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Note Nutrition 101 tutor TUTOR REQUIRED FOR NUTRITION 101 CONTACT DR. BARRE IF YOU OR SOMEONE ELSE ARE INTERESTED. A student tutoring for the Jennifer Keeping Centre is paid $15 per hour. Students typically get tutored 2 hours a week. They can be tutored right up until the end of the term or sooner depending on the student's needs. Lecture 4a 31 January 2011 Diabetes Type I Type II Pathology-4a Nutritional Intervention-4b Functional Food/Nutraceutical Approaches-4c Pathology Role of insulin -produced in the beta cells of the pancreas -initially synthesised as a single chain 86 amino acid polypeptide (pre-proinsulin) -post-translational modification removes the amino terminal signal peptide what is a signal peptide? Role of insulin -this give rise to proinsulin -insulin is created via the cleavage of an internal peptide (31mer) and the A (21mer) and B(30 mer) chains of insulin are then linked together by a disulphide linkage (enzyme responsible?) Causes of Type I-genetic -concordance is 30-70 % in identical twins -polymorphisms in HLA complex appear to account for 40-50 % of type I -HLA complex contains genes for the class II MHC molecules which present antigen to helper T cells and are thus involved in initiating the immune response -ability of class II MHC molecules to present antigen is dependent on the amino acid composition of their antigen binding sites Genetic -amino acid substitutions may influence the specificity of the immune response by altering the binding affinity of different antigens for the class II molecules -10 % of genetic risk due to polymorphisms in the promoter region of the insulin gene Causes of Type I -autoimmune- beta cells produced proteins that mediate draw lymphocytes into pancreas where they infiltrate islets (insulitis) and selectively attack beta cells- inflammation leads to atrophy of b-cells -immunological markers-islet cell autoantibodiesthese antibodies are directed at a series of b-cell proteins -environmental-viruses-coxsackie and rubella -bovine milk -nitrosamines Type II-no longer adult NIDDM - affects children and insulin can be used -genetic factors -concordance of 70-90 % in identical twinsquestion this -40 % if both parents have it-question this as well -polymorphisms or mutations in insulin receptor and enzymes involved in glucose homeostasis (candidates?) -pathophysiology -increased hepatic glucose synthesis because as insulin sensitivity drops the ability of insulin to promote glycogen synthesis and suppress gluconeogenesis drops -impaired insulin sensitivity Pathophysiology continued -impaired insulin production-reason is unknown-though glucose toxicity while undefined cripples beta cell-suggestions -increased free fatty acids impair b-cell function Metabolic syndrome -obesity -kick-off via increased free fatty acids -measures -BMI -percentage fat-skinfolds underwater weighing -height-weight tables -free fatty acids regulate insulin sensitivity Metabolic syndrome -free fatty acids regulate insulin sensitivity -free fatty acids decrease glucose utilisation and increase hepatic glucose production -lipids-including decreased anti-oxidation capacity -increased free fatty acids -decreased HDLc, increased CETP, decreased LPL -increased cholesterol, LDLc -increased triglycerides Metabolic syndrome -blood pressure -elevated -platelet aggregation- Tripepidemiology slide PLATELET HYPERREACTIVITY AND MYOCARDIAL INFARCTION* SPA STATUS AND NUMBER OF PATIENTS TOTAL MORTALITY 149 CARDIAC EVENTS 18 33 SPA NEG. 94 6 (6.4 %) 14 (14.9 %) SPA INT. 29 3 (10.3 %) 7 SPA POS. 26 9 (34.6 %) 12 (46.2 %) (24.1 %) 12 MOS. DATA OF Trip et al. NEJM 322:1549 (1990) SPA = SPONTANEOUS PLATELET AGGREGATION Metabolic syndrome -insulin sensitivity-receptor binding efficiency -right shift in insulin dose response curve and downward shift in maximal impact -as insulin sensitivity goes down the lipids are further perturbed -ultimately may get pancreatic failure with requirement for insulin injections