Tutor profile: Bryan V.
A 14-year-old boy is brought to the office because of skin lesions on his forehead that appeared 2 weeks ago. Shortly before that, he started wearing a helmet. He tries to maintain a high protein diet to build muscle, but he cheats by eating chocolate bars. He also takes vitamin D supplements daily. He presents open and closed comedones on his forehead. What is the most likely cause of the comedones?
This patient has acne and it was triggered by his football helmet. Acne vulgaris is caused by occlusion of pilosebaceous follicles due to excess keratin deposition and increased sebum production that promotes growth of the bacteria Cutibacterium acnes which leads to inflammation of the follicles.
During pregnancy, a woman had hyeprglycemia identified through glucose tolerance testing. Lab testing six weeks after delivery showed persistent fasting hyperglycemia. She feels well and has no complaints. Further work-up reveals a genetic mutation of the glucokinase gene. How do you think the function of beta cell G6P concentration and Beta cell insulin release of this patient will be compared with a normal patient?
Glucokinase is an enzyme found in the liver and the beta cells of the pancreas. It catalyzes the conversion from glucose to glucose 6 phosphate (G6P). In beta cells of pancreas, glucokinase will convert glucose to G6P in order for glycolysis to occur and produce ATP and this is extremely important in order to release insulin from these cells. If we have a mutation in glucokinase, then there will be no conversion from glucose to G6P and we will have low G6P levels; also, as there won't be ATP production, then there won't be insulin release.
A pharmaceutical cpmpany develops a new chemotherapy agent for breast cancer which inhibits eukaryotic DNA telomerase. This company is concerned about possible side effects of the new medication. What is an example of a cell type that is less likely to be affected by this new medication?
An example is cardiac myocytes. Telomeres are nucleotide sequences at the ends of chromosomes. Telomerase is an enzyme that prevents loss of telomeres and shortening of chromosomes with each cycle of DNA replication. This enzyme is important for rapidly dividing cells which are at risk for loss of telomeres during cell division. Cardiac myocytes are permanent cells, it means they don't undergo cell division. Therefore, they don't have telomerases and they wouldn't be affected by a medication that inhbits telomerase.
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