onsdag 25 januari 2012

Uutta ruusunmarjasta

Lundin Yliopistosta: Professori Cecilia Holm, Molecular Endocrinology

//Our research is focused on type 2 diabetes and lipotoxicity. Free fatty acids, derived mainly from the large triglyceride stores in adipose tissue, are the quantitatively most important fuel in mammals.

Fatty acids also constitute signaling molecules in a variety of cell types, e.g. a lipid-derived signal appears to be necessary for stimulus-secretion coupling in pancreatic beta-cells and fatty acid derivatives are ligands for a group of nuclear receptors, i.e. the peroxisome-proliferator activated receptors (PPARs). In agreement with this dual role of fatty acids, most cell types contain small triglyceride stores, from which fatty acids can be mobilized through the action hormone-sensitive lipase (HSL) and possibly other lipases.

Lipid abnormalities may be the primary pathogenetic factor in the development of insulin resistance and insulin secretion defects, the two hallmarks of type 2 diabetes, with excessive storage of triglycerides in non-adipose cells as the common precipitating event.

The project can be divided into four major parts. The first part involves studies into the structure-function relationships and 3D structure of HSL, the rate-limiting enzyme in triglyceride hydrolysis. In the second part mechanisms of catecholamine?induced lipolysis as well as novel signaling pathways involved in lipolysis regulation are studied. The third part involves the generation and characterization of cell? and animal models with over- and underexpression, respectively, of HSL and other key components in lipolysis regulation to address the role of these for insulin secretion/beta-cell function, skeletal muscle and liver function, adipogenesis and spermatogenesis. The fourth part is a recently initiated line of research, which involves exploiting functional foods with beneficial effects in relation to insulin resistance and type 2 diabetes.

The project increases the understanding of the mechanisms underlying development of lipid metabolism disorders, in particular diabetes and obesity, and may provide new concepts for prevention/intervention in these diseases. The studies on spermatogenesis may reveal novel mechanisms behind male sterility.//

torsdag 19 januari 2012


Medical and nutritional properties

Amino acid composition

Although gelatin is 98-99% protein by dry weight, it has less nutritional value than many other protein sources. Gelatin is unusually high in the non-essential amino acids glycine and proline (i.e., those produced by the human body), while lacking certain essential amino acids (i.e., those not produced by the human body). It contains no tryptophan and is deficient in isoleucine, threonine, and methionine.

The approximate amino acid composition of gelatin is:

glycine 21%, proline 12%, hydroxyproline 12%, glutamic acid 10%, alanine 9%, arginine 8%, aspartic acid 6%, lysine 4%, serine 4%, leucine 3%, valine 2%, phenylalanine 2%, threonine 2%, isoleucine 1%, hydroxylysine 1%, methionine and histidine <1% and tyrosine <0.5%. These values vary, especially the minor constituents, depending on the source of the raw material and processing technique.[10]

Several Russian researchers offer the following opinion regarding certain peptides found in gelatin: "gelatin peptides reinforce resistance of the stomach mucous tunic to ethanol and stress action, decreasing the ulcer area by twice."[11]

Gelatin is also a topical haemostatic. A piece of gelatin sponge of appropriate size is applied on bleeding wound, pressed for some time and tied in bandage. Haemostatic action is based on platelets damage at the contact of blood with gelatin, which activates the coagulation cascade. Gelatin also causes a tamponading effect - blood flow stoppage into a blood vessel by a constriction of the vessel by an outside force.[12]

Gelatin has also been claimed to promote general joint health. A study at Ball State University sponsored by Nabisco, the former parent company of Knox gelatin,[13] found that gelatin supplementation relieved knee joint pain and stiffness in athletes.[14]