raas system(renin angoitensin aldosterone )

RAAS systems is very important in our body because this control it is a part of homeostasis(control normality functioning of internal system).

RAAS can be divided into 2 parts:

1. plasmatic endocrine cascade 
2. local tissue RAAS- affecting heart , vessels, adrenal gland and brain) 

for plasmatic endocrine cascade , we can divided into 2 substances which are renin and angiotensin 1 (AT-1). renin synthesised as preprorenin in juxtaglomerular cells in kidney, then it will cleaved to prorenin which stiil inactive form and then finally to active renin. Renin is used to catalyze conversion of angiotensinogen produced by the liver into AT-1. Renin secretion will be secreted under certain condition which are:

1. when blood pressure drop in vas afferens
2. drop in sodium ion concentration detected by macula densa in distal tubule.
3. when increased in sympathetic activity(when noradrenaline and adrenaline bind to B1 receptor)

AT1 only have small to none its own physiological effect because AT-1 will be converted to AT-2 by angiotensin converting enzyme (ACE). ACE also responsible for bradykinin breakdown( bradykinin has vasodilator effect), ACE maily bound to endothelial membrane especially in pulmonary circulation.AT -2 has very shot half life , maximum inly 1 minute, because hydrolyzed by plasmatic peptidases. AT -2 has certain effect:

• cause vasoconstriction- increase peripheral vascular resistance.
• increase aldosterone secretion- cause sodium ion retention which lead to water retention
• tissue remodelling in vascular smooth muscle , fibroblast activation, collagen synthesis and cardiomyocyte hypertrophy and apoptosis.
• effect central nervous system by activate thirst center activation, increased sympathetic tonus and ADH and ACTH secretion.

hence if activation of RAAS system occur in chronic condition it can lead to many problem for example:

1. atherosclerosis
2. vascular hypertrophy
3. left ventricle hypertrophy fibrosis
4. decrease glomerular filtration rate 
5. protienuria 
6. sodium retention

this will lead to hypertension, that can lead to stroke, heart failure and renal failure finally lead to death.

grow new teeth using ultrasound transducer

20 minutes a day for four months to stimulate growth of a tooth’s root

Nanotechnology expert Dr. Jie Chen and his associate Dr. Ying Tsui from the Faculty of Engineering at the University of Alberta have developed a new ultrasound transducer to stimulate the growth of teeth and fix asymmetric jaw bones. The transducer utilizes LIPUS, which stands for “low-intensity pulsed ultrasound.” The miniature, wireless device does exactly what its name suggests: it sends pulses of ultrasound into biological matter, such as gums, muscles or bones to increase healing or stimulate growth of new tissue.

The transducer is a type of “system-on-a-chip,” which generally refers to an incredibly small system, like a microchip, that contains all the parts and electronic circuitry a system needs to run. Advances in system-on-a-chip technology allow scientists and researchers the opportunity to work on an increasingly smaller scale with computing power akin to computers from around a decade ago.

Perhaps the best part, other than growing new teeth, is the transducer doesn’t need to be surgically implanted. A patient need only apply the device topically for 20 minutes a day for four months to stimulate growth of a tooth’s root. So far it has been tested on 12 Canadian patients in the prototype stage. The team hopes to release a commercial form of the technology within the next two years.

future analgesic for migrain and pain killer: Electronic aspirin

Electronic Aspirin

For people who suffer from migraines, cluster headaches, and other causes of chronic, excruciating head or facial pain, the "take two aspirins and call me in the morning" method is useless. Doctors have long associated the most severe, chronic forms of headache with the sphenopalatine ganglion (SPG), a facial nerve bundle, but haven't yet found a treatment that works on the SPG long-term. A technology under clinical investigation at Autonomic Technologies, Inc., (Redwood City, CA) is a patient-powered tool for blocking SPG signals at the first sign of a headache.

Aspirin often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. This system not use aspirin as treatment but electric signal to block the pain.

The system involves the permanent implant of a small nerve stimulating device in the upper gum on the side of the head normally affected by headache. The lead tip of the implant connects with the SPG bundle, and when a patient senses the onset of a headache, he or she places a handheld remote controller on the cheek nearest the implant. The resulting signals stimulate the SPG nerves and block the pain-causing neurotransmitters. 

This is advantage to patients, because if you use real aspirin, it has side effect which are cause gastrointestinal ulcers, increase risk of intracerebral hemorrhage, and other complication such as nausea and so on.