|
|
| ||||
Stem cells 'created from teeth'Japanese scientists say they have created human stem cells from tissue taken from the discarded wisdom teeth of a 10-year-old girl. The researchers say their work suggests that wisdom teeth could be a suitable alternative to human embryos as a source for therapeutic stem cells. Research involving stem cells is seen as having the potential to treat many life-threatening diseases. But some people believe using human embryos is ethically controversial. The researchers, based at the National Institute of Advanced Industrial Science and Technology (AIST), say it will be at least five years before their findings result in practical medical applications. Dual benefit Stem cells have the ability to develop into other kinds of human cells, and experts believe they may eventually lead to treatments for some of the most intractable conditions, such as cancer and diabetes. The AIST researchers said they had identified a form of stem cell in the wisdom teeth which had the capability to develop and be grown successfully into other forms of cell outside the body. The cells they harvested continued to grow in the laboratory for just over a month, they added. The leader of the team, Hajime Ogushi, said the research was significant in two ways. "One is that we can avoid the ethical issues of stem cells because wisdom teeth are destined to be thrown away anyway," he told the AFP news agency. "Also, we used teeth that had been extracted three years ago and had been preserved in a freezer. That means that it's easy for us to stock this source of stem cells." In the US, dentists are starting to offer to store stem cells taken from wisdom teeth and from baby teeth, another potential source, for therapeutic purposes in the future. Last year, a team of US and Japanese scientists announced they had managed to produce stem cells from skin. Real-time microscopic evaluation of gastrointestinal tissue at cellular level during endoscopy shows promise for digestive disease patientsA novel endoscopic, high-resolution, imaging technology may revolutionize the practice of gastroenterology (GI) via the application of a laser to examine diseased tissue in the GI tract. Confocal laser microendoscopy has recently been available at Mayo Clinic in Arizona, and initial results suggest that this technology may reduce the number of biopsies required to establish a digestive disease diagnosis. The laser technology allows the endoscopists to perform microscopic examination of the gastrointestinal mucosal layer during endoscopy. This microscopic view of the lining of the digestive tract would otherwise be available only to the pathologist using a microscope to examine biopsy samples. The key advantages are real-time results, leading to potential early diagnosis of gastrointestinal cancers. Also, the more sub-surface, cellular-level imaging can be helpful in targeting biopsies of relevant areas and can potentially uncover microscopic diseases such as colitis or Helicobacter pylori. This new technology can potentially enhance the endoscopist's ability to detect subtle, early disease in a real-time fashion and manage such lesions during the same endoscopic procedure by application of techniques, such as endoscopic resection of superficial cancers. In the confocal laser microendoscopy procedure, a small, laser-based microscope is advanced through a catheter or endoscopy tube to the evaluation site. A small amount of fluorescent dye is administered intravenously, and, when activated by the laser, emits light of various wavelengths. A series of rotation mirrors direct the laser across the tissue sample and the visuals are transmitted to a nearby display screen, allowing physicians to see real-time images of cells and sub-cellular structures with 500 to 1,000 times greater magnification than the conventional endoscopic image. "This new advance shows significant promise to improve the diagnosis of a range of gastrointestinal diseases and has potential to improve the detection rate of cancers," say Cuong C. Nguyen, M.D., and Ananya Das, M.D., Division of Gastroenterology. "Being able to go to the deep, subcellular levels, where other imaging or biopsy methods have not gone previously, could eliminate unnecessary biopsies and potentially lead to earlier detection of cancers and other gastrointestinal pathology in patients." Digestive SystemTHE HUMAN DIGESTIVE SYSTEM The digestive system’s primary function is to convert food into energy and convert waste into excretable material. The digestive tract and its accompanying digestive organs are responsible for the absorption and digestion of all digestible products. The digestive system sustains life via its ability to relieve the body of its inability to provide nutrients for its systems, tissue, and bodily fluids. Without the digestive system, all other systems would eventually fail to operate, fluids would either stop production or dry up, and tissue would deteriorate. 
Digestible product is utilized at the cellular level, which the digestive system readily prepares for cellular use. Nutrients from food or other nutritious edible product are broken down and the remaining nutrients are used for chemical reactions which allow cells throughout the body to reproduce, repair, cellular division, cellular growth, heat production, energy production, and the synthesis of enzymes which allow these functions to occur. Food which is consumed by a human can not be used for cellular health until after it has been broken down both mechanically and chemically for the use of meeting cellular needs. The broken down and digested foods turn into nutrients which are then absorbed through the intestinal wall. The nutrients are then transferred to the cells via the blood stream and delivered to the site of cells which are in need of the nutrients. Food is not considered to be digested until after absorption, which applies to a small percentage of food as most of the food eaten is never absorbed and is passed through the excretory system. Only usable nutrients and chemicals are absorbed and brought to the appropriate cellular group for nutritional function. Ingestion is the process of eating. In reference to the digestive system, this typically means food however it may include vitamin supplements, medications, and liquids. Mastication is the process of mixing edible elements with saliva for the purposes of breaking the edible elements down. This process typically involves chewing. Deglutition refers to the process of moving edible elements from the mouth down through the esophagus and into the stomach. Digestion is the process of breaking down the edible elements and preparing them for absorption through the intestinal wall and use by the cells. Absorption refers to the process of passing the broken down edible elements through the intestinal wall into the blood stream where either blood cells or lymph cells retrieve the nutrients and carry them off toward their destination. Peristalsis is the action of processing waste, referring in particularly to the motion made by the intestinal tract which resembles wave-like motions to help pass the solid waste through the intestines. Defecation is the final process in the digestive system which removes solid waste product in the form of fecal matter from the body. The digestive system is generally divided into specific functional and anatomical groups that consist of the digestive tract, the tubular gastrointestinal tract, and the accessory digestive organs. The tubular gastrointestinal tract is one continuous tract, shaped for the most part in a cylinder that runs from the mouth to the anus creating a pathway for food, nutrients, and waste. At 30 feet long, it traverses the thoracic cavity and enters the abdominal cavity along the diaphragm and includes the oral cavity, thorax, esophagus, stomach, small intestines, and large intestines. The accessory digestive organs, those which are vital to the process but can not otherwise be classified, include the teeth, tongue, liver, salivary glands, pancreas, and gallbladder. Visceral organs were once meant to include the internal organs of the digestive tract which were related to digestion. However over time visceral organs became known as any internal organ that is relative to the thoracic cavity or the abdominal cavity. Anywhere from 24 to 48 hours are likely to pass before food travels through the entire digestive tract. The breakdown of edible material and therefore the breakdown of molecules with vital value to the body’s cells, is done in the body’s own version of an assembly line. Nutritional value is removed from the food on a molecular level and brought to the body’s cells for nutritional absorption. |
