscles to test the intactness of the motor pyramidal pathway. (1)
TcMEP is being used in surgeries for monitoring and mapping of the motor pathways. It
is used in the mapping of the motor cortex in resection of tumours or arteriovenous
malformations located near the motor cortex or in epilepsy surgeries. It is also used in the
subcortical mapping of corticospinal tract. It is also used in brainstem surgeries and in
Chiari malformation. It is also used in vascular surgeries like carotid endarterectomy,
reconstructive surgeries of the neck, aneurysms of the aortic arch and of
thoracoabdominal aorta or intracerebral aneurysms of middle or anterior cerebral arteries.
It is very commonly used in spinal surgeries for extradural or intradural (extramedullary
or intramedullary) tumour resection, embolization of arteriovenous malformations and in
deformity corrective surgeries like scoliosis and spondylolisthesis. (2)
Intraoperatively, there are many factors other than surgical manipulation that can affect
the quality of the CMAP like temperature, blood pressure, partial pressure of expiredcarbon dioxide, oxygen, etc. These factors need to be optimized for correct interpretation
of the MEPs. (2)
The anaesthetic agents can affect the quality of MEP intraoperatively as they inhibit
synaptic transmission. Muscle relaxants antagonize the transmission of signals across the
neuromuscular junction. Inhalational agents suppress the CMAP and should be used at a
lower minimum alveolar concentration (MAC). Opioids seem to have very little effect on
CMAP. Intravenous anaesthetics suppress MEP lesser than inhalational agents, so total
intravenous anaesthesia (TIVA) or combination of intravenous with minimal inhalational
anaesthetic supplementation is used when MEPs are monitored. (3)
TIVA with propofol and opioid is most commonly used for MEP monitoring. (4) As
propofol gets rapidly metabolised, its sedative effects and effects on MEP can be adjusted
quickly. But MEP can get depressed at high doses required to maintain surgical depth,
hence, adjuvant agents that maintain anaesthetic depth without affecting the MEP are
often required. (5)
Dexmedetomidine is a selective alpha-2 agonist. It causes sedation, analgesia,
sympatholysis and minimal respiratory depression. (6) Its addition to the anaesthetic
regimen can reduce hypnotic requirement, especially propofol. Dexmedetomidine has
invariably been used as an adjuvant to various anaesthetic agents and has been found to
have minimal affect on the MEP when combined with other agents. (7) It has found
widespread acceptance in neuroanaesthesia because of its favourable recovery
characteristics and absence of significant impact on cerebral blood flow and intracranial
pressure
An electrospun citric acid modified polyvinyl alcohol scaffold for vascular tissue engineering
No full textThe main aim of this study is to fabricate an electrospun citric acid modified polyvinyl alcohol polyester that is biodegradable with non-toxic by-products and can be used for the culture of vascular smooth muscle cells. In this study, we have optimized the conditions for the electrospinning process of this polyester. The fibre morphology was studied by scanning electron microscopy which indicated that the fibre diameter was optimum at a range of 200 to 700 µm at 5% concentration and flow rate of 0.3 mL/h. The membranes were characterized for the change in structural aspects at the molecular level. The results showed development of more crystalline domains on electrospinning. The surface characteristics were also explored. Cell culture studies confirmed that the electrospun scaffold supported the attachment and proliferation of smooth muscle cells, which was evident from the cell proliferation assay. Hence, the electrospun polyester scaffolds are non-toxic and biocompatible with vascular smooth muscle cells, and find promising potential as scaffolds for vascular tissue engineerin
Bedside Chest Ultrasound in post operative pediatric Cardiac Surgery patients: Comparison with bedside chest radiography.
No full textTraditionally, chest imaging in post operative cardiac surgical patients, is
performed using bedside chest radiography (CXR). It is considered as standard of care to
evaluate intra-thoracic structures including heart, lung, mediastinum and their
abnormalities. CXR also evaluates position of chest tubes, mediastinal tubes, central
venous lines, pulmonary artery catheters, endotracheal tubes and enteral feeding tube [1].
Respiratory complication is one of the major causes of morbidity and death in
cardiac post operative patients in adult and pediatric population. Whenever there is a
suspicion of intra thoracic pathology, including improper position of tubes and catheters,
the need for repeated bedside CXR and thus subsequent unavoidable radiation exposure
is inevitable. Other factors leading to the need for repetition of bedside CXR are
suboptimal X-ray films, improper positioning of patient and poor correlation with CT
scan [2].
Each bed side CXR exposes a patient to 0.02 milli-sieverts of radiation [3].
Though it looks invariably small, repeated CXRs exposes patient to increasing amounts
of radiation. Paediatric age group especially neonates , have greater areas of exposure,
due to small body surface area and are thus sensitive to hazardous effects of ionizing
radiation. The threat of developing immune dysfunction, cataract, cognitive decline and
malignancy in later part of life is a possibility [4]. Therefore, effort should be made to
minimize radiation exposure whenever possible [5].
Chest ultrasound (CUS) is a fast, repeatable and radiation free methodology. 2
It is simple to use and requires a limited period of training [6]. It allows for bedside
detection of primary pulmonary pathologies [7] such as pleural effusion, pneumothorax,
lung atelectasis, or secondary pulmonary pathologies due to cardiac causes (interstitial
pulmonary oedema, basal atelectasis) and conditions such as diaphragmatic palsy,
subcutaneous emphysema, pericardial effusion, cardiac tamponade and endobronchial
intubation [8]. Examination can be done alone or in combination with echocardiography
and intravascular volume assessment, thus reducing cost and time.
Diaphragmatic dysfunction, due to phrenic nerve injury, is a complication in
postoperative cardiac surgery patients, with an incidence between 0.3% - 20% [9]. Most
phrenic nerve injuries are due to transient neuroapraxia of the nerve, secondary to
traction, local application of cold solutions, or accidental injury [10]. Rarely, it is caused
by direct transection of the phrenic nerve. Diaphragmatic dysfunction impedes normal
lung expansion during inspiration [9] and weaning from mechanical ventilation becomes
difficult. It is associated with prolonged ventilatory support, intensive care stay, increased
risk of nosocomial infections, and an overall morbidity and death [11].
Chest fluoroscopy is the gold standard for diagnosis of diaphragmatic
dysfunction. But it is associated with shifting of critically ill children to radiology suite
and exposure to higher ionizing radiation. Other modalities include phrenic nerve
conduction studies and CUS. CUS being a rapid and easily available technique at the
bedside, allows for early diagnosis of abnormal diaphragmatic motion [12]. 3
The use of CUS in the post operative adult cardiac patients is gaining popularity
[6]. However, there is little data available concerning the use of CUS in the post
operative cardiac pediatric and neonatal populations [13]. To address the above issue, we
intend to study the degree of agreement between CUS and CXR; to compare the
diagnostic performance of bedside chest ultrasound (CUS) with bedside chest
radiography (CXR), for the detection of abnormalities of thorax including abnormal
diaphragmatic motion, in postoperative pediatric cardiac surgical patients. We also intend
to compare the therapeutic interventions done on basis of CUS and CXR derived
information in the postoperative setting
In Vitro And In Vivo Assessment Of Adipose Stem Cell Derived Islet Like Cells On A Novel 3D Scaffold
No full textEvaluation of Cerebral Perfusion Pressure (CPP) and Cerebral blood flow (CBF) in different Head of Bed positions using Transcranial Doppler in Neurosurgical patients
No full textIt is well known that optimal maintenance of cerebral hemodynamics is
important to reduce the risk for secondary brain injury in neurosurgical patients.
Acute Neurological illness like Traumatic brain injury, Subarachnoid haemorrhage,
Intracerebral haemorrhage, Ischemic stroke, Meningitis/Encephalitis and Brain
tumours can affect cerebral hemodynamics. Measurements of Intracranial pressure
(ICP) and Cerebral perfusion pressure (CPP) are of paramount importance to guide
the management in these conditions to avoid secondary brain injury due to
inadequate cerebral blood flow.
CBF is influenced by multiple factors including systemic arterial pressure,
position of the head with respect to heart, venous and CSF drainage, and vascular
tone of cerebral vessels. In a normal individual, as the head is raised, homeostatic
reflexes maintain the systemic arterial pressure. The higher level of the head above
the heart reduces perfusion pressure to the head, but the intracranial pressure is also
reduced because of the improved venous drainage. Together with an intact
autoregulation response of the cerebral vasculature, the net effect is little change in
CBF. However, in patients with impaired autoregulation, a raise in head position
may theoretically diminish CBF. (1-4)
Different studies demonstrated that cerebral perfusion in patients with
tumours is altered in correlation to location, size and histology of the tumour. Some
studies refute them and state that autoregulation is intact in these patients with
tumours regardless of location and size with a normal level of consciousness. Direct
measurement of cerebral perfusion pressure (CPP) as the difference between mean arterial pressure (MAP) and intracranial pressure (lCP) produces a number that does
not express the adequacy of brain perfusion. (5)
American Association of Neurological Surgeons and the Brain Trauma
Foundation (4th ed, 2016) do not include specific recommendations for optimal
patient positioning practices after severe brain injury. Current positioning practices
in neurocritical care units are largely based on studies in TBI patients that suggest
head of bed (HOB) elevation may reduce ICP. There is no consensus on the degree
of elevation for best practice. 300
of head elevation are believed to be associated
with improvements in ICP and CPP. (6,7)
Greater emphasis is focused on maintenance of adequate cerebral perfusion
pressure (CPP), but does this ensure sufficient perfusion of the brain is a matter of
debate. Perfusion pressure by itself is the propulsion force only; it does not
determine the distribution of cerebral blood flow (CBF), ensure adequate collateral
circulation, nor account for variations in the venous outflow path. CPP is rather a
determinant of cerebral blood flow than a definite number. (8,9) Despite the
importance of CPP values, there is huge confusion regarding the measurement of
MAP based on the position of transducer level with varying positions of patients
adding to the inaccuracies in measurements. Most patients with neurological injury
are managed with head elevation and the level of zero calibration is important to
measure an accurate CPP. Unfortunately, we find that studies behind the
recommended CPP thresholds often do not elaborate on how MAP and CPP were
measured. (6, 10-15) A noninvasive method, Transcranial Doppler can be used to measure the
blood flow velocities in basal arteries as a surrogate measure of cerebral blood flow.
Transcranial colour Doppler (TCCD) ultrasound is a valid measure of blood flow
velocity in the major cerebral arteries and is an accepted index of cerebral
autoregulation. This has an advantage of providing cerebrovascular imaging with
structural flow map of cerebral blood vessels. (10,11)
Near-infrared spectroscopy (NIRS), a non-invasive optical technology, is an
indirect monitor of cerebral perfusion. Regional cerebral oxygen saturation (rScO2)
of the frontal cortex is determined by comparing the specific absorbance patterns of
oxygenated and non-oxygenated haemoglobin to near-infrared light. When CBF
decreases, tissue oxygen extraction will increase to maintain cerebral metabolism
with an eventual decrease in haemoglobin saturation. In the presence of a stable
metabolic rate, rScO2 is therefore an indirect measure of CBF and provides
information on organ ischemia. (11)
However, there is surprisingly little literature, with inconsistent findings on
the impact of changes in head positioning on cerebral hemodynamics and associated
parameters. Very few studies about the postural influences on cerebral
hemodynamics have been done in postoperative setting of neurosurgical patients.
We decided to observe these changes in supine HOB 00
, 300
and 600
. We conducted
this prospective, observational study to examine the effects of patient’s HOB
positioning on NIRS, Cerebral blood flow velocities, Estimated CPP, and MAP after
craniotomy for intracranial tumours
Comparison of 3d rotational angiography with digital subtraction angiography and correlation of angioarchitecture with clinical presentations in cerebral arteriovenous malformations
No full textBrain arteriovenous malformations (AVM) are an intriguing
disease entity involving the intracranial vasculature where arteries and
veins are interconnected through a low resistance dysplastic nidus
bypassing the normal intervening capillary network.[1]
There are several morphological aspects of AVM that need to be
assessed prior to planning therapeutic approach and intervention. These
include location, feeding arteries, draining veins, nidus and size of the
lesion.[2] The presence of feeding artery, intranidal and perinidal
aneurysms, venous pouches, venous dilatations, fistulas, venous stenosis
and venous thrombosis are the other factors which necessitate therapy in
brain arteriovenous malformations.[3,4] An ideal imaging modality
should reliably reveal these parameters. Digital subtraction angiography
(DSA) very reliably predicts the presence of these varied parameters.
DSA is the standard imaging procedure for AVM. However, although it
gives a good impression of the spatial relationships between the vessels, it
is limited by overprojection of early draining veins on arterial feeders and
nidus and cannot give a true three-dimensional (3D) view from every
angle. The 3D rotational angiographic (RA) images have excellent
resolution, and can be rotated in any direction to show the structures from
any required angle, including views that would be impossible to obtain by
radiographic projections alone. An improved understanding of the 3D
vascular morphology helps to ensure optimum positioning of the image
intensifier during the intervention for guideline positioning of catheters,
coils, balloons and stents.[5] There are few studies comparing the utility
of 3D RA in cerebral aneurysm.[6,7] Hochmuth A et al., in their study
have concluded that compared with DSA, 3D RA allows more exact 2
depiction of anatomic details that are important in planning surgery and
interventional therapy for intracranial aneurysms and also RA depicted
more aneurysms.[8] The current gold standard in imaging of brain AVM
is superselective microcatheter angiography. We intended to study the
effect of addition of 3D RA in better delineation of angioarchitecture of
the lesions.
Cerebral AVM has varied clinical presentations. Broadly it can
present because of haemorrhage and unbled lesions can manifest with
seizure, headache, neurodeficit or vague neurologic symptoms. Also
asymptomatic lesions are detected incidentally due to neuroimaging for
inexplicit symptoms. Various angiographic features like deep venous
drainage, deep location, infratentorial location, distal flow related &
intranidal aneurysm, previous haemorrhage has been implicated as risk
factors or predictors of haemorrhagic complications.[9] Few studies have
attributed manifestation of seizure in AVM to angiographic features like
cortical location of feeder, feeder by MCA, absence of aneurysm,
varix/varices in venous drainage.[10] Other clinical manifestations like
headache and neurodeficit in unbled AVM has not been studied in
relation to specific angiomorphologic attribute. Combining the 2D DSA
& 3D RA is expected to generate the best possible angiomorphology of
AVM. We intend to analyse the angiographic predictors for clinical
manifestations of haemorrhage, seizure, headache & neurodeficit; thereby
prompting necessary therapeutic intervention
Sex differences in risk factor profile, clinical presentation, stroke subtype and outcome in acute ischemic stroke
No full textStroke is currently the second leading cause of death worldwide. Ischemic heart
disease and stroke together accounted for 15.2 million deaths (15–15.6 million) in 2015(1).
Stroke is the commonest cause of chronic adult disability(2). Stroke affects 33 million
individuals worldwide each year(3). The lifetime risk of stroke after 55 years of age is 1 in 5
for women and 1 in 6 for men. More than four-fifths of all strokes occur in developing
countries(4).
Women are more likely to have hypertension and atrial fibrillation(AF). Men are
more likely to have coronary artery disease, dyslipidemia, diabetes, peripheral artery disease,
tobacco and alcohol use(5). Although men have a higher incidence of AF at all age groups,
women with nonvalvular AF have double the risk of stroke than men with the same
condition(6).Women with stroke were more likely to present with ―nontraditional‖ stroke
symptoms and, in particular, altered mental status, compared with men. ―Traditional‖ stroke
symptoms of imbalance and hemiparesis were more frequently reported by men(7). Stroke
severity measured by the National Institutes of Health stroke scale (NIHSS) has been found
in studies to be consistently more in women compared to men(8).
In terms of the TOAST (Trial of Org 10172 in Acute Ischemic Stroke) subtype
etiological classification, four European based studies showed higher frequency of
cardioembolic stroke in women compared to men (9)(10)(11)(12). In men, large artery
atherosclerosis was found to be more common than women. Lacunar strokes were found to
be more common in men than women (13).Studies have shown delay in women reaching
hospital than men because of increased nontraditional stroke symptoms compared with men
and women are more likely than men to be living alone.Several studies have shown that women are less likely to receive alteplase than are men. A female stroke patient’s overall
chances of receiving thrombolysis are 13% less than a male’s(14).
Women were more likely than men to demonstrate substantial neurological
improvement in the first 24 h after IV tPA treatment(15). Overall studies from Europe and
North America have shown that women have less favourable outcomes after stroke and lower
Quality of life (QOL) than do men(8). The Swedish Risks-Stroke Registry showed that 54%
of women versus 67% of men were independent in primary ADL at 3 months’ follow-up(16).
Overall from all these studies, it is evident that significant differences exist in stroke
with regard to incidence, risk factor profile, clinical presentation, stroke subtype and outcome
between men and women. Since all studies on sex differences in stroke are from Western
world and there are few studies aimed at studying gender differences in stroke in India, this
study is planned to analyse the sex differences in risk factor profile, clinical presentation,
stroke subtype and outcome in our population and for understanding whether same gender
differences exist in our population