Felicity is a very busy 29-year-old woman in a professional ...

[lbcchick]

Felicity is a very busy 29-year-old woman in a professional career. She has diabetes mellitus and is also pregnant for the first time. Explain the potential teratogenic effect of folic acid deficiency on the developing fetus. What other risk factor is not
 
  Because of her busy schedule, it was over 3 weeks after missing her menstrual cycle when she visited her family doctor to have the pregnancy confirmed. Felicity became very concerned when her physician asked if she had been taking folic acid. It was all Felicity could do to remember to manage her insulin levels, and taking folic acid supplements was something she had not even considered. Her doctor told her to take 600 g of folic acid daily and advised Felicity to return later for maternal serum marker testing.
 
  Explain the potential teratogenic effect of folic acid deficiency on the developing fetus. What other risk factor is noteworthy in Felicity's case?
 
  What is the benefit of maternal serum marker testing? What other test would be particularly useful to monitor the development of Felicity's baby in this situation?
 
  When is the fetus most vulnerable to the effects of teratogens and why?

Question 2

Kevin worked for 10 years at a uranium mine, excavating uranium for a nearby nuclear power plant. Now, 25 years later, he has small cell lung cancer.
 
  Kevin is anorexic and has lost a considerable amount of weight. His muscles are wasting, and he is weak. He tries to move around the house throughout the day but tires easily. It has been difficult for him to access care, and the treatment for his cancer is just starting.
 
  With the ongoing exposure to the ionizing radiation, DNA damage occurred. What are the three stages of carcinogenesis that occurred after his exposure to radiation?
 
  Kevin is normally a fit and active man, and his wife often commented on how much food he used to eat after a day at the mine. Why would there be muscle wasting and weight loss now? Explain your answer using your knowledge of the metabolic changes seen with cancer.
 
  In some cancer patients, muscle weakness may result from the production of onconeural antigens. Describe the effects of these antigens. In what form would this process likely take in Kevin's situation?

[kaillie]

Answer to Question 1

Folic acid deficiency is implicated in neural tube defects such as spina bifida, anencephaly, and encephalocele. Diabetes mellitus in the mother is also a risk factor for neural tube defects in the developing fetus.

Maternal serum marker testing measures AFP in the maternal blood. AFP is produced by the fetus and circulates freely when fetal membranes and blood vessels are exposed. It is therefore elevated with neural tube and ventral wall defects. Ultrasound is another useful test because it is able to visually detect fetal cranial and spinal defects in utero.

Teratogens produce their most detrimental effects on the fetus during the period of organogenesis. The most rapid time of organ development occurs from day 15 to day 60 after conception

Answer to Question 2

The three stages of carcinogenesis are as follows:
Initiation: this describes the exposure to a carcinogen. The exposure results in irreversible damage to the genome of an otherwise healthy cell. Such an exposure may be a one-time event, or it may occur in divided doses over a period of time.
Promotion: promotion may start soon after initiation or be delayed in a latent period. Promotion involves unregulated cell growth promoted by a variety of chemicals and growth factors.
Progression: this stage defines the malignant changes that occur in cells. These changes provide cancerous cells with the characteristic properties of invasiveness, metastatic competence, autonomous growth ability, and greater karyotype instability.

Fat and muscle wasting are a result of cancer anorexia-cachexia. The syndrome involves hypermetabolism and the altered processing of nutrients. Tumors consume glucose and produce lactate. Hypermetabolism occurs when, in an inefficient process, the liver uses the lactate for gluconeogenesis. The uncoupling of the oxidative phosphorylation process at the cellular level yields heat energy, contributing to poor energy utilization and hypermetabolism. Finally, instead of sparing amino acids when generating energy, muscle mass is depleted together with fat stores. Muscle wasting, weakness, and weight loss are the result.

Lambert-Eaton syndrome is a paraneoplastic neurologic disorder seen in some patients with small cell lung cancer. The cancer cells produce onconeural antigens that trigger an immune reaction. If antibodies and primed lymphocytes are able to cross the blood-brain barrier, they recognize the neurons associated with the antigen and mount an immune response against the cells.

[lbcchick]

TYSM

[kthug]

Gracias!