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Nanoemulsion for Brain Targeting
Published in Raj K. Keservani, Anil K. Sharma, Rajesh K. Kesharwani, Nanocarriers for Brain Targeting, 2019
Khushwinder Kaur, Shivani Uppal
Pia Mater means “tender mother.” It is a skinny sheer membrane, covering the exterior of the brain and central nervous system (CNS). Compared with the other layers, this tissue holds closely to the brain, operating down into the sulci and fissures of the cortex. It forms choroid plexus by fusing with the ependyma, to produce CSF.
Current Status of Alzheimer's Disease in India: Prevalence, Stigma, and Myths
Published in Meenu Gupta, Gopal Chaudhary, Victor Hugo C. de Albuquerque, Smart Healthcare Monitoring Using IoT with 5G, 2021
Surekha Manhas, Zaved Ahmed Khan, Meenu Gupta
For the effective drug delivery to the target site, drugs should have potential to cross the blood–brain barriers (BBB) so that it could reach the target site, but BBB doesn’t allow the paracellular passive diffusion, which creates a hindrance during drug delivery. This hindrance can be overcome by using advanced nanotechnology. BBB consists of a number of capillaries of endothelial cells in the central nervous system attached together with the strong tight junctions that allow only nutrients or ions which provide neuronal protection to enter the brain part in order to maintain haemostasis to restrict the access of toxic substances or drug. The other additional barrier that inhibits the movement of certain molecules or drug entry is blood-CSF whose main role is the separation of blood from cerebrospinal fluid that is located at the choroid plexus and covers the subarachnoid space by enclosing the brain. There is some part of central nervous system where BBB is not present, but despite that, that particular regions contain micro vessels which are analogous to periphery, called as circumventricular organs, and consist of median eminence, choroid plexus. The free solute movement within interstitial fluid and blood is carried out by the capillaries which are present in the circumventricular organ. The presence of membrane transporters (influx and efflux transporters) acts as a barrier which permits the entry and exit of xenobiotics or drugs. Hindrance and degradation of drugs during drug delivery occur due to the presence of different potent enzymes in the brain which generate their effects to block the entry of drugs. To easily cross BBB by the process of passive diffusion, the drugs should be lipid molecules having the molecular weight of about less than 500 kDa with partition coefficient of 0.5 and 6.0 and pH should be neutral [59]. Certain different approaches have been used thus to overcome the problem that occurs during drug delivery to pass BBB that include biomimetics, intracranial infusion, diuretic agents, and convectional enhanced delivery [60–63]. With issues associated with safety, specificity which poses a problem to effective drug delivery to the target site [64,65]. In order to check the effectiveness of a wide range of drugs, animal models are used and are treated with the focused ultrasound that delivers a specific drug to the target site, including stem cells, viruses, antibodies, herceptin, nanoparticles, and chemotherapy [66–73].
MR neurography of the brachial plexus in adult and pediatric age groups: evolution, recent advances, and future directions
Published in Expert Review of Medical Devices, 2020
Alexander T. Mazal, Ali Faramarzalian, Jonathan D. Samet, Kevin Gill, Jonathan Cheng, Avneesh Chhabra
The brachial plexus is a large network of peripheral nerves formed by the ventral rami of the lower four cervical and first upper thoracic nerve roots (C5-C8, T1) (Figure 1). It is referred to as a pre-set or post-set brachial plexus depending upon additional contribution from C4 or T2 nerve roots, respectively. During surgical dissection, many brachial plexus variations are commonly identified, e.g., early branching or intra-branch communications, and intra-muscular course, etc [1,2]. After exiting the spinal cord at their respective levels, the contributing nerve roots pass through the interscalene and posterior triangles of the neck, respectively, before passing laterally over the first rib and descending into the axilla [1–3]. The exiting branches of the plexus eventually terminate in the named major peripheral nerves, which provide sensory and motor innervation to the ipsilateral upper extremity.